970 resultados para STAR-FORMATION HISTORY
Resumo:
A month-long intensive measurement campaign was conducted in March/April 2007 at Agnes Water, a remote coastal site just south of the Great Barrier Reef on the east coast of Australia. Particle and ion size distributions were continuously measured during the campaign. Coastal nucleation events were observed in clean, marine air masses coming from the south-east on 65% of the days. The events usually began at ~10:00 local time and lasted for 1-4 hrs. They were characterised by the appearance of a nucleation mode with a peak diameter of ~10 nm. The freshly nucleated particles grew within 1-4 hrs up to sizes of 20-50 nm. The events occurred when solar intensity was high (~1000 W m-2) and RH was low (~60%). Interestingly, the events were not related to tide height. The volatile and hygroscopic properties of freshly nucleated particles (17-22.5 nm), simultaneously measured with a volatility-hygroscopicity-tandem differential mobility analyser (VH-TDMA), were used to infer chemical composition. The majority of the volume of these particles was attributed to internally mixed sulphate and organic components. After ruling out coagulation as a source of significant particle growth, we conclude that the condensation of sulphate and/or organic vapours was most likely responsible for driving particle growth during the nucleation events. We cannot make any direct conclusions regarding the chemical species that participated in the initial particle nucleation. However, we suggest that nucleation may have resulted from the photo-oxidation products of unknown sulphur or organic vapours emitted from the waters of Hervey Bay, or from the formation of DMS-derived sulphate clusters over the open ocean that were activated to observable particles by condensable vapours emitted from the nutrient rich waters around Fraser Island or Hervey Bay. Furthermore, a unique and particularly strong nucleation event was observed during northerly wind. The event began early one morning (08:00) and lasted almost the entire day resulting in the production of a large number of ~80 nm particles (average modal concentration during the event was 3200 cm-3). The Great Barrier Reef was the most likely source of precursor vapours responsible for this event.
Resumo:
This is the first volume to capture the essence of the burgeoning field of cultural studies in a concise and accessible manner. Other books have explored the British and North American traditions, but this is the first guide to the ideas, purposes and controversies that have shaped the subject. The author sheds new light on neglected pioneers and a clear route map through the terrain. He provides lively critical narratives on a dazzling array of key figures including, Arnold, Barrell, Bennett, Carey, Fiske, Foucault, Grossberg, Hall, Hawkes, hooks, Hoggart, Leadbeater, Lissistzky, Malevich, Marx, McLuhan, McRobbie, D Miller, T Miller, Morris, Quiller-Couch, Ross, Shaw, Urry, Williams, Wilson, Wolfe and Woolf. Hartley also examines a host of central themes in the subject including literary and political writing, publishing, civic humanism, political economy and Marxism, sociology, feminism, anthropology and the pedagogy of cultural studies.
Resumo:
This paper traces the history of store (retailer-controlled) and national (manufacture controlled)brands; identifies the key historical characteristics of the past 200 years of marketing history;describes the four main time periods of U.S. retail marketing (1800 - 2000); and comments on the most likely developments within the current phases of brand marketing. Will the future focus on technology and new forms of communications? The Internet exemplifies an unconventional retailing environment, with etailer numbers growing rapidly. The central proposition of this paper is that a "cycle of control" - a pattern of marketing developments within the history of retailing and national marketing communications - Can indicate the success of marketing strategies in the future.
Resumo:
The measurement of submicrometre (< 1.0 m) and ultrafine particles (diameter < 0.1 m) number concentration have attracted attention since the last decade because the potential health impacts associated with exposure to these particles can be more significant than those due to exposure to larger particles. At present, ultrafine particles are not regularly monitored and they are yet to be incorporated into air quality monitoring programs. As a result, very few studies have analysed their long-term and spatial variations in ultrafine particle concentration, and none have been in Australia. To address this gap in scientific knowledge, the aim of this research was to investigate the long-term trends and seasonal variations in particle number concentrations in Brisbane, Australia. Data collected over a five-year period were analysed using weighted regression models. Monthly mean concentrations in the morning (6:00-10:00) and the afternoon (16:00-19:00) were plotted against time in months, using the monthly variance as the weights. During the five-year period, submicrometre and ultrafine particle concentrations increased in the morning by 105.7% and 81.5% respectively whereas in the afternoon there was no significant trend. The morning concentrations were associated with fresh traffic emissions and the afternoon concentrations with the background. The statistical tests applied to the seasonal models, on the other hand, indicated that there was no seasonal component. The spatial variation in size distribution in a large urban area was investigated using particle number size distribution data collected at nine different locations during different campaigns. The size distributions were represented by the modal structures and cumulative size distributions. Particle number peaked at around 30 nm, except at an isolated site dominated by diesel trucks, where the particle number peaked at around 60 nm. It was found that ultrafine particles contributed to 82%-90% of the total particle number. At the sites dominated by petrol vehicles, nanoparticles (< 50 nm) contributed 60%-70% of the total particle number, and at the site dominated by diesel trucks they contributed 50%. Although the sampling campaigns took place during different seasons and were of varying duration these variations did not have an effect on the particle size distributions. The results suggested that the distributions were rather affected by differences in traffic composition and distance to the road. To investigate the occurrence of nucleation events, that is, secondary particle formation from gaseous precursors, particle size distribution data collected over a 13 month period during 5 different campaigns were analysed. The study area was a complex urban environment influenced by anthropogenic and natural sources. The study introduced a new application of time series differencing for the identification of nucleation events. To evaluate the conditions favourable to nucleation, the meteorological conditions and gaseous concentrations prior to and during nucleation events were recorded. Gaseous concentrations did not exhibit a clear pattern of change in concentration. It was also found that nucleation was associated with sea breeze and long-range transport. The implications of this finding are that whilst vehicles are the most important source of ultrafine particles, sea breeze and aged gaseous emissions play a more important role in secondary particle formation in the study area.
Resumo:
“When cultural life is re-defined as a perpetual round of entertainments, when serious public conversation becomes a form of baby talk, when, in short, a people become an audience and their public business a vaudeville act, then a nation finds itself at risk.” (Postman) The dire tones of Postman quoted in Janet Cramer’s Media, History, Society: A Cultural History of US Media introduce one view that she canvasses, in the debate of the moment, as to where popular culture is heading in the digital age. This is canvassed, less systematically, in Thinking Popular Culture: War Terrorism and Writing by Tara Brabazon, who for example refers to concerns about a “crisis of critical language” that is bothering professionals—journalists and academics or elsewhere—and deplores the advent of the Internet, as a “flattening of expertise in digital environments”.
Resumo:
I argue that a divergence between popular culture as “object” and “subject” of journalism emerged during the nineteenth century in Britain. It accounts not only for different practices of journalism, but also for differences in the study of journalism, as manifested in journalism studies and cultural studies respectively. The chapter offers an historical account to show that popular culture was the source of the first mass circulation journalism, via the pauper press, but that it was later incorporated into the mechanisms of modern government for a very different purpose, the theorist of which was Walter Bagehot. Journalism’s polarity was reversed – it turned from “subjective” to “objective.” The paper concludes with a discussion of YouTube and the resurgence of self-made representation, using the resources of popular culture, in current election campaigns. Are we witnessing a further reversal of polarity, where popular culture and self-representation once again becomes the “subject” of journalism?