70 research outputs found
The finiteness of the four dimensional antisymmetric tensor field model in a curved background
A renormalizable rigid supersymmetry for the four dimensional antisymmetric
tensor field model in a curved space-time background is constructed. A closed
algebra between the BRS and the supersymmetry operators is only realizable if
the vector parameter of the supersymmetry is a covariantly constant vector
field. This also guarantees that the corresponding transformations lead to a
genuine symmetry of the model. The proof of the ultraviolet finiteness to all
orders of perturbation theory is performed in a pure algebraic manner by using
the rigid supersymmetry.Comment: 23 page
Ghost Equations and Diffeomorphism Invariant Theories
Four-dimensional Einstein gravity in the Palatini first order formalism is
shown to possess a vector supersymmetry of the same type as found in the
topological theories for Yang-Mills fields. A peculiar feature of the
gravitational theory, characterized by diffeomorphism invariance, is a direct
link of vector supersymmetry with the field equation of motion for the
Faddeev-Popov ghost of diffeomorphisms.Comment: LaTex, 10 pages; sign corrected in eq. (3.9); added and completed
reference
Algebraic structure of gravity in Ashtekar variables
The BRST transformations for gravity in Ashtekar variables are obtained by
using the Maurer-Cartan horizontality conditions. The BRST cohomology in
Ashtekar variables is calculated with the help of an operator
introduced by S.P. Sorella, which allows to decompose the exterior derivative
as a BRST commutator. This BRST cohomology leads to the differential invariants
for four-dimensional manifolds.Comment: 19 pages, report REF. TUW 94-1
BRST-antifield-treatment of metric-affine gravity
The metric-affine gauge theory of gravity provides a broad framework in which
gauge theories of gravity can be formulated. In this article we fit
metric-affine gravity into the covariant BRST--antifield formalism in order to
obtain gauge fixed quantum actions. As an example the gauge fixing of a general
two-dimensional model of metric-affine gravity is worked out explicitly. The
result is shown to contain the gauge fixed action of the bosonic string in
conformal gauge as a special case.Comment: 19 pages LATEX, to appear in Phys. Rev.
JAK-STAT inhibition impairs K-RAS-driven lung adenocarcinoma progression
Oncogenic KRAS has been difficult to target and currently there is no KRASbased targeted therapy available for patients suffering from KRASdriven lung adenocarcinoma (AC). Alternatively, targeting KRASdownstream effectors, KRAScooperating signaling pathways or cancer hallmarks, such as tumorpromoting inflammation, has been shown to be a promising therapeutic strategy. Since the JAKSTAT pathway is considered to be a central player in inflammationmediated tumorigenesis, we investigated here the implication of JAKSTAT signaling and the therapeutic potential of JAK1/2 inhibition in KRASdriven lung AC. Our data showed that JAK1 and JAK2 are activated in human lung AC and that increased activation of JAKSTAT signaling correlated with disease progression and KRAS activity in human lung AC. Accordingly, administration of the JAK1/2 selective tyrosine kinase inhibitor ruxolitinib reduced proliferation of tumor cells and effectively reduced tumor progression in immunodeficient and immunocompetent mouse models of KRASdriven lung AC. Notably, JAK1/2 inhibition led to the establishment of an antitumorigenic tumor microenvironment, characterized by decreased levels of tumorpromoting chemokines and cytokines and reduced numbers of infiltrating myeloid derived suppressor cells, thereby impairing tumor growth. Taken together, we identified JAK1/2 inhibition as promising therapy for KRASdriven lung AC.(VLID)510233
Two-dimensional gravitational anomalies, Schwinger terms and dispersion relations
We are dealing with two-dimensional gravitational anomalies, specifically
with the Einstein anomaly and the Weyl anomaly, and we show that they are fully
determined by dispersion relations independent of any renormalization procedure
(or ultraviolet regularization). The origin of the anomalies is the existence
of a superconvergence sum rule for the imaginary part of the relevant
formfactor. In the zero mass limit the imaginary part of the formfactor
approaches a -function singularity at zero momentum squared, exhibiting
in this way the infrared feature of the gravitational anomalies. We find an
equivalence between the dispersive approach and the dimensional regularization
procedure. The Schwinger terms appearing in the equal time commutators of the
energy momentum tensors can be calculated by the same dispersive method.
Although all computations are performed in two dimensions the method is
expected to work in higher dimensions too
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