Duality symmetry in four-dimensional string actions

We reduce the dual version of $D=10$, $N=1$ supergravity coupled to $n$ vector fields to four dimensions, and derive the $SL(2,R)\times O(6,6+n)$ transformations which leave the equations of motion invariant. For $n=0$ $SL(2,R)$ is also a symmetry of the action, but for $n>0$ only those $SL(2,R)$ transformations which act linearly on all fields leave the action invariant. The resulting four-dimensional theory is related to the bosonic part of the usual formulation of $N=4$ supergravity coupled to matter by a duality transformation.Comment: 9 pages, Latex fil

Generalized Conformal Quantum Mechanics of D0-brane

We study the generalized conformal quantum mechanics of the probe D0-brane in the near horizon background of the bound state of source D0-branes. We elaborate on the relationship of such model to the M theory in the light cone frame.Comment: 14 pages, RevTeX, revised version with added references to appear in Phys. Rev.

Introduction to M Theory and AdS/CFT Duality

An introductory survey of some of the developments that have taken place in superstring theory in the past few years is presented. The main focus is on three particular dualities. The first one is the appearance of an 11th dimension in the strong coupling limit of the type IIA theory, which give rise to M theory. The second one is the duality between the type IIB theory compactified on a circle and M theory on a two-torus. The final topic is an introduction to the recently proposed duality between superstring theory or M theory on certain anti de Sitter space backgrounds and conformally invariant quantum field theories.Comment: 26 pages; To be published in the Proceedings of a conference held in Corfu, Greece in September 1998. v2: reference adde

Black Rings, Supertubes, and a Stringy Resolution of Black Hole Non-Uniqueness

In order to address the issues raised by the recent discovery of non-uniqueness of black holes in five dimensions, we construct a solution of string theory at low energies describing a five-dimensional spinning black ring with three charges that can be interpreted as D1-brane, D5-brane, and momentum charges. The solution possesses closed timelike curves (CTCs) and other pathologies, whose origin we clarify. These pathologies can be avoided by setting any one of the charges, e.g. the momentum, to zero. We argue that the D1-D5-charged black ring, lifted to six dimensions, describes the thermal excitation of a supersymmetric D1-D5 supertube, which is in the same U-duality class as the D0-F1 supertube. We explain how the stringy microscopic description of the D1-D5 system distinguishes between a spherical black hole and a black ring with the same asymptotic charges, and therefore provides a (partial) resolution of the non-uniqueness of black holes in five dimensions.Comment: 33 pages, 1 figur

Age-sex specific prevalence of radiographic abnormalities of the joints of the hands, wrists and cervical spine of adult residents of the Tecumseh, Michigan, Community Health Study area, 1962-1965

Radiographs of the hands and wrists and cervical spine of 4415 residents of Tecumseh, Michigan, aged 16 yr and over, have been reviewed. Evidence of rheumatoid arthritis was observed in the hands and wrists of 0.19 per cent of males and 0.34 per cent of females. The prevalence of cervical spine changes, which could be attributed to rheumatoid arthritis or ankylosing spondylitis, was insignificant.Degenerative changes in both examined regions occurred much more frequently and showed a marked positive correlation with advancing age. Radiographic evidence of osteoarthrosis of the hands and wrists was observed in 19.5 per cent of males and 23 per cent of females. In the cervical spine, degenerative disc disease (16-19 per cent) was noted somewhat more frequently than osteoarthrosis (11 per cent).Among the other radiographic lesions which were observed, those of post traumatic changes, including amputation of digits, in the hands and wrists and fusion of cervical vertebral bodies, thought to represent a failure of segmentation in embryonic life, were most frequent.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/32700/1/0000067.pd

RG flows from Spin(7), CY 4-fold and HK manifolds to AdS, Penrose limits and pp waves

We obtain explicit realizations of holographic renormalization group (RG) flows from M-theory, from E^{2,1} \times Spin(7) at UV to AdS_4 \times \tilde{S^7} (squashed S^7) at IR, from E^{2,1} \times CY4 at UV to AdS_4 \times Q^{1,1,1} at IR, and from E^{2,1} \times HK (hyperKahler) at UV to AdS_4 \times N^{0,1,0} at IR. The dual type IIA string theory configurations correspond to D2-D6 brane systems where D6 branes wrap supersymmetric four-cycles. We also study the Penrose limits and obtain the pp-wave backgrounds for the above configurations. Besides, we study some examples of non-supersymmetric and supersymmetric flows in five-dimensional gauge theories.Comment: 42 pages, 6 eps figures, typos and misprints correcte

What is a Humanized Mouse? Remaking the Species and Spaces of Translational Medicine

Copyright © 2012 SAGE Publications. Author's draft version; post-print. Final version published by Sage available on Sage Journals Online http://online.sagepub.com/This article explores the development of a novel biomedical research organism, and its potential to remake the species and spaces of translational medicine. The humanized mouse is a complex experimental object in which mice, rendered immunodeficient through genetic alteration, are engrafted with human stem cells in the hope of reconstituting a human immune system for biomedical research and drug testing. These chimeric organisms have yet to garner the same commentary from social scientists as other human–animal hybrid forms. Yet, they are rapidly being positioned as central to translational medicine in immunological research and pharmaceutical development. This article explores the complex relations between species and spaces they seek to enact. Humanizing mice simultaneously moves these animal forms towards the intimate geographies of corporeal equivalence with humans and the expansive geographies of translational research. These multiple trajectories are achieved by the way humanized mice function as both uncertain ‘epistemic things’ and as expansive ‘collaborative things’, articulating mouse genetics with other research, notably stem cell science. In the context of post-genomics, their indeterminacy is critical to their collaborative value; their expansive potential follows as much from their biological openness as from specific expectations. Yet, these new research organisms have both accumulative and disruptive capacities, for there are patterns of interference between these trajectories, remaking boundaries between experimental practices and clinical contexts

Homozygous founder mutation in desmocollin-2 (DSC2) causes arrhythmogenic cardiomyopathy in the Hutterite population

BACKGROUND: Dominant mutations in cellular junction proteins are the major cause of arrhythmogenic cardiomyopathy, whereas recessive mutations in those proteins cause cardiocutaneous syndromes such as Naxos and Carvajal syndrome. The Hutterites are distinct genetic isolates who settled in North America in 1874. Descended from T (p.Q554X) in desmocollin-2 (DSC2), in affected individuals and determined a carrier frequency of this mutation of 9.4% (1 in 10.6) among 1535 Schmiedeleut Hutterites, suggesting a common founder in that subgroup. Immunohistochemistry of endomyocardial biopsy samples revealed altered expression of the truncated DSC2 protein at the intercalated discs but only minor changes in immunoreactivity of other desmosomal proteins. Recombinant expressed mutant DSC2 protein in cells confirmed a stable, partially processed truncated protein with cytoplasmic and membrane localization. CONCLUSIONS: A homozygous truncation mutation in DSC2 leads to a cardiac-restricted phenotype of an early onset biventricular arrhythmogenic cardiomyopathy. The truncated protein remains partially stable and localized at the intercalated discs. These data suggest that the processed DSC2 protein plays a role in maintaining desmosome integrity and function