Interaction Between Circulation of the Estuary of the James River and Transport of Oyster Larvae

Hydraulic model dye test results are examined to provide estimates of nontidal horizontal circulation and movement/retention of oyster larvae in the James River Estuary. Test conditions maintained a constant mean tide and average summer low freshwater discharge. It was assumed that movement of dye in the model would approximate movement of the planktonic (larval) stages of oysters (Crassostroa virginica) in the prototype. Test results were used to rank six dye release points (candidate brood stock locations) with respect to relative quantities of dye retained in areas of the model representing commercially important seed oyster beds during the period 20-40 tidal cycles after release (the time, after spawning, when oyster larvae will permanently attach to a suitable substrate). Under the test conditions, nontidal circulation in the model was similar to that found in a weak partially mixed estuary: upstream motion along the bottom and over the right hand shoals (looking upstream) and downstream motion elsewhere. The pattern was modified by cyclonic motion of surface waters in the upstream and downstream reaches which increased residence time of material in the seed oyster bed region. Greatest retention during the 20-40 tidal cycle period was from releases over upstream and right hand side shoals and is reflected in release point ranking.https://scholarworks.wm.edu/vimsbooks/1031/thumbnail.jp

Providing Faculty iPods to Explore Innovative Teaching and Learning

The iPod digital music player has been available since late 2001, and even in higher education, its presence has been seen, although mostly in the hands of students and rarely for outcomes-based educational purposes. In 2004, Duke University provided free iPods to all 1,650 first year students, which subsequently enabled faculty to create learning opportunities, which actively engaged students to integrate digital audio and more into their lessons. Our study takes an alternate approach in which the Center for Teaching and Learning provided a small group of faculty (n=11) from different disciplines with a free iPod, microphone, training, support and collaboration opportunities. The faculty members were asked to create innovative instructional methods and then use the tool in their classes for the 2008 spring semester. In return, faculty agreed to share their outcomes, which would become part of a resource showcase to assist other faculty. So, instead of distributing the technology to a wide audience, where only some may participate, and our goal was to identify those who would actively engage in the project, develop specific applications, and ultimately assist faculty and subsequently students, in integrating functional instructional technology. The primary purpose of this study is to share another model for using and distributing electronic media tools in higher education and secondarily to provide the results of this model in the form of varied and successful uses of the device in teaching and learning

Survey for Transiting Extrasolar Planets in Stellar Systems IV: Variables in the Field of NGC 1245

The Survey for Transiting Extrasolar Planets in Stellar Systems (STEPSS) project is a search for planetary transits in open clusters. In this paper, we analyze the STEPSS observations of the open cluster NGC 1245 to determine the variable star content of the cluster. Out of 6787 stars observed with V < 22, of which ~870 are cluster members, we find 14 stars with clear intrinsic variability that are potential cluster members, and 29 clear variables that are not cluster members. None of these variables have been previously identified. We present light curves, finding charts, and stellar/photometric data on these variable objects. Several of the interacting binaries have estimated distances consistent with the cluster distance determined from isochrone fits to the color magnitude diagram. Four stars at the main sequence turnoff of the cluster have light curves consistent with gamma Doradus variability. If these gamma Doradus candidates are confirmed, they represent the oldest and coolest members of this class of variable discovered to date.Comment: 20 pages, 15 figures. Submitted to AJ. PDF version with full-resolution figures at http://www.astronomy.ohio-state.edu/~pepper/ms.pd

The Effect of Tropical Storm Agnes on Oysters, Hard Clams, Soft Clams, and Oyster Drills in VIrginia

Tropical Storm Agnes had a major effect on the molluscan fisheries of Virginia. One effect was the direct mortality of oysters, Crassostrea virginiaa, in the upper parts of many estuaries. Typical losses on leased bottoms were: the James River, 10%; the York River, 2%; the Rappahannock River, 50%; and the Potomac River tributaries (Virginia) 70%. Economic loss was in excess of 7.9 million dollars. There was a nearly complete absence of oyster larvae attachment (setting) in 1972. Other effects of Agnes included a nearly complete loss of soft clams, Mya arenaria, in the Rappahannock River. Hard clams, Meraenaria meraenaria, were killed in the upper part of the York River. Oyster drills, Urosalpinx ainerea, were eliminated from the Rappahannock and reduced greatly in numbers in the York and James Rivers.https://scholarworks.wm.edu/vimsbooks/1074/thumbnail.jp