1,484 research outputs found
Preliminary Results of Post-Disaster Archaeological Investigations at the Kasthamandap and within Hanuman Dhoka, Kathmandu Valley UNESCO World Heritage Property (Nepal)
Mass or Gravitationally Induced Neutrino Oscillations? -- A Comparison of \B Neutrino Flux Spectra in a Three--Generation Framework
Both gravitational and mass induced neutrino oscillation mechanisms provide
possible resolutions to the Solar Neutrino Problem. The distinguishing feature
between the two mechanisms is their dependence on the neutrino energy. We
investigate the implications of this by computing the \B neutrino spectrum as
determined from each mechanism using a realistic three--flavor evolution model.
We find that in the limit of small \tetau mixing angle, the differences are
significant enough to observe in future solar neutrino experiments.Comment: 14 pages, latex, epsf, 5 figures; to appear in Phys Lett
Post-Disaster Rescue Archaeological Investigations, Evaluations and Interpretations in the Kathmandu Valley World Heritage Property (Nepal): Observations and Recommendations from a UNESCO mission in 2015
Exploring Ancient Pashupati: Preliminary Results of Archaeological Surveys and Excavations at Bhandarkhal, Kathmandu Valley UNESCO World Heritage Property (Nepal)
Thermodynamics of Black Holes in Two (and Higher) Dimensions
A comprehensive treatment of black hole thermodynamics in two-dimensional
dilaton gravity is presented. We derive an improved action for these theories
and construct the Euclidean path integral. An essentially unique boundary
counterterm renders the improved action finite on-shell, and its variational
properties guarantee that the path integral has a well-defined semi-classical
limit. We give a detailed discussion of the canonical ensemble described by the
Euclidean partition function, and examine various issues related to stability.
Numerous examples are provided, including black hole backgrounds that appear in
two dimensional solutions of string theory. We show that the Exact String Black
Hole is one of the rare cases that admits a consistent thermodynamics without
the need for an external thermal reservoir. Our approach can also be applied to
certain higher-dimensional black holes, such as Schwarzschild-AdS,
Reissner-Nordstrom, and BTZ.Comment: 63 pages, 3 pdf figures, v2: added reference
Measuring the cosmological bulk flow using the peculiar velocities of supernovae
We study large-scale coherent motion in our universe using the existing Type
IA supernovae data. If the recently observed bulk flow is real, then some
imprint must be left on supernovae motion. We run a series of Monte Carlo
Markov Chain runs in various redshift bins and find a sharp contrast between
the z 0.05 data. The$z < 0.05 data are consistent with the bulk
flow in the direction (l,b)=({290^{+39}_{-31}}^{\circ},
{20^{+32}_{-32}}^{\circ}) with a magnitude of v_bulk = 188^{+119}_{-103} km/s
at 68% confidence. The significance of detection (compared to the null
hypothesis) is 95%. In contrast, z > 0.05 data (which contains 425 of the 557
supernovae in the Union2 data set) show no evidence for bulk flow. While the
direction of the bulk flow agrees very well with previous studies, the
magnitude is significantly smaller. For example, the Kashlinsky, et al.'s
original bulk flow result of v_bulk > 600 km/s is inconsistent with our
analysis at greater than 99.7% confidence level. Furthermore, our best-fit bulk
flow velocity is consistent with the expectation for the \Lambda CDM model,
which lies inside the 68% confidence limit.Comment: Version published in JCA
The radial BAO scale and Cosmic Shear, a new observable for Inhomogeneous Cosmologies
As an alternative explanation of the dimming of distant supernovae it has
recently been advocated that we live in a special place in the Universe near
the centre of a large spherical void described by a Lemaitre-Tolman-Bondi (LTB)
metric. In this scenario, the Universe is no longer homogeneous and isotropic,
and the apparent late time acceleration is actually a consequence of spatial
gradients. We propose in this paper a new observable, the normalized cosmic
shear, written in terms of directly observable quantities, and calculable in
arbitrary inhomogeneous cosmologies. This will allow future surveys to
determine whether we live in a homogeneous universe or not. In this paper we
also update our previous observational constraints from geometrical measures of
the background cosmology. We include the Union Supernovae data set of 307 Type
Ia supernovae, the CMB acoustic scale and the first measurement of the radial
baryon acoustic oscillation scale. Even though the new data sets are
significantly more constraining, LTB models -- albeit with slightly larger
voids -- are still in excellent agreement with observations, at chi^2/d.o.f. =
307.7/(310-4)=1.005. Together with the paper we also publish the updated
easyLTB code used for calculating the models and for comparing them to the
observations.Comment: 18 pages, 8 figures, the code can be downloaded at
http://www.phys.au.dk/~haugboel/software.shtm
Attachment Styles Within the Coach-Athlete Dyad: Preliminary Investigation and Assessment Development
The present preliminary study aimed to develop and examine the psychometric properties of a new sport-specific self-report instrument designed to assess athletes’ and coaches’ attachment styles. The development and initial validation comprised three main phases. In Phase 1, a pool of items was generated based on pre-existing self-report attachment instruments, modified to reflect a coach and an athlete’s style of attachment. In Phase 2, the content validity of the items was assessed by a panel of experts. A final scale was developed and administered to 405 coaches and 298 athletes (N = 703 participants). In Phase 3, confirmatory factor analysis of the obtained data was conducted to determine the final items of the Coach-Athlete Attachment Scale (CAAS). Confirmatory factor analysis revealed acceptable goodness of fit indexes for a 3-first order factor model as well as a 2-first order factor model for both the athlete and the coach data, respectively. A secure attachment style positively predicted relationship satisfaction, while an insecure attachment style was a negative predictor of relationship satisfaction. The CAAS revealed initial psychometric properties of content, factorial, and predictive validity, as well as reliability
The fundamental cycle of concept construction underlying various theoretical frameworks
In this paper, the development of mathematical concepts over time is considered. Particular reference is given to the shifting of attention from step-by-step procedures that are performed in time, to symbolism that can be manipulated as mental entities on paper and in the mind. The development is analysed using different theoretical perspectives, including the SOLO model and various theories of concept construction to reveal a fundamental cycle underlying the building of concepts that features widely in different ways of thinking that occurs throughout mathematical learning
Chameleon Gravity, Electrostatics, and Kinematics in the Outer Galaxy
Light scalar fields are expected to arise in theories of high energy physics
(such as string theory), and find phenomenological motivations in dark energy,
dark matter, or neutrino physics. However, the coupling of light scalar fields
to ordinary (or dark) matter is strongly constrained from laboratory, solar
system, and astrophysical tests of fifth force. One way to evade these
constraints in dense environments is through the chameleon mechanism, where the
field's mass steeply increases with ambient density. Consequently, the
chameleonic force is only sourced by a thin shell near the surface of dense
objects, which significantly reduces its magnitude.
In this paper, we argue that thin-shell conditions are equivalent to
"conducting" boundary conditions in electrostatics. As an application, we use
the analogue of the method of images to calculate the back-reaction (or
self-force) of an object around a spherical gravitational source. Using this
method, we can explicitly compute the violation of equivalence principle in the
outskirts of galactic haloes (assuming an NFW dark matter profile):
Intermediate mass satellites can be slower than their larger/smaller
counterparts by as much as 10% close to a thin shell.Comment: 17 pages, 3 figure
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