133 research outputs found

    Evaluation of the risk when monthly auditing standards are imposed by sampling with weighed attributes

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    A method is developed to assist the producer in controlling the product quality where monthly auditing standards are imposed after final inspection. The control involves monitoring the numer of demerits accumulated by the auditing department and finding the risk that the product will be rated out of control at the end of the month. Thus the method is intended to be employed in addition to present control techniques

    A Multimedia Information and Education Tool on the Importance of Bull Trout and the Relationship between Bull Trout and the Salish and Pend d'Oreille People

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    The Confederated Salish and Kootenai Tribes have undertaken a large-scale watershed restoration project in an effort to benefit bull trout (Salvelinus confluentus) in the Jocko River drainage. An important component of this comprehensive project is education and outreach. In this poster and an accompanying digital presentation we will give an overview of a multimedia information and education project that describes the ecology and importance of bull trout, the relationship between bull trout and the Salish and Pend d'Oreille people, and the Tribes’ current efforts to restore habitats. The project is composed of an integrated set of educational materials that will include an interactive DVD entitled “Explore the River: Bull Trout, Tribal People and the Jocko River”, a curriculum, a website, a storybook “Bull Trout’s Gift”, and an accompanying field journal to be published by the University of Nebraska Press

    2-kW Average Power CW Phase-Conjugate Solid-State Laser

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    We have demonstrated stable operation of a 2-kW Yb:YAG phase-conjugate master oscillator power amplifier (PC-MOPA) laser system with a loop phase-conjugate mirror (LPCM). This is the first demonstration of a continuous wave (CW)-input LPCM MOPA operating at a power greater than 1 kW with a nearly diffraction-limited output beam. The single-pass beam quality incident on the LPCM varied with the specific operating conditions, but it was typically sim20{sim}20 times diffraction-limited (XDL). The measured beam quality with an MOPA output power of 1.65 kW was 1.3 XDL

    Oblique internal hydraulic jumps at a stratified estuary mouth

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    Author Posting. © American Meteorological Society, 2017. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Physical Oceanography 47 (2017): 85-100, doi:10.1175/JPO-D-15-0234.1.Observations and analyses of two tidally recurring, oblique, internal hydraulic jumps at a stratified estuary mouth (Columbia River, Oregon/Washington) are presented. These hydraulic features have not previously been studied due to the challenges of both horizontally resolving the sharp gradients and temporally resolving their evolution in numerical models and traditional observation platforms. The jumps, both of which recurred during ebb, formed adjacent to two engineered lateral channel constrictions and were identified in marine radar image time series. Jump occurrence was corroborated by (i) a collocated sharp gradient in the surface currents measured via airborne along-track interferometric synthetic aperture radar and (ii) the transition from supercritical to subcritical flow in the cross-jump direction via shipborne velocity and density measurements. Using a two-layer approximation, observed jump angles at both lateral constrictions are shown to lie within the theoretical bounds given by the critical internal long-wave (Froude) angle and the arrested maximum-amplitude internal bore angle, respectively. Also, intratidal and intertidal variability of the jump angles are shown to be consistent with that expected from the two-layer model, applied to varying stratification and current speed over a range of tidal and river discharge conditions. Intratidal variability of the upchannel jump angle is similar under all observed conditions, whereas the downchannel jump angle shows an additional association with stratification and ebb velocity during the low discharge periods. The observations additionally indicate that the upchannel jump achieves a stable position that is collocated with a similarly oblique bathymetric slope.We acknowledge the financial support of the Office of Naval Research under Awards N00014-10-1-0932 and N00014-13-1-0364.2017-07-0

    Effects of estuarine and fluvial processes on sediment transport over deltaic tidal flats

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    Author Posting. © The Author(s), 2012. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Continental Shelf Research 60, Suppl. (2013): S40–S57, doi:10.1016/j.csr.2012.02.004.Tidal flats at a river mouth feature estuarine and fluvial processes that distinguish them from tidal flats without river discharge. We combine field observations and a numerical model to investigate hydrodynamics and sediment transport on deltaic tidal flats at the mouth of the Skagit River, in Puget Sound, WA during the spring freshet. River discharge over tidal flats supplies a mean volume flux, freshwater buoyancy, and suspended sediment. Despite the shallow water depths, strong horizontal density fronts and stratification develop, resulting in a baroclinic pressure gradient and tidal variability in stratification that favor flood-directed bottom stresses. In addition to these estuarine processes, the river discharge during periods of low tide drains through a network of distributary channels on the exposed tidal flats, with strongly ebb-directed stresses. The net sediment transport depends on the balance between estuarine and fluvial processes, and is modulated on a spring-neap time scale by the tides of Puget Sound. We find that the baroclinic pressure gradient and periodic stratification enhance trapping of sediment delivered by the river on the tidal flats, particularly during neap tides, and that sediment trapping also depends on settling and scour lags, particularly for finer particles. The primary means of moving sediment off of the tidal flats are the high velocities and stresses in the distributary channels during late stages of ebbs and around low tides, with sediment export predominantly occurring during spring low tides that expose a greater portion of the flats. The 3-d finite volume numerical model was evaluated against observations and had good skill overall, particularly for velocity and salinity. The model performed poorly at simulating the shallow flows around low tides as the flats drained and river discharge was confined to distributary channels, due in part to limitations in grid resolution, seabed sediment and bathymetric data, and the wetting-and-drying scheme. Consequently, the model predicted greater sediment retention on the flats than was observed.This work was supported by the Office of Naval Research

    Estuarine exchange flow quantified with isohaline coordinates : contrasting long and short estuaries

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    Author Posting. © American Meteorological Society, 2012. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Physical Oceanography 42 (2012): 748–763, doi:10.1175/JPO-D-11-086.1.Isohaline coordinate analysis is used to compare the exchange flow in two contrasting estuaries, the long (with respect to tidal excursion) Hudson River and the short Merrimack River, using validated numerical models. The isohaline analysis averages fluxes in salinity space rather than in physical space, yielding the isohaline exchange flow that incorporates both subtidal and tidal fluxes and precisely satisfies the Knudsen relation. The isohaline analysis can be consistently applied to both subtidally and tidally dominated estuaries. In the Hudson, the isohaline exchange flow is similar to results from the Eulerian analysis, and the conventional estuarine theory can be used to quantify the salt transport based on scaling with the baroclinic pressure gradient. In the Merrimack, the isohaline exchange flow is much larger than the Eulerian quantity, indicating the dominance of tidal salt flux. The exchange flow does not scale with the baroclinic pressure gradient but rather with tidal volume flux. This tidal exchange is driven by tidal pumping due to the jet–sink flow at the mouth constriction, leading to a linear dependence of exchange flow on tidal volume flux. Finally, a tidal conversion parameter Qin/Qprism, measuring the fraction of tidal inflow Qprism that is converted into net exchange Qin, is proposed to characterize the exchange processes among different systems. It is found that the length scale ratio between tidal excursion and salinity intrusion provides a characteristic to distinguish estuarine regimes.SNC is supported by a WHOI postdoctoral scholarship, a NSF Grant OCE-0926427, and a Taiwan National Science Council Grant NSC 100- 2199-M-002-028.WRGis supported byNSFGrantOCE- 0926427. JAL is supported by NSF Grant OCE-0452054.2012-11-0

    Bigger tides, less flooding: Effects of dredging on barotropic dynamics in a highly modified estuary.

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    Author Posting. © American Geophysical Union, 2019. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research-Oceans 124 (2019): 196-211, doi:10.1029/2018JC014313.Since the late nineteenth century, channel depths have more than doubled in parts of New York Harbor and the tidal Hudson River, wetlands have been reclaimed and navigational channels widened, and river flow has been regulated. To quantify the effects of these modifications, observations and numerical simulations using historical and modern bathymetry are used to analyze changes in the barotropic dynamics. Model results and water level records for Albany (1868 to present) and New York Harbor (1844 to present) recovered from archives show that the tidal amplitude has more than doubled near the head of tides, whereas increases in the lower estuary have been slight (<10%). Channel deepening has reduced the effective drag in the upper tidal river, shifting the system from hyposynchronous (tide decaying landward) to hypersynchronous (tide amplifying). Similarly, modeling shows that coastal storm effects propagate farther landward, with a 20% increase in amplitude for a major event. In contrast, the decrease in friction with channel deepening has lowered the tidally averaged water level during discharge events, more than compensating for increased surge amplitude. Combined with river regulation that reduced peak discharges, the overall risk of extreme water levels in the upper tidal river decreased after channel construction, reducing the water level for the 10‐year recurrence interval event by almost 3 m. Mean water level decreased sharply with channel modifications around 1930, and subsequent decadal variability has depended both on river discharge and sea level rise. Channel construction has only slightly altered tidal and storm surge amplitudes in the lower estuary.Funding for D. K. R., W. R. G., and C. K. S. was provided by NSF Coastal SEES awards OCE-1325136 and OCE-1325102. Funding for S.T. and H. Z. was provided by the U.S. Army Corps of Engineers (award W1927 N-14-2-0015), and NSF (Career Award 1455350). Data supporting this study are posted to Zenodo (https://doi.org/10.5281/zenodo.1298636).2019-06-1

    Dynamic regulation of the endocannabinoid system: implications for analgesia

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    The analgesic effects of cannabinoids are well documented, but these are often limited by psychoactive side-effects. Recent studies indicate that the endocannabinoid system is dynamic and altered under different pathological conditions, including pain states. Changes in this receptor system include altered expression of receptors, differential synthetic pathways for endocannabinoids are expressed by various cell types, multiple pathways of catabolism and the generation of biologically active metabolites, which may be engaged under different conditions. This review discusses the evidence that pain states alter the endocannabinoid receptor system at key sites involved in pain processing and how these changes may inform the development of cannabinoid-based analgesics

    The temporal response of the length of a partially stratified estuary to changes in river flow and tidal amplitude

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    Author Posting. © American Meteorological Society, 2009. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Physical Oceanography 39 (2009): 915-933, doi:10.1175/2008JPO3933.1.The temporal response of the length of a partially mixed estuary to changes in freshwater discharge Qf and tidal amplitude UT is studied using a 108-day time series collected along the length of the Hudson River estuary in the spring and summer of 2004 and a long-term (13.4 yr) record of Qf, UT, and near-surface salinity. When Qf was moderately high, the tidally averaged length of the estuary L5, here defined as the distance from the mouth to the up-estuary location where the vertically averaged salinity is 5 psu, fluctuated by more than 47 km over the spring–neap cycle, ranging from 28 to >75 km. During low flow periods, L5 varied very little over the spring–neap cycle and approached a steady length. The response is quantified and compared to predictions of a linearized model derived from the global estuarine salt balance. The model is forced by fluctuations in Qf and UT relative to average discharge Qo and tidal amplitude UTo and predicts the linear response time scale τ and the steady-state length Lo for average forcing. Two vertical mixing schemes are considered, in which 1) mixing is proportional to UT and 2) dependence of mixing on stratification is also parameterized. Based on least squares fits between L5 and estuary length predicted by the model, estimated τ varied by an order of magnitude from a period of high average discharge (Qo = 750 m3 s−1, τ = 4.2 days) to a period of low discharge (Qo = 170 m3 s−1, τ = 40.4 days). Over the range of observed discharge, Lo Qo−0.30±0.03, consistent with the theoretical scaling for an estuary whose landward salt flux is driven by vertical estuarine exchange circulation. Estimated τ was proportional to the discharge advection time scale (LoA/Qo, where A is the cross-sectional area of the estuary). However, τ was 3–4 times larger than the theoretical prediction. The model with stratification-dependent mixing predicted variations in L5 with higher skill than the model with mixing proportional to UT. This model provides insight into the time-dependent response of a partially stratified estuary to changes in forcing and explains the strong dependence of the amplitude of the spring–neap response on freshwater discharge. However, the utility of the linear model is limited because it assumes a uniform channel, and because the underlying dynamics are nonlinear, and the forcing Qf and UT can undergo large amplitude variations. River discharge, in particular, can vary by over an order of magnitude over time scales comparable to or shorter than the response time scale of the estuary.This study was generously funded by Hudson River Foundation Grant 005/03A and NSF Grant OCE-0452054. Lerczak also received partial support from the Woods Hole Center for Oceans and Human Health, NSF Grant OCE-0430724 and NIEHS Grant 1-P50-ES012742-01
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