134 research outputs found
A tachyonic scalar field with mutually interacting components
We investigate the tachyonic cosmological potential in two
different cases of the quasi-exponential expansion of universe and discuss
various forms of interaction between the two components---matter and the
cosmological constant--- of the tachyonic scalar field, which leads to the
viable solutions of their respective energy densities. The distinction among
the interaction forms is shown to appear in the diagnostic. Further,
the role of the high- and low-redshift observations of the Hubble parameter is
discussed to determine the proportionality constants and hence the correct form
of matter--cosmological constant interaction.Comment: 14 page
ENGAGING CLINICIANS IN A PRE-IMPLEMENTATION ASSESSMENT OF THE WOMEN & PERSON-EMPOWERED COMMUNITY ACCESS FOR REPRODUCTIVE EQUITY (WE CARE) INTERVENTION
Objectives: To assess clinicians’ perspectives on WE CARE (an emergency department (ED) family planning counseling and referral intervention that uses an online health tool and community health workers) to inform intervention design for implementation.
Methods: We conducted one-on-one, semi-structured interviews with Emergency Medicine, Family Medicine, and Obstetrics & Gynecology clinicians until thematic saturation. The Consolidated Framework for Implementation Research (CFIR) informed the interview guide and was used to code all transcripts. A CFIR expert conducted an external coding audit.
Results: We interviewed 30 clinicians (female (77%), ED staff (47%), white (63%), and attending physicians (43%)). WE CARE was highly acceptable. Dominant CFIR domains include: (1) Clinicians suggested Design Quality and Packaging modifications, particularly the referral processes, to promote successful implementation; (2) transportation and insurance were essential Patient Needs and Resources; (3) WE CARE was Compatible with the Value of “no missed opportunity” to help patients; (4) Compatibility with Work Processes – WE CARE posed scheduling and reimbursement challenges to clinics; (5) Clinicians expressed concerns about an ED Culture of reproductive health frustrations, resistance to change, and competing priorities. Others identified the ED “safety net” culture and long wait times as assets to the intervention; (6) WE CARE had a significant Relative Advantage over the status quo. A few clinicians identified more advantageous alternatives (e.g., WE CARE in the clinic, home, or community settings); (7) Engaging Key Stakeholders throughout the hospital was a critical implementation element.
Conclusions: Clinicians contextualized several implementation constructs relevant to designing and implementing an ED family planning intervention
Unified phantom cosmology: inflation, dark energy and dark matter under the same standard
Phantom cosmology allows to account for dynamics and matter content of the
universe tracing back the evolution to the inflationary epoch, considering the
transition to the non-phantom standard cosmology (radiation/matter dominated
eras) and recovering the today observed dark energy epoch. We develop the
unified phantom cosmology where the same scalar plays the role of early time
(phantom) inflaton and late-time Dark Energy. The recent transition from
decelerating to accelerating phase is described too by the same scalar field.
The (dark) matter may be embedded in this scheme, giving the natural solution
of the coincidence problem. It is explained how the proposed unified phantom
cosmology can be fitted against the observations which opens the way to define
all the important parameters of the model.Comment: LaTeX file, 9 pages, no figure, version to appear in PL
Cosmological evolution of interacting dark energy in Lorentz violation
The cosmological evolution of an interacting scalar field model in which the
scalar field interacts with dark matter, radiation, and baryon via Lorentz
violation is investigated. We propose a model of interaction through the
effective coupling . Using dynamical system analysis, we study the
linear dynamics of an interacting model and show that the dynamics of critical
points are completely controlled by two parameters. Some results can be
mentioned as follows. Firstly, the sequence of radiation, the dark matter, and
the scalar field dark energy exist and baryons are sub dominant. Secondly, the
model also allows the possibility of having a universe in the phantom phase
with constant potential. Thirdly, the effective gravitational constant varies
with respect to time through . In particular, we consider a simple
case where has a quadratic form and has a good agreement with the
modified CDM and quintessence models. Finally, we also calculate the
first post--Newtonian parameters for our model.Comment: 14 pages, published versio
Interacting new agegraphic Phantom model of dark energy in non-flat universe
In this paper we consider the new agegraphic model of interacting dark energy
in non-flat universe. We show that the interacting agegraphic dark energy can
be described by a phantom scalar field. Then we show this phantomic description
of the agegraphic dark energy and reconstruct the potential of the phantom
scalar field.Comment: 8 pages, no figur
Interacting polytropic gas model of phantom dark energy in non-flat universe
By introducing the polytropic gas model of interacting dark energy, we obtain
the equation of state for the polytropic gas energy density in a non-flat
universe. We show that for even polytropic index by choosing
, one can obtain , which
corresponds to a universe dominated by phantom dark energy.Comment: 7 page
Statefinder diagnostic and stability of modified gravity consistent with holographic and new agegraphic dark energy
Recently one of us derived the action of modified gravity consistent with the
holographic and new-agegraphic dark energy. In this paper, we investigate the
stability of the Lagrangians of the modified gravity as discussed in [M. R.
Setare, Int. J. Mod. Phys. D 17 (2008) 2219; M. R. Setare, Astrophys. Space
Sci. 326 (2010) 27]. We also calculate the statefinder parameters which
classify our dark energy model.Comment: 12 pages, 2 figures, accepted by Gen. Relativ. Gravi
Interacting entropy-corrected new agegraphic tachyon, K-essence and dilaton scalar field models of dark energy in non-flat universe
We present the new agegraphic dark energy model by introducing the quantum
corrections to the entropy-area relation in the setup of loop quantum gravity.
Employing this new form of dark energy, we investigate the model of interacting
dark energy and derive its equation of state. We study the correspondence
between the tachyon, K-essence and dilaton scalar field models with the
interacting entropy-corrected new agegraphic dark energy model in the non-flat
FRW universe. Moreover, we reconstruct the corresponding scalar potentials
which describe the dynamics of the scalar field models.Comment: 11 pages, typos fixe
Kepler-22b: A 2.4 Earth-radius Planet in the Habitable Zone of a Sun-like Star
A search of the time-series photometry from NASA's Kepler spacecraft reveals
a transiting planet candidate orbiting the 11th magnitude G5 dwarf KIC 10593626
with a period of 290 days. The characteristics of the host star are well
constrained by high-resolution spectroscopy combined with an asteroseismic
analysis of the Kepler photometry, leading to an estimated mass and radius of
0.970 +/- 0.060 MSun and 0.979 +/- 0.020 RSun. The depth of 492 +/- 10ppm for
the three observed transits yields a radius of 2.38 +/- 0.13 REarth for the
planet. The system passes a battery of tests for false positives, including
reconnaissance spectroscopy, high-resolution imaging, and centroid motion. A
full BLENDER analysis provides further validation of the planet interpretation
by showing that contamination of the target by an eclipsing system would rarely
mimic the observed shape of the transits. The final validation of the planet is
provided by 16 radial velocities obtained with HIRES on Keck 1 over a one year
span. Although the velocities do not lead to a reliable orbit and mass
determination, they are able to constrain the mass to a 3{\sigma} upper limit
of 124 MEarth, safely in the regime of planetary masses, thus earning the
designation Kepler-22b. The radiative equilibrium temperature is 262K for a
planet in Kepler-22b's orbit. Although there is no evidence that Kepler-22b is
a rocky planet, it is the first confirmed planet with a measured radius to
orbit in the Habitable Zone of any star other than the Sun.Comment: Accepted to Ap
Cosmological evolution and statefinder diagnostic for new holographic dark energy model in non flat universe
In this paper, the holographic dark energy model with new infrared cut-off
proposed by Granda and Oliveros has been investigated in spatially non flat
universe. The dependency of the evolution of equation of state, deceleration
parameter and cosmological evolution of Hubble parameter on the parameters of
new HDE model are calculated. Also, the statefinder parameters and in
this model are derived and the evolutionary trajectories in plane are
plotted. We show that the evolutionary trajectories are dependent on the model
parameters of new HDE model. Eventually, in the light of SNe+BAO+OHD+CMB
observational data, we plot the evolutionary trajectories in and
planes for best fit values of the parameters of new HDE model.Comment: 11 pages, 5 figures, Accepted by Astrophys. Space Sc
- …