One loop superstring effective actions and N=8 supergravity

In a previous article we have shown the existence of a new independent R^4 term, at one loop, in the type IIA and heterotic effective actions, after reduction to four dimensions, besides the usual square of the Bel-Robinson tensor. It had been shown that such a term could not be directly supersymmetrized, but we showed that was possible after coupling to a scalar chiral multiplet. In this article we study the extended (N=8) supersymmetrization of this term, where no other coupling can be taken. We show that such supersymmetrization cannot be achieved at the linearized level. This is in conflict with the theory one gets after toroidal compactification of type II superstrings being N=8 supersymmetric. We interpret this result in face of the recent claim that perturbative supergravity cannot be decoupled from string theory in d>=4, and N=8, d=4 supergravity is in the swampland.Comment: 28 pages, no figure

The Levi-Civita spacetime as a limiting case of the Gamma spacetime

It is shown that the Levi-Civita metric can be obtained from a family of the Weyl metric, the Gamma metric, by taking the limit when the length of its Newtonian image source tends to infinity. In this process a relationship appears between two fundamental parameters of both metrics.Comment: LaTeX2e 17 page

The strategic relevance of business relationships: a preliminary assessment

The ubiquitous contention within the Industrial Networks literature - that business relationships are one of the firm´s most important resources - has not been, in our viewpoint, thoroughly explored. Hence we argue that the ‘Resource-based View of the Firm’ (‘RBV’) may complement the network-based reasoning on the strategic relevance of business relationships. A theoretical framework is proposed – a competence-based view of the firm – which solves RBV´s terminological and inconsistency problems and, more importantly, assures compatibility with the network perspective´s assumptions. The possibility of cross-fertilizing the Industrial Networks and RBV theories seems not only real, but also conceptually profitable for both theoretical fields.Business Relationships, Industrial Networks, Resource-Based View of the Firm, Competence-Based View of the Firm

Of the significance of business relationships

The Industrial Network Theory aims to describe and explain the business relationships and networks in which the focal firm is deeply embedded. One of its major propositions is that business relationships somehow influence, to different extents and over time, the focal firm’s survival. This pertains to the diverse and time-varying significance of business relationships for the focal firm. It has often been implicitly sustained that such significance is strongly related to the role played by business relationships and consequently the relationship outcomes accruing to the focal firm. The logic underlying the relationship significance proposition is outwardly oriented, somewhat overlooking the focal firm’s inside and in particular the conspicuous influence of business relationships on what the focal firm does competently both within and across its vertical boundaries. Arguably, the (predominantly ‘functional’) network-based arguments currently advanced represent a necessary but not sufficient condition for relationship significance. This conceptual paper tentatively suggests that there may be missing a supplementary (essentially internal) explanation supported by Competence-based Theories of the Firm.Industrial Network Theory; relationship significance proposition

Relationship significance: is it sufficiently explained?

The Industrial Networks Theory (cf. Axelsson and Easton, 1992, Hakansson and Snehota, 1995) sets out to describe and explain the business relationships and markets in which the focal firm is deeply embedded. One of its major propositions pertains to the (time-varying) significance of business relationships for the focal firm (Gadde et al., 2003), i.e., business relationships influence to some extent the focal firm’s survival. Such significance seems strongly related to the role played by business relationships and consequently the relationship outcomes accruing to the focal firm. The theoretical justification underlying this proposition is outwardly oriented, somewhat overlooking the inside of the focal firm - in particular the influence of business relationships on what the focal firm does competently within and across its boundaries. Arguably, the creation and appropriation of relationship value by the focal firm is a necessary but not sufficient condition for relationship significance. A supplementary (internal) explanation supported by Knowledge-based Theories of the Firm (e.g., see Kogut and Zander, 1992), we suggest, may be missing. Our aim here has been to intuitively pinpoint a theoretical flaw, further suggesting a feasible path for its solution.Industrial Networks Theory; relationship significance proposition; relationship functions, dysfunctions, benefits, sacrifices, and value

The innovation platform in Mozambique: evidence from Chicualacuala and Changara

As Part of the Livestock Livelihood and Markets Project (LILI Markets), two innovation platforms were implanted in the project sites. First thought to be a mechanism to promote and enhance communication and networking across value chain actors as well as providing them with a platform for addressing common problems the platform, although new, has already surpassed its expected role; it has now become an important element of interaction and problem solving stage among the value chain actors, including the government

How is the relationship significance brought about? A critical realist approach

The markets-as-networks theorists contend, at least tacitly, the significance of business relationships for the focal firm – that is, business relationships contribute somewhat to the focal firm’s survival and growth. We do not deny the existence of significant business relationships but sustain, in contrast to the consensus within the Markets-as-Networks Theory, that relationship significance should not be a self-evident assumption. Significance cannot be a taken-for-granted property of each and every one of the focal firm’s business relationships. We adopt explicitly a critical realist position in this conceptual paper and claim that the relationship significance is an event of the business world, whose causes remain yet largely unidentified. Where the powers and liabilities of business relationships (i.e., their functions and dysfunctions) are put to work, inevitably under certain contingencies (namely the surrounding networks and markets), effects result for the focal firm (often benefits in excess of sacrifices, i.e., relationship value) and as a result the relationship significance is likely to be brought about. In addition, the relationship significance can result from the dual influence that business relationships have on a great part of the structure and powers and liabilities of the focal firm, i.e., its nature and scope respectively.Markets-as-Networks Theory, relationship significance, business relationships, focal firm, resources, competences, activities

TVWS policies to enable efficient spectrum sharing

The transition from analogue to the Digital Terrestrial Television (DTV) in Europe is planned to be completed by the end of the year 2012. The DTV spectrum allocation is such that there are a number of TV channels which cannot be used for additional high power broadcast transmitters due to mutual interference and hence are left unused within a given geographical location, i.e. the TV channels are geographically interleaved. The use of geographically interleaved spectrum provides for the so-called TV white spaces (TVWS) an opportunity for deploying new wireless services. The main objective of this paper is to present the spectrum policies that are suitable for TVWS at European level, identified within the COGEU project. The COGEU project aims the efficient exploitation of the geographical interleaved spectrum (TVWS). COGEU is an ICT collaborative project supported by the European Commission within the 7th Framework Programme. Nine partners from seven EU countries representing academia, research institutes and industry are involved in the project. The COGEU project is a composite of technical, business, and regulatory/policy domains, with the objective of taking advantage of the TV digital switchover by developing cognitive radio systems that leverage the favorable propagation characteristics of the UHF broadcast spectrum through the introduction and promotion of real-time secondary spectrum trading and the creation of new spectrum commons regimes. COGEU will also define new methodologies for compliance testing and certification of TVWS equipment to ensure non-interference coexistence with the DVB-T European standard. The innovation brought by COGEU is the combination of cognitive access to TV white spaces with secondary spectrum trading mechanisms.telecommunications,spectrum management,secondary spectrum market,regulation,TV white spaces,cognitive radio

Zero-point quantum swing of magnetic couples

Quantum fluctuations are ubiquitous in physics. Ranging from conventional examples like the harmonic oscillator to intricate theories on the origin of the universe, they alter virtually all aspects of matter -- including superconductivity, phase transitions and nanoscale processes. As a rule of thumb, the smaller the object, the larger their impact. This poses a serious challenge to modern nanotechnology, which aims total control via atom-by-atom engineered devices. In magnetic nanostructures, high stability of the magnetic signal is crucial when targeting realistic applications in information technology, e.g. miniaturized bits. Here, we demonstrate that zero-point spin-fluctuations are paramount in determining the fundamental magnetic exchange interactions that dictate the nature and stability of the magnetic state. Hinging on the fluctuation-dissipation theorem, we establish that quantum fluctuations correctly account for the large overestimation of the interactions as obtained from conventional static first-principles frameworks, filling in a crucial gap between theory and experiment [1,2]. Our analysis further reveals that zero-point spin-fluctuations tend to promote the non-collinearity and stability of chiral magnetic textures such as skyrmions -- a counter-intuitive quantum effect that inspires practical guidelines for designing disruptive nanodevices