2,247 research outputs found
On the construction of QED using ERG
It has been known for some time that a smooth momentum cutoff is compatible
with local gauge symmetries. In this paper we show concretely how to construct
QED using the exact renormalization group (ERG). First, we give a new
derivation of the Ward identity for the Wilson action using the technique of
composite operators. Second, parameterizing the theory by its asymptotic
behavior for a large cutoff, we show how to fine-tune the parameters to satisfy
the identity. Third, we recast the identity as invariance of the Wilson action
under a non-linear BRST transformation.Comment: 18 pages, LaTeX2e; added appendix A to improve sects. 2 and 4; added
ref. 1
Connections on the State-Space over Conformal Field Theories
Motivated by the problem of background independence of closed string field
theory we study geometry on the infinite vector bundle of local fields over the
space of conformal field theories (CFT's). With any connection we can associate
an excluded domain for the integral of marginal operators, and an operator
one-form . The pair determines the covariant
derivative of any correlator of local fields. We obtain interesting classes of
connections in which 's can be written in terms of CFT data. For
these connections we compute their curvatures in terms of four-point
correlators, , and . Among these connections three are of
particular interest. A flat, metric compatible connection \HG, and
connections and having non-vanishing curvature, with
being metric compatible. The flat connection cannot be used to do parallel
transport over a finite distance. Parallel transport with either or , however, allows us to construct a CFT in the state space of another CFT a
finite distance away. The construction is given in the form of perturbation
theory manifestly free of divergences.Comment: 54pp. MIT-CTP-219
The Analysis of Receptor-binding Cancer Antigen Expressed on SiSo Cells (RCAS1) immunoreactivity within the microenvironment of the ovarian cancer lesion relative to the applied therapeutic strategy
RCAS1 is involved in generating the suppressive profile of the tumor microenvironment that helps cancer cells evade immune surveillance. The status of the cells surrounding the cancer nest may affect both the progression of the cancer and the development of metastases. In cases of ovarian cancer, a large number of patients do not respond to the applied therapy. The patient’s response to the applied therapy is directly linked to the status of the tumor microenvironment and the intensity of its suppressive profile. We analyzed the immunoreactivity of RCAS1 on the cells present in the ovarian cancer microenvironment in patients with the disease; these cells included macrophages and carcinoma-associated fibroblasts. Later we analyzed the immunoreactivity levels within these cells, taking into consideration the clinical stage of the cancer and the therapeutic strategy applied, such as the number of chemotherapy regiments, primary cytoreductive surgery, or the presence of advanced ascites. In the patients who did not respond to the therapy we observed significantly higher immunoreactivity levels of RCAS1 within the cancer nest than in those patients who did respond; moreover, in the non-responsive patients we found RCAS1 within both macrophages and carcinoma-associated fibroblasts. RCAS1 staining may provide information about the intensity of the immuno-suppressive microenvironment profile found in cases of ovarian cancer and its intensity may directly relate to the clinical outcome of the disease
Molecular Dynamic Simulation of Static and Dynamical Properties of Point Defects in Ceramic Materials
Evidence for Carrier-Induced High-Tc Ferromagnetism in Mn-doped GaN film
A GaN film doped with 8.2 % Mn was grown by the molecular-beam-epitaxy
technique. Magnetization measurements show that this highly Mn-doped GaN film
exhibits ferromagnetism above room temperature. It is also revealed that the
high-temperature ferromagnetic state is significantly suppressed below 10 K,
accompanied by an increase of the electrical resistivity with decreasing
temperature. This observation clearly demonstrates a close relation between the
ferromagnetism with extremely high-Tc and the carrier transport in the Mn-doped
GaN film.Comment: 9 pages, 3 figure
Orientações gerais para avaliação de macroinvertebrados aquáticos em bacias hidrográficas.
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