667 research outputs found

    IV. The Uses of the Indexes of Drilling and Completion Costs

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    Part 4 of the Monograph in Economics by Henry B. Steel

    V. Limitations on the Use of the Indexes

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    Part 5 of the Monograph in Economics by Henry B. Steel

    I. The Need for Adequate Statistical Data Concerning Trends in the Cost of Drilling and Completing Oil and Gas Wells

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    Part 1 of the Monograph in Economics by Henry B. Steel

    Historical Perspectives and New Directions in the Exploitation of Latin American Petroleum Resources

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    This paper constitutes an attempt, in a very brief compass, to provide an historical survey of the traditional roles of government and private enterprise in the exploitation of Latin American petroleum resources, to evaluate the current situation, and to speculate in a limited manner on the future implications of present developments. The basic analytical frame of reference is that of economics, but since the petroleum industry is a world industry, developments in the Latin American petroleum industry must be placed in the wider context of world oil industry economics and politics. From the standpoint of economic analysis, the major conflict between companies and governments appears to be their divergent goals: the companies strive to minimize costs, while the governments insist upon maximizing the companies\u27 contribution to national treasuries. Expropriation is of course the most dramatic of the recurring themes in Latin American petroleum, and can be understood not only in terms of the vulnerability of foreign private investment to local military force, but also as a matter of economic logic in an extractive industry such as petroleum. In addition, the decision to expropriate may reflect the belief that the nation\u27s oil industry is growing too rapidly. This growth may seem excessive relative to reserves, or it may be feared that unchecked growth over too long a time may produce an industry too large for the state to control. Regardless of intentions, expropriation generally reduces the role of a nation\u27s oil industry in world trade and orients it increasingly toward domestic consumption rather than export specialization

    Searching for transits in the Wide Field Camera Transit Survey with difference-imaging light curves

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    The Wide Field Camera Transit Survey is a pioneer program aiming at for searching extra-solar planets in the near-infrared. The images from the survey are processed by a data reduction pipeline, which uses aperture photometry to construct the light curves. We produce an alternative set of light curves using the difference-imaging method for the most complete field in the survey and carry out a quantitative comparison between the photometric precision achieved with both methods. The results show that differencephotometry light curves present an important improvement for stars with J > 16. We report an implementation on the box-fitting transit detection algorithm, which performs a trapezoid-fit to the folded light curve, providing more accurate results than the boxfitting model. We describe and optimize a set of selection criteria to search for transit candidates, including the V-shape parameter calculated by our detection algorithm. The optimized selection criteria are applied to the aperture photometry and difference-imaging light curves, resulting in the automatic detection of the best 200 transit candidates from a sample of ~475 000 sources. We carry out a detailed analysis in the 18 best detections and classify them as transiting planet and eclipsing binary candidates. We present one planet candidate orbiting a late G-type star. No planet candidate around M-stars has been found, confirming the null detection hypothesis and upper limits on the occurrence rate of short-period giant planets around M-dwarfs presented in a prior study. We extend the search for transiting planets to stars with J ≤ 18, which enables us to set a stricter upper limit of 1.1%. Furthermore, we present the detection of five faint extremely-short period eclipsing binaries and three M-dwarf/M-dwarf binary candidates. The detections demonstrate the benefits of using the difference-imaging light curves, especially when going to fainter magnitudes.Peer reviewe

    Discovery and characterization of WASP-6b, an inflated sub-Jupiter mass planet transiting a solar-type star

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    We report the discovery of WASP-6b, an inflated sub-Jupiter mass planet transiting every 3.3610060^{\rm + 0.0000022 }_ days a mildly metal-poor solar-type star of magnitude V = 11.9. A combined analysis of the WASP photometry, high-precision followup transit photometry and radial velocities yield a planetary mass M_{\rm p} = 0.503^_ MJM_{\rm J} and radius R_{\rm p} = 1.224^_ RJR_{\rm J}, resulting in a density ρp=0.27±0.05\rho_{\rm p} = 0.27 \pm 0.05 ρJ\rho_{\rm J}. The mass and radius for the host star are M_\ast = 0.88^_ MM_\odot and R_\ast = 0.870^_ RR_\odot. The non-zero orbital eccentricity e = 0.054^{\rm +0.018}_ that we measure suggests that the planet underwent a massive tidal heating ~1 Gyr ago that could have contributed to its inflated radius. High-precision radial velocities obtained during a transit allow us to measure a sky-projected angle between the stellar spin and orbital axis \beta = 11^_ deg. In addition to similar published measurements, this result favors a dominant migration mechanism based on tidal interactions with a protoplanetary disk

    Single hadron response measurement and calorimeter jet energy scale uncertainty with the ATLAS detector at the LHC

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    The uncertainty on the calorimeter energy response to jets of particles is derived for the ATLAS experiment at the Large Hadron Collider (LHC). First, the calorimeter response to single isolated charged hadrons is measured and compared to the Monte Carlo simulation using proton-proton collisions at centre-of-mass energies of sqrt(s) = 900 GeV and 7 TeV collected during 2009 and 2010. Then, using the decay of K_s and Lambda particles, the calorimeter response to specific types of particles (positively and negatively charged pions, protons, and anti-protons) is measured and compared to the Monte Carlo predictions. Finally, the jet energy scale uncertainty is determined by propagating the response uncertainty for single charged and neutral particles to jets. The response uncertainty is 2-5% for central isolated hadrons and 1-3% for the final calorimeter jet energy scale.Comment: 24 pages plus author list (36 pages total), 23 figures, 1 table, submitted to European Physical Journal

    Standalone vertex finding in the ATLAS muon spectrometer

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    A dedicated reconstruction algorithm to find decay vertices in the ATLAS muon spectrometer is presented. The algorithm searches the region just upstream of or inside the muon spectrometer volume for multi-particle vertices that originate from the decay of particles with long decay paths. The performance of the algorithm is evaluated using both a sample of simulated Higgs boson events, in which the Higgs boson decays to long-lived neutral particles that in turn decay to bbar b final states, and pp collision data at √s = 7 TeV collected with the ATLAS detector at the LHC during 2011

    Measurements of Higgs boson production and couplings in diboson final states with the ATLAS detector at the LHC

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    Measurements are presented of production properties and couplings of the recently discovered Higgs boson using the decays into boson pairs, H →γ γ, H → Z Z∗ →4l and H →W W∗ →lνlν. The results are based on the complete pp collision data sample recorded by the ATLAS experiment at the CERN Large Hadron Collider at centre-of-mass energies of √s = 7 TeV and √s = 8 TeV, corresponding to an integrated luminosity of about 25 fb−1. Evidence for Higgs boson production through vector-boson fusion is reported. Results of combined fits probing Higgs boson couplings to fermions and bosons, as well as anomalous contributions to loop-induced production and decay modes, are presented. All measurements are consistent with expectations for the Standard Model Higgs boson
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