1,509 research outputs found
Failure of Standard Conservation Laws at a Classical Change of Signature
The Divergence Theorem as usually stated cannot be applied across a change of
signature unless it is re-expressed to allow for a finite source term on the
signature change surface. Consequently all conservation laws must also be
`modified', and therefore insistence on conservation of matter across such a
surface cannot be physically justified. The Darmois junction conditions
normally ensure conservation of matter via Israel's identities for the jump in
the energy-momentum density, but not when the signature changes. Modified
identities are derived for this jump when a signature change occurs, and the
resulting surface effects in the conservation laws are calculated. In general,
physical vector fields experience a jump in at least one component, and a
source term may therefore appear in the corresponding conservation law. Thus
current is also not conserved. These surface effects are a consequence of the
change in the character of physical law. The only way to recover standard
conservation laws is to impose restrictions that no realistic cosmological
model can satisfy.Comment: 15pp, figures available on request from Charles Hellaby at
[email protected]
Post-release treatment uptake among participants of the Rhode Island Department of Corrections comprehensive medication assisted treatment program
The Rhode Island Department of Corrections (RIDOC) recently implemented the first state-wide, comprehensive medications for addiction treatment (MAT) program in the US. The objective of this study was to elucidate perceived barriers for individuals who participated in RIDOC's MAT program while incarcerated. Of the 588 individuals eligible for this study, 227 phone surveys were completed with 214 individuals. Data relevant to demographic characteristics, probation/parole status, retention in MAT treatment, MAT type received during incarceration, MAT treatment history, location where they received community treatment, perceived barriers to treatment, and future goals for MAT were collected. Simple percentages, frequencies, means, and standard deviations were calculated with SPSS. Most participants (82.4%) reported continuing MAT post-release and a majority (74.3%) received treatment at an opioid treatment program. Those who did not connect with treatment post-release reported transportation issues (23.1%) and not wanting to continue MAT (20.5%) as major reasons for not continuing treatment. The most commonly reported goal for treatment was to continue MAT long-term (43.5%). Results indicate that most participants linked to MAT treatment post-release. Participants reported reasons for why they did not continue MAT and had mixed intentions about continuing MAT in the future. Results provide identification of novel factors, such as side effects, time between release and treatment linkage, and family and friends' opinions that influence MAT continuation post-incarceration. Results highlight areas of exploration to influence treatment retention, including the role of probation/parole officers and the potential for peer support specialists to assist in reducing stigma and increasing interest in MAT
Critical points for nondifferentiable functions in presence of splitting
AbstractA classical critical point theorem in presence of splitting established by Brézis–Nirenberg is extended to functionals which are the sum of a locally Lipschitz continuous term and of a convex, proper, lower semicontinuous function. The obtained result is then exploited to prove a multiplicity theorem for a family of elliptic variational–hemivariational eigenvalue problems
A crucial role for the ubiquitously expressed transcription factor Sp1 at early stages of hematopoietic specification
Mammalian development is regulated by the interplay of tissue-specific and ubiquitously expressed transcription factors, such as Sp1. Sp1 knockout mice die in utero with multiple phenotypic aberrations, but the underlying molecular mechanism of this differentiation failure has been elusive. Here, we have used conditional knockout mice as well as the differentiation of mouse ES cells as a model with which to address this issue. To this end, we examine
Thermal treatment for radioactive waste minimisation
Safe management of radioactive waste is challenging to waste producers and waste management organisations. Deployment of thermal treatment technologies can provide significant improvements: volume reduction, waste passivation, organics destruction, safety demonstration facilitation, etc. The EC-funded THERAMIN project enables an EU-wide strategic review and assessment of the value of thermal treatment technologies applicable to Low and Intermediate Level waste streams (ion exchange media, soft operational waste, sludges, organic waste, and liquids). THERAMIN compiles an EU-wide database of wastes, which could be treated by thermal technologies and documents available thermal technologies. Applicability and benefits of technologies to the identified waste streams will be evaluated through full-scale demonstration tests by project partners. Safety case implications will also be assessed through the study of the disposability of thermally treated waste products. This paper will communicate the strategic aims of the ongoing project and highlight some key findings and results achieved to date
Red Queen Coevolution on Fitness Landscapes
Species do not merely evolve, they also coevolve with other organisms.
Coevolution is a major force driving interacting species to continuously evolve
ex- ploring their fitness landscapes. Coevolution involves the coupling of
species fit- ness landscapes, linking species genetic changes with their
inter-specific ecological interactions. Here we first introduce the Red Queen
hypothesis of evolution com- menting on some theoretical aspects and empirical
evidences. As an introduction to the fitness landscape concept, we review key
issues on evolution on simple and rugged fitness landscapes. Then we present
key modeling examples of coevolution on different fitness landscapes at
different scales, from RNA viruses to complex ecosystems and macroevolution.Comment: 40 pages, 12 figures. To appear in "Recent Advances in the Theory and
Application of Fitness Landscapes" (H. Richter and A. Engelbrecht, eds.).
Springer Series in Emergence, Complexity, and Computation, 201
A complete 3D numerical study of the effects of pseudoscalar-photon mixing on quasar polarizations
We present the results of three-dimensional simulations of quasar
polarizations in the presence of pseudoscalar-photon mixing in the
intergalactic medium. The intergalactic magnetic field is assumed to be
uncorrelated in wave vector space but correlated in real space. Such a field
may be obtained if its origin is primordial. Furthermore we assume that the
quasars, located at cosmological distances, have negligible initial
polarization. In the presence of pseudoscalar-photon mixing we show, through a
direct comparison with observations, that this may explain the observed large
scale alignments in quasar polarizations within the framework of big bang
cosmology. We find that the simulation results give a reasonably good fit to
the observed data.Comment: 15 pages, 8 figures, significant changes, to appear in EPJ
Purcell enhancement of a deterministically coupled quantum dot in an SU-8 laser patterned photonic crystal heterostructure
Enhancement of single photon source emission through cavity quantum electrodynamics is key to the realization of applicable emitters in many quantum optics technologies. In this work, we present a flexible and convenient cavity fabrication process that writes a SU-8 microstrip onto a photonic crystal waveguide deterministically, in which InGaAs/GaAs quantum dots are present as emitters. The strip cavity is laser patterned at the location of a quantum dot with a chosen emission wavelength. Micro-photoluminescence studies are undertaken, which demonstrate an enhanced emission intensity by a factor of 2.1 with weak coupling to a single quantum dot, and time-resolved photoluminescence further shows a Purcell enhancement factor of 2.16. The fabrication process is, thus, verified as a reliable recipe to introduce deterministic cavity coupling to a chosen quantum dot
New results from the NA57 experiment
We report results from the experiment NA57 at CERN SPS on hyperon production
at midrapidity in Pb-Pb collisions at 158 GeV/ and 40 GeV/.
, and yields are compared with those from the STAR
experiment at the higher energy of the BNL RHIC. , , \
and preliminary transverse mass spectra are presented and interpreted
within the framework of a hydro-dynamical blast wave model.Comment: 8 pages, 3 figures, contribution to the proceedings of The XXXVIIIth
Rencontres de Moriond "QCD and High Energy Hadronic Interactions
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