We study the decay of solutions of the wave equation in some expanding cosmological spacetimes, namely flat Friedmann-Lemaître-Robertson-Walker (FLRW) models and the cosmological region of the Reissner-Nordström-de Sitter (RNdS) solution. By introducing a partial energy and using an iteration scheme, we find that, for initial data with finite higher order energies, the decay rate of the time derivative is faster than previously existing estimates. For models undergoing accelerated expansion, our decay rate appears to be (almost) sharp.
We analyze in detail the geometry and dynamics of the cosmological region arising in spherically symmetric black hole solutions of the Einstein-Maxwell-scalar field system with a positive cosmological constant. More precisely, we solve, for such a system, a characteristic initial value problem with data emulating a dynamic cosmological horizon. Our assumptions are fairly weak, in that we only assume that the data approaches that of a subextremal Reissner-Nordström-de Sitter black hole, without imposing any rate of decay. We then show that the radius (of symmetry) blows up along any null ray parallel to the cosmological horizon ("near" i + ), in such a way that r = +∞ is, in an appropriate sense, a spacelike hypersurface. We also prove a version of the Cosmic No-Hair Conjecture by showing that in the past of any causal curve reaching infinity both the metric and the Riemann curvature tensor asymptote to those of a de Sitter spacetime. Finally, we discuss conditions under which all the previous results can be globalized.
This paper investigates the relationship between human capital in micro and small enterprises and their respective behaviors in innovation and internationalization. Based on a case study of interpretative nature, from 2010 till 2012 we collected data about the agri‑food complex of Tagus Valley (Portugal) through triangulation of techniques typically used in qualitative research: direct observation (in farms, units of processing, storage and packaging food stuffs and wines, and regulatory and promotional agents); semi‑structured interviews with individuals representing the various categories of agents involved, alongside a survey with 110 business agents; and statistical data gathered in the Portuguese Agriculture Census. Survey data were object of descriptive, correlational and regression analyses. Our research provides evidence of firms making use of stable partnerships with intermediary economic agents and promoting organizations and demonstrating how effective are endogenous assets (especially those of non‑mercantile nature) to the competitiveness of a rural territory, in the framework of Common Agricultural Policy. In terms of public policies for competitiveness and innovation, according to an institutional view, the state and regional/local governments, research institutions (public or private), higher education institutions and business training centers, sharing a common agenda for endogenous assets valuation, might play a strategic role in an economy strongly built on micro and small enterprises, whose sustainability depends on collaborative networking.
Purpose – The purpose of this paper is to show the relevance of territorial innovation systems approach for non-central regions’ development strategies. The research made allowed to identify actions of collective efficiency to strengthen endogenous capacity for regional innovation, and also to detect some institutional weaknesses that inhibit the innovation dynamics in a particular rural region (Tagus Valley). Design/methodology/approach – The research followed an interpretive case study, of explanatory type. Data collecting method comprised semi-structured face-to-face interviews with business agents and local government members, direct observation of innovation activities and documentary analysis. Statistical methods to analyse the firms’ innovation behaviour, as well as owners and managers’ perceptions, were also used in order to improve the trustworthiness of the research. Findings – The results show that innovation is positively associated to a diverse set of institutional factors that shape a territorially embedded innovation system, in which the firms’ innovation activity is chiefly based on localized learning processes. Moreover, a path of smart and creative diversification area is detected, but there are substantial differences between firms belonging to agro-food supply chain. While food industries and wineries show very interesting levels of investment in innovation activities and external knowledge synergies, farmers/producers depend greatly from producers’ organizations. Research limitations/implications – Given the absence of generalizability and some speculative argumentation, further research needs to be done, especially about the critical role of higher education institutions to promote innovation. Practical implications – The paper provides empirical insights about the role of actors belonging to the governance layer inherent to the territorial innovation system in discussion. Originality/value – The paper fulfils an identified need to systematize institutional factors able to affect non-central regions innovation.
This paper aims to analyse the innovation performance, within a set of economic activities - namely the regional agrofood supply chain - that characterize the pattern of productive specialization of Tagus Valley, under the hypothesis of several determinant factors, of entrepreneurial and/or territorial nature, framed by an analysis model extensible to other regions. Following an investigation of interpretative nature, methodology for collecting data was guided through triangulation of sources: direct observation; semi-structured interviews to individuals representing the various categories of agents involved, and documentary research. These were complemented with an inquiry to business agents, whose data were subject to statistical treatment. Besides the identification of an important set of deficits of institutional nature, inhibitors of innovation performance, the study also allowed formulating various proposals for the purpose of territorial governance, highlighting the need to strengthen the transfer of knowledge to the micro and small companies engaged in agricultural activities. In general, this paper proposes an analytical framework to a better understanding of innovation dynamics in any region according to its specificities including the role of public institutions in this process.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.