Search results for "general [Quasars]"
showing 10 items of 3787 documents
Enabling and constraining family: young women building their educational paths in Tanzania
2015
For an increasing number of African girls and women, upgrading the level of education has become a strategy for life improvement. This paper analyses the role that family plays in enabling women's education and contributes to understanding on the interconnectivity of education, work and family in women's lives in collective societies. The analysis focuses on how young Tanzanian women perceive the role of family and education in their ‘youth task’, of becoming adult. The analysis is based on interviews with seven young Tanzanian women enrolled in non-formal secondary education and nine professional women enrolled in higher education. The results show that the women were determined to pursue …
Parasite avoidance behaviours in aquatic environments
2018
Parasites, including macroparasites, protists, fungi, bacteria and viruses, can impose a heavy burden upon host animals. However, hosts are not without defences. One aspect of host defence, behavioural avoidance, has been studied in the terrestrial realm for over 50 years, but was first reported from the aquatic environment approximately 20 years ago. Evidence has mounted on the importance of parasite avoidance behaviours and it is increasingly apparent that there are core similarities in the function and benefit of this defence mechanism between terrestrial and aquatic systems. However, there are also stark differences driven by the unique biotic and abiotic characteristics of terrestrial …
Retos en la internacionalización y supervivencia de los nuevos emprendimientos manufactureros
2015
El objetivo de este trabajo es analizar la relación entre la orientación internacional y la supervivencia de empresas manufactureras de reciente creación. Para ello se estudió una muestra de 2.975 nuevos emprendimientos constituidos durante el período 2001-2010 en la industria textil-confección de España. Metodológicamente, se han empleado modelos de duración mediante regresiones de Cox, que modelizan el riesgo relativo asociado con una variable en función del tiempo transcurrido hasta que sucede el evento. Los principales resultados evidencian que la internacionalización de los nuevos emprendimientos es una condición necesaria aunque no suficiente para sobrevivir en una industria globaliza…
Scattering of Co-Current Surface Waves on an Analogue Black Hole
2018
We report on what is to our knowledge the first scattering experiment of surface waves on an accelerating transcritical flow, which in the analogue gravity context is described by an effective spacetime with a black-hole horizon. This spacetime has been probed by an incident co-current wave, which partially scatters into an outgoing countercurrent wave on each side of the horizon. The measured scattering amplitudes are compatible with the predictions of the hydrodynamical theory, where the kinematical description in terms of the effective metric is exact.
Remembering an Era: Roger Penrose’s Paper on “Gravitational Collapse: The Role of General Relativity”
2018
Back in the 1960s, Einstein’s theory of general relativity re-emerged as a field of important research activity. Much of the impetus behind this resurgence came from powerful new mathematical ideas that Roger Penrose and Stephen Hawking applied to prove general singularity theorems for global space-time structures. Their results stirred the imaginations of astrophysicists and gave relativistic cosmology an entirely new research agenda. A decade later, black holes and the big hang model were on the tongues of nearly everyone who followed recent trends in science. As popular expositions dealing with quasars, pulsars, and the geometry of black holes began to appear in magazines and textbooks, …
Anomaly-free scale symmetry and gravity
2023
In this Letter, we address the question of whether the conformal invariance can be considered as a global symmetry of a theory of fundamental interactions. To describe Nature, this theory must contain a mechanism of spontaneous breaking of the scale symmetry. Besides that, the fundamental theory must include gravity, whereas all known extensions of the conformal invariance to the curved space-time suffer from the Weyl anomaly. We show that conformal symmetry can be made free from the quantum anomaly only in the flat space. The presence of gravity would reduce the global symmetry group of the fundamental theory to the scale invariance only. We discuss how the effective Lagrangian respecting …
Crowdsourcing as a mode of open innovation: Exploring drivers of success of a multisided platform through system dynamics modelling
2020
This article aims to explore drivers of success of a crowdsourcing platform. The study conceptualizes crowdsourcing as a mode of open innovation and places such a concept within the context of the sharing economy. Upon this framework, the paper analyses the case of InnoCentive, a successful crowdsourcing platform where innovation-driven organizations search for solutions to their R&D tasks. The system dynamics model frames main InnoCentive business processes and offers a causal perspective on the relationships between platform performance—in terms of users base—and resources structure. The discussion on simulation outputs is carried out through a dynamic performance management view of p…
The Quest for Underpinning Theory of Enterprise Architecture - General Systems Theory
2017
Enterprise architecture originates from the 1980’s. It emerged among ICT practitioners to solve complex problems related to information systems. Currently EA is also utilised to solve business problems, although the focus is still in ICT and its alignment with business. EA can be defined as a description of the current and future states of the enterprise, and as a change between these states to meet stakeholder’s goals. Despite its popularity and 30 years of age, the literature review conducted on top information and management science journals revealed that EA is still lacking the sound theoretical foundation. In this conceptual paper, we propose General Systems Theory (GST) for underpinni…
A posteriori error estimates for time-dependent reaction-diffusion problems based on the Payne-Weinberger inequality
2015
We consider evolutionary reaction-diffusion problem with mixed Dirichlet--Robin boundary conditions. For this class of problems, we derive two-sided estimates of the distance between any function in the admissible energy space and exact solution of the problem. The estimates (majorants and minorants) are explicitly computable and do not contain unknown functions or constants. Moreover, it is proved that the estimates are equivalent to the energy norm of the deviation from the exact solution.
Estimating Regional Input Coefficients and Multipliers: The Use of FLQ is Not a Gamble
2014
Flegg A. T. and Tohmo T. Estimating regional input coefficients and multipliers: the use of FLQ is not a gamble, Regional Studies. This paper re-examines the Finnish evidence presented by Lehtonen and Tykkylainen on the use of location quotients (LQs) in estimating regional input coefficients and multipliers. They argue that the choice of an LQ-based method is a gamble and that there is no single method that can be recommended for general use. It is contended here that this evidence is erroneous and that the FLQ (Flegg's location quotient) yields results far superior to those from competing formulae, so it should provide a satisfactory way of generating an initial set of input coefficients.…