3,758 research outputs found
Real time statistical field theory
We have written a {\it Mathematica} program that calculates the integrand
corresponding to any amplitude in the closed-time-path formulation of real time
statistical field theory. The program is designed so that it can be used by
someone with no previous experience with {\it Mathematica}. It performs the
contractions over the tensor indices that appear in real time statistical field
theory and gives the result in the 1-2, Keldysh or RA basis. We have used the
program to calculate the ward identity for the QED 3-point function, the QED
4-point function for two photons and two fermions, and the QED 5-point function
for three photons and two fermions. In real time statistical field theory,
there are seven 3-point functions, 15 4-point functions and 31 5-point
functions. We produce a table that gives the results for all of these
functions. In addition, we give a simple general expression for the KMS
conditions between -point green functions and vertex functions, in both the
Keldysh and RA basesComment: 25 pages, 12 figure
Results from the 4PI Effective Action in 2- and 3-dimensions
We consider a symmetric scalar theory with quartic coupling and solve the
equations of motion from the 4PI effective action in 2- and 3-dimensions using
an iterative numerical lattice method. For coupling less than 10 (in
dimensionless units) good convergence is obtained in less than 10 iterations.
We use lattice size up to 16 in 2-dimensions and 10 in 3-dimensions and
demonstrate the convergence of the results with increasing lattice size. The
self-consistent solutions for the 2-point and 4-point functions agree well with
the perturbative ones when the coupling is small and deviate when the coupling
is large.Comment: 14 pages, 11 figures; v5: added numerical calculations in 3D; version
accepted for publication in EPJ
Protein-protein Interactions of the Androgen Receptor in Living Cells
__Abstract__
Natural androgens, testosterone (T) and its derivative dihydrotestosterone (DHT) play a
crucial role in the development and maintenance of the male phenotype. Androgens are
steroids that exert their function via the androgen receptor (AR), a ligand dependent transcription
factor. The human AR gene, is located on the X chromosome, and contains 8 exons,
coding for a 110 kDa, 919 amino acids protein (Brinkmann et al., 1989; Hughes and Deeb,
2006). In the classical model of AR action, the unliganded AR is located in the cytoplasm in
complex with chaperone proteins (Pratt and Toft, 1997; Prescott and Coetzee, 2006). Upon
androgen binding the chaperone complex is modifi ed and the AR translocates to the nucleus
(Georget et al., 1997; Tyagi et al., 2000; Black and Paschal, 2004). In the nucleus, the AR binds
to specifi c sequences in promoters and enhancers of target genes, interacts with specifi c
coregulators and enhances the recruitment of the general transcription machinery, leading
to transcription initiation (Fig. 1) (Glass and Rosenfeld, 2000; Claessens et al., 2001; Cosma,
2002; Orphanides and Reinberg, 2002; Heemers and Tindall, 2007). Recently, many reviews
on AR function have been published (e.g. Dehm and Tindall, 2007; Heemers and Tindall, 2007;
Trapman and Dubbink, 2007; Centenera et al., 2008; Claessens et al., 2008). The focus of this
thesis is on molecular mechanisms underlying AR function in living cells
On Bogovski\u{\i} and regularized Poincar\'e integral operators for de Rham complexes on Lipschitz domains
We study integral operators related to a regularized version of the classical
Poincar\'e path integral and the adjoint class generalizing Bogovski\u{\i}'s
integral operator, acting on differential forms in . We prove that these
operators are pseudodifferential operators of order -1. The Poincar\'e-type
operators map polynomials to polynomials and can have applications in finite
element analysis. For a domain starlike with respect to a ball, the special
support properties of the operators imply regularity for the de Rham complex
without boundary conditions (using Poincar\'e-type operators) and with full
Dirichlet boundary conditions (using Bogovski\u{\i}-type operators). For
bounded Lipschitz domains, the same regularity results hold, and in addition we
show that the cohomology spaces can always be represented by
functions.Comment: 23 page
Poly (glycerol adipate) (PGA), an enzymatically synthesized functionalizable polyester and versatile drug delivery carrier : A literature update
The enzymatically synthesized poly (glycerol adipate) (PGA) has demonstrated all the desirable key properties required from a performing biomaterial to be considered a versatile "polymeric-tool" in the broad field of drug delivery. The step-growth polymerization pathway catalyzed by lipase generates a highly functionalizable platform while avoiding tedious steps of protection and deprotection. Synthesis requires only minor purification steps and uses cheap and readily available reagents. The final polymeric material is biodegradable, biocompatible and intrinsically amphiphilic, with a good propensity to self-assemble into nanoparticles (NPs). The free hydroxyl group lends itself to a variety of chemical derivatizations via simple reaction pathways which alter its physico-chemical properties with a possibility to generate an endless number of possible active macromolecules. The present work aims to summarize the available literature about PGA synthesis, architecture alterations, chemical modifications and its application in drug and gene delivery as a versatile carrier. Following on from this, the evolution of the concept of enzymatically-degradable PGA-drug conjugation has been explored, reporting recent examples in the literature.Peer reviewedFinal Published versio
Dimensional Reduction in Non-Supersymmetric Theories
It is shown that regularisation by dimensional reduction is a viable
alternative to dimensional regularisation in non-supersymmetric theories.Comment: 13 pages, phyzzx, LTH 32
Striding out with Parkinson disease: evidence-based physical therapy for gait disorders
Although Parkinson disease (PD) is common throughout the world, the evidence for physical therapy interventions that enable long-term improvement in walking is still emerging. This article critiques the major physical therapy approaches related to gait rehabilitation in people with PD: compensatory strategies, motor skill learning, management of secondary sequelae, and education to optimize physical activity and reduce falls. The emphasis of this review is on gait specifically, although balance and falls are of direct importance to gait and are addressed in that context. Although the researchers who have provided the evidence for these approaches grounded their studies on different theoretical paradigms, each approach is argued to have a valid place in the comprehensive management of PD generally and of gait in particular. The optimal mix of interventions for each individual varies according to the stage of disease progression and the patient's preferred form of exercise, capacity for learning, and age
Characterization of quantum states in predicative logic
We develop a characterization of quantum states by means of first order
variables and random variables, within a predicative logic with equality, in
the framework of basic logic and its definitory equations. We introduce the
notion of random first order domain and find a characterization of pure states
in predicative logic and mixed states in propositional logic, due to a focusing
condition. We discuss the role of first order variables and the related
contextuality, in terms of sequents.Comment: 14 pages, Boston, IQSA10, to appea
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