94 resultados para De Morgan, William, 1839-1917.
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We describe the Pan-STARRS Moving Object Processing System (MOPS), a modern software package that produces automatic asteroid discoveries and identifications from catalogs of transient detections from next-generation astronomical survey telescopes. MOPS achieves >99.5% efficiency in producing orbits from a synthetic but realistic population of asteroids whose measurements were simulated for a Pan-STARRS4-class telescope. Additionally, using a nonphysical grid population, we demonstrate that MOPS can detect populations of currently unknown objects such as interstellar asteroids. MOPS has been adapted successfully to the prototype Pan-STARRS1 telescope despite differences in expected false detection rates, fill-factor loss, and relatively sparse observing cadence compared to a hypothetical Pan-STARRS4 telescope and survey. MOPS remains highly efficient at detecting objects but drops to 80% efficiency at producing orbits. This loss is primarily due to configurable MOPS processing limits that are not yet tuned for the Pan-STARRS1 mission. The core MOPS software package is the product of more than 15 person-years of software development and incorporates countless additional years of effort in third-party software to perform lower-level functions such as spatial searching or orbit determination. We describe the high-level design of MOPS and essential subcomponents, the suitability of MOPS for other survey programs, and suggest a road map for future MOPS development.
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We present initial results from observations and numerical analyses aimed at characterizing the main-belt comet P/2012 T1 (PANSTARRS). Optical monitoring observations were made between 2012 October and 2013 February using the University of Hawaii 2.2 m telescope, the Keck I telescope, the Baade and Clay Magellan telescopes, Faulkes Telescope South, the Perkins Telescope at Lowell Observatory, and the Southern Astrophysical Research Telescope. The object's intrinsic brightness approximately doubles from the time of its discovery in early October until mid-November and then decreases by ~60% between late December and early February, similar to photometric behavior exhibited by several other main-belt comets and unlike that exhibited by disrupted asteroid (596) Scheila. We also used Keck to conduct spectroscopic searches for CN emission as well as absorption at 0.7 μm that could indicate the presence of hydrated minerals, finding an upper limit CN production rate of Q CN <1.5 × 1023 mol s-1, from which we infer a water production rate of Q_H_2O100 Myr and is unlikely to be a recently implanted interloper from the outer solar system, while a search for potential asteroid family associations reveals that it is dynamically linked to the ~155 Myr old Lixiaohua asteroid family. Some of the data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration, and made possible by the generous financial support of the W. M. Keck Foundation, the Magellan Telescopes located at Las Campanas Observatory, Chile, and the Southern Astrophysical Research (SOAR) telescope, which is a joint project of the Ministério da Ciência, Tecnologia, e Inovação (MCTI) da República Federativa do Brasil, the U.S. National Optical Astronomy Observatory (NOAO), the University of North Carolina at Chapel Hill (UNC), and Michigan State University (MSU).
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Strand lamps selected for inclusion in this exhibition in the Ruthin Crafts Gallery
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We are conducting an ESO Large Program that includes optical photometry, thermal-IR observations, and optical-NIR spectroscopy of selected NEAs. Among the principal goals of the program are shape and spin-state modeling, and searching for YORP-induced changes in rotation periods. One of our targets is asteroid (1917) Cuyo, a near-Earth asteroid from the Amor group. We carried out an extensive observing campaign on Cuyo between April 2010 and April 2013, operating primarily at the ESO 3.6m NTT for optical photometry, and the 8.2m VLT at Paranal for thermal-IR imaging. Further optical observations were acquired at the ESO 2.2m telescope, the Palomar 200" Hale telescope (California), JPL’s Table Mountain Observatory (California) and the Faulkes Telescope South (Australia). We obtained optical imaging data for rotational lightcurves throughout this period, as the asteroid passed through a wide range of observational geometries, conducive to producing a good shape model and spin state solution. The preliminary shape and spin state model indicates a nearly spherical shape and a rotation pole at ecliptic longitude λ = 53° ± 20° and latitude β = -37° ± 10° (1-sigma error bars are approximate). The sidereal rotation period was measured to be 2.6899522 ± (3 × 10^-7) hours. Linkage with earlier lightcurve data shows possible evidence of a small change in rotation rate during the period 1989-2013. We applied the NEATM thermal model (Harris A., Icarus 131, 291, 1998) to our VLT thermal-IR measurements (8-19.6 μm), obtained in September and December 2011. The derived effective diameter ranges from 3.4 to 4.2 km, and the geometric albedo is 0.16 (+0.07, -0.04). Using the shape model and thermal fluxes we will perform a detailed thermophysical analysis using the new Advanced Thermophysical Model (Rozitis, B. & Green, S.F., MNRAS 415, 2042, 2011; Rozitis, B. & Green, S.F., MNRAS 423, 367, 2012). This work was performed in part at the Jet Propulsion Laboratory under a contract with NASA.
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Performance by Tyrone Guthrie Society, South Dining Hall, Queen's University, Belfast.
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Biodiversity continues to decline in the face of increasing anthropogenic pressures such as habitat destruction, exploitation, pollution and introduction of alien species. Existing global databases of species' threat status or population time series are dominated by charismatic species. The collation of datasets with broad taxonomic and biogeographic extents, and that support computation of a range of biodiversity indicators, is necessary to enable better understanding of historical declines and to project - and avert - future declines. We describe and assess a new database of more than 1.6 million samples from 78 countries representing over 28,000 species, collated from existing spatial comparisons of local-scale biodiversity exposed to different intensities and types of anthropogenic pressures, from terrestrial sites around the world. The database contains measurements taken in 208 (of 814) ecoregions, 13 (of 14) biomes, 25 (of 35) biodiversity hotspots and 16 (of 17) megadiverse countries. The database contains more than 1% of the total number of all species described, and more than 1% of the described species within many taxonomic groups - including flowering plants, gymnosperms, birds, mammals, reptiles, amphibians, beetles, lepidopterans and hymenopterans. The dataset, which is still being added to, is therefore already considerably larger and more representative than those used by previous quantitative models of biodiversity trends and responses. The database is being assembled as part of the PREDICTS project (Projecting Responses of Ecological Diversity In Changing Terrestrial Systems - http://www.predicts.org.uk). We make site-level summary data available alongside this article. The full database will be publicly available in 2015.
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Why were some areas of the Ireland more active than others during the War of Independence, and why did the areas of most activity change over the course of the war between 1919 and 1921? In the context of the Irish midlands, County Longford stands out as one of the most violent counties surrounded by areas where there was much less activity by the IRA. Even within the county there was a significant difference in the strength of republican activity between north and south Longford. This article will examine the factors that were responsible for the strength of the IRA campaign in this midland enclave, including socio-economic conditions, administrative decisions and failures, and the contemporary political context.
Much of the evidence upon which the paper is based comes from applications made by Longford Volunteers for military service pensions, granted to veterans of the campaign by the Irish government after 1924. Many of these documents are soon to be released by the Irish government. The paper will also include a discussion of these sources and the way in which they can be used by historians to advance our understanding of Ireland’s revolutionary decade.
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Anthropological inquiry has often been considered an agent of intellectual secularization. Not least is this so in the sphere of religion, where anthropological accounts have often been taken to represent the triumph of naturalism. This metanarrative however fails to recognise that naturalistic explanations could sometimes be espoused for religious purposes and in defence of confessional creeds. This essay examines two late nineteenth-century figures – Alexander Winchell in the United States, and William Robertson Smith in Britain – who found in anthropological analysis resources to bolster rather than undermine faith. In both cases these individuals found themselves on the receiving end of ecclesiastical censure and were dismissed from their positions at church-governed institutions. But their motivation was to vindicate divine revelation, in Winchell’s case from the physical anthropology of human origins and in Smith’s from the cultural anthropology of Semitic ritual.
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We analyze a set of 760 475 observations of 333 026 unique main-belt objects obtained by the Pan-STARRS1(PS1) survey telescope between 2012 May 20 and 2013 November 9, a period during which PS1 discoveredtwo main-belt comets, P/2012 T1 (PANSTARRS) and P/2013 R3 (Catalina-PANSTARRS). PS1 cometdetection procedures currently consist of the comparison of the point spread functions (PSFs) of movingobjects to those of reference stars, and the flagging of objects that show anomalously large radial PSFwidths for human evaluation and possible observational follow-up. Based on the number of missed discoveryopportunities among comets discovered by other observers, we estimate an upper limit comet discoveryefficiency rate of 70% for PS1. Additional analyses that could improve comet discovery yields infuture surveys include linear PSF analysis, modeling of trailed stellar PSFs for comparison to trailed movingobject PSFs, searches for azimuthally localized activity, comparison of point-source-optimized photometryto extended-source-optimized photometry, searches for photometric excesses in objects withknown absolute magnitudes, and crowd-sourcing. Analysis of the discovery statistics of the PS1 surveyindicates an expected fraction of 59 MBCs per 106 outer main-belt asteroids (corresponding to a totalexpected population of 140 MBCs among the outer main-belt asteroid population with absolute magnitudesof 12 < HV < 19:5), and a 95% confidence upper limit of 96 MBCs per 106 outer main-belt asteroids(corresponding to a total of 230 MBCs), assuming a detection efficiency of 50%. We note howeverthat significantly more sensitive future surveys (particularly those utilizing larger aperture telescopes)could detect many more MBCs than estimated here. Examination of the orbital element distribution ofall known MBCs reveals an excess of high eccentricities (0:1 < e < 0:3) relative to the background asteroidpopulation. Theoretical calculations show that, given these eccentricities, the sublimation rate for atypical MBC is orders of magnitude larger at perihelion than at aphelion, providing a plausible physicalexplanation for the observed behavior of MBCs peaking in observed activity strength near perihelion.These results indicate that the overall rate of mantle growth should be slow, consistent with observationalevidence that MBC activity can be sustained over multiple orbit passages.
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Law's Ethical, Global and Theoretical Contexts examines William Twining's principal contributions to law and jurisprudence in the context of three issues which will receive significant scholarly attention over the coming decades. Part I explores human rights, including torture, the role of evidence in human rights cases, the emerging discourse on 'traditional values', the relevance of 'Southern voices' to human rights debates, and the relationship between human rights and peace agreements. Part II assesses the impact of globalization through the lenses of sociology and comparative constitutionalism, and features an analysis of the development of pluralistic ideas of law in the context of privatization. Finally, Part III addresses issues of legal theory, including whether global legal pluralism needs a concept of law, the importance of context in legal interpretation, the effect of increasing digitalization on legal theory, and the utility of feminist and postmodern approaches to globalization and legal theory.