10,559 research outputs found

    Realizing the Potential of Marine Biotechnology : Challenges and Opportunities

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    A paid open access option is available for this journal. Author's final version or publisher's version/PDF Authors may deposit in funding agency designated repository after 12 monthsPeer reviewedPublisher PD

    The Production of HI in Photodissociation Regions and A Comparison with CO(1-0) Emission

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    The gas at the surfaces of molecular clouds in galaxies is heated and dissociated by photons from young stars both near and far. HI resulting from the dissociation of molecular hydrogen H2 emits hyperfine line emission at 21 cm, and warmed CO emits dipole rotational lines such as the 2.6 mm line of CO(1-0). We use previously developed models for photodissociation regions (PDRs) to compute the intensities of these HI and CO(1-0) lines as a function of the total volume density n in the cloud and the far ultraviolet flux G0 incident upon it and present the results in units familiar to observers. The intensities of these two lines behave differently with changing physical conditions in the PDR, and, taken together, the two lines can provide a ground-based radio astronomy diagnostic for determining n and G0 separately in distant molecular clouds. This diagnostic is particularly useful in the range Gzero <~ 100, 10 cm^{-3} <~ n <~ 10^5 cm^{-3}, which applies to a large fraction of the volume of the interstellar medium in galaxies. If the molecular cloud is located near discrete sources of far-UV (FUV) emission, the PDR-generated HI and CO(1-0) emission on the cloud surface can be more easily identified, appearing as layered ``blankets'' or ``blisters'' on the side of the cloud nearest to the FUV source. As an illustration, we consider the Galactic object G216 -2.5, i.e. ``Maddalena's Cloud'', which has been previously identified as a large PDR in the Galaxy. We determine that this cloud has n ~ 200 cm^{-3}, G0 ~ 0.8, consistent with other data.Comment: 13 Pages, 3 Figures. Accepted for publication in the Astrophysical Journa

    Guidance and Control of an Autonomous Soaring Vehicle with Flight Test Results

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    A guidance and control method was developed to detect and exploit thermals for energy gain. Latency in energy rate estimation degraded performance. The concept of a UAV harvesting energy from the atmosphere has been shown to be feasible with existing technology. Many UAVs have similar mission constraints to birds and sailplanes. a) Surveillance; b) Point to point flight with minimal energy; and c) Increased ground speed

    Guidance and control for an autonomous soaring UAV

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    The present invention provides a practical method for UAVs to take advantage of thermals in a manner similar to piloted aircrafts and soaring birds. In general, the invention is a method for a UAV to autonomously locate a thermal and be guided to the thermal to greatly improve range and endurance of the aircraft

    The Role of Actual Confusion Evidence in Federal Trademark Infringement Litigation

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    This article seeks to provide an overall discussion of the role of actual confusion evidence in federal trademark infringement actions and to reconcile the differences among the courts as to the value given to various types of actual confusion evidence. Section I discusses the effect of the existence or absence of actual confusion evidence in infringement actions, and the relative importance which the courts place on such evidence. Section II discusses the various types of evidence which trademark infringement plaintiffs have proffered in attempting to prove the existence of actual confusion, and the weight which the courts have given to these types of evidence. This section also discusses whose confusion (e.g., consumers, suppliers, competitors) is relevant to and probative of actual confusion, and how much evidence of actual confusion is necessary to have this factor support a finding of a likelihood of confusion. Finally, Section III discusses the evidentiary problems, such as hearsay and other concerns, encountered by those attempting to introduce evidence of actual confusion

    UNESCO and the ILO: A Tale of Two UN Agencies

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    A Choice that Leaves No Choice: Unconstitutional Coercion Under Real ID

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