5,061 research outputs found
Toric Duality Is Seiberg Duality
We study four N=1 SU(N)^6 gauge theories, with bi-fundamental chiral matter
and a superpotential. In the infrared, these gauge theories all realize the
low-energy world-volume description of N coincident D3-branes transverse to the
complex cone over a del Pezzo surface dP_3 which is the blowup of P^2 at three
generic points. Therefore, the four gauge theories are expected to fall into
the same universality class--an example of a phenomenon that has been termed
"toric duality." However, little independent evidence has been given that such
theories are infrared-equivalent.
In fact, we show that the four gauge theories are related by the N=1 duality
of Seiberg, vindicating this expectation. We also study holographic aspects of
these gauge theories. In particular we relate the spectrum of chiral operators
in the gauge theories to wrapped D3-brane states in the AdS dual description.
We finally demonstrate that the other known examples of toric duality are
related by N=1 duality, a fact which we conjecture holds generally.Comment: 46 pages, 2 figures, harvma
Some Experimental Signatures to look for Time-reversal Violating superconductors
We discuss some experimental signatures associated with the topological
structures of unconventional superconductor order parameters of form
, where , or . Specifically, we study
the topological surface states on the and equivalent surfaces of such
superconductors which are observable in Andreev tunneling experiments, as well
as evaluate the magnetic flux trapped in superconducting rings of such
superconductors with multiple grain-boundary Josephson junctions. Previous
experiments are examined and several new experiments suggested.Comment: 11 pages, 3 figure
On F-theory Quiver Models and Kac-Moody Algebras
We discuss quiver gauge models with bi-fundamental and fundamental matter
obtained from F-theory compactified on ALE spaces over a four dimensional base
space. We focus on the base geometry which consists of intersecting F0=CP1xCP1
Hirzebruch complex surfaces arranged as Dynkin graphs classified by three kinds
of Kac-Moody (KM) algebras: ordinary, i.e finite dimensional, affine and
indefinite, in particular hyperbolic. We interpret the equations defining these
three classes of generalized Lie algebras as the anomaly cancelation condition
of the corresponding N =1 F-theory quivers in four dimensions. We analyze in
some detail hyperbolic geometries obtained from the affine A base geometry by
adding a node, and we find that it can be used to incorporate fundamental
fields to a product of SU-type gauge groups and fields.Comment: 13 pages; new equations added in section 3, one reference added and
typos correcte
A study of the possible preventive effects of muscular exercises and intermittent venous occlusion on the cardiovascular deconditioning observed after 10 days bed recumbency - Experimental design
Experiment designed to study preventive effects of muscular exercises on intermittent venous occlusion on cardiovascular deconditioning observed after 10 days bed recumbenc
Experiences of a Curriculum Development Specialist with the Office of the Superintendent of Public Instruction
The purpose of this project is to report the planned activities of experience pertinent to the position of a Curriculum Development Specialist with the Office of the Superintendent of Public Instruction (OSPI). The official work assignment of the Curriculum Development Specialist was with the Southern Illinois Regional Office of the Office of the Superintendent located at Mt. Vernon. This regional office is composed of approximately twenty-six professional personnel and operates under the direct leadership of Assistant Superintendent Richard Haney. The report was intended to follow a Curriculum Development Specialist for a fixed period of time beginning March 8, 1973 and ending June 21, 1974. Chapter II of this report contains a comprehensive weekly log of activities presenting detailed information relative to the specialist\u27s activities during the stated time frame
Serum iron uptake and virulence in Staphylococcus aureus
The high affinity iron scavenging glycoprotein transferrin sequesters trace amounts of serum Fe3+ to concentrations below what is required to sustain microbial life. Iron may be liberated from this important innate immune factor after interaction with molecules that chelate or reduce Fe3+. Organisms with cognate transport systems for these iron coordinating molecules can survive in the bloodstream using transferrin iron.
Staphylococcus aureus is an opportunistic bacterial pathogen. S. aureus executes numerous strategies for overcoming the innate immune barrier of iron deprivation in the bloodstream. In addition to specialized mechanisms for hemoglobin iron extraction, S. aureus can proliferate on serum iron, but factors enabling this growth are not described. Production of at least two siderophores (microbial iron chelators) has been documented on numerous occasions, and their contribution to growth on transferrin is documented here. Genomic inactivation of genes involved in production of molecules subsequently termed staphyloferrin A (SA; the sfa locus) and staphyloferrin B (SB; the sbn operon) resulted in a mutant severely incapacitated for growth in serum as well as on rarefied human transferrin as sole iron sources. Transport of staphyloferrins was correlated to adjacently encoded cognate ABC type transporter operons, hts (SA) and sir (SB), using previously constructed transport mutant strains. Mass spectrometry confirmed the molecular structure of SB as being the same as the previously described S. aureus metabolite, staphylobactin.
Alternate siderophores were not detectable for the double biosynthetic mutant. Growth in the presence of transferrin could be rescued by addition of saturating concentrations of iron, and restored by molecules that bind Fe3+ through catechol-iron coordination, including mammalian catecholamine stress hormones. In silico analysis and mutational inactivation confirmed this transport function to be encoded by the sst operon. Biochemical assays revealed that the Sst transporter lipoprotein has a high affinity for ferrated catecholate iron ligands.
Siderophore biosynthesis and transport mutants displayed reduced virulence during systemic mouse infection. Decreased bacterial loads were documented in mouse hearts, an important finding as S. aureus is a leading cause of endocarditis. The data collected in this study show that acquisition of serum iron is an important part of staphylococcal pathogenesis, and suggest that therapeutics targeting the numerous facets of this process may be effective in combating invasive infection
Experiences of a Curriculum Development Specialist with the Office of the Superintendent of Public Instruction
The purpose of this project is to report the planned activities of experience pertinent to the position of a Curriculum Development Specialist with the Office of the Superintendent of Public Instruction (OSPI). The official work assignment of the Curriculum Development Specialist was with the Southern Illinois Regional Office of the Office of the Superintendent located at Mt. Vernon. This regional office is composed of approximately twenty-six professional personnel and operates under the direct leadership of Assistant Superintendent Richard Haney. The report was intended to follow a Curriculum Development Specialist for a fixed period of time beginning March 8, 1973 and ending June 21, 1974. Chapter II of this report contains a comprehensive weekly log of activities presenting detailed information relative to the specialist\u27s activities during the stated time frame
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