Polarization in Disks

This white paper discusses how disk polarization observations can be used to study disk and grain properties during the planet formation process. Such studies require very sensitive and high resolution multi-wavelength observations.Fil: Stephens, Ian W.. Harvard-Smithsonian Center for Astrophysics; Estados UnidosFil: Li, Zhi Yun. University of Virginia; Estados UnidosFil: Yang, Haifeng. Tsinghua University; ChinaFil: Kataoka, Akimasa. National Astronomical Observatory of Japan; JapónFil: Looney, Leslie. University of Illinois at Urbana; Estados UnidosFil: Hull, Charles L. H.. National Astronomical Observatory Of Japan; JapónFil: Fernandez Lopez, Manuel. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomía; ArgentinaFil: Sadavoy, Sarah. Harvard-Smithsonian Center for Astrophysics; Estados UnidosFil: Kwon, Woojin. Korea Astronomy And Space Science Institute; Corea del SurFil: Satoshi, Ohashi. Riken Cluster For Pioneering Research; JapónFil: Tazaki, Ryo. Tohoku University; JapónFil: Li, Dan. National Optical Astronomy Observatory; Estados UnidosFil: Hoang, Thiem. Korea Astronomy And Space Science Institute; Corea del SurFil: Bertrang, Gesa H. M.. Max Planck Institute For Extraterrestrial Physics; AlemaniaFil: Carrasco Gonzalez, Carlos Eugenio. Instituto de Radioastronomía y Astrofísica; MéxicoFil: Dent, William. Atacama Large (sub)millimeter Array; ChileFil: Takahashi, Satoko. National Institutes Of Natural Sciences - National Astronomical Observatory Of Japan; JapónFil: Bacciotti, Francesca. Istituto Nazionale di Astrofisica; ItaliaFil: Alves, Felipe O.. Max Planck Institute For Extraterrestrial Physics; AlemaniaFil: Girart, Josep M.. Instituto de Ciencias del Espacio; España. Consejo Superior de Investigaciones Científicas; EspañaFil: Zhang, Qizhou. Harvard-Smithsonian Center for Astrophysics; Estados UnidosFil: Rao, Ramprasad. Academia Sinica; ChinaFil: Pohl, Adriana. Max Planck Institute For Extraterrestrial Physics; AlemaniaFil: Padovani, Marco. Istituto Nazionale di Astrofisica; ItaliaFil: Galli, Daniele. Istituto Nazionale di Astrofisica; ItaliaFil: Lee, Chin Fei. Academia Sinica; ChinaFil: Segura Cox, Dominique. Max Planck Institute For Extraterrestrial Physics; AlemaniaAstro2020: APC Science White PapersEstados UnidosAmerica Astronomical Societ

Achieving equal standards in medical student education: is a national exit examination the answer?

The document attached has been archived with permission from the editor of the Medical Journal of Australia. An external link to the publisher’s copy is included.Although it is commonly assumed that the quality of medical school education in Australia is uniformly high, there is no national process for assessing its outcomes. There is substantial variability in the content of medical school curricula, and the process of curriculum change is becoming more challenging because of intense competition for time and space in the course. A national exit examination could provide a uniform standard of assessment for all medical school graduates in Australia, as well as foreign graduates applying to work in Australia. Such an examination could assess medical school outcomes, monitor the effects of curriculum change, and provide a benchmark for new medical schools that would help medical curricula evolve to better meet society’s needs.Bogda Koczwara, Martin H N Tattersall, Michael B Barton, Brendon J Coventry, Joanna M Dewar, Jeremy L Millar, Ian N Olver, Max A Schwarz, Darren L Starmer, David R Turner and Martin R Stockler, for the Cancer Council of Australia Oncology Education Committe

Big and little Lipschitz one sets

Given a continuous function $f: {{\mathbb R}}\to {{\mathbb R}}$ we denote the so-called "big Lip" and "little lip" functions by ${{\mathrm {Lip}}} f$ and ${{\mathrm {lip}}} f$ respectively}. In this paper we are interested in the following question. Given a set $E {\subset} {{\mathbb R}}$ is it possible to find a continuous function $f$ such that ${{\mathrm {lip}}} f=\mathbf{1}_E$ or ${{\mathrm {Lip}}} f=\mathbf{1}_E$? For monotone continuous functions we provide the rather straightforward answer. For arbitrary continuous functions the answer is much more difficult to find. We introduce the concept of uniform density type (UDT) and show that if $E$ is $G_\delta$ and UDT then there exists a continuous function $f$ satisfying ${{\mathrm {Lip}}} f =\mathbf{1}_E$, that is, $E$ is a ${{\mathrm {Lip}}} 1$ set. In the other direction we show that every ${{\mathrm {Lip}}} 1$ set is $G_\delta$ and weakly dense. We also show that the converse of this statement is not true, namely that there exist weakly dense $G_{{\delta}}$ sets which are not ${{\mathrm {Lip}}} 1$. We say that a set $E\subset \mathbb{R}$ is ${{\mathrm {lip}}} 1$ if there is a continuous function $f$ such that ${{\mathrm {lip}}} f=\mathbf{1}_E$. We introduce the concept of strongly one-sided density and show that every ${{\mathrm {lip}}} 1$ set is a strongly one-sided dense $F_\sigma$ set.Comment: This is the final preprint version accepted to appear in European Journal of Mathematic

Simple Pricing Schemes for the Cloud

The problem of pricing the cloud has attracted much recent attention due to the widespread use of cloud computing and cloud services. From a theoretical perspective, several mechanisms that provide strong efficiency or fairness guarantees and desirable incentive properties have been designed. However, these mechanisms often rely on a rigid model, with several parameters needing to be precisely known in order for the guarantees to hold. In this paper, we consider a stochastic model and show that it is possible to obtain good welfare and revenue guarantees with simple mechanisms that do not make use of the information on some of these parameters. In particular, we prove that a mechanism that sets the same price per time step for jobs of any length achieves at least 50% of the welfare and revenue obtained by a mechanism that can set different prices for jobs of different lengths, and the ratio can be improved if we have more specific knowledge of some parameters. Similarly, a mechanism that sets the same price for all servers even though the servers may receive different kinds of jobs can provide a reasonable welfare and revenue approximation compared to a mechanism that is allowed to set different prices for different servers.Comment: To appear in the 13th Conference on Web and Internet Economics (WINE), 2017. A preliminary version was presented at the 12th Workshop on the Economics of Networks, Systems and Computation (NetEcon), 201

Mather sets for sequences of matrices and applications to the study of joint spectral radii

The joint spectral radius of a compact set of d-times-d matrices is defined ?to be the maximum possible exponential growth rate of products of matrices drawn from that set. In this article we investigate the ergodic-theoretic structure of those sequences of matrices drawn from a given set whose products grow at the maximum possible rate. This leads to a notion of Mather set for matrix sequences which is analogous to the Mather set in Lagrangian dynamics. We prove a structure theorem establishing the general properties of these Mather sets and describing the extent to which they characterise matrix sequences of maximum growth. We give applications of this theorem to the study of joint spectral radii and to the stability theory of discrete linear inclusions. These results rest on some general theorems on the structure of orbits of maximum growth for subadditive observations of dynamical systems, including an extension of the semi-uniform subadditive ergodic theorem of Schreiber, Sturman and Stark, and an extension of a noted lemma of Y. Peres. These theorems are presented in the appendix