Gravitational Thermodynamics of Space-time Foam in One-loop Approximation

We show from one-loop quantum gravity and statistical thermodynamics that the thermodynamics of quantum foam in flat space-time and Schwarzschild space-time is exactly the same as that of Hawking-Unruh radiation in thermal equilibrium. This means we show unambiguously that Hawking-Unruh thermal radiation should contain thermal gravitons or the contribution of quantum space-time foam. As a by-product, we give also the quantum gravity correction in one-loop approximation to the classical black hole thermodynamics.Comment: 7 pages, revte

Structure and Thermodynamical Properties of Zirconium hydrides from first-principle

Zirconium alloys are used as nuclear fuel cladding material due to their mechanical and corrosion resistant properties together with their favorable cross-section for neutron scattering. At running conditions, however, there will be an increase of hydrogen in the vicinity of the cladding surface at the water side of the fuel. The hydrogen will diffuse into the cladding material and at certain conditions, such as lower temperatures and external load, hydrides will precipitate out in the material and cause well known embrittlement, blistering and other unwanted effects. Using phase-field methods it is now possible to model precipitation build-up in metals, for example as a function of hydrogen concentration, temperature and external load, but the technique relies on input of parameters, such as the formation energy of the hydrides and matrix. To that end, we have computed, using the density functional theory (DFT) code GPAW, the latent heat of fusion as well as solved the crystal structure for three zirconium hydride polymorphs: \delta-ZrH1.6, \gamma-ZrH, and \epsilon-ZrH2.Comment: 9 pages, 9 figures, 15th Int. Conf. Environmental Degradation of Materials in Nuclear Power Systems-water reactors Uses graficx, subfigure, threeparttable (2012

On the Radiatively Induced Lorentz and CPT Violating Chern-Simons Term

The radiatively induced Lorentz and CPT violating Chern-Simons terms in QED is calculated based on the recently developed loop regularization method [Y.L. Wu, Int.J.Mod.Phys.A18 (2003) 5363, hep-th/0209021; Y.L. Wu, Mod.Phys.Lett.A19 (2004) 2191, hep-th/0311082] for quantum field theories. It enables us to make general comments on the various results in literature and obtain a consistent result when simultaneously combining the evaluation for the chiral anomaly which has a unique form once the vector current is kept conserved.Comment: 10 pages, no figures, published versio

A clinico-pathologic review of 56 cases of ossifying fibroma of the jaws with emphasis on the histomorphologic variations

Objective: This study aims at contributing to the definitive diagnosis of ossifying fibroma (OF) based on histomorphological features. The study also aims to determine some demographic features of OF, common sites of occurrence and to determine whether behavior correlates well with the histomorphological variations seen in the lesion.Materials and Methods: A total of 80 patients who were diagnosed either as cementifying fibroma CF, OF and cemento.ossifying fibroma (COF) of the jaws from the files of the Oral Pathology Department of the University of the Witwatersrand Dental School were retrieved and the histology slides of each case were reviewed with the most recent diagnostic criteria for OF and the authors additional criteria. A total of 56 cases that met the set criteria were analyzed.Results: The patients were clustered within the third and fourth decades of life (n = 39, 69.6%). Majority of the patients were black (83.93%), whereas the rest were whites (12.50%) and Asians (3.57%). There were 17 males (30.4%) and 39 females (69.6%), giving a male to female ratio of 1:2.3. Most of the lesions (70.3%) occurred in the mandible, involving the premolar molar region (56.7%). Scanty fibrous tissues in highly cellular lesions were found in 36 (64.3%) of the cases. There were globular, dystrophic or granular calcifications mixed with irregularly shaped trabeculae of lamellar or cellular woven bone or osteoid were found, in 36 (64.3%) cases. Conclusion: Demographic data, clinicoradiologic features, combined with histopathology will continue to be relevantin the definitive diagnosis of OF and in predicting its behavior. Highly aggr essive lesions with shorter duration in people below 15 years  were called juvenile OF and treated as such, while OF applies to other conventional ones.Key words: Clinical-features, histomorphology, jaws, ossifying fibrom

Strengthened currents override the effect of warming on lobster larval dispersal & survival.

Human-induced climate change is projected to increase ocean temperature and modify circulation patterns, with potential widespread implications for the transport and survival of planktonic larvae of marine organisms. Circulation affects the dispersal of larvae, whereas temperature impacts larval development and survival. However, the combined effect of changes in circulation and temperature on larval dispersal and survival has rarely been studied in a future climate scenario. Such understanding is crucial to predict future species distributions, anticipate ecosystem shifts and design effective management strategies. We simulate contemporary (1990s) and future (2060s) dispersal of lobster larvae using an eddy-resolving ocean model in south-eastern Australia, a region of rapid ocean warming. Here we show that the effects of changes in circulation and temperature can counter each other: ocean warming favours the survival of lobster larvae, whereas a strengthened western boundary current diminishes the supply of larvae to the coast by restricting cross-current larval dispersal. Furthermore, we find that changes in circulation have a stronger effect on connectivity patterns of lobster larvae along south-eastern Australia than ocean warming in the future climate so that the supply of larvae to the coast reduces by ~4% and the settlement peak shifts poleward by ~270 km in the model simulation. Thus, ocean circulation may be one of the dominant factors contributing to climate-induced changes of species ranges

Electroweak Symmetry Breaking induced by Dark Matter

The mechanism behind Electroweak Symmetry Breaking (EWSB) and the nature of dark matter (DM) are currently among the most important issues in high energy physics. Since a natural dark matter candidate is a weakly interacting massive particle or WIMP, with mass around the electroweak scale, it is clearly of interest to investigate the possibility that DM and EWSB are closely related. In the context of a very simple extension of the Standard Model, the Inert Doublet Model, we show that dark matter could play a crucial role in the breaking of the electroweak symmetry. In this model, dark matter is the lightest component of an inert scalar doublet. The coupling of the latter with the Standard Model Higgs doublet breaks the electroweak symmetry at one-loop, "a la Coleman-Weinberg". The abundance of dark matter, the breaking of the electroweak symmetry and the constraints from electroweak precision measurements can all be accommodated by imposing an (exact or approximate) custodial symmetry.Comment: 4 pages, no figure, one tabl

The Four-Fermi Model in Three Dimensions at Non-Zero Density and Temperature

The Four Fermi model with discrete chiral symmetry is studied in three dimensions at non-zero chemical potential and temperature using the Hybrid Monte Carlo algorithm. The number of fermion flavors is chosen large $(N_f=12)$ to compare with analytic results. A first order chiral symmetry restoring transition is found at zero temperature with a critical chemical potential $\mu_c$ in good agreement with the large $N_f$ calculations. The critical index $\nu$ of the correlation length is measured in good agreement with analytic calculations. The two dimensional phase diagram (chemical potential vs. temperature) is mapped out quantitatively. Finite size effects on relatively small lattices and non-zero fermion mass effects are seen to smooth out the chiral transition dramatically.Comment: 21 pages, sorry, no figure