1,672 research outputs found
Black Hole Physics from Liouville Theory
In a previous paper it was shown that the quantum consistency conditions for
the dilaton-gravity theory of Callan et al., imply that the cosmological
constant term undergoes a dilaton dependent renormalization, in such a manner
that the theory can be written as a Liouville-like theory. In this paper we
discuss the physical interpretation of the solutions of this theory. In
particular we demonstrate explicitly how quantum corrections tame the black
hole singularity. Also under the assumption that in asymptotically Minkowski
coordinates, there are no incoming or outgoing ghosts, we show that the Hawking
radiation rate is independent of the number of matter fields and is determined
by the ghost conformal anomaly.Comment: 15 pages, phyzzx (Note on Bondi mass added to end of paper
Proposal for Higgs and Superpartner Searches at the LHCb Experiment
The spectrum of supersymmetric theories with R-parity violation are much more
weakly constrained than that of supersymmetric theories with a stable
neutralino. We investigate the signatures of supersymmetry at the LHCb
experiment in the region of parameter space where the neutralino decay leaves a
displaced vertex. We find sensitivity to squark production up to squark masses
of order 1 TeV. We note that if the Higgs decays to neutralinos in this
scenario, LHCb should see the lightest Higgs boson before ATLAS and CMS.Comment: 7 pages, 5 figure
Zn Diffusion and α-Fe(Zn) Layer Growth During Annealing of Zn-Coated B Steel
Direct hot press forming of Zn-coated 22MnB5 steels is impeded by micro-cracks that occur in the substrate due to the presence of Zn during the forming process. A study was therefore undertaken to quantify concentration of Zn across the α-Fe(Zn) coating and on grain boundaries in the α-Fe(Zn) layer and the underlying γ-Fe(Zn) substrate after isothermal annealing of Zn-coated 22MnB5 at 1173 K (900 °C) and to link the Zn distribution to the amount and type of micro-cracks observed in deformed samples. Finite difference model was developed to describe Zn diffusion and the growth of the α-Fe(Zn) layer. The penetration of Zn into the γ-Fe(Zn) substrate after 600 seconds annealing at 1173 K (900 °C) through bulk diffusion is estimated to be 3 μm, and the diffusion depth of Zn on the γ-Fe(Zn) grain boundaries is estimated to be 6 μm, which is significantly shorter than the maximum length (15 to 50 μm) of the micro-cracks formed in the severely stressed conditions, indicating that the Zn diffusion into the γ-Fe(Zn) from the α-Fe(Zn) during annealing is not correlated to the depth of micro-cracks. On the other hand, the maximum amount of Zn present in α-Fe(Zn) layer decreases with annealing time as the layer grows and Zn oxidizes, and the amount of Zn-enriched areas inside the α-Fe(Zn) layer is reduced leading to reduced length of cracking. Solid-Metal-Induced Embrittlement mechanism is proposed to explain the benefit of extended annealing on reduced depth of micro-crack penetration into the γ-Fe(Zn) substrate
Solar Neutrinos with Three Flavor Mixings
The recent 71Ga solar neutrino observation is combined with the 37Cl and
Kamiokande-II observations in an analysis for neutrino masses and mixings. The
allowed parameter region is found for matter enhanced mixings among all three
neutrino flavors. Distortions of the solar neutrino spectrum unique to three
flavors are possible and may be observed in continuing and next generation
experiments.Comment: August 1992 (Revised) PURD-TH-92-
Ergodic properties of a model for turbulent dispersion of inertial particles
We study a simple stochastic differential equation that models the dispersion
of close heavy particles moving in a turbulent flow. In one and two dimensions,
the model is closely related to the one-dimensional stationary Schroedinger
equation in a random delta-correlated potential. The ergodic properties of the
dispersion process are investigated by proving that its generator is
hypoelliptic and using control theory
Exploring General Gauge Mediation
We explore various aspects of General Gauge Mediation(GGM). We present a
reformulation of the correlation functions used in GGM, and further elucidate
their IR and UV properties. Additionally we clarify the issue of UV sensitivity
in the calculation of the soft masses in the MSSM, highlighting the role of the
supertrace over the messenger spectrum. Finally, we present weakly coupled
messenger models which fully cover the parameter space of GGM. These examples
demonstrate that the full parameter space of GGM is physical and realizable.
Thus it should be considered a valid basis for future phenomenological
explorations of gauge mediation.Comment: 27 pages, minor changes, typos fixed in appendix
Singapore's health-care system:key features, challenges, and shifts
Since Singapore became an independent nation in 1965, the development of its health-care system has been underpinned by an emphasis on personal responsibility for health, and active government intervention to ensure access and affordability through targeted subsidies and to reduce unnecessary costs. Singapore is achieving good health outcomes, with a total health expenditure of 4·47% of gross domestic product in 2016. However, the health-care system is contending with increased stress, as reflected in so-called pain points that have led to public concern, including shortages in acute hospital beds and intermediate and long-term care (ILTC) services, and high out-of-pocket payments. The main drivers of these challenges are the rising prevalence of non-communicable diseases and rapid population ageing, limitations in the delivery and organisation of primary care and ILTC, and financial incentives that might inadvertently impede care integration. To address these challenges, Singapore's Ministry of Health implemented a comprehensive set of reforms in 2012 under its Healthcare 2020 Masterplan. These reforms substantially increased the capacity of public hospital beds and ILTC services in the community, expanded subsidies for primary care and long-term care, and introduced a series of financing health-care reforms to strengthen financial protection and coverage. However, it became clear that these measures alone would not address the underlying drivers of system stress in the long term. Instead, the system requires, and is making, much more fundamental changes to its approach. In 2016, the Ministry of Health encapsulated the required shifts in terms of the so-called Three Beyonds—namely, beyond health care to health, beyond hospital to community, and beyond quality to value
Coupling of thermal and mass diffusion in regular binary thermal lattice-gases
We have constructed a regular binary thermal lattice-gas in which the thermal
diffusion and mass diffusion are coupled and form two nonpropagating diffusive
modes. The power spectrum is shown to be similar in structure as for the one in
real fluids, in which the central peak becomes a combination of coupled entropy
and concentration contributions. Our theoretical findings for the power spectra
are confirmed by computer simulations performed on this model.Comment: 5 pages including 3 figures in RevTex
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