20,605 research outputs found

    The economic evolution of petroleum property rights in the United States.

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    We examine Harold Demsetz's (1967) prediction that property rights emerge and are refined as the benefits of doing so exceed the costs in the context of oil and gas resources in the U.S. Familiar influences on the development of petroleum property rights, technology, market demand, and politics, provide support for the hypothesis, and those issues are examined. Our primary contribution is to demonstrate the important role of a less familiar factor, the presence in the reservoir of both oil and gas with differentially volatile prices. This factor has affected the nature of the property rights assigned with unitization, an institutional arrangement to internalize the common pool externality. Information asymmetries and conflicting price expectations have resulted in unit agreements that would not have been predicted in a strict neo-classical sense. Our analysis provides new insights regarding the nature of voluntary unitization contracts, inherent limits to producers' ability to internalize externalities, and the welfare implications of compulsory unitization.

    The Self-Enforcing Provisions of Oil and Gas Unit Operating Agreements: Theory and Evidence

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    This paper extends the existing theory and empirical investigation of unitization contracts. It highlights the importance of incentive-compatibility and self-enforcement and the bargaining problems faced in achieving viable, long-term contracts. We argue that only if the parties to a unitization contract have unit production shares that are the same as their cost shares will the contract be incentive compatible. Using a data base of sixty unit operating agreements, we measure the industry's actual behavior against the principles of production from a common pool. Our survey of units that have only one production phase and that are relatively homogeneous reveals that such equal sharing rules are always found and they appear to encourage the parties to behave optimally. In more complex units with multiple production phases and/or separate concentrations of oil and gas (gas caps) we find deviations from the theoretical ideal. In the case of multi-phase units, we find equal cost and production shares within phases, but not across phases. A pre-set trigger for shifting from one production phase to the next helps to maintain optimal behavior. For gas cap units, however, we generally do not find the equal sharing rule. Conflicts and rent dissipation follow as illustrated by the case of the Prudhoe Bay Unit. The paper describes the desirable contract rules for avoiding moral hazard. It also shows how the effects of those rules can be replicated in difficult situations.

    Is the Cepheus E Outflow driven by a Class 0 Protostar?

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    New early release observations of the Cepheus E outflow and its embedded source, obtained with the Spitzer Space Telescope, are presented. We show the driving source is detected in all 4 IRAC bands, which suggests that traditional Class 0 classification, although essentially correct, needs to accommodate the new high sensitivity infrared arrays and their ability to detected deeply embedded sources. The IRAC, MIPS 24 and 70 microns new photometric points are consistent with a spectral energy distribution dominated by a cold, dense envelope surrounding the protostar. The Cep E outflow, unlike its more famous cousin the HH 46/47 outflow, displays a very similar morphology in the near and mid-infrared wavelengths, and is detected at 24 microns. The interface between the dense molecular gas (where Cep E lies) and less dense interstellar medium, is well traced by the emission at 8 and 24 microns, and is one of the most exotic features of the new IRAC and MIPS images. IRS observations of the North lobe of the flow confirm that most of the emission is due to the excitation of pure H2 rotational transitions arising from a relatively cold (Tex~700 K) and dense (N{H}~9.6E20 cm-2 molecular gas.Comment: 14 pages (pre-print format), including 6 figures. Published in ApJ Special Spitzer Issue (2004

    Comorbidity, Pain, Utilization, and Psychosocial Outcomes in Older versus Younger Sickle Cell Adults: The PiSCES Project

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    Background. Patients with SCD now usually live well into adulthood. Whereas transitions into adulthood are now often studied, little is published about aging beyond the transition period. We therefore studied age-associated SCD differences in utilization, pain, and psychosocial variables. Methods. Subjects were 232 adults in the Pain in Sickle Cell Epidemiology Study (PiSCES). Data included demographics, comorbidity, and psychosocial measures. SCD-related pain and health care utilization were recorded in diaries. We compared 3 age groups: 16–25 (transition), 26–36 (younger adults), and 37–64 (older adults) years. Results. Compared to the 2 adult groups, the transition group reported fewer physical challenges via comorbidities, somatic complaints, and pain frequency, though pain intensity did not differ on crisis or noncrisis pain days. The transition group utilized opioids less often, made fewer ambulatory visits, and had better quality of life, but these differences disappeared after adjusting for pain and comorbidities. However, the transition group reported more use of behavioral coping strategies. Conclusion. We found fewer biological challenges, visits, and better quality of life, in transition-aged versus older adults with SCD, but more behavioral coping. Further study is required to determine whether age-appropriate health care, behavioral, or other interventions could improve age-specific life challenges of patients with SCD

    A Digital Neuromorphic Architecture Efficiently Facilitating Complex Synaptic Response Functions Applied to Liquid State Machines

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    Information in neural networks is represented as weighted connections, or synapses, between neurons. This poses a problem as the primary computational bottleneck for neural networks is the vector-matrix multiply when inputs are multiplied by the neural network weights. Conventional processing architectures are not well suited for simulating neural networks, often requiring large amounts of energy and time. Additionally, synapses in biological neural networks are not binary connections, but exhibit a nonlinear response function as neurotransmitters are emitted and diffuse between neurons. Inspired by neuroscience principles, we present a digital neuromorphic architecture, the Spiking Temporal Processing Unit (STPU), capable of modeling arbitrary complex synaptic response functions without requiring additional hardware components. We consider the paradigm of spiking neurons with temporally coded information as opposed to non-spiking rate coded neurons used in most neural networks. In this paradigm we examine liquid state machines applied to speech recognition and show how a liquid state machine with temporal dynamics maps onto the STPU-demonstrating the flexibility and efficiency of the STPU for instantiating neural algorithms.Comment: 8 pages, 4 Figures, Preprint of 2017 IJCN
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