1,264 research outputs found
Duality for massive spin two theories in arbitrary dimensions
Using the parent Lagrangian approach we construct a dual formulation, in the
sense originally proposed by Curtright and Freund, of a massive spin two
Fierz-Pauli theory in arbitrary dimensions . This is achieved in terms of a
mixed symmetry tensor , without the need of
auxiliary fields. The relation of this method with an alternative formulation
based on a gauge symmetry principle proposed by Zinoviev is elucidated. We show
that the latter formulation in four dimensions, with a given gauge fixing
together with a definite sequence of auxiliary fields elimination via their
equations of motion, leads to the parent Lagrangian already considered by West
completed by a Fierz-Pauli mass term, which in turns yields the
Curtright-Freund action. This motivates our generalization to arbitrary
dimensions leading to the corresponding extension of the four dimensional
result. We identify the transverse true degrees of freedom of the dual theory
and verify that their number is in accordance with those of the massive
Fierz-Pauli field.Comment: 14 pages, no figures, revtex 4. Some new comments and explanations
have been added and the notation homogeneize
An extended solution space for Chern-Simons gravity: the slowly rotating Kerr black hole
In the Einstein-Cartan formulation, an iterative procedure to find solutions
in non-dynamical Chern-Simons (CS) gravity in vacuum is proposed. The
iterations, in powers of a small parameter which codifies the CS
coupling, start from an arbitrary torsionless solution of Einstein equations.
With Schwarzschild as the zeroth-order choice, we derive a second-order
differential equation for the corrections to the metric,
for an arbitrary zeroth-order embedding parameter. In particular, the slowly
rotating Kerr metric is an solution in either the
canonical or the axial embeddings.Comment: 5 pages, PRD accepte
Recommended from our members
Assessment of 21st Century Climate Change Projections in Tropical South America and the Tropical Andes
The tropical Andes are one of the regions where climate change has been most evident. This is consistent with the notion that tropical high-elevation mountains will be more affected by warming. One of the main impacts of this warming is the retreat of glaciers; a process that may affect the availability of water for human consumption, irrigation and power production.
This study presents results related to the most important changes in climate that might be expected in tropical South America, but especially in the tropical Andes, at the end of the 21st century. Results are provided by the comparison of two Regional Climate Model simulations based on the Hadley Center Regional Climate Modeling System, PRECIS. A medium-high CO2 emission scenario simulation for the period 2071-2100 (A2) is compared to a base-line mean climate state simulation for the 1961-1990 period. In addition, some results using a low-medium CO2 emission scenario (B2) are also presented for comparison.
Results show a clear warming trend over South America reaching up to 8º C in northeastern South America. In this same place the largest decrease in precipitation and cloud cover are found. Along the Andes warming reaches up to 7º C in Cordillera Blanca in the A2 scenario and precipitation presents a mixed pattern of increases and decreases across the Cordillera. Warming is expected to be larger at higher elevations and significant changes in temperature variability are expected along both slopes of the Andes based on the A2 scenario. In addition both scenarios (B2 and A2) show an amplification of free tropospheric warming at higher altitudes. Finally, pressure-longitude cross-sections of zonal winds and vertical velocities at the latitudes of the Altiplano and the Cordillera Blanca show weakened mid- and upper tropospheric easterlies and strengthened westerlies in the A2 scenario. This change in the atmospheric circulation is conducive to a decrease in precipitation in those areas, and consequently may negatively impact glacier mass balance.
In summary the obtained results reveal that anthropogenic climate change, as predicted with the A2 scenario, may constitute a serious threat to the survival of many tropical glaciers along the Andes Cordillera
Evidence for Quasar Activity Triggered by Galaxy Mergers in HST Observations of Dust-reddened Quasars
We present Hubble ACS images of thirteen dust reddened Type-1 quasars
selected from the FIRST/2MASS Red Quasar Survey. These quasars have high
intrinsic luminosities after correction for dust obscuration (-23.5 > M_B >
-26.2 from K-magnitude). The images show strong evidence of recent or ongoing
interaction in eleven of the thirteen cases, even before the quasar nucleus is
subtracted. None of the host galaxies are well fit by a simple elliptical
profile. The fraction of quasars showing interaction is significantly higher
than the 30% seen in samples of host galaxies of normal, unobscured quasars.
There is a weak correlation between the amount of dust reddening and the
magnitude of interaction in the host galaxy, measured using the Gini
coefficient and the Concentration index. Although few host galaxy studies of
normal quasars are matched to ours in intrinsic quasar luminosity, no evidence
has been found for a strong dependence of merger activity on host luminosity in
samples of the host galaxies of normal quasars. We thus believe that the high
merger fraction in our sample is related to their obscured nature, with a
significant amount of reddening occurring in the host galaxy. The red quasar
phenomenon seems to have an evolutionary explanation, with the young quasar
spending the early part of its lifetime enshrouded in an interacting galaxy.
This might be further indication of a link between AGN and starburst galaxies.Comment: 18 pages, 6 low resolution figures, accepted for publication in Ap
Neostigmine versus Sugammadex and the Relationship to Reintubation Rates in the PACU
Background Findings Discussion Reintubation in the post-anesthesia care unit (PACU) is a complication that may be related to residual neuromuscular blockade. Neostigmine and sugammadex have different pharmacokinetics that effect speed and completeness of reversal of paralysis. According to Tillquist et al. (2016) reintubation following general anesthesia in the PACU is associated with a 50% increased risk of mortality. Few studies have investigated the incidence rate of PACU reintubation and its possible relationship and choice of reversal medication.
Methods • Retrospective Observational Research Study. • This project was approved by the PSHMC Clinical Innovation and Research Council and deemed human subjects exempt by the Providence Health Care institutional review board. • Patient data was extracted from Epic electronic medical records and accessed from secured REDCap database. • Eligibility Criteria: • Inclusion – Patients \u3e 18 years of age undergoing general anesthesia, intubated at start of procedure and extubated by out of OR time between 2013 and 2019. • Descriptive analyses examined baseline group comparability, incidence of reintubation and reintubation risk factors in the study population. • Additional statistical analyses were conducted: a-priori power analysis, univariate, bivariate, and multivariable. • Time series examined rates of PACU reintubation over time, with stratification into low risk and high risk patient groups. • Risk factors associated with reintubation were extrapolated based upon Bruekmann et al. (2013) score for prediction of postoperative respiratory complications (SPORC).
Discussion Reintubation in the PACU is rare. Rates of reintubation increased in the years 2016 and 2017. Rates in 2019 were below levels observed in 2014. Patients were stratified into low risk (reintubation risk score 0-2) and high risk (\u3e3) groups. Reintubation rates peaked for high risk patients in 2016 and peaked for low risk patients in 2017. A reduction of reintubation in PACU was not associated with the utilization of sugammadex in comparison to neostigmine. Due to the lack of current research evidence investigating the relationship between reintubation rates and reversal medication, this retrospective observational research study aims to serve as a foundation for generating hypotheses for future randomized control trials that may inform treatment decisions in clinical practice.https://digitalcommons.psjhealth.org/other_pubs/1108/thumbnail.jp
Paper Session II-C - Legal Challenges in Realizing Interstellar Initiatives
Exploration of our solar system and beyond has barely begun. The challenges of space are limitless, and each addition to our ability to operate there opens new legal concerns between ourselves and our international partners. We are in fact living at the very beginning of time. Our descendants of far-off ages will use the legal framework we put in place to reach unimaginable opportunities. In the past our forefathers never envisioned the United States Constitution to be such a strong source of power for the government. Consequently We the people of the United States have the Bill of Rights. Will the legal framework we establish provide the guidance to extend beyond the solar system and journey to other stars?
In taking the logical steps in space to realize Space Exploration Initiative and beyond we must consider the legalities associated with birth, life, and death. Thus, the issue of birth on another planet is discussed. Would a lunar or Mars born space traveler obtain citizenship through the United Nations registry? To what earth bound land would this traveler be sovereign? The time of the birth, the day, and even the calendar year must be described in such a manner that when man does go beyond the solar system to other stars the legal framework established goes as well. Will the framework provide for genetic engineering to be realized in other worlds and not be suppressed by social and political earthbound ways
Two hard spheres in a pore: Exact Statistical Mechanics for different shaped cavities
The Partition function of two Hard Spheres in a Hard Wall Pore is studied
appealing to a graph representation. The exact evaluation of the canonical
partition function, and the one-body distribution function, in three different
shaped pores are achieved. The analyzed simple geometries are the cuboidal,
cylindrical and ellipsoidal cavities. Results have been compared with two
previously studied geometries, the spherical pore and the spherical pore with a
hard core. The search of common features in the analytic structure of the
partition functions in terms of their length parameters and their volumes,
surface area, edges length and curvatures is addressed too. A general framework
for the exact thermodynamic analysis of systems with few and many particles in
terms of a set of thermodynamic measures is discussed. We found that an exact
thermodynamic description is feasible based in the adoption of an adequate set
of measures and the search of the free energy dependence on the adopted measure
set. A relation similar to the Laplace equation for the fluid-vapor interface
is obtained which express the equilibrium between magnitudes that in extended
systems are intensive variables. This exact description is applied to study the
thermodynamic behavior of the two Hard Spheres in a Hard Wall Pore for the
analyzed different geometries. We obtain analytically the external work, the
pressure on the wall, the pressure in the homogeneous zone, the wall-fluid
surface tension, the line tension and other similar properties
The extraordinary mid-infrared spectral properties of FeLoBAL Quasars
We present mid-infrared spectra of six FeLoBAL QSOs at 1<z<1.8, taken with
the Spitzer space telescope. The spectra span a range of shapes, from hot dust
dominated AGN with silicate emission at 9.7 microns, to moderately obscured
starbursts with strong Polycyclic Aromatic Hydrocarbon (PAH) emission. The
spectrum of one object, SDSS 1214-0001, shows the most prominent PAHs yet seen
in any QSO at any redshift, implying that the starburst dominates the mid-IR
emission with an associated star formation rate of order 2700 solar masses per
year. With the caveats that our sample is small and not robustly selected, we
combine our mid-IR spectral diagnostics with previous observations to propose
that FeLoBAL QSOs are at least largely comprised of systems in which (a) a
merger driven starburst is ending, (b) a luminous AGN is in the last stages of
burning through its surrounding dust, and (c) which we may be viewing over a
restricted line of sight range.Comment: ApJ, accepte
Integral field spectroscopy of nearby QSOs II. The molecular gas content and condition for star formation
We present single-dish 12CO(1 − 0) and 12CO(2 − 1) observations for 14 low-redshift quasi-stellar objects (QSOs). In combination with optical integral field spectroscopy we study how the cold gas content relates to the star formation rate (SFR) and black hole accretion rate. 12CO(1 − 0) is detected in 8 of 14 targets and 12CO(2 − 1) is detected in 7 out of 11 cases. The majority of disc-dominated QSOs reveal gas fractions and depletion times well matching normal star forming systems. Two gas-rich major mergers show clear starburst signatures with higher than average gas fractions and shorter depletion times. Bulge-dominated QSO hosts are mainly undetected in 12CO(1 − 0) which corresponds, on average, to lower gas fractions than in disc-dominated counterparts. Their SFRs however imply shorter than average depletion times and higher star formation efficiencies. Negative QSO feedback through removal of cold gas seems to play a negligible role in our sample. We find a trend between black hole accretion rate and total molecular gas content for disc-dominated QSOs when combined with literature samples. We interpret this as an upper envelope for the nuclear activity and is well represented by a scaling relation between the total and circum-nuclear gas reservoir accessible for accretion. Bulge-dominated QSOs significantly differ from that scaling relation and appear uncorrelated with the total molecular gas content. This could be explained either by a more compact gas reservoir, blow out of the gas envelope through outflows, or a different ISM phase composition
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