1,452 research outputs found

    American & British Aircraft Carrier Development, 19-19-1941

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    Biological characteristics and mortality of western butterfish (Pentapodus vitta), an abundant bycatch species of prawn trawling and recreational fishing in a large subtropical embayment

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    The western butterfish (Pentapodus vitta) is numerous in the bycatch of prawn trawling and recreational fishing in Shark Bay, Western Australia. We have thus determined crucial aspects of its biological characteristics and the potential impact of fishing on its abundance within this large subtropical marine embayment. Although both sexes attained a maximum age of 8 years, males grow more rapidly and to a larger size. Maturity is attained at the end of the first year of life and spawning occurs between October and January. The use of a Bayesian approach to combine independent estimates for total mortality, Z, and natural mortality, M, yielded slightly higher point estimates for Z than M. This result indicates that P. vitta is lightly impacted by fishing. It is relevant that, potentially, the individuals can spawn twice before recruitment into the fishery and that 73% of recreationally caught individuals are returned live to the water

    Using Sequential Two-Part Focus Groups As A Supplemental Instrument For Student Course Evaluations

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    This paper describes the use of a sequential two-part focus group program designed to be a supplemental instrument for eliciting student suggestions to improve the teaching/learning process.   The sequential two-part focus group program provides students with two opportunities to provide feedback and have that feedback both noted and mirrored back to them. Many of the student comments and suggestions elicited during the focus group sessions were positive and constructive.  Moreover, use of the sequential two-part focus group program resulted in statistically significant improvement in student evaluations in all but one of the seven major sections of the Educational Testing Service’s SIR II, the primary instrument utilized to obtain the student course evaluations.  The “Overall Evaluation” of the course, wherein students are asked to, “Rate the quality of instruction in this course as it contributed to your learning,” improved most significantly.&nbsp

    Discovery of a High Proper Motion L Dwarf Binary: 2MASS J15200224-4422419AB

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    We report the discovery of the wide L1.5+L4.5 binary 2MASS J15200224-4422419AB, identified during spectroscopic followup of high proper motion sources selected from the Two Micron All Sky Survey. This source was independently identified by Kendall et al. in the SuperCOSMOS Sky Survey. Resolved JHK photometry and low resolution near-infrared spectroscopy demonstrate that this system is composed of two well-separated (1"174+/-0"016) L dwarfs. Component classifications are derived using both spectral ratios and comparison to near-infrared spectra of previously classified field L dwarfs. Physical association for the pair is deduced from the large (mu = 0"73+/-0"03 /yr) common proper motion of the components and their similar spectrophotometric distances (19+/-2 pc). The projected separation of the binary, 22+/-2 AU, is consistent with maximum separation/total system mass trends for very low mass binaries. The 2MASS J1520-4422 system exhibits both large tangential (66+/-7 km/s) and radial velocities (-70+/-18 km/s), and its motion in the local standard of rest suggests that it is an old member of the Galactic disk population. This system joins a growing list of well-separated (>0"5), very low mass binaries, and is an excellent target for resolved optical spectroscopy to constrain its age as well as trace activity/rotation trends near the hydrogen-burning limit.Comment: 35 pages, 8 figures; accepted for publication to ApJ; see also Kendall et al. astro-ph/060939

    Thermodynamics of ideal quantum gas with fractional statistics in D dimensions

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    We present exact and explicit results for the thermodynamic properties (isochores, isotherms, isobars, response functions, velocity of sound) of a quantum gas in dimensions D>=1 and with fractional exclusion statistics 0<=g<=1 connecting bosons (g=0) and fermions (g=1). In D=1 the results are equivalent to those of the Calogero-Sutherland model. Emphasis is given to the crossover between boson-like and fermion-like features, caused by aspects of the statistical interaction that mimic long-range attraction and short-range repulsion. The full isochoric heat capacity and the leading low-T term of the isobaric expansivity in D=2 are independent of g. The onset of Bose-Einstein condensation along the isobar occurs at a nonzero transition temperature in all dimensions. The T-dependence of the velocity of sound is in simple relation to isochores and isobars. The effects of soft container walls are accounted for rigorously for the case of a pure power-law potential.Comment: 15 pages, 31 figure

    The Program for climate Model diagnosis and Intercomparison: 20-th anniversary Symposium

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    Twenty years ago, W. Lawrence (Larry) Gates approached the U.S. Department of Energy (DOE) Office of Energy Research (now the Office of Science) with a plan to coordinate the comparison and documentation of climate model differences. This effort would help improve our understanding of climate change through a systematic approach to model intercomparison. Early attempts at comparing results showed a surprisingly large range in control climate from such parameters as cloud cover, precipitation, and even atmospheric temperature. The DOE agreed to fund the effort at the Lawrence Livermore National Laboratory (LLNL), in part because of the existing computing environment and because of a preexisting atmospheric science group that contained a wide variety of expertise. The project was named the Program for Climate Model Diagnosis and Intercomparison (PCMDI), and it has changed the international landscape of climate modeling over the past 20 years. In spring 2009 the DOE hosted a 1-day symposium to celebrate the twentieth anniversary of PCMDI and to honor its founder, Larry Gates. Through their personal experiences, the morning presenters painted an image of climate science in the 1970s and 1980s, that generated early support from the international community for model intercomparison, thereby bringing PCMDI into existence. Four talks covered GatesÃÂñÃÂÃÂÃÂÃÂs early contributions to climate research at the University of California, Los Angeles (UCLA), the RAND Corporation, and Oregon State University through the founding of PCMDI to coordinate the Atmospheric Model Intercomparison Project (AMIP). The speakers were, in order of presentation, Warren Washington [National Center for Atmospheric Research (NCAR)], Kelly Redmond (Western Regional Climate Center), George Boer (Canadian Centre for Climate Modelling and Analysis), and Lennart Bengtsson [University of Reading, former director of the European Centre for Medium-Range Weather Forecasts (ECMWF)]. The afternoon session emphasized the scientific ideas that are the basis of PCMDIÃÂñÃÂÃÂÃÂÃÂs success, summarizing their evolution and impact. Four speakers followed the various PCMDI-supported climate model intercomparison projects, beginning with early work on cloud representations in models, presented by Robert D. Cess (Distinguished Professor Emeritus, Stony Brook University), and then the latest Cloud Feedback Model Intercomparison Projects (CFMIPs) led by Sandrine Bony (Laboratoire de MĂƒĂ‚ĂƒĂ‚ĂƒĂ‚ĂƒĂ‚Â©tĂƒĂ‚ĂƒĂ‚ĂƒĂ‚ĂƒĂ‚Â©orologie Dynamique). Benjamin Santer (LLNL) presented a review of the climate change detection and attribution (D & A) work pioneered at PCMDI, and Gerald A. Meehl (NCAR) ended the day with a look toward the future of climate change research

    A discursive psychology analysis of emotional support for men with colorectal cancer

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    Recent research into both masculinity and health, and the provision of social support for people with cancer has focussed upon the variations that may underlie broad assumptions about masculine health behaviour. The research reported here pursues this interest in variation by addressing the discursive properties of talk about emotional support, by men with colorectal cancer - an understudied group in the social support and cancer literature. Semi-structured interviews were conducted with eight men with colorectal cancer, and the transcripts analysed using an intensive discursive psychology approach. From this analysis two contrasting approaches to this group of men’s framing of emotional support in the context of cancer are described. First, talk about cancer was positioned as incompatible with preferred masculine identities. Second, social contact that affirms personal relationships was given value, subject to constraints arising from discourses concerning appropriate emotional expression. These results are discussed with reference to both the extant research literature on masculinity and health, and their clinical implications, particularly the advice on social support given to older male cancer patients, their families and friends

    Uncoupled evolution of the Polycomb system and deep origin of non-canonical PRC1

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    Polycomb group proteins, as part of the Polycomb repressive complexes, are essential in gene repression through chromatin compaction by canonical PRC1, mono-ubiquitylation of histone H2A by non-canonical PRC1 and tri-methylation of histone H3K27 by PRC2. Despite prevalent models emphasizing tight functional coupling between PRC1 and PRC2, it remains unclear whether this paradigm indeed reflects the evolution and functioning of these complexes. Here, we conduct a comprehensive analysis of the presence or absence of cPRC1, nPRC1 and PRC2 across the entire eukaryotic tree of life, and find that both complexes were present in the Last Eukaryotic Common Ancestor (LECA). Strikingly, ~42% of organisms contain only PRC1 or PRC2, showing that their evolution since LECA is largely uncoupled. The identification of ncPRC1-defining subunits in unicellular relatives of animals and fungi suggests ncPRC1 originated before cPRC1, and we propose a scenario for the evolution of cPRC1 from ncPRC1. Together, our results suggest that crosstalk between these complexes is a secondary development in evolution.</p
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