216 research outputs found

    Neutrino-Accelerated Hot Hydrogen Burning

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    We examine the effects of significant electron anti-neutrino fluxes on hydrogen burning. Specifically, we find that the bottleneck weak nuclear reactions in the traditional pp-chain and the hot CNO cycle can be accelerated by anti-neutrino capture, increasing the energy generation rate. We also discuss how anti-neutrino capture reactions can alter the conditions for break out into the rp-process. We speculate on the impact of these considerations for the evolution and dynamics of collapsing very- and super- massive compact objects.Comment: 14 pages, 6 figures, submitted to ApJ; minor content chang

    Exploring the financial and investment implications of the Paris Agreement

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    A global energy transition is underway. Limiting warming to 2°C (or less), as envisaged in the Paris Agreement, will require a major diversion of scheduled investments in the fossil-fuel industry and other high-carbon capital infrastructure towards renewables, energy efficiency, and other low or negative carbon technologies. The article explores the scale of climate finance and investment needs embodied in the Paris Agreement. It reveals that there is little clarity in the numbers from the plethora of sources (official and otherwise) on climate finance and investment. The article compares the US100billiontargetintheParisAgreementwitharangeofotherfinancialmetrics,suchasinvestment,incrementalinvestment,energyexpenditure,energysubsidies,andwelfarelosses.WhiletherelativelynarrowlydefinedclimatefinanceincludedintheUS100 billion target in the Paris Agreement with a range of other financial metrics, such as investment, incremental investment, energy expenditure, energy subsidies, and welfare losses. While the relatively narrowly defined climate finance included in the US100 billion figure is a fraction of the broader finance and investment needs of climate-change mitigation and adaptation, it is significant when compared to some estimates of the net incremental costs of decarbonization that take into account capital and operating cost savings. However, even if the annual US$100 billion materializes, achieving the much larger implied shifts in investment will require the enactment of long-term internationally coordinated policies, far more stringent than have yet been introduced.</i

    Ahead of the Curve

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    The Robert Bosch Academy in cooperation with the German Commission for UNESCO invited thinkers, activists and representatives of key civil society organisations from around the globe to come together for a workshop in Berlin to explore the 2005 UNESCO Convention on the Protection and Promotion of the Diversity of Cultural Expressions and its relevance for our contemporary world

    Solar Mikheyev-Smirnov-Wolfenstein Effect with Three Generations of Neutrinos

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    Under the assumption that the density variation of the electrons can be approximated by an exponential function, the solar Mikheyev-Smirnov-Wolfenstein effect is treated for three generations of neutrinos. The generalized hypergeometric functions that result from the exact solution of this problem are studied in detail, and a method for their numerical evaluation is presented. This analysis plays a central role in the determination of neutrino masses, not only the differences of their squares, under the assumption of universal quark-lepton mixing.Comment: 22 pages, LaTeX, including 2 figure

    Gravitational Collapse in Turbulent Molecular Clouds. I. Gasdynamical Turbulence

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    Observed molecular clouds often appear to have very low star formation efficiencies and lifetimes an order of magnitude longer than their free-fall times. Their support is attributed to the random supersonic motions observed in them. We study the support of molecular clouds against gravitational collapse by supersonic, gas dynamical turbulence using direct numerical simulation. Computations with two different algorithms are compared: a particle-based, Lagrangian method (SPH), and a grid-based, Eulerian, second-order method (ZEUS). The effects of both algorithm and resolution can be studied with this method. We find that, under typical molecular cloud conditions, global collapse can indeed be prevented, but density enhancements caused by strong shocks nevertheless become gravitationally unstable and collapse into dense cores and, presumably, stars. The occurance and efficiency of local collapse decreases as the driving wave length decreases and the driving strength increases. It appears that local collapse can only be prevented entirely with unrealistically short wave length driving, but observed core formation rates can be reproduced with more realistic driving. At high collapse rates, cores are formed on short time scales in coherent structures with high efficiency, while at low collapse rates they are scattered randomly throughout the region and exhibit considerable age spread. We suggest that this naturally explains the observed distinction between isolated and clustered star formation.Comment: Minor revisions in response to referee, thirteen figures, accepted to Astrophys.

    Is it possible to construct excited-state energy functionals by splitting k-space?

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    We show that our procedure of constructing excited-state energy functionals by splitting k-space, employed so far to obtain exchange energies of excited-states, is quite general. We do so by applying the same method to construct modified Thomas-Fermi kinetic energy functional and its gradient expansion up to the second order for the excited-states. We show that the resulting kinetic energy functional has the same accuracy for the excited-states as the ground-state functionals do for the ground-states.Comment: 20 pages, 1 figur

    'I-I' and 'I-me' : Transposing Buber's interpersonal attitudes to the intrapersonal plane

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    Hermans' polyphonic model of the self proposes that dialogical relationships can be established between multiple I-positions1 (e.g., Hermans, 2001a). There have been few attempts, however, to explicitly characterize the forms that these intrapersonal relationships may take. Drawing on Buber's (1958) distinction between the 'I-Thou' and 'I-It' attitude, it is proposed that intrapersonal relationships can take one of two forms: an 'I-I' form, in which one I-position encounters and confirms another I-position in its uniqueness and wholeness; and an 'I-Me' form, in which one I-position experiences another I-position in a detached and objectifying way. This article argues that this I-Me form of intrapersonal relating is associated with psychological distress, and that this is so for a number of reasons: Most notably, because an individual who objectifies and subjugates certain I-position cannot reconnect with more central I-positions when dominance reversal (Hermans, 2001a) takes place. On this basis, it is suggested that a key role of the therapeutic process is to help clients become more able to experience moments of I-I intrapersonal encounter, and it is argued that this requires the therapist to confirm the client both as a whole and in terms of each of his or her different voices

    Resonance Lifetimes from Complex Densities

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    The ab-initio calculation of resonance lifetimes of metastable anions challenges modern quantum-chemical methods. The exact lifetime of the lowest-energy resonance is encoded into a complex "density" that can be obtained via complex-coordinate scaling. We illustrate this with one-electron examples and show how the lifetime can be extracted from the complex density in much the same way as the ground-state energy of bound systems is extracted from its ground-state density

    Looking for magnetic monopoles at LHC with diphoton events

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    Magnetic monopoles have been a subject of interest since Dirac established the relation between the existence of monopoles and charge quantization. The intense experimental search carried thus far has not met with success. The Large Hadron Collider is reaching energies never achieved before allowing the search for exotic particles in the TeV mass range. In a continuing effort to discover these rare particles we propose here other ways to detect them. We study the observability of monopoles and monopolium, a monopole-antimonopole bound state, at the Large Hadron Collider in the γγ\gamma \gamma channel for monopole masses in the range 500-1000 GeV. We conclude that LHC is an ideal machine to discover monopoles with masses below 1 TeV at present running energies and with 5 fb1^{-1} of integrated luminosity.Comment: This manuscript contains information appeared in Looking for magnetic monopoles at LHC, arXiv:1104.0218 [hep-ph] and Monopolium detection at the LHC.,arXiv:1107.3684 [hep-ph] by the same authors, rewritten for joint publication in The European Physica Journal Plus. 26 pages, 22 figure

    Mass Parameterizations and Predictions of Isotopic Observables

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    We discuss the accuracy of mass models for extrapolating to very asymmetric nuclei and the impact of such extrapolations on the predictions of isotopic observables in multifragmentation. We obtain improved mass predictions by incorporating measured masses and extrapolating to unmeasured masses with a mass formula that includes surface symmetry and Coulomb terms. We find that using accurate masses has a significant impact on the predicted isotopic observables.Comment: 12 pages, 4 figure
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