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DEFUELING THE S2G REACTOR
The defueling of the S2G Reactor which was conducted at the Electric Boat Division, General Dynamics Corporation Groton Connecticut during January 1959, is reported from the viewpoint of the participating personnel from Knolls Atomic Power Laboratory. The sequence of events is outlined, difficulties encountered during the operation are described, and conclusions of possible interest to other naval nuclear reactors are given (auth
Branes, Rings and Matrix Models in Minimal (Super)string Theory
We study both bosonic and supersymmetric (p,q) minimal models coupled to
Liouville theory using the ground ring and the various branes of the theory.
From the FZZT brane partition function, there emerges a unified, geometric
description of all these theories in terms of an auxiliary Riemann surface
M_{p,q} and the corresponding matrix model. In terms of this geometric
description, both the FZZT and ZZ branes correspond to line integrals of a
certain one-form on M_{p,q}. Moreover, we argue that there are a finite number
of distinct (m,n) ZZ branes, and we show that these ZZ branes are located at
the singularities of M_{p,q}. Finally, we discuss the possibility that the
bosonic and supersymmetric theories with (p,q) odd and relatively prime are
identical, as is suggested by the unified treatment of these models.Comment: 72 pages, 3 figures, improved treatment of FZZT and ZZ branes, minor
change
Notes on the algebraic curves in (p,q) minimal string theory
Loop amplitudes in (p,q) minimal string theory are studied in terms of the
continuum string field theory based on the free fermion realization of the KP
hierarchy. We derive the Schwinger-Dyson equations for FZZT disk amplitudes
directly from the W_{1+\infty} constraints in the string field formulation and
give explicitly the algebraic curves of disk amplitudes for general
backgrounds. We further give annulus amplitudes of FZZT-FZZT, FZZT-ZZ and ZZ-ZZ
branes, generalizing our previous D-instanton calculus from the minimal unitary
series (p,p+1) to general (p,q) series. We also give a detailed explanation on
the equivalence between the Douglas equation and the string field theory based
on the KP hierarchy under the W_{1+\infty} constraints.Comment: 61 pages, 1 figure, section 2.5 and Appendix B added, references
added, final version to appear in JHE
Annulus Amplitudes and ZZ Branes in Minimal String Theory
We study the annulus amplitudes of (p,q) minimal string theory. Focusing on
the ZZ-FZZT annulus amplitude as a target-space probe of the ZZ brane, we use
it to confirm that the ZZ branes are localized in the strong-coupling region.
Along the way we learn that the ZZ-FZZT open strings are fermions, even though
our theory is bosonic! We also provide a geometrical interpretation of the
annulus amplitudes in terms of the Riemann surface M_{p,q} that emerges from
the FZZT branes. The ZZ-FZZT annulus amplitude measures the deformation of
M_{p,q} due to the presence of background ZZ branes; each kind of ZZ-brane
deforms only one A-period of the surface. Finally, we use the annulus
amplitudes to argue that the ZZ branes can be regarded as "wrong-branch"
tachyons which violate the bound \alpha<Q/2.Comment: 33 pages, new results in appendix, minor change
String Theoretic Bounds on Lorentz-Violating Warped Compactification
We consider warped compactifications that solve the 10 dimensional
supergravity equations of motion at a point, stabilize the position of a
D3-brane world, and admit a warp factor that violates Lorentz invariance along
the brane. This gives a string embedding of ``asymmetrically warped'' models
which we use to calculate stringy (\alpha') corrections to standard model
dispersion relations, paying attention to the maximum speeds for different
particles. We find, from the dispersion relations, limits on gravitational
Lorentz violation in these models, improving on current limits on the speed of
graviton propagation, including those derived from field theoretic loops. We
comment on the viability of models that use asymmetric warping for self-tuning
of the brane cosmological constant.Comment: 20pg, JHEP3; v2 additional references, slight change to intro; v3.
added referenc
Geometric K-Homology of Flat D-Branes
We use the Baum-Douglas construction of K-homology to explicitly describe
various aspects of D-branes in Type II superstring theory in the absence of
background supergravity form fields. We rigorously derive various stability
criteria for states of D-branes and show how standard bound state constructions
are naturally realized directly in terms of topological K-cycles. We formulate
the mechanism of flux stabilization in terms of the K-homology of non-trivial
fibre bundles. Along the way we derive a number of new mathematical results in
topological K-homology of independent interest.Comment: 45 pages; v2: References added; v3: Some substantial revision and
corrections, main results unchanged but presentation improved, references
added; to be published in Communications in Mathematical Physic
Occupational Communication as Boundary Mechanism
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/69000/2/10.1177_073088847400100404.pd
The Role of Current and Historical Alcohol Use in Hepatic Fibrosis Among HIV-Infected Individuals
We examined risk factors for advanced hepatic fibrosis [fibrosis-4 (FIB)-4 >3.25] including both current alcohol use and a diagnosis of alcohol use disorder among HIV-infected patients. Of the 12,849 patients in our study, 2133 (17%) reported current hazardous drinking by AUDIT-C, 2321 (18%) had a diagnosis of alcohol use disorder, 2376 (18%) were co-infected with chronic hepatitis C virus (HCV); 596 (5%) had high FIB-4 scores >3.25 as did 364 (15%) of HIV/HCV coinfected patients. In multivariable analysis, HCV (adjusted odds ratio (aOR) 6.3, 95% confidence interval (CI) 5.2–7.5), chronic hepatitis B (aOR 2.0, 95% CI 1.5–2.8), diabetes (aOR 2.3, 95% CI 1.8–2.9), current CD4 <200 cells/mm3 (aOR 5.4, 95% CI 4.2–6.9) and HIV RNA >500 copies/mL (aOR 1.3, 95% CI 1.0–1.6) were significantly associated with advanced fibrosis. A diagnosis of an alcohol use disorder (aOR 1.9, 95% CI 1.6–2.3) rather than report of current hazardous alcohol use was associated with high FIB-4. However, among HIV/HCV coinfected patients, both current hazardous drinkers (aOR 1.6, 95% CI 1.1–2.4) and current non-drinkers (aOR 1.6, 95% CI 1.2–2.0) were more likely than non-hazardous drinkers to have high FIB-4, with the latter potentially reflecting the impact of sick abstainers. These findings highlight the importance of using a longitudinal measure of alcohol exposure when evaluating the impact of alcohol on liver disease and associated outcomes
The statistics of string/M theory vacua
We discuss systematic approaches to the classification of string/M theory
vacua, and physical questions this might help us resolve. To this end, we
initiate the study of ensembles of effective Lagrangians, which can be used to
precisely study the predictive power of string theory, and in simple examples
can lead to universality results. Using these ideas, we outline an approach to
estimating the number of vacua of string/M theory which can realize the
Standard Model.Comment: harvmac, 72pp (v4: fixed error in discussion of quiver ensembles
Phase Behavior of Type-II Superconductors with Quenched Point Pinning Disorder: A Phenomenological Proposal
A general phenomenology for phase behaviour in the mixed phase of type-II
superconductors with weak point pinning disorder is outlined. We propose that
the ``Bragg glass'' phase generically transforms via two separate thermodynamic
phase transitions into a disordered liquid on increasing the temperature. The
first transition is into a glassy phase, topologically disordered at the
largest length scales; current evidence suggests that it lacks the long-ranged
phase correlations expected of a ``vortex glass''. This phase has a significant
degree of short-ranged translational order, unlike the disordered liquid, but
no quasi-long range order, in contrast to the Bragg glass. This glassy phase,
which we call a ``multi-domain glass'', is confined to a narrow sliver at
intermediate fields, but broadens out both for much larger and much smaller
field values. The multi-domain glass may be a ``hexatic glass''; alternatively,
its glassy properties may originate in the replica symmetry breaking envisaged
in recent theories of the structural glass transition. Estimates for
translational correlation lengths in the multi-domain glass indicate that they
can be far larger than the interline spacing for weak disorder, suggesting a
plausible mechanism by which signals of a two-step transition can be obscured.
Calculations of the Bragg glass-multi-domain glass and the multi-domain
glass-disordered liquid phase boundaries are presented and compared to
experimental data. We argue that these proposals provide a unified picture of
the available experimental data on both high-T and low-T materials,
simulations and current theoretical understanding.Comment: 70 pages, 9 postscript figures, modified title and minor changes in
published versio
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