5,421 research outputs found

    XLOOPS -- A Program Package calculating One- and Two-Loop Feynman Diagrams

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    The aim of XLOOPS is to calculate one-particle irreducible Feynman diagrams with one or two closed loops for arbitrary processes in the Standard model of particles and related theories. Up to now this aim is realized for all one-loop diagrams with at most three external lines and for two-loop diagrams with two external lines.Comment: 84 pages, Postscript, program package and this manual also available at http://wwwthep.physik.uni-mainz.de/~xloops/, minor changes and bug fixes are included no

    Hybrid stars in the light of GW170817

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    We have studied the effect of tidal deformability constraint given by the binary neutron star merger event GW170817 on the equations of state (EOS) of hybrid stars. The EOS are constructed by matching the hadronic EOS described by relativistic mean field (RMF) model and parameter sets NL3, TM1 and NL3ωρ\omega\rho with the quark matter EOS described by modified MIT bag model, via Gibbs' construction. It is found that the tidal deformability constraints along with the lower bound on maximum mass (Mmax=2.01±0.04MM_{\rm max}=2.01\pm0.04M_\odot) significantly limit the bag model parameter space (Beff1/4B_{\rm eff}^{1/4}, a4a_4). We also obtain upper limits on the radius of 1.4M1.4M_\odot and 1.6M1.6M_\odot stars as R1.413.213.5R_{1.4}\leq13.2-13.5 km and R1.613.213.4R_{1.6}\leq13.2-13.4 km, respectively for different hadronic EOS considered here.Comment: version accepted by Ap

    Massive Neutron Stars with Antikaon Condensates in a Density Dependent Hadron Field Theory

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    The measurement of 1.97±0.04Msolar1.97 \pm 0.04 M_{solar} for PSR J1614-2230 and 2.01±0.04Msolar2.01 \pm 0.04M_{solar} for PSR J0348+0432 puts a strong constraint on the neutron star equation of state and its exotic composition at higher densities. In this paper, we investigate the possibility of exotic equation of state within the observational mass constraint of 2Msolar2M_{solar} in the framework of relativistic mean field model with density-dependent couplings. We particularly study the effect of antikaon condensates in the presence of hyperons on the mass-radius relationship of the neutron star.Comment: 6 figures, submitted to Phy. Rev.

    Thoughts about a General Theory of Influence in a DIME/PMESII/ASCOP/IRC2 Model

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    The leading question of this paper is: “How would influence warfare (“iWar”) work and how can we simulate it?” The paper discusses foundational aspects of a theory and model of influence warfare by discussing a framework built along the DIME/PMESII/ASCOP dimension forming a prism with three axes. The DIME concept groups the many instruments of power a nation state can muster into four categories: Diplomacy, Information, Military and Economy. PMESII describes the operational environment in six domains: Political, Military, Economic, Social, Information and Infrastructure. ASCOPE is used in counter insurgency (COIN) environments to analyze the cultural and human environment (aka the “human terrain”) and encompasses Areas, Structures, Capabilities, Organization, People and Events. In addition, the model reflects about aspects of information collection requirements (ICR) and information capabilities requirements (ICR) - hence DIME/PMESII/ASCOP/ICR2. This model was developed from an influence wargame that was conducted in October 2018. This paper introduces basic methodical questions around model building in general and puts a special focus on building a framework for the problem space of influence/information/hybrid warfare takes its shape in. The article tries to describe mechanisms and principles in the information/influence space using cross discipline terminology (e.g. physics, chemistry and literature). On a more advanced level this article contributes to the Human, Social, Culture, Behavior (HSCB) models and community. One goal is to establish an academic, multinational and whole of government influence wargamer community. This paper introduces the idea of the perception field understood as a molecule of a story or narrative that influences an observer. This molecule can be drawn as a selection of vectors that can be built inside the DIME/PMESII/ASCOP prism. Each vector can be influenced by a shielding or shaping action. These ideas were explored in this influence wargame

    Embers

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    After living in Southern California for nine years, I should be used to fire season—and the fact that there is something called fire season—but I’m not. My wife and I moved to the Southland in late summer 2007, and within the month we saw some of the region’s most horrific firestorms consume vast stretches of chaparral-cloaked foothills, deep canyons filled with alder and oak and, at higher elevations, thick stands of pine and cedar

    Fire Inevitable, Despite Attempts to Tame Chaparral

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    You didn’t need to fly into Ontario International Airport this past week to know that Southern California’s fire season had begun. But the view from 10,000 feet offered a unique perspective on how wildfires impact the region

    Uncle Sam’s Badge: Identity and Representation in the USDA Forest Service, 1905–2013

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    Howard Abbey could recall the exact moment when he learned that he had passed the forest ranger’s examination for the newly established USDA Forest Service (USFS). In the early morning of Aug. 1, 1905, while he was managing a team of horses pulling a mowing machine on the McIntosh Ranch in the northern Sierra Nevada Mountains, Allen Ray Powers, a Forest Assistant on the Plumas Forest Reserve, rode up and “informed me that I was wanted at the Forest Supervisor’s office in Quincy.” Abbey handed over the reins to his boss and walked the 2 miles to town where he met with Supervisor Louis A. Barrett, who congratulated the young ranch hand on having passed the exam. After accepting the offer of a job as a Forest Guard on the Plumas, and “taking the Oath of Office,” Abbey was “given a bronze badge—insignia of office” (Abbey 1940, p. 5)

    A Better Way to Restore Wildfire-Burned Forests

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