Evaluating information in zero-sum games with incomplete information on both sides

In a Bayesian game some players might receive a noisy signal regarding the specific game actually being played before it starts. We study zero-sum games where each player receives a partial information about his own type and no information about that of the other player and analyze the impact the signals have on the payoffs. It turns out that the functions that evaluate the value of information share two property. The first is Blackwell monotonicity, which means that each player gains from knowing more. The second is concavity on the space of conditional probabilities.Value of information, Blackwell monotonicity, concavity.

Welfare Effects of Uzbekistanís Foreign Exchange Regime

In addition to transferring about 16 percent of GDP from exporters to importers, Uzbekistanís quasi-fiscal multiple exchange rate regime generates identifiable welfare losses of 2-8 percent of GDP on import markets and up to 15 percent on export markets. These excess burdens have increased substantially with the growing difference among exchange rates. The welfare analysis allows some conclusions regarding the optimal reform strategy: (i) welfare losses will decline overproportionally as exchange rates unify, (ii) exchange rate unification should be supplemented by changing the explicit fiscal system; (iii) at a minimum, Uzbekistan would benefit from moving to an explicit fiscal regime. Copyright 2001, International Monetary Fund

Solving the Optimal Trading Trajectory Problem Using a Quantum Annealer

We solve a multi-period portfolio optimization problem using D-Wave Systems' quantum annealer. We derive a formulation of the problem, discuss several possible integer encoding schemes, and present numerical examples that show high success rates. The formulation incorporates transaction costs (including permanent and temporary market impact), and, significantly, the solution does not require the inversion of a covariance matrix. The discrete multi-period portfolio optimization problem we solve is significantly harder than the continuous variable problem. We present insight into how results may be improved using suitable software enhancements, and why current quantum annealing technology limits the size of problem that can be successfully solved today. The formulation presented is specifically designed to be scalable, with the expectation that as quantum annealing technology improves, larger problems will be solvable using the same techniques.Comment: 7 pages; expanded and update

The Arecibo Dual-Beam Survey: The HI Mass Function of Galaxies

We use the HI-selected galaxy sample from the Arecibo Dual-Beam Survey (Rosenberg & Schneider 2000) to determine the shape of the HI mass function of galaxies in the local universe using both the step-wise maximum likelihood and the 1/V_tot methods. Our survey region spanned all 24 hours of right ascension at selected declinations between 8 and 29 degrees covering ~430 deg^2 of sky in the main beam. The survey is not as deep as some previous Arecibo surveys, but it has a larger total search volume and samples a much larger area of the sky. We conducted extensive tests on all aspects of the galaxy detection process, allowing us to empirically correct for our sensitivity limits, unlike the previous surveys. The mass function for the entire sample is quite steep, with a power-law slope of \alpha ~ -1.5. We find indications that the slope of the HI mass function is flatter near the Virgo cluster, suggesting that evolutionary effects in high density environments may alter the shape of the HI mass function. These evolutionary effects may help to explain differences in the HI mass function derived by different groups. We are sensitive to the most massive sources (log M > 5x10^10 M\solar) over most of the declination range, \~1 sr, and do not detect any massive low surface brightness galaxies. These statistics restrict the population of Malin 1-like galaxies to <5.5x10^-6 Mpc^-3.Comment: ApJ accepted, 12 page

Image Ellipticity from Atmospheric Aberrations

We investigate the ellipticity of the point-spread function (PSF) produced by imaging an unresolved source with a telescope, subject to the effects of atmospheric turbulence. It is important to quantify these effects in order to understand the errors in shape measurements of astronomical objects, such as those used to study weak gravitational lensing of field galaxies. The PSF modeling involves either a Fourier transform of the phase information in the pupil plane or a ray-tracing approach, which has the advantage of requiring fewer computations than the Fourier transform. Using a standard method, involving the Gaussian weighted second moments of intensity, we then calculate the ellipticity of the PSF patterns. We find significant ellipticity for the instantaneous patterns (up to more than 10%). Longer exposures, which we approximate by combining multiple (N) images from uncorrelated atmospheric realizations, yield progressively lower ellipticity (as 1 / sqrt(N)). We also verify that the measured ellipticity does not depend on the sampling interval in the pupil plane using the Fourier method. However, we find that the results using the ray-tracing technique do depend on the pupil sampling interval, representing a gradual breakdown of the geometric approximation at high spatial frequencies. Therefore, ray tracing is generally not an accurate method of modeling PSF ellipticity induced by atmospheric turbulence unless some additional procedure is implemented to correctly account for the effects of high spatial frequency aberrations. The Fourier method, however, can be used directly to accurately model PSF ellipticity, which can give insights into errors in the statistics of field galaxy shapes used in studies of weak gravitational lensing.Comment: 9 pages, 5 color figures (some reduced in size). Accepted for publication in the Astrophysical Journa

Modelling of quasi-optical arrays

A model for analyzing quasi-optical grid amplifiers based on a finite-element electromagnetic simulator is presented. This model is deduced from the simulation of the whole unit cell and takes into account mutual coupling effects. By using this model, the gain of a 10×10 grid amplifier has been accurately predicted. To further test the validity of the model three passive structures with different loads have been fabricated and tested using a new focused-beam network analyzer that we developed

On compact generation of deformed schemes

We obtain a theorem which allows to prove compact generation of derived categories of Grothendieck categories, based upon certain coverings by localizations. This theorem follows from an application of Rouquier's cocovering theorem in the triangulated context, and it implies Neeman's result on compact generation of quasi-compact separated schemes. We prove an application of our theorem to non-commutative deformations of such schemes, based upon a change from Koszul complexes to Chevalley-Eilenberg complexes.Comment: 21 page

A 6.5 GHz-11.5 GHz source using a grid amplifier with a twist reflector

The authors have constructed and tested an oscillator using a grid amplifier with external feedback from a twist reflector. The twist reflector serves two functions; it changes the output polarization to match the input, and its position sets the feedback phase. This permits a wider tuning range than has been possible with previous grid oscillators. The source could be continuously tuned from 8.2 GHz to 11.0 GHz by moving the twist reflector. By moving the polarizer and mirror in the twist reflector independently, a 1.8-to-1 frequency range from 6.5 GHz to 11.5 GHz was achieved. The peak effective radiated power was 6.3 W at 9.9 GHz

Complete Assembly of the Genome of an Acidovorax citrulli Strain Reveals a Naturally Occurring Plasmid in This Species

Acidovorax citrulli is the causal agent of bacterial fruit blotch (BFB), a serious threat to cucurbit crop production worldwide. Based on genetic and phenotypic properties, A. citrulli strains are divided into two major groups: group I strains have been generally isolated from melon and other non-watermelon cucurbits, while group II strains are closely associated with watermelon. In a previous study, we reported the genome of the group I model strain, M6. At that time, the M6 genome was sequenced by MiSeq Illumina technology, with reads assembled into 139 contigs. Here, we report the assembly of the M6 genome following sequencing with PacBio technology. This approach not only allowed full assembly of the M6 genome, but it also revealed the occurrence of a ∼53 kb plasmid. The M6 plasmid, named pACM6, was further confirmed by plasmid extraction, Southern-blot analysis of restricted fragments and obtention of M6-derivative cured strains. pACM6 occurs at low copy numbers (average of ∼4.1 ± 1.3 chromosome equivalents) in A. citrulli M6 and contains 63 open reading frames (ORFs), most of which (55.6%) encoding hypothetical proteins. The plasmid contains several genes encoding type IV secretion components, and typical plasmid-borne genes involved in plasmid maintenance, replication and transfer. The plasmid also carries an operon encoding homologs of a Fic-VbhA toxin-antitoxin (TA) module. Transcriptome data from A. citrulli M6 revealed that, under the tested conditions, the genes encoding the components of this TA system are among the highest expressed genes in pACM6. Whether this TA module plays a role in pACM6 maintenance is still to be determined. Leaf infiltration and seed transmission assays revealed that, under tested conditions, the loss of pACM6 did not affect the virulence of A. citrulli M6. We also show that pACM6 or similar plasmids are present in several group I strains, but absent in all tested group II strains of A. citrulli