1,153 research outputs found

    Alternative derivation of the relativistic contribution to perihelic precession

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    An alternative derivation of the first-order relativistic contribution to perihelic precession is presented. Orbital motion in the Schwarzschild geometry is considered in the Keplerian limit, and the orbit equation is derived for approximately elliptical motion. The method of solution makes use of coordinate transformations and the correspondence principle, rather than the standard perturbative approach. The form of the resulting orbit equation is similar to that derived from Newtonian mechanics and includes first-order corrections to Kepler's orbits due to general relativity. The associated relativistic contribution to perihelic precession agrees with established first-order results. The reduced radius for the circular orbit is in agreement to first-order with that calculated from the Schwarzschild effective potential. The method of solution is understandable by undergraduate students.Comment: 12 pages, 2 figures. Accepted for publication in the American Journal of Physic

    A Continuum Model for Highly Porous Aluminium Foam

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    Mean-payoff Automaton Expressions

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    Quantitative languages are an extension of boolean languages that assign to each word a real number. Mean-payoff automata are finite automata with numerical weights on transitions that assign to each infinite path the long-run average of the transition weights. When the mode of branching of the automaton is deterministic, nondeterministic, or alternating, the corresponding class of quantitative languages is not robust as it is not closed under the pointwise operations of max, min, sum, and numerical complement. Nondeterministic and alternating mean-payoff automata are not decidable either, as the quantitative generalization of the problems of universality and language inclusion is undecidable. We introduce a new class of quantitative languages, defined by mean-payoff automaton expressions, which is robust and decidable: it is closed under the four pointwise operations, and we show that all decision problems are decidable for this class. Mean-payoff automaton expressions subsume deterministic mean-payoff automata, and we show that they have expressive power incomparable to nondeterministic and alternating mean-payoff automata. We also present for the first time an algorithm to compute distance between two quantitative languages, and in our case the quantitative languages are given as mean-payoff automaton expressions

    Fourth order indirect integration method for black hole perturbations: even modes

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    On the basis of a recently proposed strategy of finite element integration in time domain for partial differential equations with a singular source term, we present a fourth order algorithm for non-rotating black hole perturbations in the Regge-Wheeler gauge. Herein, we address even perturbations induced by a particle plunging in. The forward time value at the upper node of the (r,t)(r^*,t) grid cell is obtained by an algebraic sum of i) the preceding node values of the same cell, ii) analytic expressions, related to the jump conditions on the wave function and its derivatives, iii) the values of the wave function at adjacent cells. In this approach, the numerical integration does not deal with the source and potential terms directly, for cells crossed by the particle world line. This scheme has also been applied to circular and eccentric orbits and it will be object of a forthcoming publication.Comment: This series of papers deals with EMRI for LISA. With the respect to the v1 version, the algorithm has been improved; convergence tests and references have been added; v2 is composed by 23 pages, and 6 figures. Paper accepted by Class. Quantum Gravity for the special issue on Theory Meets Data Analysis at Comparable and Extreme Mass Ratios (Capra and NRDA) at Perimeier Institute in June 201

    Insights in Health Administration Education: Understanding the Role of Personality in Teamwork

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    Background: Developing a health promotion program plan requires attention to the links between objectives, activities, and overall program goals. Instructors developed the “Connecting the Dots” worksheet to help students establish these linkages. Methods: The “Connecting the Dots” worksheet included six questions pertinent to the students’ health promotion program plans. The worksheet was given to the students in a flipped classroom setting. Evaluation of the effectiveness of the tool was based upon group presentations at the end of the semester. Results: Students developed more viable program plans that included stronger links between objectives and corresponding program activities. Conclusions: The “Connecting the Dots” worksheet is a promising tool for engaging public health students in the process of developing health promotion program plans

    Nonlocal Astroparticles in Einstein's Universe

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    Gravitational probes should maintain spatial flatness for Einsten-Infeld-Hoffmann dynamics of relativistic matter-energy. The continuous elementary source/particle in Einstein's gravitational theory is the r^{-4} radial energy density rather than the delta-operator density in empty-space gravitation. The space energy integral of such an infinite (astro)particle is finite and determines its nonlocal gravitational charge for the energy-to-energy attraction of other nonlocal (astro)particles. The non-empty flat space of the undivided material Universe is charged continuously by the world energy density of the global ensemble of overlapping radial particles. Nonlocal gravitational/inertial energy-charges incorporate Machian relativism quantitatively into Einstein's gravitation for self-contained SR-GR dynamics without references on Newton's mass-to-mass attraction.Comment: 9 pages, typos and arguments adde

    Complex Lithofacies Relationships between the Ste. Genevieve and Paoli Limestones: Clarifying Reservoir Relationships in the Indiana Subsurface

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    This poster was presented at the American Association of Petroleum Geologists (AAPG) Eastern Section Meeting in Evansville, Indiana,on September 22, 2009.Typically irregular vertical and lateral distribution of lithofacies within the Ste. Genevieve and Paoli Limestones (Mississippian Blue River Group) has historically resulted in the inaccurate correlation of uppermost Ste. Genevieve lithologies (Joppa Member) with Paoli units of similar composition and appearance (Aux Vases and Renault Members). The Joppa Member of the Ste. Genevieve thins northeastward toward the Illinois Basin margin, losing the distinctive log signature that characterizes this unit in more basinward locations. The Aux Vases and Renault Members of the Paoli Limestone also become difficult to distinguish from each other and from the Joppa Member in basin margin locations because of rapid changes in composition and bed distribution. As a consequence, many Ste. Genevieve and Paoli Limestone pay zones have been assigned to the wrong reservoir pool, sometimes within the same field. Pay zones from Ste. Genevieve and Paoli Limestone reservoirs were reassigned according to current stratigraphic divisions. These new correlations more accurately reflect spatial relationships within and between hydrocarbon pools, and could contribute to more effective reservoir management. Improved correlations should also provide a useful tool for future hydrocarbon exploration and development activities in Indiana. Our investigation also suggests that revisions to formal Ste. Genevieve-Paoli stratigraphic nomenclature should be considered

    The role of the ecological fiscal transfers for water conservation policies

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    The purpose of this chapter is to fill the lacuna found in the literature with regard to describing the role of EFTs for water conservation policies. The literature tells us that ecological fiscal transfers (EFTs) are analysed so to pursue biodiversity conservation policies and solid waste management (SWM). For biodiversity conservation policies, EFTs have two purposes: (1) to incentivize municipalities to create local protected areas (PA); and (2) to compensate municipalities for corresponding land-use restrictions. In the case of SWM, the main idea is that, even considering the fees paid by the households, it is still costly to maintain waste services in the municipal territories. In this context, EFTs are appealing policy instrument to help local governments create landfills or composting plants. However, in Brazil EFTs are functioning as a policy instrument which also includes a wide range of policy domains, such as water conservation, indigenous land, fire-control, and so on. Six states adopted EFTs specifically for water conservation policies: Goiás, Paraná, Pernambuco, Piauí, Rio de Janeiro, and Tocantins. Descriptive analyses, focusing on legislative differences are conducted for each of these states.(undefined

    A Classification of Countable Lower 1-transitive Linear Orders

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    This paper contains a classification of countable lower 1-transitive linear orders. This is the first step in the classification of countable 1-transitive trees given in Chicot and Truss (2009): the notion of lower 1-transitivity generalises that of 1-transitivity for linear orders, and it is essential for the structure theory of 1-transitive trees. The classification is given in terms of coding trees, which describe how a linear order is fabricated from simpler pieces using concatenations, lexicographic products and other kinds of construction. We define coding trees and show that a coding tree can be constructed from a lower 1-transitive linear order (X,≤) by examining all the invariant partitions on X. Then we show that a lower 1-transitive linear order can be recovered from a coding tree up to isomorphism
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