4,873 research outputs found
Planning Systems Facing Heritage Issues in Europe: from Protection to Management, in the Plural Interpretations of the Values of the Past
Creation of magnetic spots at the neutron star surface
According to the partially screened gap scenario, an efficient
electron-positron pair creation, a general precondition of radio-pulsar
activity, relies on the existence of magnetic spots, i.e., local concentrations
of strong and small scale magnetic field structures at the surface of neutron
stars. They have a strong impact on the surface temperature, which is
potentially observable. Here we reinforce the idea that such magnetic spots can
be formed by extracting magnetic energy from the toroidal field that resides in
deep crustal layers, via Hall drift. We study and discuss the magneto-thermal
evolution of qualitatively different neutron star models and initial magnetic
field configurations that lead to the creation of magnetic spots. We find that
magnetic spots can be created on a timescale of years with magnetic
field strengths G, provided almost the whole magnetic
energy is stored in its toroidal component, and that the conductivity in the
inner crust is not too large. The lifetime of the magnetic spots is at least
one million of years, being longer if the initial field permeates both
core and crust.Comment: Accepted by M.N.R.A.
The evolution of core and surface magnetic field in isolated neutron stars
We apply the model of flux expulsion from the superfluid and superconductive
core of a neutron star, developed by Konenkov & Geppert (2000), both to neutron
star models based on different equations of state and to different initial
magnetic field structures. When initially the core and the surface magnetic
field are of the same order of magnitude, the rate of flux expulsion from the
core is almost independent of the equation of state, and the evolution of the
surface field decouples from the core field evolution with increasing
stiffness. When the surface field is initially much stronger than the core
field, the magnetic and rotational evolution resembles to those of a neutron
star with a purely crustal field configuration; the only difference is the
occurence of a residual field. In case of an initially submerged field
significant differences from the standard evolution occur only during the early
period of neutron star's life, until the field has been rediffused to the
surface. The reminder of the episode of submergence is a correlation of the
residual field strength with the submergence depth of the initial field. We
discuss the effect of the rediffusion of the magnetic field on to the
difference between the real and the active age of young pulsars and on their
braking indices. Finally, we estimate the shear stresses built up by the moving
fluxoids at the crust--core interface and show that preferentially in neutron
stars with a soft equation of state these stresses may cause crust cracking.Comment: 10 pages with 5 figures. accepted by MNRA
Research on Cold Cathodes First Quarterly Report, 14 May - 14 Aug. 1965
Application of gallium phosphide crystals for hot-electron cold cathode research - life tests for silver-barium oxide phototubes - surface film, semiconductor, and vacuum requirement
Micro-political aspects of mandate development and learning in local subsidiaries of multinational corporations
Beyond functional-structuralist approaches this paper sheds some light on micro political aspects of mandate development and learning processes in multinational corporations (MNC). As classical micro-political studies have shown, management behaviour and learning are not only constrained or enabled by certain structural and (national) cultural patterns, but have its own political agendas and are shaped by individual interests which leads to game playing, active or passive resistance and (re)negotiation of the 'rules of the game'. Based on the assumption that actors are neither the organs of given structures nor acting fully autonomous, the paper focuses on how subsidiary managers interpret and integrate individual, organisational as well as home and host country institutional factors into certain strategies of action. By discussing critical events in mini case studies on mandate development and learning in German subsidiaries in France we will highlight the interactive dynamics between key-actors micro-political strategies and particular institutional settings. Here we, firstly, discuss institutionalist approaches and investigate how different forms of home and host country embeddedness do influence the development of distinct managerial competences and decision making strategies at the subsidiary level. The paper refers then to the question how the overall strategy and multinational organisational design and policies relate to individual interests of key subsidiary actors. These can to higher or lower degrees be influenced by e.g. differences in nationalities, professional backgrounds as well as career stages, orientations and aspirations. By integrating these diverse relational layers, the paper will provide a more dynamic actor centred approach stressing both, the micro-political aspects and interactive construction of intra and intersubsidiary power relations, a key variable to explain mandate development and learning processes in MNCs. -- Über funktional-strukturalistische Ansätze hinausgehend, beschäftigt sich dieser Beitrag mit den mikropolitischen Aspekten von Mandatsentwicklungsprozessen in multinationalen Unternehmen. Im Zentrum der Betrachtung stehen die Strategien und Handlungsrationalitäten von Tochtergesellschaftsmanagern im Ausland. Anhand von drei Fallbeispielen zeigt der Beitrag wie Manager deutscher Auslandsgesellschaften in Frankreich individuelle, organisationale und institutionelle Faktoren (Heimat- und Gastlandeffekte) interpretieren und zu einer Handlungsstrategie verbinden. Ausgangspunkt ist dabei zunächst eine Diskussion relevanter Ansätze des Internationalen Managements und der international vergleichenden Organisationsforschung. Diese Ansätze werden um einen mikropolitischen Ansatz erweitert, der auf die spezifische Bedeutung von Nationalzugehörigkeit, professionellem Background und individueller Karriereorientierung bei Tochtergesellschaftsmanagern im Ausland abstellt.
Corporate Donations to the Arts: Philanthropy or Advertising?
This paper is an attempt to provide evidence on two questions: Why do companies sponsor art events, and where exactly does the money go? We analyse data collected on the revenue structure of cultural institutions in Berlin and Hamburg. This data set not only tells us where the money goes, it also allows us to draw conclusions with respect to donors' motives. We regress sponsorships received on the number of visitors and other independent variables. The results are significantly different from those which one would expect if sponsoring were merely a form of advertising.
Regional Patterns of Intangible Capital, Agglomeration Effects and Localised Spillovers in Germany
We use a large micro-dataset to assess the importance of intangible capital - organisation, R&D and ICT capital - for the economic performance of establishments and regions in Germany. In 2003 self-produced intangible capital accounted for more than one fifth of the total capital stock of estab-lishments. More than half of the intangible capital is R&D capital. This high proportion is mainly due to a relatively strong and research-intensive manufacturing sector in Germany. At the regional level, we find descriptive evidence for a positive relationship between intangible capital and the economic performance of regions. This is true both for the level of economic activities and for growth. The results of cross-sectional regressions for the years from 1999 to 2003 indicate that dou-bling the intangible capital intensity of establishments increases the average wage levels by one percent. Regarding the regional economic environment of establishments, we find that the substan-tial net advantages of agglomeration have more to do with broad knowledge and diversity than with regional clustering and specialisation. Separate regressions for the wage levels of non-intangible workers show very similar results. These workers can share the rents of the activities of intangible workers. Thus, intangible capital generates positive externalities not only at the regional level, but also at the level of establishments.Firm productivity, intangible capital, agglomeration, local spillovers
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