139 research outputs found
General solutions of the Wess-Zumino consistency condition for the Weyl anomalies
The general solutions of the Wess-Zumino consistency condition for the
conformal (or Weyl, or trace) anomalies are derived. The solutions are
obtained, in arbitrary dimensions, by explicitly computing the cohomology of
the corresponding Becchi-Rouet-Stora-Tyutin differential in the space of
integrated local functions at ghost number unity. This provides a purely
algebraic, regularization-independent classification of the Weyl anomalies in
arbitrary dimensions. The so-called type-A anomaly is shown to satisfy a
non-trivial descent of equations, similarly to the non-Abelian chiral anomaly
in Yang-Mills theory.Comment: 9 pages. RevTeX fil
Gravitational excitons from extra dimensions
Inhomogeneous multidimensional cosmological models with a higher dimensional
space-time manifold are investigated under dimensional reduction. In the
Einstein conformal frame, small excitations of the scale factors of the
internal spaces near minima of an effective potential have a form of massive
scalar fields in the external space-time. Parameters of models which ensure
minima of the effective potentials are obtained for particular cases and masses
of gravitational excitons are estimated.Comment: Revised version --- 12 references added, Introduction enlarged, 20
pages, LaTeX, to appear in Phys.Rev.D56 (15.11.97
Euler Top Dynamics of Nambu-Goto P-Branes
We propose a method to obtain new exact solutions of spinning p-branes in
flat space-times for any p, which manifest themselves as higher dimensional
Euler Tops and minimize their energy functional. We provide concrete examples
for the case of spherical topology S^{2}, S^{3} and rotational symmetry
\prod_{i}SO(q_{i}). In the case of toroidal topology T^{2}, T^{3} the
rotational symmetry is \prod SU(q_{i}) and m target dimensions are compactified
on the torus T^{m} . By double dimensional reduction the Light Cone
Hamiltonians of T^{2}, T^{3} reduce to those of closed string S^{1} and T^{2}
membranes respectively. The solutions are interpreted as non-perturbative
spinning soliton states of type IIA-IIB superstrings.Comment: 33 pages, LATEX; more typos corrected; some equation numbering
correction
2017 American Heart Association Focused Update on Pediatric Basic Life Support and Cardiopulmonary Resuscitation Quality: An Update to the American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care
This focused update to the American Heart Association guidelines for cardiopulmonary resuscitation (CPR) and emergency cardiovascular care follows the Pediatric Task Force of the International Liaison Committee on Resuscitation evidence review. It aligns with the International Liaison Committee on Resuscitation's continuous evidence review process, and updates are published when the International Liaison Committee on Resuscitation completes a literature review based on new science. This update provides the evidence review and treatment recommendation for chest compression-only CPR versus CPR using chest compressions with rescue breaths for children <18 years of age. Four large database studies were available for review, including 2 published after the "2015 American Heart Association Guidelines Update for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care." Two demonstrated worse 30-day outcomes with chest compression-only CPR for children 1 through 18 years of age, whereas 2 studies documented no difference between chest compression-only CPR and CPR using chest compressions with rescue breaths. When the results were analyzed for infants <1 year of age, CPR using chest compressions with rescue breaths was better than no CPR but was no different from chest compression-only CPR in 1 study, whereas another study observed no differences among chest compression-only CPR, CPR using chest compressions with rescue breaths, and no CPR. CPR using chest compressions with rescue breaths should be provided for infants and children in cardiac arrest. If bystanders are unwilling or unable to deliver rescue breaths, we recommend that rescuers provide chest compressions for infants and children
Dimensionless cosmology
Although it is well known that any consideration of the variations of
fundamental constants should be restricted to their dimensionless combinations,
the literature on variations of the gravitational constant is entirely
dimensionful. To illustrate applications of this to cosmology, we explicitly
give a dimensionless version of the parameters of the standard cosmological
model, and describe the physics of Big Bang Neucleosynthesis and recombination
in a dimensionless manner. The issue that appears to have been missed in many
studies is that in cosmology the strength of gravity is bound up in the
cosmological equations, and the epoch at which we live is a crucial part of the
model. We argue that it is useful to consider the hypothetical situation of
communicating with another civilization (with entirely different units),
comparing only dimensionless constants, in order to decide if we live in a
Universe governed by precisely the same physical laws. In this thought
experiment, we would also have to compare epochs, which can be defined by
giving the value of any {\it one} of the evolving cosmological parameters. By
setting things up carefully in this way one can avoid inconsistent results when
considering variable constants, caused by effectively fixing more than one
parameter today. We show examples of this effect by considering microwave
background anisotropies, being careful to maintain dimensionlessness
throughout. We present Fisher matrix calculations to estimate how well the fine
structure constants for electromagnetism and gravity can be determined with
future microwave background experiments. We highlight how one can be misled by
simply adding to the usual cosmological parameter set
Therapeutic jurisprudence and procedural justice in Scottish drug courts
Scotland, like other Western jurisdictions, has recently witnessed the development of problem-solving courts aimed at responding more effectively to issues that underlie certain types of offending behaviour. The first to be established were two pilot Drug Courts which drew upon experience of Scottish Drug Treatment and Testing Orders. In common with Drug Courts elsewhere, the Scottish pilots combined treatment, drug testing, supervision and judicial oversight. This article focuses upon the role of judicial involvement in the ongoing review of Drug Court participants’ progress, drawing upon court observation and interviews with offenders and Drug Court professionals. Drug Court dialogues were typically encouraging on the part of sheriffs, aimed at recognising and reinforcing the progress made by participants and motivating then to maintain and build upon their achievements to date, while participants were generally responsive to the positive feedback they received from the sheriffs as their orders progressed. Interactions within the Scottish Drug Courts reflect key features of procedural justice (Tyler, 1990), including ethicality, efforts to be fair and representation. By contributing to enhanced perceptions of procedural justice, Drug Court dialogues may, it is argued, increase the perceived legitimacy of the court and by so doing encourage increased compliance with treatment and desistance from crime
Field Measurements of Terrestrial and Martian Dust Devils
Surface-based measurements of terrestrial and martian dust devils/convective vortices provided from mobile and stationary platforms are discussed. Imaging of terrestrial dust devils has quantified their rotational and vertical wind speeds, translation speeds, dimensions, dust load, and frequency of occurrence. Imaging of martian dust devils has provided translation speeds and constraints on dimensions, but only limited constraints on vertical motion within a vortex. The longer mission durations on Mars afforded by long operating robotic landers and rovers have provided statistical quantification of vortex occurrence (time-of-sol, and recently seasonal) that has until recently not been a primary outcome of more temporally limited terrestrial dust devil measurement campaigns. Terrestrial measurement campaigns have included a more extensive range of measured vortex parameters (pressure, wind, morphology, etc.) than have martian opportunities, with electric field and direct measure of dust abundance not yet obtained on Mars. No martian robotic mission has yet provided contemporaneous high frequency wind and pressure measurements. Comparison of measured terrestrial and martian dust devil characteristics suggests that martian dust devils are larger and possess faster maximum rotational wind speeds, that the absolute magnitude of the pressure deficit within a terrestrial dust devil is an order of magnitude greater than a martian dust devil, and that the time-of-day variation in vortex frequency is similar. Recent terrestrial investigations have demonstrated the presence of diagnostic dust devil signals within seismic and infrasound measurements; an upcoming Mars robotic mission will obtain similar measurement types
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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