985 resultados para Newman, John Henry


Relevância:

20.00% 20.00%

Publicador:

Resumo:

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.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The question of whether there is or was life on Mars has been one of the most pivotal since Schiaparellis' telescopic observations of the red planet. With the advent of the space age, this question can be addressed directly by exploring the surface of Mars and by bringing samples to Earth for analysis. The latter, however, is not free of problems. Life can be found virtually everywhere on Earth. Hence the potential for contaminating the Mars samples and compromising their scientific integrity is not negligible. Conversely, if life is present in samples from Mars, this may represent a potential source of extraterrestrial biological contamination for Earth. A range of measures and policies, collectively termed ‘planetary protection’, are employed to minimise risks and thereby prevent undesirable consequences for the terrestrial biosphere. This report documents discussions and conclusions from a workshop held in 2012, which followed a public conference focused on current capabilities for performing life-detection studies on Mars samples. The workshop focused on the evaluation of Mars samples that would maximise scientific productivity and inform decision making in the context of planetary protection. Workshop participants developed a strong consensus that the same measurements could be employed to effectively inform both science and planetary protection, when applied in the context of two competing hypotheses: 1) that there is no detectable life in the samples; or 2) that there is martian life in the samples. Participants then outlined a sequence for sample processing and defined analytical methods that would test these hypotheses. They also identified critical developments to enable the analysis of samples from Mars.

Relevância:

20.00% 20.00%

Publicador:

Relevância:

20.00% 20.00%

Publicador:

Resumo:

John Doherty (1900-1980) was one of the most influential Irish musicians of the twentieth century. His music has had a lasting impact on Irish traditional music making around the globe. This paper traces the development of his setting of the canonical reel 'Bonnie Kate'. Using transcription historical investigation Doherty's style is examined in comparison to his contemporaries.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The accurate definition of the extreme wave loads which act on offshore structures represents a significant challenge for design engineers and even with decades of empirical data to base designs upon there are still failures attributed to wave loading. The environmental conditions which cause these loads are infrequent and highly non-linear which means that they are not well understood or simple to describe. If the structure is large enough to affect the incident wave significantly further non-linear effects can influence the loading. Moreover if the structure is floating and excited by the wave field then its responses, which are also likely to be highly non-linear, must be included in the analysis. This makes the description of the loading on such a structure difficult to determine and the design codes will often suggest employing various tools including small scale experiments, numerical and analytical methods, as well as empirical data if available.
Wave Energy Converters (WECs) are a new class of offshore structure which pose new design challenges, lacking the design codes and empirical data found in other industries. These machines are located in highly exposed and energetic sites, designed to be excited by the waves and will be expected to withstand extreme conditions over their 25 year design life. One such WEC is being developed by Aquamarine Power Ltd and is called Oyster. Oyster is a buoyant flap which is hinged close to the seabed, in water depths of 10 to 15m, piercing the water surface. The flap is driven back and forth by the action of the waves and this mechanical energy is then converted to electricity.
It has been identified in previous experiments that Oyster is not only subject to wave impacts but it occasionally slams into the water surface with high angular velocity. This slamming effect has been identified as an extreme load case and work is ongoing to describe it in terms of the pressure exerted on the outer skin and the transfer of this short duration impulsive load through various parts of the structure.
This paper describes a series of 40th scale experiments undertaken to investigate the pressure on the face of the flap during the slamming event. A vertical array of pressure sensors are used to measure the pressure exerted on the flap. Characteristics of the slam pressure such as the rise time, magnitude, spatial distribution and temporal evolution are revealed. Similarities are drawn between this slamming phenomenon and the classical water entry problems, such as ship hull slamming. With this similitude identified, common analytical tools are used to predict the slam pressure which is compared to that measured in the experiment.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Using genome-wide data from 253,288 individuals, we identified 697 variants at genome-wide significance that together explained one-fifth of the heritability for adult height. By testing different numbers of variants in independent studies, we show that the most strongly associated 1/42,000, 1/43,700 and 1/49,500 SNPs explained 1/421%, 1/424% and 1/429% of phenotypic variance. Furthermore, all common variants together captured 60% of heritability. The 697 variants clustered in 423 loci were enriched for genes, pathways and tissue types known to be involved in growth and together implicated genes and pathways not highlighted in earlier efforts, such as signaling by fibroblast growth factors, WNT/I 2-catenin and chondroitin sulfate-related genes. We identified several genes and pathways not previously connected with human skeletal growth, including mTOR, osteoglycin and binding of hyaluronic acid. Our results indicate a genetic architecture for human height that is characterized by a very large but finite number (thousands) of causal variants.

Relevância:

20.00% 20.00%

Publicador:

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This article provides an empirical analysis of voting behaviour in the second ballot of the 1990 Conservative leadership contest that resulted in John Major becoming party leader and prime minister. Seven hypotheses of voting behaviour are generated from the extant literature relating voting to socio-economic variables (occupational and educational background), political variables (parliamentary experience, career status, age and electoral marginality) and ideological variables (drawn from survey data on MPs' positions on economic, European and moral issues). These hypotheses are tested using data on voting intentions gathered from published lists of MPs' declarations, interviews with each of the leadership campaign teams, and correspondence with MPs. Bivariate relationships are presented, followed by logistic regression analysis to isolate the unique impact that each variable had on voting. This shows that educational background, parliamentary experience and (especially) attitudes to Europe were the key factors determining voting. The importance of Europe in the contest is particularly instructive: the severe problems for Major's leadership which were caused by the issue can be attributed to, and understood in the context of, the 1990 contest in which he became leader.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

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.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This article explores the conformation in discourse of a verbal exchange and its subsequent mediatised and legal ramifications. The event concerns an allegedly racist insult directed by high profile English professional footballer John Terry towards another player, Anton Ferdinand, during a televised match in October 2011. The substance of Terry’s utterance, which included the noun phrase ‘fucking black cunt’, was found by a Chief Magistrate not to be a racist insult, although the fact that these actual words were framed within the utterance was not in dispute. The upshot of this ruling was that Terry was acquitted of a racially aggravated public order offence. A subsequent investigation by the regulatory commission of the English Football Association (FA) ruled, almost a year after the event, that Terry was guilty of racially abusing Ferdinand. Terry was banned for four matches and fined £220,000.

It is our contention that this event, played out in legal rulings, social media and print and broadcast media, constitutes a complex web of linguistic structures and strategies in discourse, and as such lends itself well to analysis with a broad range of tools from pragmatics, discourse analysis and cognitive linguistics. Amongst other things, such an analysis can help explain the seemingly anomalous - even contradictory - position adopted in the legal ruling with regard to the speech act status of ‘fucking black cunt’; namely, that the racist content of the utterance was not contested but that the speaker was found not to have issued a racist insult. Over its course, the article addresses this broader issue by making reference to the systemic-functional interpersonal function of language, particularly to the concepts of modality, polarity and modalisation. It also draws on models of verbal irony from linguistic pragmatics, notably from the theory of irony as echoic mention (c.f. Sperber and Wilson, 1981; Wilson and Sperber, 1992). Furthermore, the article makes use of the cognitive-linguistic framework, Text World Theory (c.f. Gavins, 2007; Werth, 1999) to examine the discourse positions occupied by key actors and adapts, from cognitive poetics, the theory of mind-modelling (c.f. Stockwell, 2009) to explore the conceptual means through which these actors discursively negotiate the event.

It is argued that the pragmatic and cognitive strategies that frame the entire incident go a long way towards mitigating the impact of so ostensibly stark an act of racial abuse. Moreover, it is suggested here that the reconciliation of Terry’s action was a result of the confluence of strategies of discourse with relations of power as embodied by the media, the law and perceptions of nationhood embraced by contemporary football culture. It is further proposed that the outcome of this episode, where the FA was put in the spotlight, and where both the conflict and its key antagonists were ‘intranational’, was strongly impelled by the institution of English football and its governing body both to reproduce and maintain social, cultural and ethnic cohesion and to avoid any sense that the event featured a discernable ‘out-group’.