7,245 research outputs found
Enhanced Instability of de Sitter Space in Einstein-Gauss-Bonnet Gravity
We show that the addition of a topological Gauss-Bonnet term to the
gravitational action can greatly increase the instability of four-dimensional
de Sitter space, by favoring the nucleation of black holes. The pair-production
rate given by the Euclidean action for the instanton takes the form exp(Delta
S) where S is the entropy in Einstein-Gauss-Bonnet theory. The coefficient of
the Gauss-Bonnet term in the action sets a stability bound on the curvature of
empty de Sitter space. For that coefficient in the low-energy effective action
of heterotic string theory, the maximal curvature of de Sitter space is in
general much lower than the Planck scale.Comment: 8 page
Swift observations of the dwarf nova ASASSN-18fs
The All Sky Automated Survey for SuperNovae (ASAS-SN) reported a possible
Galactic dwarf nova ASASSN-18fs on 2018 March 19 at 13.2 mag in the V
band, with a quiescent magnitude of V17.6. Here we report on the follow-up
photometry using the {\it Neil Gehrels Swift Observatory}.Comment: Published by AAS Research Note
Variable quiescent state for the neutron-star X-ray transient SAX J1750.8-2900: not such a hot neutron star after all?
We monitored the neutron star low-mass X-ray binary SAX J1750.8-2900 after
the end of its 2015/2016 outburst using the X-ray Telescope (XRT) aboard Swift
to detect possible post-outburst 'rebrightenings', similar to those seen after
its 2008 outburst. We did not detect any rebrightening behaviour, suggesting
that the physical mechanism behind the rebrightening events is not always
active after each outburst of the source. Any model attempting to explain these
rebrightenings should thus be able to reproduce the different outburst profiles
of the source at different times. Surprisingly, our Swift/XRT observations were
unable to detect the source, contrary to previous Swift/XRT observations in
quiescence. We determined a temperature upper limit of 106 eV, much
colder than the post 2008 outburst value of 145 eV. We also report on an
archival Chandra observation of the source after its 2011 outburst and found a
temperature of 126 eV. These different temperatures, including the
non-detection very close after the end of the 2015/2016 outburst, are difficult
to explain in any model assuming we observe the cooling emission from a neutron
star core or an accretion-heated crust. We discuss our observations in the
context of a change in envelope (the outer 100 m of the crust)
composition and (possibly in combination with) a cooling crust. Both hypotheses
cannot explain our results unless potentially unrealistic assumptions are made.
Irrespective of what causes the temperature variability, it is clear that the
neutron star in SAX J1750.8-2900 may not be as hot as previously assumed.Comment: Accepted for publication in MNRA
Perturbations of vortex ring pairs
We study pairs of co-axial vortex rings starting from the action for a
classical bosonic string in a three-form background. We complete earlier work
on the phase diagram of classical orbits by explicitly considering the case
where the circulations of the two vortex rings are equal and opposite. We then
go on to study perturbations, focusing on cases where the relevant
four-dimensional transfer matrix splits into two-dimensional blocks. When the
circulations of the rings have the same sign, instabilities are mostly limited
to wavelengths smaller than a dynamically generated length scale at which
single-ring instabilities occur. When the circulations have the opposite sign,
larger wavelength instabilities can occur.Comment: 62 pages, 21 figure
Segmented strings and the McMillan map
We present new exact solutions describing motions of closed segmented strings
in in terms of elliptic functions. The existence of analytic
expressions is due to the integrability of the classical equations of motion,
which in our examples reduce to instances of the McMillan map. We also obtain a
discrete evolution rule for the motion in of arbitrary bound states of
fundamental strings and D1-branes in the test approximation.Comment: 18 page
Massage Therapy in Outpatient Cancer Care: A Metropolitan Area Analysis.
Massage offers cancer patients general quality of life benefits as well as alleviation of cancer-related symptoms/cancer-treatment-related symptoms including pain, anxiety, and fatigue. Little is known about whether massage is accessible to cancer patients who receive treatment in the outpatient setting and how massage is incorporated into the overall cancer treatment plan. Outpatient cancer centers (n = 78) in a single metropolitan area were included this mixed-methods project that included a systematic analysis of website information and a telephone survey. Massage was offered at only 40 centers (51.3% of total). A range of massage modalities were represented, with energy-based therapies (Reiki and Therapeutic Touch) most frequently provided. Although massage therapists are licensed health care providers in the states included in this analysis, massage was also provided by nurses, physical therapists, and other health care professionals
O(N) and O(N) and O(N)
Three related analyses of theory with symmetry are presented.
In the first, we review the model over the -adic numbers and the
discrete renormalization group transformations which can be understood as spin
blocking in an ultrametric context. We demonstrate the existence of a
Wilson-Fisher fixed point using an expansion, and we show how to
obtain leading order results for the anomalous dimensions of low dimension
operators near the fixed point. Along the way, we note an important aspect of
ultrametric field theories, which is a non-renormalization theorem for kinetic
terms. In the second analysis, we employ large methods to establish
formulas for anomalous dimensions which are valid equally for field theories
over the -adic numbers and field theories on . Results for
anomalous dimensions agree between the first and second analyses when they can
be meaningfully compared. In the third analysis, we consider higher derivative
versions of the model on , the simplest of which has been
studied in connection with spatially modulated phases. Our general formula for
anomalous dimensions can still be applied. Analogies with two-derivative
theories hint at the existence of some interesting unconventional field
theories in four real Euclidean dimensions.Comment: 44 pages, 8 figure
An Analysis on CSR Reporting Practices of Asian Paints Limited
This paper studies the CSR reporting practices of Asian Paints Limited for the period of five years from 2017-18 to 2021-22. The objective of this paper is to study CSR fund allocation and CSR amount spent on various CSR activities of Asian Paints Limited. Descriptive research design and content analysis method is used by the researcher for the study. The result shows that Asian Paints Limited is not able to spent full amount of CSR in the financial year 2017-18, 2020-21 and 2021-22 whereas able to spent full amount of CSR in the financial year 2018-19 and 2019-20. Further the result also shows that Asian Paints Limited is spending most of the amount of CSR in Vocational Skills and spending very less amount in CSR activities like Education, HealthCare, Disaster Management, Safe Drinking Water and Prime Minister National Relief Fund
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