Constraining holographic inflation with WMAP

In a class of recently proposed models, the early universe is strongly coupled and described holographically by a three-dimensional, weakly coupled, super-renormalizable quantum field theory. This scenario leads to a power spectrum of scalar perturbations that differs from the usual empirical LCDM form and the predictions of generic models of single field, slow roll inflation. This spectrum is characterized by two parameters: an amplitude, and a parameter g related to the coupling constant of the dual theory. We estimate these parameters, using WMAP and other astrophysical data. We compute Bayesian evidence for both the holographic model and standard LCDM and find that their difference is not significant, although LCDM provides a somewhat better fit to the data. However, it appears that Planck will permit a definitive test of this holographic scenario.Comment: 24 pages, 9 figs, published versio

Trace Anomaly of Dilaton Coupled Scalars in Two Dimensions

Conformal scalar fields coupled to the dilaton appear naturally in two-dimensional models of black hole evaporation. We calculate their trace anomaly. It follows that an RST-type counterterm appears naturally in the one-loop effective action.Comment: 11 pages, LaTeX2e; submitted to Phys. Rev. Lett., minor change

Comparative study on utilization of charcoal, sawdust and rice husk in heating oven

Segun R. Bello1, T. A. Adegbulugbe2, P. S. N. Onyekwere1(1. Department of Agricultural Engineering, Federal College of Agriculture P.M.B 7008 Ishiagu, Ebonyi State Nigeria;2. Department of Agricultural Engineering, Federal College of Agriculture, Moor Plantation, Ibadan Nigeria)Abstract: Three biofuels, charcoal, sawdust and rice husk were used in furnace and their thermal capacities and efficiency were measured.  0.01 m3 of each fuel used in the tests were measured to and fired in the heating chamber until all the material completely burn out.  Air is supplied into the furnace by natural convection through air ducts.  The drying chamber was lagged (insulated) by a 25.4 mm air space between inner wall and the outer casing to prevent heat loss.  Three tests were replicated on each fuel and the mean values were used to evaluate heat flow by conduction, radiation and the thermal efficiency of the oven.  The performance characteristics of the machine, including overall efficiency, drying chamber efficiency and thermal capacities of each fuel were evaluated.  The results indicated that charcoal exhibit the highest combustion properties producing 2.54 kJ of energy per hour, sawdust produced 2.68 kJ while rice husk produced the least energy of 1.96 kJ per kg of burnt the products per hour.  The overall furnace efficiency of the oven was 75%, and drying chamber efficiency was 62%.  Characteristic temperature curves observed in the drying chamber indicated that charcoal attained very high thermal value within a short period than other fuels, while saw dust and rice husk had much lower heat buildup and longer temperature rise response time.  By these results, charcoal is suitable for short time heat processes such as baking and roasting, rice husk could be suitable for milk and fruit juice pasteurization, which require heat processing conditions between 63–85℃ for about 15 to  30 minutes.  Sawdust can be used in sterilization of meat, fish; soup etc.  Charcoal is more environmentally friendly than the other products because of the smokeless burning process thus suitable for indoor cooking.Keywords: Thermal capacity, heat process, thermal efficiency, differential, temperatureCitation: Segun R. Bello, T. A. Adegbulugbe, P. S. N. Onyekwere.  Comparative study on utilization of charcoal, sawdust and rice husk in heating oven.  Agric Eng Int: CIGR Journal, 2010, 12(2): 29-33.&nbsp

Dust Emission and Dynamics

When viewed from Earth, most of what we observe of a comet is dust. The influence of solar radiation pressure on the trajectories of dust particles depends on their cross-section to mass ratio. Hence solar radiation pressure acts like a mass spectrometer inside a cometary tail. The appearances of cometary dust tails have long been studied to obtain information on the dust properties, such as characteristic particle size and initial velocity when entering the tail. Over the past two decades, several spacecraft missions to comets have enabled us to study the dust activity of their targets at much greater resolution than is possible with a telescope on Earth or in near-Earth space, and added detail to the results obtained by the spacecraft visiting comet 1P/Halley in 1986. We now know that the dynamics of dust in the inner cometary coma is complex and includes a significant fraction of particles that will eventually fall back to the surface. The filamented structure of the near-surface coma is thought to result from a combination of topographic focussing of the gas flow, inhomogeneous distribution of activity across the surface, and projection effects. It is possible that some larger-than-centimetre debris contains ice when lifted from the surface, which can affect its motion. Open questions remain regarding the microphysics of the process that leads to the detachment and lifting of dust from the surface, the evolution of the dust while travelling away from the nucleus, and the extent to which information on the nucleus activity can be retrieved from remote observations of the outer coma and tail.Comment: Chapter in press for the book Comets III, edited by K. Meech and M. Combi, University of Arizona Pres

P16 expression and clinicopathological features of oral and oropharyngeal squamous cell carcinoma

Background: There is an epidemiological shift in head and neck squamous cell carcinoma (HNSCC) attributable to HPV infection. HPV positive HNSCC has unique biology, risk factors, clinicopathological characteristics and outcome. There is a large variation in the published prevalence of HPV-related HNSCCs in India ranging from 7 to 78.7%. This study aims to find the P16 expression in the oral cavity and oropharyngeal SCC, thereby prevalence of HPV in our setting and to define the clinicopathological characteristics of HPV positive tumours in our setting.Methods: 210 specimens of primary Oral squamous cell carcinoma (OSCC) and Oropharyngeal Squamous cell carcinoma (OPSCC) were included. Immunohistochemistry was done using monoclonal mouse p16 antibody. Clinical details of each case were collected. Analysis was done using SPSS software and the association of P16 and clinicopathological variables were calculated using Fishers exact test.Results: P16 positive expression is observed only in 1/122 (0.82%) of OSCC and 8/88 (9%) of OPSCC. P16 positivity showed significant association with Grade of tumor (p= 0.008) and histological variant of SCC (p=0.00). 77.7% of P16 positive tumours are Grade 2 and 66.6% of Basaloid SCC was P16 positive. There is no significant association between p16 expression and other variables (subsite, age, gender, alcoholism, smoking, betel chewing and stage).Conclusions: P16 positivity was higher in oropharyngeal than in oral cancer. However, the HPV positivity rates are lower than other parts of India

On the Lagrangian structure of 3D consistent systems of asymmetric quad-equations

Recently, the first-named author gave a classification of 3D consistent 6-tuples of quad-equations with the tetrahedron property; several novel asymmetric 6-tuples have been found. Due to 3D consistency, these 6-tuples can be extended to discrete integrable systems on Z^m. We establish Lagrangian structures and flip-invariance of the action functional for the class of discrete integrable systems involving equations for which some of the biquadratics are non-degenerate and some are degenerate. This class covers, among others, some of the above mentioned novel systems.Comment: 21 pp, pdfLaTe

Modeling the evolution space of breakage fusion bridge cycles with a stochastic folding process

Breakage-Fusion-Bridge cycles in cancer arise when a broken segment of DNA is duplicated and an end from each copy joined together. This structure then 'unfolds' into a new piece of palindromic DNA. This is one mechanism responsible for the localised amplicons observed in cancer genome data. The process has parallels with paper folding sequences that arise when a piece of paper is folded several times and then unfolded. Here we adapt such methods to study the breakage-fusion-bridge structures in detail. We firstly consider discrete representations of this space with 2-d trees to demonstrate that there are 2^(n(n-1)/2) qualitatively distinct evolutions involving n breakage-fusion-bridge cycles. Secondly we consider the stochastic nature of the fold positions, to determine evolution likelihoods, and also describe how amplicons become localised. Finally we highlight these methods by inferring the evolution of breakage-fusion-bridge cycles with data from primary tissue cancer samples

Proliferation of de Sitter Space

I show that de Sitter space disintegrates into an infinite number of copies of itself. This occurs iteratively through a quantum process involving two types of topology change. First a handle is created semiclassically, on which multiple black hole horizons form. Then the black holes evaporate and disappear, splitting the spatial hypersurfaces into large parts. Applied to cosmology, this process leads to the production of a large or infinite number of universes in most models of inflation and yields a new picture of global structure.Comment: 19 pages, LaTeX2e, 4 figure

Stresses in isostatic granular systems and emergence of force chains

Progress is reported on several questions that bedevil understanding of granular systems: (i) are the stress equations elliptic, parabolic or hyperbolic? (ii) how can the often-observed force chains be predicted from a first-principles continuous theory? (iii) How to relate insight from isostatic systems to general packings? Explicit equations are derived for the stress components in two dimensions including the dependence on the local structure. The equations are shown to be hyperbolic and their general solutions, as well as the Green function, are found. It is shown that the solutions give rise to force chains and the explicit dependence of the force chains trajectories and magnitudes on the local geometry is predicted. Direct experimental tests of the predictions are proposed. Finally, a framework is proposed to relate the analysis to non-isostatic and more realistic granular assemblies.Comment: 4 pages, 2 figures, Corrected typos and clkearer text, submitted to Phys. Rev. Let