The Gauss-linking integral for disjoint oriented smooth closed curves is derived linking integrals from the Biot-Savart description of the magnetic field. DeTurck and Gluck extend this linking from 3-space <em>R...The Gauss-linking integral for disjoint oriented smooth closed curves is derived linking integrals from the Biot-Savart description of the magnetic field. DeTurck and Gluck extend this linking from 3-space <em>R</em><sup>3</sup> to <em>SU</em> (2) space of the unit 3-sphere and hyperbolic space in Minkowski <em>R</em><sup>1,3</sup>. I herein extend Gauss-linking to self-linking and develop the concept of self-dual, which is then applied to gravitomagnetic dynamics. My purpose is to redefine Wheeler’s <em>geon</em> from unstable field structures based on the electromagnetic field to self-stabilized gravitomagnetic field structures.展开更多
Recently the cultivation of opium poppy in Afghanistan reached unprecedented levels.It is agreed that the complex and coupled interactions of social,economic and environmental drivers are crucial for understanding the...Recently the cultivation of opium poppy in Afghanistan reached unprecedented levels.It is agreed that the complex and coupled interactions of social,economic and environmental drivers are crucial for understanding the spatial and temporal dynamics of opium poppy cultivation in Afghanistan.In this context,we present an integrated risk concept,which considers environmental and socio-economic drivers of opium poppy cultivation.A set of spatially explicit indicators for the environmental suitability and socio-economic vulnerability was established and populated from a variety of databases.Subsequently,novel methods of modelling homogeneous and spatially explicit regions of opium poppy cultivation suitability,socio-economic vulnerability and risk are developed and applied.The risk assessment results demonstrate the complex nature of the illicit crops production in Afghanistan and prompt a more profound examination of the drivers of opium poppy cultivation in a spatial context.The study also confirms what has already been widely discussed in literature:that reasons for cultivation are spatially diverse and often distinct,meaning that any formulation of generalized explanations cannot be drawn without ignoring a more complex reality.Thus,an integrative spatial view of risk,which integrates the social dimension as well as environmental parameters,is required to better identify context-specific intervention measures.展开更多
La Chines’est rapidement développée ces dernières années,elle est maintenant la deuxième puissance économique du monde.Nous pouvons en être fiers,mais,c’est loin d’être suffi...La Chines’est rapidement développée ces dernières années,elle est maintenant la deuxième puissance économique du monde.Nous pouvons en être fiers,mais,c’est loin d’être suffisant si展开更多
文摘The Gauss-linking integral for disjoint oriented smooth closed curves is derived linking integrals from the Biot-Savart description of the magnetic field. DeTurck and Gluck extend this linking from 3-space <em>R</em><sup>3</sup> to <em>SU</em> (2) space of the unit 3-sphere and hyperbolic space in Minkowski <em>R</em><sup>1,3</sup>. I herein extend Gauss-linking to self-linking and develop the concept of self-dual, which is then applied to gravitomagnetic dynamics. My purpose is to redefine Wheeler’s <em>geon</em> from unstable field structures based on the electromagnetic field to self-stabilized gravitomagnetic field structures.
基金This work was supported by the Seventh Framework Programme[312912].
文摘Recently the cultivation of opium poppy in Afghanistan reached unprecedented levels.It is agreed that the complex and coupled interactions of social,economic and environmental drivers are crucial for understanding the spatial and temporal dynamics of opium poppy cultivation in Afghanistan.In this context,we present an integrated risk concept,which considers environmental and socio-economic drivers of opium poppy cultivation.A set of spatially explicit indicators for the environmental suitability and socio-economic vulnerability was established and populated from a variety of databases.Subsequently,novel methods of modelling homogeneous and spatially explicit regions of opium poppy cultivation suitability,socio-economic vulnerability and risk are developed and applied.The risk assessment results demonstrate the complex nature of the illicit crops production in Afghanistan and prompt a more profound examination of the drivers of opium poppy cultivation in a spatial context.The study also confirms what has already been widely discussed in literature:that reasons for cultivation are spatially diverse and often distinct,meaning that any formulation of generalized explanations cannot be drawn without ignoring a more complex reality.Thus,an integrative spatial view of risk,which integrates the social dimension as well as environmental parameters,is required to better identify context-specific intervention measures.
文摘La Chines’est rapidement développée ces dernières années,elle est maintenant la deuxième puissance économique du monde.Nous pouvons en être fiers,mais,c’est loin d’être suffisant si
