21,484 research outputs found
Gauged Thirring Model in the Heisenberg Picture
We consider the (2+1)-dimensional gauged Thirring model in the Heisenberg
picture. In this context we evaluate the vacuum polarization tensor as well as
the corrected gauge boson propagator and address the issues of generation of
mass and dynamics for the gauge boson (in the limits of QED and Thirring
model as a gauge theory, respectively) due to the radiative corrections.Comment: 14 pages, LaTex, no figure
The experiences of patients and carers in the daily management of care at the end of life
Background
Home is the preferred location for most people with an advanced disease and at the end of life. A variety of care professionals work in community settings to provide support to this population. Patients and their spouses, who also care for them (spouse-carers), are rarely accompanied by these sources of support at all times, and have to manage independently between their contact with care professionals.
Aim
To explore how patients and spouse-carers manage their involvement with care professionals in the community setting.
Method
Interpretive phenomenology informs the design of the research, whereby 16 interviews were conducted with the patients and spouse-carers. Interviews were recorded and transcribed verbatim. Data were analysed using phenomenological techniques including template analysis.
Findings
Patients and spouse-carers were interdependent and both parties played a role in co-ordinating care and managing relationships with professional care providers. The patients and spouse-carers actively made choices about how to manage their situation, and develop and modify managing strategies based on their experiences.
Conclusions
When daily management is effective and care professionals acknowledge the dyadic nature of the patient and spouse-carer relationship, people have confidence in living with advanced disease
The three-dimensional noncommutative Gross-Neveu model
This work is dedicated to the study of the noncommutative Gross-Neveu model.
As it is known, in the canonical Weyl-Moyal approach the model is inconsistent,
basically due to the separation of the amplitudes into planar and nonplanar
parts. We prove that if instead a coherent basis representation is used, the
model becomes renormalizable and free of the aforementioned difficulty. We also
show that, although the coherent states procedure breaks Lorentz symmetry in
odd dimensions, in the Gross-Neveu model this breaking can be kept under
control by assuming the noncommutativity parameters to be small enough. We also
make some remarks on some ordering prescriptions used in the literature.Comment: 10 pages, IOP article style; v3: revised version, accepted for
publication in J. Phys.
Astrometry of mutual approximations between natural satellites. Application to the Galilean moons
Typically we can deliver astrometric positions of natural satellites with
errors in the 50-150 mas range. Apparent distances from mutual phenomena, have
much smaller errors, less than 10 mas. However, this method can only be applied
during the equinox of the planets. We developed a method that can provide
accurate astrometric data for natural satellites -- the mutual approximations.
The method can be applied when any two satellites pass close by each other in
the apparent sky plane. The fundamental parameter is the central instant
of the passage when the distances reach a minimum.
We applied the method for the Galilean moons. All observations were made with
a 0.6 m telescope with a narrow-band filter centred at 889 nm with width of 15
nm which attenuated Jupiter's scattered light. We obtained central instants for
14 mutual approximations observed in 2014-2015. We determined with an
average precision of 3.42 mas (10.43 km). For comparison, we also applied the
method for 5 occultations in the 2009 mutual phenomena campaign and for 22
occultations in the 2014-2015 campaign. The comparisons of determined by
our method with the results from mutual phenomena show an agreement by less
than 1-sigma error in , typically less than 10 mas. This new method is
particularly suitable for observations by small telescopes.Comment: 13 pages, 11 figures and 8 tables. Based on observations made at the
Laborat\'orio Nacional de Astrof\'isica (LNA), Itajub\'a-MG, Brazi
Slavnov-Taylor identities for noncommutative QED
In this work we present an analysis of the one-loop Slavnov-Taylor identities
in noncommutative QED. The vectorial fermion-photon and the triple photon
vertex functions were studied, with the conclusion that no anomalies arise.Comment: 24 pages, revtex4, v2: typos correcte
Tuning in magnetic modes in Tb(Co_{x}Ni_{1-x})_{2}B_{2}C: from longitudinal spin-density waves to simple ferromagnetism
Neutron diffraction and thermodynamics techniques were used to probe the
evolution of the magnetic properties of Tb(Co_{x}Ni_{1-x})_{2}B_{2}C. A
succession of magnetic modes was observed as x is varied: the longitudinal
modulated k=(0.55,0,0) state at x=0 is transformed into a collinear
k=([nicefrac]\nicefrac{1}{2},0,[nicefrac]\nicefrac{1}{2})
antiferromagnetic state at x= 0.2, 0.4; then into a transverse c-axis modulated
k=(0,0,[nicefrac]\nicefrac{1}{3}) mode at x= 0.6, and finally
into a simple ferromagnetic structure at x= 0.8 and 1. Concomitantly, the
low-temperature orthorhombic distortion of the tetragonal unit cell at x=0 is
reduced smoothly such that for x >= 0.4 only a tetragonal unit cell is
manifested. Though predicted theoretically earlier, this is the first
observation of the k=(0,0,[nicefrac]\nicefrac{1}{3}) mode in
borocarbides; our findings of a succession of magnetic modes upon increasing x
also find support from a recently proposed theoretical model. The implication
of these findings and their interpretation on the magnetic structure of the
RM_{2}B_{2}C series are also discussed
- …