The Theory of Brown Dwarfs and Extrasolar Giant Planets

Straddling the traditional realms of the planets and the stars, objects below the edge of the main sequence have such unique properties, and are being discovered in such quantities, that one can rightly claim that a new field at the interface of planetary science and and astronomy is being born. In this review, we explore the essential elements of the theory of brown dwarfs and giant planets, as well as of the new spectroscopic classes L and T. To this end, we describe their evolution, spectra, atmospheric compositions, chemistry, physics, and nuclear phases and explain the basic systematics of substellar-mass objects across three orders of magnitude in both mass and age and a factor of 30 in effective temperature. Moreover, we discuss the distinctive features of those extrasolar giant planets that are irradiated by a central primary, in particular their reflection spectra, albedos, and transits. Aspects of the latest theory of Jupiter and Saturn are also presented. Throughout, we highlight the effects of condensates, clouds, molecular abundances, and molecular/atomic opacities in brown dwarf and giant planet atmospheres and summarize the resulting spectral diagnostics. Where possible, the theory is put in its current observational context.Comment: 67 pages (including 36 figures), RMP RevTeX LaTeX, accepted for publication in the Reviews of Modern Physics. 30 figures are color. Most of the figures are in GIF format to reduce the overall size. The full version with figures can also be found at: http://jupiter.as.arizona.edu/~burrows/papers/rm

Large expert-curated database for benchmarking document similarity detection in biomedical literature search

Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe

EFFECT OF HYDRODYNAMIC PRESSURE TREATMENT AND COOKING ON INACTIVATION OF ESCHERICHIA COLI O157:H7 IN BLADE-TENDERIZED BEEF STEAKS

The efficacy of hydrodynamic pressure (HDP) treatment for inactivation of Escherichia coli O157:H7 in blade-tenderized beef steaks was studied. Beef steaks (N = 48) were inoculated with a five-strain cocktail of Escherichia coli O157:H7 and treated with blade tenderization (BT), HDP or a combination of BT followed by HDP (BTH). Control and treated steaks were cooked to 54.4C (undercooked), 62.8C (medium rare) and 71.1C (medium) on open-hearth Farberware grills. HDP treatment reduced E. coli O157:H7 populations by 0.3 log10 cfu/g, which was not different (P\u3e 0.05) from untreated controls. At each endpoint cooking temperature, E. coli O157:H7 survival was always higher in BT-treated steaks than in untreated steaks cooked to corresponding temperatures. This could be due to migration of surface bacteria to the interior of the muscle thereby protecting bacteria from the lethality of heat. E. coli O157:H7 populations in BTH-treated steaks cooked to 71.1C were nondetectable and were significantly different from BT-treated steaks cooked to 71.1C. Results suggest that BT of intact beef muscle does transfer surface bacteria to the interior of the muscle, which would necessitate a combination of elevated cooking temperatures (\u3e71.1C) and a treatment like HDP for inactivation of bacteria