Suchergebnisse

The story of the SN 1987A explosion is briefly reviewed. Although this supernova was somewhat peculiar, the study of SN 1987A has clarified quite a number of important aspects of the nature and the properties of supernovae, such as the confirmation of the core collapse of a massive star as the cause of the explosion, as well the confirmation that the decays 56Ni–56Co–56Fe at early times and 44Ti–44Sc at late times, are the main sources of the energy radiated by the ejecta. Still we have not been able to ascertain whether the progenitor was a single star or a binary system, nor have we been able to detect the stellar remnant, a neutron star that should be produced in the core collapse process.

Since 1996 the blast wave driven by SN 1987A has been interacting with the dense circumstellar material, which provides us with a unique opportunity to study the early evolution of a newborn supernova remnant (SNR). Based on the XMM-Newton RGS and EPIC-pn X-ray observations from 2007 to 2019, we investigated the post-impact evolution of the X-ray-emitting gas in SNR 1987A. The hot plasma is represented by two nonequilibrium ionization components with temperatures of ∼0.6 keV and ∼2.5 keV. The low-temperature plasma has a density ∼2400 cm−3, which is likely dominated by the lower-density gas inside the equatorial ring (ER). The high-temperature plasma with a density ∼550 cm−3 could be dominated by the H ii region and the high-latitude material beyond the ring. In the last few years, the emission measure of the low-temperature plasma has been decreasing, indicating that the blast wave has left the main ER. But the blast wave is still propagating into the high-latitude gas, resulting in the steady increase of the high-temperature emission measure. Meanwhile, the average abundances of N, O, Ne, and Mg are found to be declining, which may reflect the different chemical compositions between the two plasma components. We also detected Fe K lines in most of the observations, showing increasing flux and centroid energy. We interpret the Fe K lines as originating from a third hot component, which may come from the reflected shock heated gas or originate from Fe-rich ejecta clumps shocked by the reverse shock.

First published in 1992. Routledge is an imprint of Taylor & Francis, an informa company.

Resumo: Em "O narrador. Reflexões sobre a obra de Nicolai Leskov" (1987a), Walter Benjamin entende que a arte de narrar está em vias de extinção uma vez que o narrador, aquele que reúne em si mesmo o conhecimento do camponês sedentário e do marinheiro comerciante, parece não estar mais entre nós a partir da modernidade. Entretanto, se seguirmos a argumentação de Maria Lugones em "Rumo a um feminismo descolonial" (2014a), que coloca o [des]colonial dentro de uma categoria de não moderno, poderemos considerar que a presença do narrador é perene e se manifesta muitas vezes exatamente no romance, forma literária que Benjamin (1987a) aponta como um indicativo da evolução que vai culminar na morte da narrativa. Em The Distant Marvels (2015), a autora cubana-americana Chantel Acevedo constrói uma protagonista que é a representação literária de um narrador que reúne em si as características benjaminianas e que é, assim, capaz de transmitir experiência. A proposta do presente trabalho é verificar como uma leitura deste romance a partir do viés da descolonialidade pode contribuir para o debate acerca da potência que a intervenção estética feminista tem de contribuir para a construção de novas epistemologias.

Ch6- The Turbulent Beginnings of the US Institute of PeacePassing the US Institute of Peace Act; The Transformation froma Peace Academy to a Peace Institute; Turbulent Beginnings (1984â#x80;#x93;1987); From Education to Policy (1987â#x80;#x93;1992); Notes; Ch7- New Wars, New Directions; New Presidents; New Wars; Managing International Chaos; From a Think Tank to a â#x80;#x9C;Think and Do Tankâ#x80;#x9D;; The Global War on Terror; Notes; Ch8- The Continuing Debate; Notes; Bibliography; Index; About the Book.

10 Patterns of Adaptation Adopted by the Arabs from 1967 to 199011 After â#x80;#x9C;Land Dayâ#x80;#x9D;: New Arab Political Structures; 12 Signs of Growing Activism on the Background of the First Lebanese War; 13 Accelerated Processes of Politicization, 1982â#x80;#x93;1990; 14 Central Government Resolutions and Politics in the Aftermath of Two Waves of Violence; Part Two The Governmentâ#x80;#x99;s Policy, 1987â#x80;#x93;2010; 1 The Civil Dimension of the Policy towards the Arabs: The First Signs of a Change in the Direction of Narrowing the Gap; 2 After the 1992 Elections: From Intentions to Deeds

RX-J0852−4622, a supernova remnant, is demonstrated to be closer than 500 pc, based on the measurements of the angular radius, the angular expansion rate and the TeV g-ray flux. This is a new method of limiting the distance to any supernova remnant with hadronic induced TeV g-ray flux. The progenitor star of RX-J0852−4622 probably exploded in its blue supergiant wind, like SN 1987A, preceeded by a red supergiant phase. A cool dense shell, expected around the outskirts of the red wind, my have been identified. The distance (200 pc) and age (680 yr) of the supernova remnant, originally proposed, are supported.

PREVIOUS RESEARCH ON CONGRESSIONAL ELECTIONS HAS DEMONSTRATED THAT, DESPITE HIGHER VOTE PROPORTIONS, INCUMBENT CANDIDATES ARE NOT NECESSARILY WINNING WITH GREATER FREQUENCY. JACOBSON (1987A) ATTRIBUTES THIS PATTERN TO HIGHER INTERELECTION VOTE SWINGS IN RACES INVOLVING INCUMBENTS. IN THIS PAPER I UTILIZE NEWLY COLLECTED DATA IN 16 STATES FROM 1968 TO 1986 TO EXPLORE THE CHANGING MEANING OF MARGINALITY IN U.S. STATE LEGISLATIVE ELECTIONS. I FIND THAT, WHILE INCUMBENT VOTE PROPORTIONS HAVE INCREASED, INCUMBENT DEFEAT RATES HAVE NOT DECLINED APPRECIABLY, POSSIBLY BECAUSE THE VOLATILITY OF INTERELECTION VOTE SWINGS HAS INCREASED FORM 1970 TO 1986. THESE RESULTS PROVIDE MODEST (BUT IMPERFECT) EVIDENCE THAT PATTERNS SIMILAR TO THOSE DESCRIBED BY JACOBSON ARE AT WORK IN STATE LEGISLATIVE ELECTIONS.

Politicas redaktion har velvilligt givet mig plads til en præciserende bemærkning om min brug af ordet beskrivelse. Niels Bohr bruger glosen som overbegreb for videnskabelige udsagn om virkeligheden. For ham er atomfysikken i sin avancerede kvanteteoretiske udformning en naturbeskrivelse. Blot et eksempel blandt mange: med kvantemekanikken "opnås en fuldstændighed i beskrivelsen i lighed med den, der tilstræbes i den klassiske fysik" (Bohr, 1964a: 17), jf. også titlen på en artikelsamling, som jeg ikke brugte i min artikel: Niels Bohr, Atomteori og naturbeskrivelse, København: J.H. Schultz Forlag, 1965 (første oplag 1958). På samme måde bruger Rasmussen stedvis ordet også om forskningsresultater i politologi (fx Rasmussen, 1987a: 85; 1987b: 185). Det er på den måde, jeg bruger ordet i artiklen her, og, ser jeg nu, det burde jeg have ofret en sætning på.

Through their work, walking tour guides make the abstract histories and cultural flows of cities present and tangible for their followers – merging physical spaces, mental maps of information, and experiences through a kind of spatial storytelling. This social actor's position in regard to consumption and production thus lends itself to conceptualization as a pivotal cultural worker. To better understand this condition, this article has two interrelated goals: first, to raise the importance of Bourdieu's 'cultural intermediary' and the practice of spatial narratives as concerns for the study of culture, and, second, to refit Wendy Griswold's (1987a) 1987 framework for a sociology of culture in order to better suit social actors located within a 'circuit of culture'. Through the study of walking guides, this article places Bourdieu's provocative concept in dialogue with a clear epistemological framework.

Literacy underwent revolutionary growth in northwestern Europe during the seventeenth and eighteenth centuries. This revolution coincided with other dramatic changes in European society, such as the industrial, demographic, agricultural, political, and religious revolutions (Deane 1969: 20–84). While the relationships between literacy and these other revolutions are not fully understood, their association is apparent and many potential influences exist (Cipolla 1969; Cremin 1970; Graff 1981: 232–60; 1987a, 1987b; Jensen 1986: 114–28; Maynes 1985: 117–31; Mitch 1984, 1988; Sanderson 1983; West 1978). The transplantation of European society across the Atlantic brought the literacy revolution to the American periphery. While numerous studies have shown that colonial America participated in this expansion of literacy, the common longitudinal patterns of literacy growth across the various regions and populations of colonial America have received less attention.

Modelling the monetary sector has long been seen as problematic. Conventional demand for money functions have typically failed to cope with the experience of the past 15 years (Judd and Scadding, 1982) and models based upon the counterparts to monetary growth have fared little better. The current interest in buffer stock money (see Cuthbertson and Taylor, 1987, for a recent survey) can be seen as a response to the failure of the more traditional approaches. We believe that the issues involved in the empirical implementation of the buffer stock hypothesis are subtle and that the literature to date has not dealt with them satisfactorily. In spite of the substantial difficulties involved, we think that a system approach to buffer stock modelling (for example, Davidson, 1987a) may be unavoidable to ensure theoretical consistency.

In the contemporary era, there are new modes of political discourse, product of the crisis in the mass media and the emergence of social networks. In this article, the discursiveness of Mauricio Macri's official accounts on Facebook and Twitter are analyzed, considering three phases of his political activity: the presidential pre-candidature at the end of 2010, which was later aborted; the candidature for the re-election for the Government of the city of Buenos Aires, in 2011; and the presidential campaign of 2015. The analysis is based on a methodology of discourse analysis and sociosemiotics (Verón, 1987a), and incorporates tools from hypermedia circulation theory (Carlón, 2015). It is concluded that the discourse of the 2015 campaign, in which Macri reached the presidency of Argentina, was characterized by a mix of features that cross the private and the public —in a continuity with the discursive modes of 2010 and 2011— as well as a diversification of the addressees and the incorporation of mediatic modes of argumentation, appropriation and interrelation. ; En la era contemporánea existen nuevos modos del discurso político, que son producto de la crisis en los medios masivos y del surgimiento de las redes sociales. En este artículo se analizan las discursividades presentes en las cuentas oficiales de Mauricio Macri en Facebook y en Twitter, a lo largo de tres fases sucesivas de su actividad política: la precandidatura presidencial de fines de 2010, que fue luego abortada; la candidatura a la reelección de la jefatura de Gobierno de la ciudad de Buenos Aires, en 2011; y la campaña presidencial de 2015. Se utiliza una metodología de análisis del discurso y sociosemiótica (Verón, 1987a), y se incorporan herramientas de la teoría de la circulación hipermediática (Carlón, 2015). Se concluye que la campaña de 2015, que consagró a Macri como presidente de Argentina, se caracteriza por una mixtura de rasgos que cruzan lo privado y lo público —en continuidad con los modos discursivos de 2010 y 2011—, así como por una diversificación en la destinación y una incorporación de modos de argumentación, apropiación e interrelación mediáticos.