A mass-transportation approach to a one dimensional fluid mechanics model with nonlocal velocity

We consider a one dimensional transport model with nonlocal velocity given by the Hilbert transform and develop a global well-posedness theory of probability measure solutions. Both the viscous and non-viscous cases are analyzed. Both in original and in self-similar variables, we express the corresponding equations as gradient flows with respect to a free energy functional including a singular logarithmic interaction potential. Existence, uniqueness, self-similar asymptotic behavior and inviscid limit of solutions are obtained in the space $\mathcal{P}_{2}(\mathbb{R})$ of probability measures with finite second moments, without any smallness condition. Our results are based on the abstract gradient flow theory developed in \cite{Ambrosio}. An important byproduct of our results is that there is a unique, up to invariance and translations, global in time self-similar solution with initial data in $\mathcal{P}_{2}(\mathbb{R})$, which was already obtained in \textrm{\cite{Deslippe,Biler-Karch}} by different methods. Moreover, this self-similar solution attracts all the dynamics in self-similar variables. The crucial monotonicity property of the transport between measures in one dimension allows to show that the singular logarithmic potential energy is displacement convex. We also extend the results to gradient flow equations with negative power-law locally integrable interaction potentials

Are Magnetic Wind-Driving Disks Inherently Unstable?

There have been claims in the literature that accretion disks in which a centrifugally driven wind is the dominant mode of angular momentum transport are inherently unstable. This issue is considered here by applying an equilibrium-curve analysis to the wind-driving, ambipolar diffusion-dominated, magnetic disk model of Wardle & Konigl (1993). The equilibrium solution curves for this class of models typically exhibit two distinct branches. It is argued that only one of these branches represents unstable equilibria and that a real disk/wind system likely corresponds to a stable solution.Comment: 5 pages, 2 figures, to be published in ApJ, vol. 617 (2004 Dec 20). Uses emulateapj.cl

Structure of potentials with NN Higgs doublets

Extensions of the Standard Model with $N$ Higgs doublets are simple extensions presenting a rich mathematical structure. An underlying Minkowski structure emerges from the study of both variable space and parameter space. The former can be completely parametrized in terms of two future lightlike Minkowski vectors with spatial parts forming an angle whose cosine is $-(N-1)^{-1}$. For the parameter space, the Minkowski parametrization enables one to impose sufficient conditions for bounded below potentials, characterize certain classes of local minima and distinguish charge breaking vacua from neutral vacua. A particular class of neutral minima presents a degenerate mass spectrum for the physical charged Higgs bosons.Comment: 11 pages. Revtex4. Typos corrected. Few comments adde

Wearing failure as a path to innovation

Innovation is a widely acknowledged key component of corporate performance management. However, most of the literature on this topic has tended to focus on determinants of corporate failure, thereby neglecting to look at the role of innovation failure in triggering innovative initiatives. By using a sample of companies covered by 2014 Community Innovation Survey data and applying econometric models, this study sought to analyze the impacts of innovative project failure. The results show that innovation failure is negatively correlated with companies’ experience and acquisition of external knowledge. The main findings are consistent with the scarce literature on this research topic, and highlight the positive role that companies’ accumulated experience has in their assimilation of knowledge flows.info:eu-repo/semantics/publishedVersio

Technology transfer, climate change mitigation, and environmental patent impact on sustainability and economic growth: a comparison of European countries

Most of the literature on technology transfer has tended to focus on the country or regional level, neglecting to look at the continent-level flow of knowledge that is becoming more important due to regional trading blocs. This study sought to fill the gap in research on the role of technology transfer in the European continent (i.e., countries inside and outside the Eurozone) by focusing on environment-related patents. The research also included examining the effects of environmental water-related adaptation technology and climate change mitigation patents on real gross domestic product. The results contribute to the literature on technology transfer policies by highlighting how environmental patents influence Europe’s economic growth rate and whether countries’ geographical location can affect their level of entrepreneurship and innovation. The technology-organization-environment (TOE) and sustainability perspectives were used as a theoretical framework for understanding how geographical contexts influence technology transfer in terms of environment-related patents. Implications for management, theory and policy are discussed together with the study’s limitations and suggestions for future research.info:eu-repo/semantics/publishedVersio