The Eccentricity-Mass Distribution of Exoplanets: Signatures of Different Formation Mechanisms?

We examine the distributions of eccentricity and host star metallicity of exoplanets as a function of their mass. Planets with M sin i >~ 4 M_J have an eccentricity distribution consistent with that of binary stars, while planets with M sin i <~ 4 M_J are less eccentric than binary stars and more massive planets. In addition, host star metallicities decrease with planet mass. The statistical significance of both of these trends is only marginal with the present sample of exoplanets. To account for these trends, we hypothesize that there are two populations of gaseous planets: the low-mass population forms by gas accretion onto a rock-ice core in a circumstellar disk and is more abundant at high metalliticities, and the high-mass population forms directly by fragmentation of a pre-stellar cloud. Planets of the first population form in initially circular orbits and grow their eccentricities later, and may have a mass upper limit from the total mass of the disk that can be accreted by the core. The second population may have a mass lower limit resulting from opacity-limited fragmentation. This would roughly divide the two populations in mass, although they would likely overlap over some mass range. If most objects in the second population form before the pre-stellar cloud becomes highly opaque, they would have to be initially located in orbits larger than ~30 AU, and would need to migrate to the much smaller orbits in which they are observed. The higher mean orbital eccentricity of the second population might be caused by the larger required intervals of radial migration, and the brown dwarf desert might be due to the inability of high-mass brown dwarfs to migrate inwards sufficiently in radius.Comment: 7 pages, 4 figures. Version with expanded discussion section. Accepted for publication in A&

Houses in a Landscape: Memory and Everyday Life in Mesoamerica

In Houses in a Landscape, Julia A. Hendon examines the connections between social identity and social memory using archaeological research on indigenous societies that existed more than one thousand years ago in what is now Honduras. While these societies left behind monumental buildings, the remains of their dead, remnants of their daily life, intricate works of art, and fine examples of craftsmanship such as pottery and stone tools, they left only a small body of written records. Despite this paucity of written information, Hendon contends that an archaeological study of memory in such societies is possible and worthwhile. It is possible because memory is not just a faculty of the individual mind operating in isolation, but a social process embedded in the materiality of human existence. Intimately bound up in the relations people develop with one another and with the world around them through what they do, where and how they do it, and with whom or what, memory leaves material traces. Hendon conducted research on three contemporaneous Native American civilizations that flourished from the seventh century through the eleventh CE: the Maya kingdom of Copan, the hilltop center of Cerro Palenque, and the dispersed settlement of the Cuyumapa valley. She analyzes domestic life in these societies, from cooking to crafting, as well as public and private ritual events including the ballgame. Combining her findings with a rich body of theory from anthropology, history, and geography, she explores how objects—the things people build, make, use, exchange, and discard—help people remember. In so doing, she demonstrates how everyday life becomes part of the social processes of remembering and forgetting, and how “memory communities” assert connections between the past and the present.https://cupola.gettysburg.edu/books/1050/thumbnail.jp

Stratified Static Analysis Based on Variable Dependencies

In static analysis by abstract interpretation, one often uses widening operators in order to enforce convergence within finite time to an inductive invariant. Certain widening operators, including the classical one over finite polyhedra, exhibit an unintuitive behavior: analyzing the program over a subset of its variables may lead a more precise result than analyzing the original program! In this article, we present simple workarounds for such behavior

Literary translation and cultural memory

This article intends to investigate the relationship between literary translation and cultural memory, using a twentieth century film version of one of Shakespeare’s plays as a case study in inter-semiotic translation. The common perception of translation is often confined to its use as a language learning tool or as a means of information transfer between languages. The wider academic concept embraces not only inter-lingual translation, but both intra-lingual activity or rewording in the same language and inter-semiotic translation defined by Roman Jacobson as “the interpretation of verbal signs by means of signs of nonverbal sign systems” (Jakobson, 1959: 114)

Remembering the Falklands War: subjectivity and identification

This paper explores the ways in which remembering is enacted, performed and contested with media and how this becomes intrinsically linked to issues of power, agency and identity. Drawing on ethnographic data collected with Falkland Islanders during the 30th Anniversary of the 1982 Falklands War I critically consider the context, motivation and agency involved in how and why Islanders remember through and with the media, and the potentially profound implications this may be having on their understanding, negotiation and performance of identity, that is (at times) at odds with their everyday existence. The result of the analysis raises critical questions about what societies remember, and want to be remembered for, the implications of which extend far beyond the Falklands

What a Local Sample of Spectroscopic Binaries can tell us about the Field-Binary Population

We study a sample of spectroscopic binaries (SBs) in the local solar neighbourhood to 100 pc and to an absolute magnitude of 4 in an attempt to find the distributions of the period, primary mass and the mass ratio as well as the IMF of the local population of field binaries. The sample was collated using available SB data and the Hipparcos catalogue, the latter being used for distances and to refer numbers of objects to fractions of the local stellar population as a whole. We use the better-determined double-lined SBs (SB2s) to calibrate a Monte-Carlo approach to modelling the mass ratio distribution of the single-lined SBs (SB1s) from their mass functions and primary masses. While a complete sample is not possible, given the data available, we are able to address important questions of incompleteness and parameter-specific biases by comparing subsamples of SBs with different ranges in parameter space. Our results show a clear peak in the mass ratio distribution of field binaries near unity. This is dominated by the SB2s, but the flat distribution of the SB1s is inconsistent with their components being chosen independently at random from a steep IMF.Comment: 9 pages, 9 figures, 4 tables. Published in MNRA

Understanding young people's transitions in university halls through space and time

This article contributes to the theoretical discussion about young people's transitions through space and time. Space and time are complex overarching concepts that have creative potential in deepening understanding of transition. The focus of this research is young people's experiences of communal living in university halls. It is argued that particular space-time concepts draw attention to different facets of experience and in combination deepen the understanding of young people's individual and collective transitions. The focus of the article is the uses of the space-time concepts 'routine', 'representation', 'rhythm' and 'ritual' to research young people's experiences. The article draws on research findings from two studies in the North of England. © 2010 SAGE Publications