Group a streptococcal serotypes isolated from healthy schoolchildren in iran

Serotypes of group A streptococci are still a major cause of pharyngitis and some post-infectious sequelae such as rheumatic fever. As part of the worldwide effort to clarify the epidemiological pattern of group A streptococci in different countries, the present study was conducted to assess the prevalence of Streptococcus pyogenes serotypes in Iran. A total of 1588 throat swabs were taken from healthy school children in the city of Gorgan during February and March 1999. Of those isolates, 175 resulted positive for group A streptococci. The distribution pattern was similar for girls and boys, with 10.8 and 11.2, respectively. Urban school children showed a higher rate of colonization compared to those in rural areas. Serotyping was performed on 65 of the positive isolates using standard techniques, and only 21 (32) were M-type isolates. Their profiles fell into four types with M1 predominating, which could reflect the presence of rheumatic fever in the region. However, when isolates were challenged for T-antigen types, nearly all were positive (94). The pattern of T types was diverse (18 types), with the most common T types being T1 (26), TB3264 (15), TB\1-19 & B\25\1-19 (9.2) and T2 & 2\28 (7.7). When isolates were tested for opacity factor, only 23 (35) were positive while 34 (52) responded to the serum opacity reaction test. Although the number of isolates in this study was not sufficient to make any epidemiological conclusions, the scarcity of serotyping studies in Iran could render these data useful for future attempts to develop a streptococcal vaccine

Supersymmetry on a Spatial Lattice

We construct a variety of supersymmetric gauge theories on a spatial lattice, including N=4 supersymmetric Yang-Mills theory in 3+1 dimensions. Exact lattice supersymmetry greatly reduces or eliminates the need for fine tuning to arrive at the desired continuum limit in these examples.Comment: Version 3: Text brought in line with published version (extended discussion of orbifolding

Regularization of Non-commutative SYM by Orbifolds with Discrete Torsion and SL(2,Z) Duality

We construct a nonperturbative regularization for Euclidean noncommutative supersymmetric Yang-Mills theories with four (N= (2,2)), eight (N= (4,4)) and sixteen (N= (8,8)) supercharges in two dimensions. The construction relies on orbifolds with discrete torsion, which allows noncommuting space dimensions to be generated dynamically from zero dimensional matrix model in the deconstruction limit. We also nonperturbatively prove that the twisted topological sectors of ordinary supersymmetric Yang-Mills theory are equivalent to a noncommutative field theory on the topologically trivial sector with reduced rank and quantized noncommutativity parameter. The key point of the proof is to reinterpret 't Hooft's twisted boundary condition as an orbifold with discrete torsion by lifting the lattice theory to a zero dimensional matrix theory.Comment: 36 pages, references added, minor typos fixe

Deconstruction, Lattice Supersymmetry, Anomalies and Branes

We study the realization of anomalous Ward identities in deconstructed (latticized) supersymmetric theories. In a deconstructed four-dimensional theory with N=2 supersymmetry, we show that the chiral symmetries only appear in the infrared and that the anomaly is reproduced in the usual framework of lattice perturbation theory with Wilson fermions. We then realize the theory on the world-volume of fractional D-branes on an orbifold. In this brane realization, we show how deconstructed theory anomalies can be computed via classical supergravity. Our methods and observations are more generally applicable to deconstructed/latticized supersymmetric theories in various dimensions.Comment: 1+27 pages, 2 figures, references adde

Supersymetry on the Noncommutative Lattice

Built upon the proposal of Kaplan et.al. [hep-lat/0206109], we construct noncommutative lattice gauge theory with manifest supersymmetry. We show that such theory is naturally implementable via orbifold conditions generalizing those used by Kaplan {\sl et.al.} We present the prescription in detail and illustrate it for noncommutative gauge theories latticized partially in two dimensions. We point out a deformation freedom in the defining theory by a complex-parameter, reminiscent of discrete torsion in string theory. We show that, in the continuum limit, the supersymmetry is enhanced only at a particular value of the deformation parameter, determined solely by the size of the noncommutativity.Comment: JHEP style, 1+22 pages, no figure, v2: two references added, v3: three more references adde

Compact Gauge Fields for Supersymmetric Lattices

We show that a large class of Euclidean extended supersymmetric lattice gauge theories constructed in [hep-lat/0302017 - hep-lat/0503039] can be regarded as compact formulations by using the polar decomposition of the complex link fields. In particular, the gauge part of the supersymmetric lattice action is the standard Wilson action. This formulation facilitates the construction of gauge invariant operators.Comment: 15 pages, 2 figures. Minor change

Quantum carpet interferometry for trapped atomic Bose-Einstein condensates

We propose an ``interferometric'' scheme for Bose-Einstein condensates using near-field diffraction. The scheme is based on the phenomenon of intermode traces or quantum carpets; we show how it may be used in the detection of weak forces.Comment: 4 figures. Submitted to Phys. Rev.

Supersymmetric Unification Without Low Energy Supersymmetry And Signatures for Fine-Tuning at the LHC

The cosmological constant problem is a failure of naturalness and suggests that a fine-tuning mechanism is at work, which may also address the hierarchy problem. An example -- supported by Weinberg's successful prediction of the cosmological constant -- is the potentially vast landscape of vacua in string theory, where the existence of galaxies and atoms is promoted to a vacuum selection criterion. Then, low energy SUSY becomes unnecessary, and supersymmetry -- if present in the fundamental theory -- can be broken near the unification scale. All the scalars of the supersymmetric standard model become ultraheavy, except for a single finely tuned Higgs. Yet, the fermions of the supersymmetric standard model can remain light, protected by chiral symmetry, and account for the successful unification of gauge couplings. This framework removes all the difficulties of the SSM: the absence of a light Higgs and sparticles, dimension five proton decay, SUSY flavor and CP problems, and the cosmological gravitino and moduli problems. High-scale SUSY breaking raises the mass of the light Higgs to about 120-150 GeV. The gluino is strikingly long lived, and a measurement of its lifetime can determine the ultraheavy scalar mass scale. Measuring the four Yukawa couplings of the Higgs to the gauginos and higgsinos precisely tests for high-scale SUSY. These ideas, if confirmed, will demonstrate that supersymmetry is present but irrelevant for the hierarchy problem -- just as it has been irrelevant for the cosmological constant problem -- strongly suggesting the existence of a fine-tuning mechanism in nature.Comment: Typos and equations fixed, references adde

Brane World Susy Breaking from String/M Theory

String and M-theory realizations of brane world supersymmetry breaking scenarios are considered in which visible sector Standard Model fields are confined on a brane, with hidden sector supersymmetry breaking isolated on a distant brane. In calculable examples with an internal manifold of any volume the Kahler potential generically contains brane--brane non-derivative contact interactions coupling the visible and hidden sectors and is not of the no-scale sequestered form. This leads to non-universal scalar masses and without additional assumptions about flavor symmetries may in general induce dangerous sflavor violation even though the Standard Model and supersymmetry branes are physically separated. Deviations from the sequestered form are dictated by bulk supersymmetry and can in most cases be understood as arising from exchange of bulk supergravity fields between branes or warping of the internal geometry. Unacceptable visible sector tree-level tachyons arise in many models but may be avoided in certain classes of compactifications. Anomaly mediated and gaugino mediated contributions to scalar masses are sub-dominant except in special circumstances such as a flat or AdS pure five--dimensional bulk geometry without bulk vector multiplets.Comment: Latex, 83 pages, references adde