33,706 research outputs found

    Insect species described from Big Bend National Park

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    The list contains 192 insect species, of which 139 are primary types. All have been described from material collected in or near Big Bend National Park, Texas

    UK Competition Policy and Shareholder Value: The Impact of Merger Inquiries

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    Some previous studies have suggested that competition re´gimes can destroy shareholder value. This study examines data on 50 mergers in the UK between 1989 and 2002. The study confirms the finding from earlier studies of greater gains to shareholders in target than bidding companies, but does not find evidence supporting overall loss of shareholder value to target company shareholders when a merger is prohibited. It finds evidence that when the regulatory re´gime is stable and well understood the capital market behaves efficiently in response to new information. However, for a subgroup of the mergers involving companies with a new regulatory re´gime, where the industry and the stock market had little or no experience with respect to mergers, the capital market operated less efficiently

    Does the Doctor Need a Boss?

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    The traditional model of medical delivery, in which the doctor is trained, respected, and compensated as an independent craftsman, is anachronistic. When a patient has multiple ailments, there is no longer a simple doctor-patient or doctor-patient-specialist relationship. Instead, there are multiple specialists who have an impact on the patient, each with a set of interdependencies and difficult coordination issues that increase exponentially with the number of ailments involved. Patients with multiple diagnoses require someone who can organize the efforts of multiple medical professionals. It is not unreasonable to imagine that delivering health care effectively, particularly for complex patients, could require a corporate model of organization. At least two forces stand in the way of robust competition from corporate health care providers. First is the regime of third-party fee-for-service payment, which is heavily entrenched by Medicare, Medicaid, and the regulatory and tax distortions that tilt private health insurance in the same direction. Consumers should control the money that purchases their health insurance, and should be free to choose their insurer and health care providers. Second, state licensing regulations make it difficult for corporations to design optimal work flows for health care delivery. Under institutional licensing, regulators would instead evaluate how well a corporation treats its patients, not the credentials of the corporation's employees. Alternatively, states could recognize clinician licenses issued by other states. That would let corporations operate in multiple states under a single set of rules and put pressure on states to eliminate unnecessarily restrictive regulations

    Binary weight distributions of some Reed-Solomon codes

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    The binary weight distributions of the (7,5) and (15,9) Reed-Solomon (RS) codes and their duals are computed using the MacWilliams identities. Several mappings of symbols to bits are considered and those offering the largest binary minimum distance are found. These results are then used to compute bounds on the soft-decoding performance of these codes in the presence of additive Gaussian noise. These bounds are useful for finding large binary block codes with good performance and for verifying the performance obtained by specific soft-coding algorithms presently under development

    Emerging standards for still image compression: A software implementation and simulation study

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    The software implementation is described of an emerging standard for the lossy compression of continuous tone still images. This software program can be used to compress planetary images and other 2-D instrument data. It provides a high compression image coding capability that preserves image fidelity at compression rates competitive or superior to most known techniques. This software implementation confirms the usefulness of such data compression and allows its performance to be compared with other schemes used in deep space missions and for data based storage

    The Labor Required for Crop Production in Ohio

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    Exact date of bulletin unknown.PDF pages: 1

    Transit Lightcurve Signatures of Artificial Objects

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    The forthcoming space missions, able to detect Earth-like planets by the transit method, will a fortiori also be able to detect the transit of artificial planet-size objects. Multiple artificial objects would produce lightcurves easily distinguishable from natural transits. If only one artificial object transits, detecting its artificial nature becomes more difficult. We discuss the case of three different objects (triangle, 2-screen, louver-like 6-screen) and show that they have a transit lightcurve distinguishable from the transit of natural planets, either spherical or oblate, although an ambiguity with the transit of a ringed planet exists in some cases. We show that transits, especially in the case of multiple artificial objects, could be used for the emission of attention-getting signals, with a sky coverage comparable to the laser pulse method. The large number of expected planets (several hundreds) to be discovered by the transit method by next space missions will allow to test these ideas.Comment: Accepted for publication in ApJ. Manuscript: 17 pages, 8 figure

    Comparison of beam generation techniques using a phase only spatial light modulator

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    Whether in art or for QR codes, images have proven to be both powerful and efficient carriers of information. Spatial light modulators allow an unprecedented level of control over the generation of optical fields by using digital holograms. There is no unique way of obtaining a desired light pattern however, leaving many competing methods for hologram generation. In this paper, we test six hologram generation techniques in the creation of a variety of modes as well as a photographic image: rating the methods according to obtained mode quality and power. All techniques compensate for a non-uniform mode profile of the input laser and incorporate amplitude scaling. We find that all methods perform well and stress the importance of appropriate spatial filtering. We expect these results to be of interest to those working in the contexts of microscopy, optical trapping or quantum image creation
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