59,996 research outputs found
Nonperturbative Solution of the Super-Virasoro Constraints
We present the solution of the discrete super-Virasoro constraints to all
orders of the genus expansion. Integrating over the fermionic variables we get
a representation of the partition function in terms of the one-matrix model. We
also obtain the nonperturbative solution of the super-Virasoro constraints in
the double scaling limit but do not find agreement between our flows and the
known supersymmetric extensions of KdV.Comment: 12 pages, CERN-TH.6761/9
Osteoarthritis, entheses, and long bone cross-sectional geometry in the Andes: Usage, history, and future directions.
Akin to approaches encouraged by Verano (1997) in the Andes, and Ortner (2011, 2012) for general paleopathological studies, this article focuses on accurate descriptions and definitions of osteoarthritis, entheses, and long bone cross-sectional geometry. By evaluating these conditions as part of biological responses to abnormal skeletal changes and biomechanical stress, this research discusses each condition's pathogenesis. Further, this article emphasizes a "small data" approach to evaluating these conditions in ancient culturally and biologically related human populations, where the study samples must have good skeletal preservation, where estimates of age and sex need to be included as major factors, and where abnormalities need to be described and evaluated. This article also discusses global clinical and osteological research on ways scholars are currently trying to establish industry-wide methods to evaluate osteoarthritis, entheses, and long bone cross-sectional geometry. Recent studies have focused on rigorous evaluation of methodological techniques, recording protocols, and inter- and intra-observer error problems. Additionally, scholars have focused on physical intensity of movement using biomechanics, evaluated burials of known occupation, and used complex statistical methods to help interpret skeletal changes associated with these conditions. This article also narrows to focus on these conditions within thematic "small data" areas throughout the Andes. This research concludes with describing future directions to understand skeletal changes, such as more multidisciplinary studies between osteologists and pathologists, collaborations with living people to collect CT, x-rays, or computer-aided motion capture, and a stronger focus on how these conditions correlate with intense biomechanical changes in younger individuals
Higher Order Graviton Scattering in M(atrix) Theory
In matrix theory the effective action for graviton-graviton scattering is a
double expansion in the relative velocity and inverse separation. We discuss
the systematics of this expansion and subject matrix theory to a new test. Low
energy supergravity predicts the coefficient of the term, a
two-loop effect, in agreement with explicit matrix model calculation.Comment: 15 pages, 1 epsf figure, LaTeX. Minor change
Renormalization of the electron-phonon interaction: a reformulation of the BCS-gap equation
A recently developed renormalization approach is used to study the
electron-phonon coupling in many-electron systems. By starting from an
Hamiltonian which includes a small gauge symmetry breaking field, we directly
derive a BCS-like equation for the energy gap from the renormalization
approach. The effective electron-electron interaction for Cooper pairs does not
contain any singularities. Furthermore, it is found that phonon-induced
particle-hole excitations only contribute to the attractive electron-electron
interaction if their energy difference is smaller than the phonon energy.Comment: 8 pages, version to appear in Eur. Phys. J.
A Note on Flux Induced Superpotentials in String Theory
Non-vanishing fluxes in M-theory and string theory compactifications induce a
superpotential in the lower dimensional theory. Gukov has conjectured the
explicit form of this superpotential. We check this conjecture for the
heterotic string compactified on a Calabi-Yau three-fold as well as for warped
M-theory compactifications on Spin(7) holonomy manifolds, by performing a
Kaluza-Klein reduction.Comment: 19 pages, no figure
Magnetically tuned spin dynamics resonance
We present the experimental observation of a magnetically tuned resonance
phenomenon resulting from spin mixing dynamics of ultracold atomic gases. In
particular we study the magnetic field dependence of spin conversion in F=2
87Rb spinor condensates in the crossover from interaction dominated to
quadratic Zeeman dominated dynamics. We discuss the observed phenomenon in the
framework of spin dynamics as well as matter wave four wave mixing. Furthermore
we show that the validity range of the single mode approximation for spin
dynamics is significantly extended in the regime of high magnetic field
Optical measurement methods in thermogasdynamics
A review is presented of a number of optical methods of flow measurements. Consideration is given to such spectroscopic methods as emission and absorption techniques, electron beam-stimulated fluorescence, and light scattering - Rayleigh, Raman and Mie - methods. The following visualization methods are also discussed: shadow photography, schlieren photography, interferometry, holographic interferometry, laser anemometry, particle holography, and electron-excitation imaging. A large bibliography is presented and the work is copiously illustrated with figures and photographs
PMNCH Knowledge Summary 23: Human Rights & Accountability
Panel presentation for the Global Maternal Health Conference, held in Tanzania in January 2013, organised by Kate Sabot
Presentation Outline
(1) Overview of PMNCH
(2) Overview of Knowledge Summary Process
(3) KS 23 Highlight
- …