754 research outputs found

    EEMCS final report for the causal modeling for air transport safety (CATS) project

    Get PDF
    This document reports on the work realized by the DIAM in relation to the completion of the CATS model as presented in Figure 1.6 and tries to explain some of the steps taken for its completion. The project spans over a period of time of three years. Intermediate reports have been presented throughout the project’s progress. These are presented in Appendix 1. In this report the continuous‐discrete distribution‐free BBNs are briefly discussed. The human reliability models developed for dealing with dependence in the model variables are described and the software application UniNet is presente

    A survey for oysters and shell in the vicinity of the proposed construction site for a city of Norfolk water line across the Lafayette River near the Hampton Boulevard bridge

    Get PDF
    At the request of the Department of Utilities of the City of Norfolk, the Virginia Institute of Marine Science conducted a survey of the oyster ground in the Lafayette River in the immediate vicinity of the proposed construction site for a 20 11 water line across the river just below the Hampton Blvd. bridge and in front of the Norfolk Yacht and Country Club (Figure 1). The section of river bottom surveyed was delineated by the Department of Utilities engineers on their site plans. It consisted of a strip across an oyster ground leased by Holland Fisheries. Inc. (Virginia Marine Resources Commission Plat File No. 1403), with boundaries parallel to the proposed water line, approximately 680 ft long on the SE side and 550 ft long on the NV side (Figure 2). The strip was approximately 35 ft wide on the NW side of the proposed water line and 82 ft wide on the SE side. The total area surveyed was estimated to be 1.8 acres. Overall area of the oyster ground lease is 33.80 acres

    The Status of Virginia\u27s Public Oyster Fishery 1994

    Get PDF
    This report summarizes data collected during 1994 in the Virginia portion of the Chesapeake Bay. The report is composed of two parts, part one, oyster recruitment (shell string) in Virginia and part two, dredge survey of selected oyster bars in Virginia

    The Status of Virginia\u27s Public Oyster Fishery 1994

    Get PDF
    This report summarizes data collected during 1994 in the Virginia portion of the Chesapeake Bay. The report is composed of two parts, part one, oyster recruitment (shell string) in Virginia and part two, dredge survey of selected oyster bars in Virginia

    The Status of Virginia\u27s Public Oyster Resource 1993

    Get PDF
    This report summarizes data collected during 1993 in the Virginia portion of the Chesapeake Bay. The report is composed of two parts, part one, oyster recruitment (shell string) in Virginia and part two, dredge survey of selected oyster bars in Virginia

    The Status of Virginia\u27s Public Oyster Resource 1997

    Get PDF
    This report summarizes data collected during 1997 in the Virginia portion of the Chesapeake Bay. The report is composed of two parts, part one, oyster recruitment (shell string) in Virginia and part two, dredge survey of selected oyster bars in Virginia

    A Survey for Oysters and Shell in the Vicinity of the Proposed Bridge Construction at the Site of the Hampton Boulevard Bridge (Rte. 337) Over the Lafayette River in Norfolk, VA.

    Get PDF
    At the request of the Virginia Department of Transportation (VDOT), the Virginia Institute of Marine Science (VIMS) conducted a survey of certain parcels of oyster grounds in the Lafayette River in the immediate vicinity of a proposed construction site for a new bridge across the river on Hampton Blvd., east of the present bridge, in Norfolk, Va

    Anatomical features in histological sections of Crassostrea virginica (Gmelin, 1791) as an aid in management of gonad area for reproductive assessment

    Get PDF
    The relationship between gonad area in transverse histological sections of the American oyster Crassostrea virginica (Gmelin 1790) and body location from which the section was cut was studied in specimens collected from four stations in the James River, Virginia in 1984 and 1986. Gonad area, expressed as percentage of total body area, increases in an antero-posterior direction; this requires use of sections from the same body location in comparisons between oysters. Approximate body locations, identified according to the anatomy and arrangement of the internal organs in the sections, were grouped into five types with similar gonad area percentages. One of those types is uniquely suitable for identification of a specific body location because it includes an easily recognizable pair of H-shaped structures corresponding to the posterior appendix of the anterior stomach caecum; furthermore, the recommended section type can be readily found on the whole oyster because it is located close to the junction of the gills and the labial palps. Gamete volume fraction (GVF) was positively correlated with percent gonad area (PGA) in most of the section types at three of the stations, suggesting that either measurement may be used to estimate the relative gonadal development in oysters. Differences between collection dates at the fourth station indicated what external factors may disrupt the correlation. It is suggested that gonad area measurements from a series of selected histological sections could be combined with gamete density measurements to estimate total gamete production by an oyster

    Recruitment and growth of oysters on shell planted at four monthly intervals in the lower Potomac River, Maryland

    Get PDF
    Oyster shells were planted on four successive months (May to August 1986) in contiguous plots at Jones Shore Bar in the Potomac River, Maryland, to study the effect of differences in time of cultch planting on settlement and survival of oyster spat. The plots were usually sampled at two-week intervals from time of planting through November, 1986, and once in June, 1987. A massive concentration of the tunicate Molgula manhattensis covered the bottom in all plots within four to six or eight weeks following shell planting. A commercially acceptable number of spat per shell, between 1.8 and 2.2 (approximately equivalent to 900-1200 spat per bu), was recorded at three of the plots on June 26, 1987, in spite of the heavy tunicate fouling of 1986. Recruitment of oyster spat was lower in the plot on which cultch was planted earliest, on May 13, than in the other three plots on which cultch was planted 1-3 months later. Number of spat was highest in the plot on which shells were planted on July 14; accidental planting of cultch into two elongated mounds on that plot may have contributed to the high recruitment of spat observed. Mean spat height was lowest in the plot on which cultch was planted on August 12 and highest in the plots on which shell was planted on May 13 and June 16. The lower number of spat found on shells planted on May 13 was probably associated with the early planting date. The data suggest that combined maximum recruitment and growth of oyster spat is most likely to occur at Jones Shore on cultch planted between late June and mid-July, although plantings as early as mid-June and as late as early August may also produce commercially-acceptable results
    corecore