180 research outputs found

    Regional cooperation in a thriving entrepreneurial economy : a holistic view on innovation, entrepreneurship and economic development

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    In this research, we investigate the role of innovation and entrepreneurship as well as entrepreneurial communities in the process of economic growth and development. Current research on development issues strongly focusses either on the micro-level or on the macro-level of national economies disregarding the holistic nature of economic development. Entrepreneurial communities represent a conceptual link between the macro-perspective on economic development and the micro-perspective on entrepreneurial initiatives as a tipping point for economic development. In this paper, we present a theoretical construct of entrepreneurial communities. Additionally, we introduce a qualitative model of thriving entrepreneurial economies following a holistic perspective on development issues. The theoretical analysis is based on systems thinking and systems approaches to management. Structures of entrepreneurial communities and networking between regional communities will be explored and reflected in a theoretical exploration. The introduced theoretical construct of an entrepreneurial community is based on living systems theory. The qualitative systems model of the thriving entrepreneurial economy is deduced from a descriptive model (word model).http://www.worldscientific.com/worldscinet/ijitmhj2021Graduate School of Technology Management (GSTM

    The vital entrepreneurial learning organization : a corporate mindset for entrepreneurial change management

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    A globally competitive technology business environment requires a dual perspective for entrepreneurial change management to secure long-term and short-term vitality in mature organizations. Entrepreneurial organizations should shape the environment-organization relation and pursue entrepreneurial activities in new businesses and in existing businesses to integrate efficiency, innovation and adaptation. The presented concept of a vital entrepreneurial learning organization describes a systematic theoretical framework for firm-level entrepreneurship in dynamic environments. The theoretical constructs developed on theoretical exploration are: nine design elements of holistic intrapreneurship, three entrepreneurial tasks and process model, role model for the entrepreneurial organization, conceptual framework of the business environment, qualitative systems model for entrepreneurial change management, and five organizational learning elements. These theoretical building blocks provide new insights into the nature of holistic intrapreneurship.http://www.worldscinet.com/ijitm2015-12-31hb201

    Numerical simulations with a first order BSSN formulation of Einstein's field equations

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    We present a new fully first order strongly hyperbolic representation of the BSSN formulation of Einstein's equations with optional constraint damping terms. We describe the characteristic fields of the system, discuss its hyperbolicity properties, and present two numerical implementations and simulations: one using finite differences, adaptive mesh refinement and in particular binary black holes, and another one using the discontinuous Galerkin method in spherical symmetry. The results of this paper constitute a first step in an effort to combine the robustness of BSSN evolutions with very high accuracy numerical techniques, such as spectral collocation multi-domain or discontinuous Galerkin methods.Comment: To appear in Physical Review

    European derived Saccharomyces cerevisiae colonization of New Zealand vineyards aided by humans

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    Humans have acted as vectors for species and expanded their ranges since at least the dawn of agriculture. While relatively well characterized for macrofauna and macroflora, the extent and dynamics of human-aided microbial dispersal is poorly described. We studied the role which humans have played in manipulating the distribution of Saccharomyces cerevisiae, one of the world’s most important microbes, using whole genome sequencing. We include 52 strains representative of the diversity in New Zealand to the global set of genomes for this species. Phylogenomic approaches show an exclusively European origin of the New Zealand population, with a minimum of ten founder events mostly taking place over the last 1,000 years. Our results show that humans have expanded the range of S. cerevisiae and transported it to New Zealand where it was not previously present, where it has now become established in vineyards, but radiation to native forests appears limited

    How can we get close to zero? The potential contribution of biomedical prevention and the investment framework towards an effective response to HIV.

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    BACKGROUND: In 2011 an Investment Framework was proposed that described how the scale-up of key HIV interventions could dramatically reduce new HIV infections and deaths in low and middle income countries by 2015. This framework included ambitious coverage goals for prevention and treatment services resulting in a reduction of new HIV infections by more than half. However, it also estimated a leveling in the number of new infections at about 1 million annually after 2015. METHODS: We modeled how the response to AIDS can be further expanded by scaling up antiretroviral treatment (ART) within the framework provided by the 2013 WHO treatment guidelines. We further explored the potential contributions of new prevention technologies: 'Test and Treat', pre-exposure prophylaxis and an HIV vaccine. FINDINGS: Immediate aggressive scale up of existing approaches including the 2013 WHO guidelines could reduce new infections by 80%. A 'Test and Treat' approach could further reduce new infections. This could be further enhanced by a future highly effective pre-exposure prophylaxis and an HIV vaccine, so that a combination of all four approaches could reduce new infections to as low as 80,000 per year by 2050 and annual AIDS deaths to 260,000. INTERPRETATION: In a set of ambitious scenarios, we find that immediate implementation of the 2013 WHO antiretroviral therapy guidelines could reduce new HIV infections by 80%. Further reductions may be achieved by moving to a 'Test and Treat' approach, and eventually by adding a highly effective pre-exposure prophylaxis and an HIV vaccine, if they become available

    Are moving punctures equivalent to moving black holes?

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    When simulating the inspiral and coalescence of a binary black-hole system, special care needs to be taken in handling the singularities. Two main techniques are used in numerical-relativity simulations: A first and more traditional one ``excises'' a spatial neighbourhood of the singularity from the numerical grid on each spacelike hypersurface. A second and more recent one, instead, begins with a ``puncture'' solution and then evolves the full 3-metric, including the singular point. In the continuum limit, excision is justified by the light-cone structure of the Einstein equations and, in practice, can give accurate numerical solutions when suitable discretizations are used. However, because the field variables are non-differentiable at the puncture, there is no proof that the moving-punctures technique is correct, particularly in the discrete case. To investigate this question we use both techniques to evolve a binary system of equal-mass non-spinning black holes. We compare the evolution of two curvature 4-scalars with proper time along the invariantly-defined worldline midway between the two black holes, using Richardson extrapolation to reduce the influence of finite-difference truncation errors. We find that the excision and moving-punctures evolutions produce the same invariants along that worldline, and thus the same spacetimes throughout that worldline's causal past. This provides convincing evidence that moving-punctures are indeed equivalent to moving black holes.Comment: 4 pages, 3 eps color figures; v2 = major revisions to introduction & conclusions based on referee comments, but no change in analysis or result

    Using Biostimulants Containing Phytohormones to Recover Hail-Damaged Essential Oil Plants

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    Hail can cause significant damage to aromatic and medicinal plants; however, this has never been investigated scientifically on most of aromatic and medicinal plants. Globally, essential oil crop producers primarily make use of agricultural crop insurance and costly mitigation strategies to recover lost production costs and alleviate hail-damaged plants. However, most aromatic and medicinal plants are not covered under agricultural crop insurance, and many commercial farmers are not able to regularly employ expensive alternative strategies. Therefore, hail damage may present a challenge to essential oil growers. The use of natural and synthetic phytohormones in a form of biostimulants, as an alternative biological mitigation strategy against hail damage in essential oil crops, has not received much attention, and there is no information on this topic. Exogenous applications of natural and synthetic biostimulants have consistently demonstrated growth enhancement, nutrient acquisition, yield and quality optimization, as well as physiological efficiency in plants. Biostimulants in a form of phytohormones are involved in diverse plant physiological processes, including the regulation of gene expression for adaptive responses to biotic and abiotic stresses. Using biostimulants, this chapter will detail the potential recovery response of aromatic and medicinal plants to hail damage, and the response of plants treated with biostimulants

    SDSS 0956+5128: A Broad-line Quasar with Extreme Velocity Offsets

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    We report on the discovery of a Type 1 quasar, SDSS 0956+5128, with a surprising combination of extreme velocity offsets. SDSS 0956+5128 is a broad-lined quasar exhibiting emission lines at three substantially different redshifts: a systemic redshift of z ~ 0.714 based on narrow emission lines, a broad MgII emission line centered 1200 km/s bluer than the systemic velocity, at z ~ 0.707, and broad H\alpha and H\beta emission lines centered at z ~ 0.690. The Balmer line peaks are 4100 km/s bluer than the systemic redshift. There are no previously known objects with such an extreme difference between broad MgII and broad Balmer emission. The two most promising explanations are either an extreme disk emitter or a high-velocity black hole recoil. However, neither explanation appears able to explain all of the observed features of SDSS 0956+5128, so the object may provide a challenge to our general understanding of quasar physics.Comment: ApJ, accepte

    The spin-flip phenomenon in supermassive black hole binary mergers

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    Massive merging black holes will be the primary sources of powerful gravitational waves at low frequency, and will permit to test general relativity with candidate galaxies close to a binary black hole merger. In this paper we identify the typical mass ratio of the two black holes but then show that the distance when gravitational radiation becomes the dominant dissipative effect (over dynamical friction) does not depend on the mass ratio. However the dynamical evolution in the gravitational wave emission regime does. For the typical range of mass ratios the final stage of the merger is preceded by a rapid precession and a subsequent spin-flip of the main black hole. This already occurs in the inspiral phase, therefore can be described analytically by post-Newtonian techniques. We then identify the radio galaxies with a super-disk as those in which the rapidly precessing jet produces effectively a powerful wind, entraining the environmental gas to produce the appearance of a thick disk. These specific galaxies are thus candidates for a merger of two black holes to happen in the astronomically near future.Comment: v3: 36 pages, 1 figure; discussion on the validity of the model and estimates for the angular value of the spin-flip added to Section 5; v4: minor changes, 2 new references, published versio

    Renormalized spin coefficients in the accumulated orbital phase for unequal mass black hole binaries

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    We analyze galactic black hole mergers and their emitted gravitational waves. Such mergers have typically unequal masses with mass ratio of the order 1/10. The emitted gravitational waves carry the inprint of spins and mass quadrupoles of the binary components. Among these contributions, we consider here the quasi-precessional evolution of the spins. A method of taking into account these third post-Newtonian (3PN) effects by renormalizing (redefining) the 1.5 PN and 2PN accurate spin contributions to the accumulated orbital phase is developed.Comment: 10 pages, to appear in Class. Quantum Grav. GWDAW13 Proceedings Special Issue, v2: no typos conjectur
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