Public climate-change skepticism,energy preferences and political participation     

Anita Engels  Otto Hüther  Mike Schäfer  Hermann Held 《Global Environmental Change》2013,23(5):1018-1027

Many studies have shown a general decline of public concern about climate change or vice versa a rise in public climate-change skepticism, in particular in the U.S. and other Anglo-Saxon countries. There is a vivid debate on whether this is a global phenomenon, on which factors explain the decline, and on the broader societal implications of these trends in the context of the transformation toward a low-carbon society. We add to this literature by presenting the results of a recent general population survey in Germany in which we looked for systematic linkages between public climate-change skepticism on one hand, and energy preferences and political participation on the other. Germany is an interesting testbed as it is currently involved in a large-scale restructuring of its system of energy supply toward renewable energy sources (the “Energiewende”). Our results indicate that climate-change skepticism has not diffused widely in Germany, but that it correlates with less support of renewable energy sources. However, skepticism correlates negatively with political participation, and there is no strong political outlet for public climate-change skepticism in Germany. Alternative potential barriers for the successful implementation of the “Energiewende” are also discussed.  相似文献   

Long gamma-ray burst progenitors: boundary conditions and binary models     

E. P. J. van den Heuvel  S.-C. Yoon 《Astrophysics and Space Science》2007,311(1-3):177-183

The observed association of Long Gamma-Ray Bursts (LGRBs) with peculiar Type Ic supernovae gives support to Woosley‘s collapsar/hypernova model, in which the GRB is produced by the collapse of the rapidly rotating core of a massive star to a black hole. The association of LGRBs with small star-forming galaxies suggests low-metallicity to be a condition for a massive star to evolve to the collapsar stage. Both completely-mixed single star models and binary star models are possible. In binary models the progenitor of the GRB is a massive helium star with a close companion. We find that tidal synchronization during core-helium burning is reached on a short timescale (less than a few millennia). However, the strong core-envelope coupling in the subsequent evolutionary stages is likely to rule out helium stars with main-sequence companions as progenitors of hypernovae/GRBs. On the other hand, helium stars in close binaries with a neutron-star or black-hole companion can, despite the strong core-envelope coupling in the post-helium burning phase, retain sufficient core angular momentum to produce a hypernova/GRB.  相似文献   

On derivation of EIH (Einstein–Infeld–Hoffman) equations of motion from the linearized metric of general relativity theory     

Victor Brumberg 《Celestial Mechanics and Dynamical Astronomy》2007,99(3):245-252

The half-century old idea of Infeld to use the variational principle of the general relativity field equations is reminded to show that the commonly employed EIH (Einstein–Infeld–Hoffman) equations of motion may be derived from the linearized (weak-field) metric alone. Based on it, the linearized metric might be sufficient for post-Newtonian celestial mechanics and astrometry enabling one to derive the post-Newtonian equations of motion and rotation of celestial bodies as well as the post-Newtonian equations of light propagation within the general relativity framework.  相似文献   

The emergence of cosmic repulsion     

《Astroparticle Physics》2015

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基于GPU-OpenACC的气候模式加速优化研究     

肖洒  魏敏  邓帅  徐达  张晨琛 《气象》2019,45(7):1001-1008

为使数值模式适应异构架构在高性能计算领域的快速发展趋势,本文基于OpenACC语言,对气候模式BCC_AGCM3.0中动力框架三段程序段进行GPU加速优化试验。通过异步执行设置、循环内移、数据管理及向量参数化配置等方式,对模式中计算密集部分程序段进行GPU加速并行化,并进行了优化运行效率对比及正确性验证。试验结果表明,BCC_AGCM3.0模式中三段程序段GPU加速后效率提升均在3倍以上,BCC_AGCM气候模式全球涡度均方根相对误差控制在一定范围之内。加速方法及策略对于数值天气气候模式在异构环境下的移植与优化具有一定参考价值。  相似文献   

Linearized stability of Reissner Nordstrom de-Sitter thin shell wormholes     

《New Astronomy》2015

Using the Darmois–Israel formalism the dynamical analysis of Reissner Nordstrom de-Sitter thin shell wormholes, at the wormhole throat, are determined by considering linearized radial perturbations around static solutions.The region of stability in the presence of a large value of charge is significantly increased. Also, the region of stability in the presence of a positive large value of cosmological constant is significantly increased.  相似文献   

The post-Newtonian mean anomaly advance as further post-Keplerian parameter in pulsar binary systems     

Lorenzo Iorio 《Astrophysics and Space Science》2007,312(3-4):331-335

The post-Newtonian gravitoelectric secular rate of the mean anomaly ℳ is worked out for a two-body system in the framework of the General Theory of Relativity. The possibility of using such an effect, which is different from the well known decrease of the orbital period due to gravitational wave emission, as a further post-Keplerian parameter in binary systems including at least one pulsar is examined. The resulting effect is almost three times larger than the periastron advance . E.g., for the recently discovered double pulsar system PSR J0737-3039 A+B it would amount to −47.79 deg yr⁻¹. This implies that it could be extracted from the linear part of a quadratic fit of the orbital phase because the uncertainties both in the linear drift due to the mean motion and in the quadratic shift due to the gravitational wave are smaller. The availability of such additional post-Keplerian parameter would be helpful in further constraining the General Theory of Relativity, especially for such systems in which some of the other post-Keplerian parameters can be measured with limited accuracy. Moreover, also certain pulsar-white dwarf binary systems, characterized by circular orbits like PSR B1855+09 and a limited number of measured post-Keplerian parameters, could be used for constraining competing theories of gravity.  相似文献   

Investigating cross-contamination of aquifers     

Paul M. Santi  John E. McCray  Jamie L. Martens 《Hydrogeology Journal》2006,14(1-2):51-68

Shallow aquifers can cross-contaminate deeper aquifers through penetration of an intervening aquitard, via sandy intervals in the aquitard, along well casings, across long well screens, or around aquitard pinchouts. Distinguishing among these potential pathways requires the use of evaluation tools that may support or eliminate certain pathways. These tools include groundwater gradient and aquitard penetration calculations, aquifer pumping test interpretation techniques, chemical concentration plots and statistical methods, hydraulic conductivity-based travel time calculations, pumping-concentration tests, methods for evaluating leaky wells, and methods for evaluating aquitard continuity. Based on analysis of several of these techniques at three sites experiencing aquifer cross-contamination, the authors conclude that calculation of flow rates for various pathways is the single most useful method to confirm or refute specific pathways. Evaluation of leaky wells and aquitard continuity generally must be coupled with other tools to adequately test specific pathways. While fingerprinting, statistical analysis or ratio analysis of contaminants from various sources and receptors was not completed for any of the evaluated sites, the authors believe that these techniques have strong potential for confirming or eliminating pathways. Future research in this area is suggested. Furthermore, the interpretation of pumping-concentration tests is not well developed and needs further assessment.

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Resumen Acuíferos someros pueden ocasionar contaminación transversal de acuíferos profundos mediante la penetración de un acuitardo intermedio, a través de intervalos arenosos en el acuitardo, a lo largo del revestimiento de pozos, o en las inmediaciones de lentes de acuitardos. Para distinguir entre estas trayectorias potenciales se requiere el uso de herramientas de evaluación que pueden apoyar o eliminar ciertas trayectorias. Estas herramientas incluyen cálculos de gradientes de agua subterránea y penetración de acuitardos, técnicas de interpretación de pruebas de bombeo de acuíferos, diagramas de concentración química y métodos estadísticos, estimaciones de conductividad hidráulica en base al tiempo de viaje, pruebas de concentración de bombeo, métodos para evaluar pozos con fugas, y métodos para evaluar la continuidad de acuitardos. Basándose en el análisis de varias de estas técnicas en tres sitios que experimentan contaminación transversal de acuíferos, los autores concluyen que la estimación de ritmos de flujo para varias trayectorias es el único método más útil para confirmar o rechazar trayectorias de flujo específicas. La evaluación de pozos con fugas y continuidad de acuitardos generalmente debe estar acompañada con otras herramientas para probar adecuadamente trayectorias específicas. Aunque no se completó para ninguno de los sitios evaluados técnicas de huellas, análisis estadístico o análisis de relaciones de contaminantes de varias fuentes y receptores, los autores creen que estas técnicas tienen fuerte potencial en la confirmación o eliminación de trayectorias. Se sugiere investigación futura en esta área. Además, la interpretación de pruebas de concentración de bombeo no se ha desarrollado bien y necesita evaluación posterior.

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Résumé Les aquifères de surface peuvent contaminer les aquifères plus profonds à travers un aquitard, un intersection sableuse dans laquitard, le long des forages et de leur crépines, ou de la terminaison biseautée des aquitards. Distinguer et sélectionner ces différents modes de contamination nécessite lutilisation doutils dévaluation. Ces outils incluent le gradient découlement des eaux souterraines et le calcul de pénétration des aquitards, les techniques dinterprétation des essais de pompage, les méthodes dinterprétation chimiques et de traitement statistique, les calculs des temps de transferts sur base de la conductivité, les tests de pompage couplé aux analyses de concentration, les méthodes pour évaluer linfiltration directe alimentant les forages, et les méthodes permettant dévaluer la continuité des aquitards. Basé sur lanalyse de plusieurs de ces techniques sur trois sites expérimentales présentant des contaminations transversale, les auteurs concluent que le calcul des rapports découlement est la méthode la plus simple pour confirmer ou refuser les voies spécifiques. Alors que le traçage, les analyses statistiques et les analyses de la contamination provenant de différentes sources et récepteurs nétait pas complètes pour la plus part des différents sites évalués nétaient pas compléments certains, les auteurs croient que ces techniques ont un potentiel fort pour confirmer ou éliminer ces techniques. Des recherches futures dans cette zone est suggérée. Par ailleurs, linterprétation des tests de pompage couplés à lanalyse des concentrations nest pas développée et nécessite de meilleurs estimations.

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切仑科夫线状辐射与类星体的宽发射线起源探讨     

刘当波  袁爱芳  孟宪茹  单增罗布  尤峻汉 《天文学报》2009,50(4)

当具有各向同性速度分布的相对论电子穿过稠密气体区,或者轰击稠密气体区的表面时,切仑科夫效应将会产生1种特殊的原子或离子发射线,称做切仑科夫线状发射.这一预言在光学波段已由实验室的实验所证实.研究指出了切仑科夫线状辐射在类星体和赛弗特1星系的宽发射线研究中的重要性,利用此新机制有可能解决类星体研究中的一些重大且长期没有解决的疑惑.例如宽氢线之间存在的反常强度比,特别是反常Lyα/Lyβ强度比的问题.并且进一步估计了相对论电子穿过宇宙气体时所产生的各种效应的能耗的数量级,并对各种能耗进行比较,证实了切仑科夫线状发射机制在类星体和塞弗特1型星系中的有效性.  相似文献   

Matter wave explorer of gravity (MWXG)     

《Experimental Astronomy》2009,23(2):611-649

In response to ESA’s Call for proposals of 5 March 2007 of the COSMIC VISION 2015–2025 plan of the ESA science programme, we propose a M-class satellite mission to test of the Equivalence Principle in the quantum domain by investigating the extended free fall of matter waves instead of macroscopic bodies as in the case of GAUGE, MICROSCOPE or STEP. The satellite, called Matter Wave Explorer of Gravity, will carry an experiment to test gravity, namely the measurement of the equal rate of free fall with various isotopes of distinct atomic species with precision cold atom interferometry in the vicinity of the earth. This will allow for a first quantum test the Equivalence Principle with spin polarised particles and with pure fermionic and bosonic atomic ensembles. Due to the space conditions, the free fall of Rubidium and Potassium isotopes will be compared with a maximum accelerational sensitivity of 5·10^− 16 m/s² corresponding to an accuracy of the test of the Equivalence Principle of 1 part in 10¹⁶. Besides the primary scientific goal, the quantum test of the Equivalence Principle, the mission can be extended to provide additional information about the gravitational field of the earth or for testing theories of fundamental processes of decoherence which are investigated by various theory groups in the context of quantum gravity phenomenology. In this proposal we present in detail the mission objectives and the technical aspects of the proposed mission.  相似文献