22,947 research outputs found

    Mixing of Xi_c and Xi_c' Baryons

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    The mixing angle between the Xi_c and Xi_c' baryons is shown to be small, with a negligible shift in the Xi_c masses.Comment: One missprint corrected. The numerator of Eq. (12) should read {2[(Sigma_c^{*++}-Sigma_c^{++})-(Xi_c^{*+}-Xi_c^{'+})]} The correct equation was used in the calculation so no other change is mad

    Sum rules for charmed baryon masses

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    The measured masses of the three charge states of the charmed Σc\Sigma_c baryon are found to be in disagreement with a sum rule based on the quark model, but relying on no detailed assumptions about the form of the interaction. This poses a significant problem for the charmed baryon sector of the quark model. Other relations among charmed baryon masses are also discussed.Comment: 5 pages, latex, no figure

    Study of lunar earthshine by photoelectric photometry Final report, 1 Nov. 1965 - 30 Sep. 1967

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    Design feasibility and performance of semiportable field instrument for monitoring changes in earth albedo via earthshine measurement

    Censusing manatees: a report on the feasibility of using aerial surveys and mark and recapture techniques to conduct a population survey of the West Indian Manatee

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    This report results from an invitation to review the needs and prospects for capture-recapture and aerial census studies of the manatee (Trichechus manatus) in Florida. Three aerial reconnaissance flights provided a first hand view of manatee habitats, as follows: May 3, Suwannee River to Kings Bay and Crystal River (Rathbun, Eberhardt), May 4, Vero Beach to Ft. Lauderdale and Ft. Myers by way of Whitewater Bay (Rose, Percival, Eberhardt), and May 5, Cape Canaveral to Jacksonville, St. Johns River and Blue Spring (Rose, Kinnaird, Eberhardt). (24 page document

    Effect of Tidal Cycling Rate on the Distribution and Abundance of Nitrogen-Oxidizing Bacteria in a Bench-Scale Fill-and-Drain Bioreactor

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    Most domestic wastewater can be effectively treated for secondary uses by engineered biological systems. These systems rely on microbial activity to reduce nitrogen (N) content of the reclaimed water. Such systems often employ a tidal-flow process to minimize space requirements for the coupling of aerobic and anaerobic metabolic processes. In this study, laboratory-scale tidal-flow treatment systems were studied to determine how the frequency and duration of tidal cycling may impact reactor performance. Fluorescent in situ hybridization and epifluorescence microscopy were used to enumerate the key functional groups of bacteria responsible for nitrification and anaerobic ammonium oxidation (anammox), and N-removal efficiency was calculated via a mass-balance approach. When water was cycled (i.e., reactors were filled and drained) at high frequencies (16–24 cycles day−1), nitrate accumulated in the columns—presumably due to inadequate periods of anoxia that limited denitrification. At lower frequencies, such as 4 cycles day−1, nearly complete N removal was achieved (80–90%). These fill-and-drain systems enriched heavily for nitrifiers, with relatively few anammox-capable organisms. The microbial community produced was robust, surviving well through short (up to 3 h) anaerobic periods and frequent system-wide perturbation

    Conceptual model of salt marsh management on Merritt Island National Wildlife Refuge, Florida: final report

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    Diking and holding water on salt marshes ("impounding" the marsh) is a management technique used on Merritt Island National Wildlife Refuge (MINWR) and elsewhere in the Southeast to: a) prevent the reproduction of saltmarsh mosquitos, and b) attract wintertering waterfowl and other marsh, shore, and wading birds. Because of concern that diking and holding water may interfere with the production of estuarine fish and shellfish, impoundment managers are being asked to consider altering management protocol to reduce or eliminate any such negative influence. How to change protocol and preserve effective mosquito control and wildlife management is a decision of great complexity because: a) the relationships between estuarine organisms and the fringing salt marshes at the land-water interface are complex, and b) impounded marshes are currently good habitat for a variety of species of fish and wildlife. Most data collection by scientists and managers in the area has not been focused on this particular problem. Furthermore, collection of needed data may not be possible before changes in protocol are demanded. Therefore, the purpose of this document is two-fold: 1) to suggest management alternatives, given existing information, and 2) to help identify research needs that have a high probability of leading to improved simultaneous management of mosquitos, waterfowl, other wildlife, freshwater fish, and estuarine fish and shellfish on the marshland of the Merritt Island National Wildlife Refuge. (92 page document
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