A von Bertalanffy Based Model for the Estimation of Oyster (Crassostrea virginica) Growth on Restored Oyster Reefs in Chesapeake Bay

A model to estimate the mean monthly growth of Crassostrea virginica oysters in Chesapeake Bay was developed. This model is based on the classic von Bertalanffy growth function, however the growth constant is changed every monthly timestep in response to short term changes in temperature and salinity. Using a dynamically varying growth constant allows the model to capture seasonal oscillations in growth, and growth responses to changing environmental conditions that previous applications of the von Bertalanffy model do not capture. This model is further expanded to include an estimation of Perkinsus marinus impacts on growth rates as well as estimations of ecosystem services provided by a restored oyster bar over time. The model was validated by comparing growth estimates from the model to oyster shell height observations from a variety of restoration sites in the upper Chesapeake Bay. Without using the P. marinus impact on growth, the model consistently overestimates mean oyster growth. However, when P. marinus effects are included in the model, the model estimates match the observed mean shell height closely for at least the first 3 years of growth. The estimates of ecosystem services suggested by this model imply that even with high levels of mortality on an oyster reef, the ecosystem services provided by that reef can still be maintained by growth for several years. Because larger oyster filter more water than smaller ones, larger oysters contribute more to the filtration and nutrient removal ecosystem services of the reef. Therefore a reef with an abundance of larger oysters will provide better filtration and nutrient removal. This implies that if an oyster restoration project is trying to improve water quality through oyster filtration, it is important to maintain the larger older oysters on the reef.

RECITAL REPERTOIRE FOR TROMBONE AND PERCUSSION

The solo trombone recital was once a rare musical event, but in recent years professional and amateur trombonists frequently present solo performances. The trombone has been around since the latter half of the 15th century and there is a wealth of ensemble repertoire, written for the instrument; however, there is no corresponding corpus of solo works. A small body of solo works does exist, from baroque sonatas and the alto trombone concertos of Leopold Mozart and Georg Wagenseil, to the romantic works by Ferdinand David and Nicolai Rimsky-Korsakov. This repertoire is small in number and a modern trombonist often has to resort to orchestral reductions and arrangements for modern performance in a solo recital setting. The trombone came into its own as a solo instrument in the 20th century and it is in this era where the bulk of a modern trombonist's repertoire resides. While there is now no shortage of music to choose from, presenting a diverse, yet musically cohesive recital remains a challenge though many interesting musical opportunities can arise to meet this challenge. While the piano is an extremely versatile instrument, pairing trombone with percussion opens up possibilities that are absent from the more traditional piano pairing. Percussion instruments can offer an almost unlimited variation of timbre and dynamics to complement the trombone. Dynamic range of the trombone must be considered as the instrument has the ability to play at the extremes of the dynamic range. Percussion instruments can match the trombone in these extremes. When presenting a recital of 20th and 21st century music, using timbre and dynamic range as selection criteria when planning the program are effective ways to bring a unique and intense musical experience to the audience. In this paper, the two considerations of dynamics and timbre will be explored and the need for a dissertation recital project will be explained.

Reducing Electronic Information Overload

College students receive a wealth of information through electronic communications that they are unable to process efficiently. This information overload negatively impacts their affect, which is officially defined in the field of psychology as the experience of feeling or emotion. To address this problem, we postulated that we could create an application that organizes and presents incoming content in a manner that optimizes users’ ability to process information. First, we conducted surveys that quantitatively measured each participant’s psychological affect while handling electronic communications, which was used to tailor the features of the application to what the user’s desire. After designing and implementing the application, we again measured the user's affect using this product. Our goal was to find that the program promoted a positive change in affect. Our application, Brevitus, was able to match Gmail on affect reduction profiles, while succeeding in implementing certain user interface specifications.