190 research outputs found

    Incidence of Auroras and Their North-South Motions in the Northern Auroral Zone

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    Studies of the incidence of auroral forms and their north and south motions are made by using a close-spaced array of all-sky cameras located in the northern auroral zone at the approximate geomagnetic longitude 250°E. It is found that during the observing season 1957-58 the peak of the average auroral zone occurred at 66-67° geomagnetic latitude. Although the southern extent of auroras retreats northward after local magnetic midnight, the southward motion of the individual forms, observed at the southern edge of the auroral zone, predominates over the northward motion throughout most of the night. The data indicate the existence on any given night of a latitude position near which many auroral forms occur. The first motion of auroras incident north of this position tends to be northward, and the first motion of auroras incident south of this position tends to be southward. A curve showing the occurrence of auroral forms peaks at, and is nearly symmetrical about, local geographic midnight, but the intensity of auroral emissions measured over the celestial hemisphere remains at a high level after midnight.NSP Grant No. Y/22.6/327Ye

    The Prey of Common Barn Owls (Tyto alba) in Dry Limestone Scrub Forest of Southern Jamaica

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    A collection of common barn-owl (Tyto alba Scopoli) pellets from caves on the Portland Ridge of Jamaica reveals that whereas introduced rodents constitute approximately 90% of the total prey, bats and birds are also frequent prey items. Of the bats, frugivorous species predominate with Ariteus flavescens Gray and Artibeus jamaicensis Leach accounting for the largest portion of the bat prey. Insectivorous bats are markedly under-represented with respect to the known diversity of insectivorous species in the habitat

    The History and Development of a Consolidated Communications System and an Emergency Medical Services System in Nebraska

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    •A Chronology of Events •Nebraska Vital Statistics •A Consolidated Communications Concept •A Total Emergency Medical Service System Concept •The Nebraska Adjutant General\u27s Study of Telecommunications •Nebraska State Civil Defense •The Nebraska Consolidated Communications Corporation •Emergency Telecommunications Service: Planning for the State Disaster Plan •Evolution of Ambulance Service in Nebraska •The Nebraska Committee on Transportation and Communication •The University of Nebraska College of Medicine •Extension Service, the University of Nebraska College of Agriculture •The Nebraska State Department of Health •Area Funding •The Department of Health, Education and Welfare •The Six EMS Regions in Nebraska •The Office of Traffic Highway Safety in Nebraska •The Robert Wood Johnson Foundation •Comprehensive Health Planning •Project 20/20 •Operation Sky-Aid •The Use of Helicopters in EMS Services in Nebraska •The Common Emergency Calling Number-911 •Immediate Dial Tone/Coin Free Telephone •Identification of Calling Number and Ring-back Capability •Visit of DOT People to Nebraska to Inspect Communications •The Omaha Fire Department Ambulance Service •A Paramedic Service for Nebraska •The Nebraska Committee on Trauma, American College of Surgeons •Full-time Emergency Department Staffing (American College of Emergency Physicians) •The Lincoln Medical Education Foundation •Categorization of Hospitals •The American Red Cross Handbook •Veterans Administration TV Network •Some Early Day Activities in Emergency Services in which Nebraskans were Involved •Things That Might Have Been •A Few of Lynn\u27s Comments •Mid-America Research Corporation •Interest in Joint Funding Lincoln/Lancaster Pilot Project •Changes in Pre-hospital Survival in Nebraska •People Involved in Early Day Consolidated Communications •People Involved in Early Day EMS •Appendix A-Original Members of Dr. Thompson\u27s Committee •Appendix B-Professional Staff, EMS Division Department of Health •Appendix C-Report by Del Maier in Washington •Appendix D-Joint Funding Report •Appendix E-ETV Network Development •Bibliographyhttps://digitalcommons.unmc.edu/nehist_books/1000/thumbnail.jp

    Speciation in Duckweeds (Lemnaceae): Phylogenetic and Ecological Inferences

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    Species of duckweeds (Letnnaceae) that were resolved as sister taxa in a phylogeny based on combined molecular and non-molecular data were compared for morphological, physiological, and ecological attributes to infer factors important in the initial divergence leading to speciation. The ability to survive extreme conditions such as desiccation and cold temperatures is the most common difference identified between species. Two morphological characters facilitating survival in extreme environments are production of special resting buds called turions and increased seed production. The prevalent geographic pattern for species pairs consists of one restricted species occurring on the periphery of a more widespread taxon; this pattern indicates that divergence of peripheral isolates is a common geographical mode of speciation in duckweeds. Other species differ in optimal environmental conditions for growth, and these species are largely sympatric. In only one instance does it appear that divergence and speciation occurred following long-distance dispersal. Sympatric species pairs have the lowest molecular divergence; widespread primarily allopatric, and distantly allopatric species have the highest molecular divergence. Despite infrequent sexual reproduction, some degree of detectable variation (molecular, physiological, etc.) occurs within populations and among populations of the same species. Molecular evidence indicates that variation within duckweeds extends from the population and intraspecific levels to very different levels of divergence among recognized species. Contrary to the appearance of morphological and ecological uniformity implied by their reduced morphology and restricted occurrence in fresh water habitats, duckweeds are not a group in evolutionary stasis. Rather, these smallest of all flowering plants are dynamic evolutionarily, and comprise a model system for studying plant evolution and speciation

    Design of a 3-Stage ADR for the Soft X-Ray Spectrometer Instrument on the Astro-H Mission

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    The Japanese Astro-H mission will include the Soft X-ray Spectrometer (SXS) instrument, whose 36-pixel detector array of ultra-sensitive x-ray microcalorimeters requires cooling to 50 mK. This will be accomplished using a 3-stage adiabatic demagnetization refrigerator (ADR). The design is dictated by the need to operate with full redundancy with both a superfluid helium dewar at 1.3 K or below, and with a 4.5 K Joule-Thomson (JT) cooler. The ADR is configured as a 2-stage unit that is located in a well in the helium tank, and a third stage that is mounted to the top of the helium tank. The third stage is directly connected through two heat switches to the JT cooler and the helium tank, and manages heat flow between the two. When liquid helium is present, the 2-stage ADR operates in a single-shot manner using the superfluid helium as a heat sink. The third stage may be used independently to reduce the time-average heat load on the liquid to extend its lifetime. When the liquid is depleted, the 2nd and 3rd stages operate as a continuous ADR to maintain the helium tank at as low a temperature as possible - expected to be 1.2 K - and the 1st stage cools from that temperature as a single-stage, single-shot ADR. The ADR s design and operating modes are discussed, along with test results of the prototype 3-stage ADR

    Noninvasive vagus nerve stimulation alters neural response and physiological autonomic tone to noxious thermal challenge.

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    The mechanisms by which noninvasive vagal nerve stimulation (nVNS) affect central and peripheral neural circuits that subserve pain and autonomic physiology are not clear, and thus remain an area of intense investigation. Effects of nVNS vs sham stimulation on subject responses to five noxious thermal stimuli (applied to left lower extremity), were measured in 30 healthy subjects (n = 15 sham and n = 15 nVNS), with fMRI and physiological galvanic skin response (GSR). With repeated noxious thermal stimuli a group Ă— time analysis showed a significantly (p < .001) decreased response with nVNS in bilateral primary and secondary somatosensory cortices (SI and SII), left dorsoposterior insular cortex, bilateral paracentral lobule, bilateral medial dorsal thalamus, right anterior cingulate cortex, and right orbitofrontal cortex. A group Ă— time Ă— GSR analysis showed a significantly decreased response in the nVNS group (p < .0005) bilaterally in SI, lower and mid medullary brainstem, and inferior occipital cortex. Finally, nVNS treatment showed decreased activity in pronociceptive brainstem nuclei (e.g. the reticular nucleus and rostral ventromedial medulla) and key autonomic integration nuclei (e.g. the rostroventrolateral medulla, nucleus ambiguous, and dorsal motor nucleus of the vagus nerve). In aggregate, noninvasive vagal nerve stimulation reduced the physiological response to noxious thermal stimuli and impacted neural circuits important for pain processing and autonomic output
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