3,256 research outputs found
An Alternative Approach to the Calculation and Analysis of Connectivity in the World City Network
Empirical research on world cities often draws on Taylor's (2001) notion of
an 'interlocking network model', in which office networks of globalized service
firms are assumed to shape the spatialities of urban networks. In spite of its
many merits, this approach is limited because the resultant adjacency matrices
are not really fit for network-analytic calculations. We therefore propose a
fresh analytical approach using a primary linkage algorithm that produces a
one-mode directed graph based on Taylor's two-mode city/firm network data. The
procedure has the advantage of creating less dense networks when compared to
the interlocking network model, while nonetheless retaining the network
structure apparent in the initial dataset. We randomize the empirical network
with a bootstrapping simulation approach, and compare the simulated parameters
of this null-model with our empirical network parameter (i.e. betweenness
centrality). We find that our approach produces results that are comparable to
those of the standard interlocking network model. However, because our approach
is based on an actual graph representation and network analysis, we are able to
assess cities' position in the network at large. For instance, we find that
cities such as Tokyo, Sydney, Melbourne, Almaty and Karachi hold more strategic
and valuable positions than suggested in the interlocking networks as they play
a bridging role in connecting cities across regions. In general, we argue that
our graph representation allows for further and deeper analysis of the original
data, further extending world city network research into a theory-based
empirical research approach.Comment: 18 pages, 9 figures, 2 table
Investigation of vehicle glow in the far ultraviolet
To data, all vehicle glow observations have been conducted in the visible and near infrared wavelength regions. As the Space Telescope's wavelength coverage extends to the far ultraviolet range and current plasma theory of the spacecraft glow phenomena predicts bright glow intensities, a study of the ram glow effects in the 800-1400 angstrom region was undertaken. The data were collected between March 21-28, 1979, from 600 km altitude near local midnight by the University of California, Berkeley's extreme ultraviolet spectrometer on board the polar orbiting STP78-1 satellite. Data from several nighttime orbits obtained outside the South Atlantic Anomaly region and within + or - 30 deg magnetic latitude range were separated into forward (south viewing) and backward (north viewing) bins. Each of these binds was subdivided into three directional categories: (1) up (zenith angles 30-80 deg), (2) side (zenith angles 80-100 deg), and (3) down (zenith angles 120-150 deg). The maximum ram glow effects are expected in the side viewing directions. Our data include possible effects of ram glow signatures in the 800-1400 angstrom wavelength region
Lifetime of Kaonium
The kaon--antikaon system is studied in both the atomic and the strongly
interacting sector. We discuss the influence of the structures of the
and the mesons on the lifetime of kaonium. The strong
interactions are generated by vector meson exchange within the framework of the
standard invariant effective Lagrangian. In the atomic
sector, the energy levels and decay widths of kaonium are determined by an
eigenvalue equation of the Kudryavtsev--Popov type, with the strong interaction
effects entering through the complex scattering length for scattering
and annihilation. The presence of two scalar mesons, and ,
leads to a ground state energy for the kaonium atom that is shifted above the
point Coulomb value by a few hundred eV. The effect on the lifetime for the
kaonium decay into two pions is much more dramatic. This lifetime is reduced by
two orders of magnitude from sec for annihilation in a
pure Coulomb field down to sec when the strong
interactions are included. The analysis of the two photon decay width of the
suggests a generalization of the molecular picture which reduces the
lifetime of kaonium still further to .Comment: 33 pages, 12 figures;3 new figures and new comment concerning the a
Job creation and regional change under New Labour : a shift-share analysis
The paper examines changes in UK regional employment during the period of the New Labour administration, 1997–2010, with the Blair and Brown administrations considered separately. The paper employs a shift-share analysis of workplace employment data by industry and subregion, using annual data from the UK Labour Force Survey. The results reveal significant regional shifts, with interesting spatial dynamics in and around the capital and resilient employment growth in the provinces
Critiquing Construct Validity in World City Network Research: Moving from Office Location Networks to Inter-Organizational Projects in the Modeling of Intercity Business Flows
The interlocking world city network model and other office location approaches (OLAs) have become the most widely used empirical models of the world city network (WCN). Despite numerous methodological improvements, they continue to rely on a legacy of using data on office locations of firms to indirectly estimate intercity business flows. To advance the dialogue about how to improve on existing empirical models of the WCN, we examine the content, construct and structural validity of OLAs. We analyze the link between the theoretical construct of intercity business flows and network projections obtained from office location data and uncover evidence that calls into question the validity of OLAs as empirical models of the WCN. In the spirit of no deconstruction without reconstruction, we then develop an alternative empirical model of the WCN, based on directly observable relational ties among APS firms, which are formed through co-production of complex services. We call this the inter-organizational project approach (IOPA). We argue for IOPA's construct validity as an empirical model of the WCN and offer empirical evidence for its structural validity. We demonstrate it using a global sample of 161,114 investment bank syndicates in the 2000–2015 period
Social Preferences, Skill Segregation and Wage Dynamics
We study the earning structure and the equilibrium asignment of workers to firms in a model in which workers have social preferences, and skills are perfectly substitutable in production. Firms offer long-term contracts, and we allow for frictions in the labour market in the form of mobility costs. The model delivers specific predictions about the nature of worker flows, about the characteristic of workplace skill segregation, and about wage dispersion both within and cross firms. We shows that long-term contracts in the resence of social preferences associate within-firm wage dispersion with novel "internal labour market" features such as gradual promotions, productivity-unrelated wage increases, and downward wage flexibility. These three dynamic features lead to productivity-unrelated wage volatily within firms.Publicad
Exploring the role of professional associations in collective learning in London and New York's advertising and law professional service firm clusters.
The value of regional economies for collective learning has been reported by numerous scholars. However often work has been criticised for lacking analytical clarity and failing to explore the architectures of collective learning and the role of the knowledge produced in making firms in a cluster economy successful. This paper engages with these problematics and investigates how collective learning is facilitated in the advertising and law professional service firm clusters in London and New York. It explores the role of professional associations and investigates how they mediate a collective learning process in each city. It argues that professional associations seed urban communities of practice that emerge outside of the formal activities of professional associations. In these communities individual with shared interests in advertising and law learn from one-another and are therefore able to adapt and evolve one-another approaches to common industry challenges. The paper suggests this is another form of the variation Marshall highlighted in relation to cluster-based collective learning. The paper also shows how the collective learning process is affected by the presence, absence and strength of an institutional thickness. It is therefore argued that a richer understanding of institutional affects is needed in relation to CL
The reaction pi N to pi pi N in a meson-exchange approach
A resonance model for two-pion production in the pion-nucleon reaction is
developed that includes information obtained in the analysis of pion-nucleon
scattering in a meson-exchange model. The baryonic resonances Delta(1232),
N*(1440), N*(1520), N*(1535), and N*(1650) are included. The model reproduces
the total cross sections up to kinetic energies of the incident pion of 350 MeV
and obtains the shapes of the differential cross sections in reasonable
agreement with the data.Comment: 7 pages, 7 figures, 2 table
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