1,160 research outputs found

    Photographic quantification of water quality in mixing zones

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    A method was developed to quantitatively delineate waste concentrations throughout waste effluent mixing zones on the basis of densitometric measurements extracted from aerial photography. A mixing zone is the extent of a receiving water body ultilized to dilute a waste discharge to a concentration characteristic of a totally mixed condition. Simultaneously-acquired color infrared photography and suspended solids water samples were used to quantitatively delineate the mixing zone resulting from the discharge of a paper mill effluent. Digital scanning microdensitometer data was used to estimate and delineate suspended solids concentrations on the basis of a semi-empirical model. Photographic photometry, when predicated on a limited amount of ground sampling, can measure and delineate mixing zone waste distributions in more detail then conventional surface measuring techniques. The method has direct application to: (1) the establishment of definite and rational water quality guidelines; (2) the development of sampling and surveillance programs for use by governmental and private agencies; and (3) the development of design and location criteria for industrial and municipal waste effluent outfalls

    Snow wetness measurements for melt forecasting

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    A microwave technique for directly measuring snow pack wetness in remote installations is described. The technique, which uses satellite telemetry for data gathering, is based on the attenuation of a microwave beam in transmission through snow

    Coherent microwave backscatter of natural snowpacks

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    The backscatter of natural snowpacks was measured using a swept-frequency system operating from 5.8 to 8.0 GHz. Snow layering produced sequences of maxima and minima in backscatter intensity, with typical peak-to-valley ratios of 15 db. Wetness produced in the upper portion of the snowpack by solar heat input enhanced the effect of layering. The layer response persisted for incidence exhibits predominantly coherent properties. Frequency modulation of the incident signal masked the layer response by averaging the unmodulated response over the bandwidth represented by the modulation. Further changes in backscatter were attributed to changes in wetness in the surface regions of the snowpack; for a fixed frequency of 13.5 GHz and incidence angle of 39 deg, the backscatter decreased typically 15 db between 11 A.M. and noon, and returned to approximately its initial level of overnight

    Evaluation of the application of ERTS-1 data to the regional land use planning process

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    The author has identified the following significant results. Employing simple and economical extraction methods, ERTS can provide valuable data to the planners at the state or regional level with a frequency never before possible. Interactive computer methods of working directly with ERTS digital information show much promise for providing land use information at a more specific level, since the data format production rate of ERTS justifies improved methods of analysis

    Movement of Smallmouth Bass within the Beaver Island Archipelago, Northern Lake Michigan.

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    Fish movement may vary across a wide array of aquatic ecosystems and may be related to the overall size of the system inhabited. We investigated movement of smallmouth bass in Lake Michigan because this information is lacking for larger systems. A total of 16 smallmouth bass were surgically implanted with ultrasonic transmitters within the Beaver Archipelago, northern Lake Michigan. During 2007–2008, a maximum of one location per individual was recorded daily during three specific tracking periods – pre-spawn, spawning, and post-spawn – to determine diurnal movement patterns. Movement was evaluated as site fidelity, minimum displacement rate,maximumexcursion rate, and distance from shore. Smallmouth bass exhibited greatermaximum excursion rates during the spawn period compared to pre-spawn. Movement rates did not differ between tracking periods; however, movement rates were greater during the spawn period in 2007 than 2008. Both sexes moved further offshore to deeper water during post-spawn, but females were located further offshore than males during this period. Annual site fidelity was more evident during post-spawn than during spawning for both sexes. Two smallmouth bass emigrated outside of the Archipelago, suggesting this population may be more “open” in terms of individuals moving throughout northern Lake Michigan than previously thought. These results indicate smallmouth bass may move greater distances in larger aquatic systems and therefore larger management units (in terms of total area) should be established in Lake Michigan to account for these greater excursion distances

    Movement of Smallmouth Bass within the Beaver Island Archipelago, Northern Lake Michigan.

    Get PDF
    Fish movement may vary across a wide array of aquatic ecosystems and may be related to the overall size of the system inhabited. We investigated movement of smallmouth bass in Lake Michigan because this information is lacking for larger systems. A total of 16 smallmouth bass were surgically implanted with ultrasonic transmitters within the Beaver Archipelago, northern Lake Michigan. During 2007–2008, a maximum of one location per individual was recorded daily during three specific tracking periods – pre-spawn, spawning, and post-spawn – to determine diurnal movement patterns. Movement was evaluated as site fidelity, minimum displacement rate,maximumexcursion rate, and distance from shore. Smallmouth bass exhibited greatermaximum excursion rates during the spawn period compared to pre-spawn. Movement rates did not differ between tracking periods; however, movement rates were greater during the spawn period in 2007 than 2008. Both sexes moved further offshore to deeper water during post-spawn, but females were located further offshore than males during this period. Annual site fidelity was more evident during post-spawn than during spawning for both sexes. Two smallmouth bass emigrated outside of the Archipelago, suggesting this population may be more “open” in terms of individuals moving throughout northern Lake Michigan than previously thought. These results indicate smallmouth bass may move greater distances in larger aquatic systems and therefore larger management units (in terms of total area) should be established in Lake Michigan to account for these greater excursion distances

    Fish Assemblage Shifts and Population Dynamics of Smallmouth Bass (Micropterus dolomieu) in the Beaver Archipelago, Northern Lake Michigan: A Comparison Between Historical and Recent Time Periods Amidst Ecosystem Changes.

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    The ecological and economic importance of Great Lakes nearshore areas and the paucity of information on nearshore Lake Michigan fish assemblages prompted us to document changes that occurred from a historical time period (1969–1972, 1975, 1977, and 1984) to a recent period (2005–2008) in a nearshore northern Lake Michigan (Beaver Archipelago) fish assemblage, with an emphasis on smallmouth bass Micropterus dolomieu. From historical to recent periods, the Beaver Archipelago fish assemblage shifted from predominantly brown bullheads Ameiurus nebulosus to predominantly smallmouth bass. Relative abundance of brown bullheads and white suckers Catostomus commersonii declined from historical to recent time periods, as did overall species richness. The relative abundance, recruitment variability, and mortality rates of smallmouth bass have not significantly changed since the historical time period, whereas both condition (ages 5–7) and growth (ages 2–7) of this species have significantly increased. Our results suggest that the smallmouth bass population in the Beaver Archipelago area has not been negatively affected by recent ecological changes (i.e., declining primary productivity, increasing benthic invertebrate densities, increasing numbers of double-crested cormorants Phalacrocorax auritus, and increasing introductions of nonnative species). The smallmouth bass is currently the dominant nearshore species and remains a critical component of the nearshore fish assemblage in northern Lake Michigan

    Prostanoid receptors in GtoPdb v.2023.1

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    Prostanoid receptors (nomenclature as agreed by the NC-IUPHAR Subcommittee on Prostanoid Receptors [701]) are activated by the endogenous ligands prostaglandins PGD2, PGE1, PGE2 , PGF2α, PGH2, prostacyclin [PGI2] and thromboxane A2. Differences and similarities between human and rodent prostanoid receptor orthologues, and their specific roles in pathophysiologic conditions are reviewed in [452]. Measurement of the potency of PGI2 and thromboxane A2 is hampered by their instability in physiological salt solution; they are often replaced by cicaprost and U46619, respectively, in receptor characterization studies

    Prostanoid receptors in GtoPdb v.2023.1

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    Prostanoid receptors (nomenclature as agreed by the NC-IUPHAR Subcommittee on Prostanoid Receptors [701]) are activated by the endogenous ligands prostaglandins PGD2, PGE1, PGE2 , PGF2α, PGH2, prostacyclin [PGI2] and thromboxane A2. Differences and similarities between human and rodent prostanoid receptor orthologues, and their specific roles in pathophysiologic conditions are reviewed in [452]. Measurement of the potency of PGI2 and thromboxane A2 is hampered by their instability in physiological salt solution; they are often replaced by cicaprost and U46619, respectively, in receptor characterization studies

    Prostanoid receptors in GtoPdb v.2021.2

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    Prostanoid receptors (nomenclature as agreed by the NC-IUPHAR Subcommittee on Prostanoid Receptors [694]) are activated by the endogenous ligands prostaglandins PGD2, PGE1, PGE2 , PGF2α, PGH2, prostacyclin [PGI2] and thromboxane A2. Differences and similarities between human and rodent prostanoid receptor orthologues, and their specific roles in pathophysiologic conditions are reviewed in [448]. Measurement of the potency of PGI2 and thromboxane A2 is hampered by their instability in physiological salt solution; they are often replaced by cicaprost and U46619, respectively, in receptor characterization studies
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