3,432 research outputs found
The Picaresque Novel of Spain
Review of books on the picaresque novel, and their treatment of the subject. The importance of this field of literature. The picaresque type as mainly and typically Spanish
Electronic properties of antidot lattices fabricated by atomic force lithography
Antidot lattices were fabricated by atomic force lithography using local
oxidation. High quality finite 20 x20 lattices are demonstrated with periods of
300 nm. The low temperature magnetoresistance shows well developed
commensurability oscillations as well as a quenching of the Hall effect around
zero magnetic field. In addition, we find B periodic oscillations superimposed
on the classical commensurability peaks at temperatures as high as 1.7 K. These
observations indicate the high electronic quality of our samples.Comment: Appl. Phys. Lett., in prin
On the AdS Higher Spin / O(N) Vector Model Correspondence: degeneracy of the holographic image
We explore the conjectured duality between the critical O(N) vector model and
minimal bosonic massless higher spin (HS) theory in AdS. In the boundary free
theory, the conformal partial wave expansion (CPWE) of the four-point function
of the scalar singlet bilinear is reorganized to make it explicitly
crossing-symmetric and closed in the singlet sector, dual to the bulk HS gauge
fields. We are able to analytically establish the factorized form of the fusion
coefficients as well as the two-point function coefficient of the HS currents.
We insist in directly computing the free correlators from bulk graphs with the
unconventional branch. The three-point function of the scalar bilinear turns
out to be an "extremal" one at d=3. The four-leg bulk exchange graph can be
precisely related to the CPWs of the boundary dual scalar and its shadow. The
flow in the IR by Legendre transforming at leading 1/N, following the pattern
of double-trace deformations, and the assumption of degeneracy of the hologram
lead to the CPWE of the scalar four-point function at IR. Here we confirm some
previous results, obtained from more involved computations of skeleton graphs,
as well as extend some of them from d=3 to generic dimension 2<d<4.Comment: 22 pages, 5 figure
A Framework for Implementing Type Systems
Type systems are ubiquitous in the study of programming languages. Although the basic mechanisms are well understood, a new type system can still be a challenge to implement. We present the design and implementation of a domain-specific language (i.e., a functional framework) for writing type system implementations. This domain-specific language has been embedded in both Haskell and Scheme. It allows users to write down the axioms and inference rules of the type system in a stylized notation that closely resembles the formal type rules, and automates the rest of the work of type checking or type inference
A Type Notation for Scheme
This report defines a type notation for Scheme. This notation was used in the undergraduate programming languages class at Iowa State in Spring 2005
The focus of light - linear polarization breaks the rotational symmetry of the focal spot
We experimentally demonstrate for the first time that a linearly polarized
beam is focussed to an asymmetric spot when using a high-numerical aperture
focussing system. This asymmetry was predicted by Richards and Wolf
[Proc.R.Soc.London A, 253, 358 (1959)] and can only be measured when a
polarization insensitive sensor is placed in the focal region. We used a
specially modified photodiode in a knife edge type set up to obtain highly
resolved images of the total electric energy density distribution at the focus.
The results are in good agreement with the predictions of a vectorial focussing
theory.Comment: to be published in "Journal of Modern Optics
Accumulation horizons and period-adding in optically injected semiconductor lasers
We study the hierarchical structuring of islands of stable periodic
oscillations inside chaotic regions in phase diagrams of single-mode
semiconductor lasers with optical injection. Phase diagrams display remarkable
{\it accumulation horizons}: boundaries formed by the accumulation of infinite
cascades of self-similar islands of periodic solutions of ever-increasing
period. Each cascade follows a specific period-adding route. The riddling of
chaotic laser phases by such networks of periodic solutions may compromise
applications operating with chaotic signals such as e.g. secure communications.Comment: 4 pages, 4 figures, laser phase diagrams, to appear in Phys. Rev. E,
vol. 7
Propagators and WKB-exactness in the plane wave limit of AdSxS
Green functions for the scalar, spinor and vector fields in a plane wave
geometry arising as a Penrose limit of are obtained. The
Schwinger-DeWitt technique directly gives the results in the plane wave
background, which turns out to be WKB-exact. Therefore the structural
similarity with flat space results is unveiled. In addition, based on the local
character of the Penrose limit, it is claimed that for getting the correct
propagators in the limit one can rely on the first terms of the direct geodesic
contribution in the Schwinger-DeWitt expansion of the original propagators .
This is explicitly shown for the Einstein Static Universe, which has the same
Penrose limit as with equal radii, and for a number of other
illustrative cases.Comment: 18 pages, late
Human Escherichia coli O157:H7 Genetic Marker in Isolates of Bovine Origin
The antiterminator Q gene of bacteriophage 933W (Q933) was identified upstream of the stx2 gene in 90% of human disease–origin Escherichia coli O157:H7 isolates and in 44.5% of bovine isolates. Shiga toxin production was higher in Q933-positive isolates than Q933-negative isolates. This genetic marker may provide a useful molecular tool for epidemiologic studies
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