Empirical Constraints on the Oblateness of an Exoplanet

We show that the gas giant exoplanet HD 189733b is less oblate than Saturn, based on Spitzer Space Telescope photometry of seven transits. The observable manifestations of oblatenesswould have been slight anomalies during the ingress and egress phases, as well as variations in the transit depth due to spin precession. Our nondetection of these effects gives the first empirical constraints on the shape of an exoplanet. The results are consistent with the theoretical expectation that the planetary rotation period and orbital period are synchronized, in which case the oblateness would be an order of magnitude smaller than our upper limits. Conversely, if HD 189733b is assumed to be in a synchronous, zero-obliquity state, then the data give an upper bound on the quadrupole moment of the planet (J2 < 0.068 with 95% confidence) that is too weak to constrain the interior structure of the planet. An Appendix describes a fast algorithm for computing the transit light curve of an oblate planet, which was necessary for our analysis.Comment: 14 pages, accepted for publication in The Astrophysical Journa

The status of paediatric medicines initiatives around the world-what has happened and what has not?

Purpose: This review was conducted to examine the current status of paediatric medicines initiatives across the globe. Methods: The authors made a non-systematic descriptive review of current world situation. Results: Two regions, the United States (US) and the European Union (EU), and the World Health Organization (WHO) have introduced strong paediatric initiatives to improve children's health through improving access to better paediatric medicines. The experience from the US initiative indicates that it is possible to stimulate development and study of paediatric medicines and provide important new information for improvement of paediatric therapy. The early results from the EU initiative are similarly encouraging. In Canada, Japan, Australia and other developed countries, specific paediatric medicines initiatives have been less extensive and weaker, with modest results. Disappointingly, current evidence suggests that results from clinical trials outside the US often do not benefit children in the country in which the trials were largely conducted. Pharmaceutical companies that have derived a financial benefit commensurate with the cost of doing the paediatric trials in one country do not seem to be making the results of these trials available to all countries if there is no financial incentive to the company. The WHO campaign 'make medicines child size' has produced substantive accomplishments in building improved foundations to improve mechanisms that will enhance children's access to critical medicines in resource-limited settings. However, practically all of this work has been performed using an amalgamation of short-term funding from a variety of sources as opposed to a sustained, programmatic commitment. Conclusions: Although much still needs to be done, it's clear that with concerted efforts and appropriate resources, change is possible but slow. Retaining and fostering public and political interest in paediatric medicines is challenging, but pivotal for success.Fil: Hoppu, Kalle. Helsinki University Central Hospital; FinlandiaFil: Anabwani, Gabriel. Botswana-Baylor Children’s Clinical Centre of Excellence; BotsuanaFil: Garcia Bournissen, Facundo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños "Ricardo Gutiérrez"; ArgentinaFil: Gazarian, Madlen. University of New South Wales; Australia. Sydney Children’s Hospital; AustraliaFil: Kearns, Gregory L.. The Children’s Mercy Hospital; Estados Unidos. University of Missouri; Estados UnidosFil: Nakamura, Hidefumi. National Center for Child Health and Development; JapónFil: Peterson, Robert G.. University of British Columbia; CanadáFil: Sri Ranganathan, Shalini. University Of Colombo. Faculty Of Medicine; Sri LankaFil: De Wildt, Saskia N.. Sophia Children’s Hospital; Países Bajo

The Transit Ingress and the Tilted Orbit of the Extraordinarily Eccentric Exoplanet HD 80606b

We present the results of a transcontinental campaign to observe the 2009 June 5 transit of the exoplanet HD 80606b. We report the first detection of the transit ingress, revealing the transit duration to be 11.64 +/- 0.25 hr and allowing more robust determinations of the system parameters. Keck spectra obtained at midtransit exhibit an anomalous blueshift, giving definitive evidence that the stellar spin axis and planetary orbital axis are misaligned. The Keck data show that the projected spin-orbit angle is between 32-87 deg with 68.3% confidence and between 14-142 deg with 99.73% confidence. Thus the orbit of this planet is not only highly eccentric (e=0.93), but is also tilted away from the equatorial plane of its parent star. A large tilt had been predicted, based on the idea that the planet's eccentric orbit was caused by the Kozai mechanism. Independently of the theory, it is noteworthy that all 3 exoplanetary systems with known spin-orbit misalignments have massive planets on eccentric orbits, suggesting that those systems migrate differently than lower-mass planets on circular orbits.Comment: ApJ, in press [13 pg

Gravitating monopole and its black hole solution in Brans-Dicke Theory

We find a self-gravitating monopole and its black hole solution in Brans-Dicke theory. We mainly discuss the properties of these solutions in the Einstein frame and compare the solutions with those in general relativity.Comment: 20 pages,revtex,26 figure

A data compression and optimal galaxy weights scheme for Dark Energy Spectroscopic Instrument and weak lensing data sets

Combining different observational probes, such as galaxy clustering and weak lensing, is a promising technique for unveiling the physics of the Universe with upcoming dark energy experiments. The galaxy redshift sample from the Dark Energy Spectroscopic Instrument (DESI) will have a significant overlap with major ongoing imaging surveys specifically designed for weak lensing measurements: The Kilo-Degree Survey (KiDS), the Dark Energy Survey (DES), and the Hyper Suprime-Cam (HSC) survey. In this work, we analyse simulated redshift and lensing catalogues to establish a new strategy for combining high-quality cosmological imaging and spectroscopic data, in view of the first-year data assembly analysis of DESI. In a test case fitting for a reduced parameter set, we employ an optimal data compression scheme able to identify those aspects of the data that are most sensitive to cosmological information and amplify them with respect to other aspects of the data. We find this optimal compression approach is able to preserve all the information related to the growth of structures

Categorizing Different Approaches to the Cosmological Constant Problem

We have found that proposals addressing the old cosmological constant problem come in various categories. The aim of this paper is to identify as many different, credible mechanisms as possible and to provide them with a code for future reference. We find that they all can be classified into five different schemes of which we indicate the advantages and drawbacks. Besides, we add a new approach based on a symmetry principle mapping real to imaginary spacetime.Comment: updated version, accepted for publicatio

A data compression and optimal galaxy weights scheme for Dark Energy Spectroscopic Instrument and weak lensing datasets

Combining different observational probes, such as galaxy clustering and weak lensing, is a promising technique for unveiling the physics of the Universe with upcoming dark energy experiments. The galaxy redshift sample from the Dark Energy Spectroscopic Instrument (DESI) will have a significant overlap with major ongoing imaging surveys specifically designed for weak lensing measurements: the Kilo-Degree Survey (KiDS), the Dark Energy Survey (DES) and the Hyper Suprime-Cam (HSC) survey. In this work we analyse simulated redshift and lensing catalogues to establish a new strategy for combining high-quality cosmological imaging and spectroscopic data, in view of the first-year data assembly analysis of DESI. In a test case fitting for a reduced parameter set, we employ an optimal data compression scheme able to identify those aspects of the data that are most sensitive to the cosmological information, and amplify them with respect to other aspects of the data. We find this optimal compression approach is able to preserve all the information related to the growth of structure; we also extend this scheme to derive weights to be applied to individual galaxies, and show that these produce near-optimal results.Comment: 14 pages, 12 Figures, DESI collaboration articl