2,409 research outputs found

    Magnitude and Extent of Contaminated Sediment and Toxicity in Chesapeake Bay

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    INTRODUCTION: This report summarizes the results of NOAA's sediment toxicity, chemistry, and benthic community studies in the Chesapeake Bay estuary. As part of the National Status and Trends (NS&T) Program, NOAA has conducted studies to determine the spatial extent and severity of chemical contamination and associated adverse biological effects in coastal bays and estuaries of the United States since 1991. Sediment contamination in U.S. coastal areas is a major environmental issue because of its potential toxic effects on biological resources and often, indirectly, on human health. Thus, characterizing and delineating areas of sediment contamination and toxicity and demonstrating their effect(s) on benthic living resources are viewed as important goals of coastal resource management. Benthic community studies have a history of use in regional estuarine monitoring programs and have been shown to be an effective indicator for describing the extent and magnitude of pollution impacts in estuarine ecosystems, as well as for assessing the effectiveness of management actions. Chesapeake Bay is the largest estuarine system in the United States. Including tidal tributaries, the Bay has approximately 18,694 km of shoreline (more than the entire US West Coast). The watershed is over 165,000 km2 (64,000 miles2), and includes portions of six states (Delaware, Maryland, New York, Pennsylvania, Virginia, and West Virginia) and the District of Columbia. The population of the watershed exceeds 15 million people. There are 150 rivers and streams in the Chesapeake drainage basin. Within the watershed, five major rivers - the Susquehanna, Potomac, Rappahannock, York and James - provide almost 90% of the freshwater to the Bay. The Bay receives an equal volume of water from the Atlantic Ocean. In the upper Bay and tributaries, sediments are fine-grained silts and clays. Sediments in the middle Bay are mostly made of silts and clays derived from shoreline erosion. In the lower Bay, by contrast, the sediments are sandy. These particles come from shore erosion and inputs from the Atlantic Ocean. The introduction of European-style agriculture and large scale clearing of the watershed produced massive shifts in sediment dynamics of the Bay watershed. As early as the mid 1700s, some navigable rivers were filled in by sediment and sedimentation caused several colonial seaports to become landlocked. Toxic contaminants enter the Bay via atmospheric deposition, dissolved and particulate runoff from the watershed or direct discharge. While contaminants enter the Bay from several sources, sediments accumulate many toxic contaminants and thus reveal the status of input for these constituents. In the watershed, loading estimates indicate that the major sources of contaminants are point sources, stormwater runoff, atmospheric deposition, and spills. Point sources and urban runoff in the Bay proper contribute large quantities of contaminants. Pesticide inputs to the Bay have not been quantified. Baltimore Harbor and the Elizabeth River remain among the most contaminated areas in the Unites States. In the mainstem, deep sediment core analyses indicate that sediment accumulation rates are 2-10 times higher in the northern Bay than in the middle and lower Bay, and that sedimentation rates are 2-10 times higher than before European settlement throughout the Bay (NOAA 1998). The core samples show a decline in selected PAH compounds over the past several decades, but absolute concentrations are still 1 to 2 orders of magnitude above 'pristine' conditions. Core data also indicate that concentrations of PAHs, PCBs and, organochlorine pesticides do not demonstrate consistent trends over 25 years, but remain 10 times lower than sediments in the tributaries. In contrast, tri-butyl-tin (TBT) concentrations in the deep cores have declined significantly since it=s use was severely restricted. (PDF contains 241 pages

    (N,p,q) Harmonic Superspace

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    A family of harmonic superspaces associated with four-dimensional spacetime is described. Some applications to supersymmetric field theories, including supergravity, are given.Comment: 25 pages, latex file, improved. Minor text errors correcte

    \u3cb\u3eTHE OREGON PLAN A SYMPOSIUM\u3c/b\u3e Introduction to the Cleveland Conference on Bioethics

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    \u3cb\u3eTHE OREGON PLAN A SYMPOSIUM\u3c/b\u3e Introduction to the Cleveland Conference on Bioethics

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    Guillerme Jacques. Jacques Reclus (1894-1984). In: Études chinoises, n°3, 1984. pp. 113-114

    EVIDENCE-ADMISSIBILITY OF UNCOMMUNICATED THREATS

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    The defendant was convicted of murder in the first degree, following his killing of one Hunter as the outcome of a quarrel. The defendant had pleaded self-defense, contending that Hunter had appeared to threaten him. The defendant was the only witness to testify as to any aggression on the part of Hunter, while the four eyewitnesses to the killing all testified that the accused had attacked Hunter without warning and had fired upon Hunter\u27s wife and child. Defendant\u27s motion for new trial on the ground of newly discovered evidence showing that Hunter had in his pocket an open knife, which constituted an uncommunicated threat against him, was dismissed. Held, order reversed,. motion for new trial granted. Such evidence was relevant as it could be construed by the jury as a threat which, although uncommunicated to the prisoner, bore on the question of the apparent conduct of the deceased. Judge Clark dissented. Griffin v. United States, (D.C. Cir. 1950) 183 F. (2d) 990

    JURISDICTION-BASIS AND RANGE OF PROCESS-RECENT DEVELOPMENTS

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    Since Pennoyer v. Neff, holding that mere notice was an insufficient basis for in personam jurisdiction, it has generally been held that an in personam judgment requires service, as distinguished from notice, on a defendant present or domiciled within the jurisdiction. With the increased tempo of interstate activities, however, it has become expedient to relax the concept of physical power as being the basis of jurisdiction, which prompted the Pennoyer decision. Presence has assumed a more elaborate meaning, while service has become more closely equated with adequate notice. Illustrative of this development is the recent decision of Traveler\u27s Health Assn. v. Virginia, where peculiar problems were presented relating to a state\u27s ability to regulate activity carried on substantially beyond its borders, but seriously affecting those within its jurisdiction

    JURISDICTION-BASIS AND RANGE OF PROCESS-RECENT DEVELOPMENTS

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    Since Pennoyer v. Neff, holding that mere notice was an insufficient basis for in personam jurisdiction, it has generally been held that an in personam judgment requires service, as distinguished from notice, on a defendant present or domiciled within the jurisdiction. With the increased tempo of interstate activities, however, it has become expedient to relax the concept of physical power as being the basis of jurisdiction, which prompted the Pennoyer decision. Presence has assumed a more elaborate meaning, while service has become more closely equated with adequate notice. Illustrative of this development is the recent decision of Traveler\u27s Health Assn. v. Virginia, where peculiar problems were presented relating to a state\u27s ability to regulate activity carried on substantially beyond its borders, but seriously affecting those within its jurisdiction

    Person-specific gesture set selection for optimised movement classification from EMG signals

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    © 2016 IEEE.Movement classification from electromyography (EMG) signals is a promising vector for improvement of human computer interaction and prosthetic control. Conventional work in this area typically makes use of expert knowledge to select a set of movements a priori and then design classifiers based around these movements. The disadvantage of this approach is that different individuals might have different sets of movements that would lead to high classification accuracy. The novel approach we take here is to instead use a data-driven diagnostic test to select a set of person-specific movements. This new approach leads to an optimised set of movements for a specific person with regards to classification performance
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