Adaptive Management for Impacts to Eelgrass Habitat in Gloucester Harbor

The Massachusetts Office of Coastal Zone Management and the Massachusetts Institute of Technology Sea Grant College Program, along with partners, led an effort to create an eelgrass bank, raise awareness of the value of eelgrass habitat, and facilitate transplanting efforts to Boston Harbor in the summer and fall of 2006. A planned impact to eelgrass habitat in Gloucester Harbor warranted efforts to try to save this valuable and declining resource. This unfortunate circumstance was used to educate interested citizens, students and teachers from regional schools, and government employees. Methods to transplant and store eelgrass were researched and tested in attempt to facilitate restoration of the impact area. Two community events were organized at Pavilion Beach to harvest eelgrass from the impact area. These events were attended by a variety of government (city, state, and federal) and non-government employees, along with students and teachers, and attracted much attention of the citizens of Gloucester. Eelgrass was successfully transplanted to Boston Harbor by the Massachusetts Division of Marine Fisheries. Harvested eelgrass was also maintained in a hydroponic raft system for three months (October-December) and used to set-up an interpretative display in a flow-through tank at the Gloucester Maritime Heritage Center. While the harvested eelgrass was ultimately not transplanted back to the impact corridor, experience in storing eelgrass within hydroponic and tank systems could assist future restoration efforts. By teaming up to save the eelgrass at Pavilion Beach in Gloucester Harbor, project partners demonstrated the advantage of creative, adaptive, and cooperative efforts to manage coastal resources. The project was a learning experience in adaptive management for eelgrass habitat and a success in outreach

DECISION SYSTEMS RESEARCH FOR THE TOURISM/RECREATION INDUSTRY

Resource /Energy Economics and Policy,

Spray automated balancing of rotors: Methods and materials

The work described consists of two parts. In the first part, a survey is performed to assess the state of the art in rotor balancing technology as it applies to Army gas turbine engines and associated power transmission hardware. The second part evaluates thermal spray processes for balancing weight addition in an automated balancing procedure. The industry survey reveals that: (1) computerized balancing equipment is valuable to reduce errors, improve balance quality, and provide documentation; (2) slow-speed balancing is used exclusively, with no forseeable need for production high-speed balancing; (3) automated procedures are desired; and (4) thermal spray balancing is viewed with cautious optimism whereas laser balancing is viewed with concern for flight propulsion hardware. The FARE method (Fuel/Air Repetitive Explosion) was selected for experimental evaluation of bond strength and fatigue strength. Material combinations tested were tungsten carbide on stainless steel (17-4), Inconel 718 on Inconel 718, and Triballoy 800 on Inconel 718. Bond strengths were entirely adequate for use in balancing. Material combinations have been identified for use in hot and cold sections of an engine, with fatigue strengths equivalent to those for hand-ground materials

Effects of Calcium, Strontium, and Magnesium on the Coccolithophorid Cricosphaera (Hymenomonas) carterae. I. Calcification

The present investigation concerns the effects of calcium, strontium, and magnesium on calcification and mineralogy of the calcified bodies (coccoliths) of the coccolithophorid Cricosphaera (Hymenomonas) carterae. The capacity of cells to calcify in various concentrations of these ions was examined following preliminary decalcification in CO2. At a concentration of 10-2 M Ca, 75% of the cells formed coccoliths within 24 h and almost all cells were recalcified after 2 days. At 10-3 or 10-4 M Ca no recalcification occurred. However, with the addition of Sr to the Ca-deficient media, calcification took place as shown by observations of coccoliths and by analysis of Ca. The percentage of calcified cells increased with increasing concentrations of Sr. Strontium added to a Ca-deficient media was much more effective than an equivalent concentration of Ca. No Sr was deposited in the coccoliths. X-ray analysis demonstrated that calcite was deposited by cells in all concentrations of Ca and Sr at which calcification took place. At concentrations of Mg in the media from 0.0 to 4.2×10-2 M, the cells retained their ability to calcify, although calcification was markedly reduced in the absence of Mg. In low Mg concentrations (1.3×10-4 and 4.2×10-6 M), the coccoliths were 60% calcite and 40% aragonite, and in the absence of Mg, only calcite was formed

Resonant electron transmission through a finite quantum spin chain

Electron transport in a finite one dimensional quantum spin chain (with ferromagnetic exchange) is studied within an $s-d$ exchange Hamiltonian. Spin transfer coefficients strongly depend on the sign of the $s-d$ exchange constant. For a ferromagnetic coupling, they exhibit a novel resonant pattern, reflecting the salient features of the combined electron-spin system. Spin-flip processes are inelastic and feasible at finite voltage or at finite temperature.Comment: 4 pages including 4 .eps figure

STATISTICAL ISSUES IN THE ANALYSIS OF MICROBIAL COMMUNITIES IN SOIL

Corn and soybean production dominates the agricultural systems of the mid-western United States. Studies have found that when a single crop species is grown continually, without the rotation of other crops, yield decline occurs. At present, this phenomenon, remains poorly understood, but there are possible links to microbial community dynamics in the associated rhizosphere soil. In this study, corn plants were grown in disturbed and undisturbed soils with a 24 year history of growth as a mono culture crop or two crops grown in annual rotation. Characteristic profiles of the microbial communities were obtained by denaturing gradient gel electrophoresis of polymerase chain reaction amplified 16S rDNA from soil extracted DNA. This problem is approached as the statistical analysis of high-dimensional multivariate binary data with an emphasis on modeling and variable selection

Potential Mercurian Analogues: Aubrite and Enstatite Chondrite Impact Melt Meteorites

The MESSENGER (MErcury Surface Space ENvironment GEochemistry and Ranging Spacecraft) mission provided new data that have helped us better constrain the surficial mineralogy and composition of Mercury. Mercury has an extremely low oxygen fugacity (f O2) (Iron Wustite (IW) -7.3 to IW -2.6), and at these unique conditions, elements, which usually exhibit lithophile behavior on Earth, can exhibit chalcophile or siderophile behavior on Mercury. No samples have been returned from Mercury; therefore, we must study candidate meteorite analogs to better understand the formation conditions of minerals inferred to be present at the Mercurian surface and Mercurian magmatic processes. In this study, we present a comprehensive analysis of a representative suite of eight aubrites and four enstatite chondrite impact melts (ECIM), which both have a similar f O2 to Mercury, and contain exotic sulfides that have been inferred to be present at the Mercurian surface. These characteristics allow us to assess their relevance for understanding the mineralogy and magmatic processes of Mercury. The ECIM were previously classified as aubrites, but we show that they are actually ECIM with a potential EH (high enstatite) parent body origin due to the presence of niningerite, Si-enriched kamacite, and uniform Ni in schreibersite. We propose that, with respect to the aubrites, the ECIM represent an ideal candidate for Mercurian studies due to their mineralogy and modal mineralogy. Compared to the aubrites, the ECIM samples do not contain forsterite or diopside, show a poorer sulfide diversity, contain graphite, and have a higher volume percentage of metal phases. Although the Mercurian surface contains forsterite and diopside, graphite and a similar amount of metal and sulfides as seen in the ECIM are inferred to be present on Mercury. According to the calculated normative Mercurian mineralogy, both candidate meteorites are most analogous to the Caloris Basin and Northern Plains Lower Mg regions

Aubrite and Impact Melt Enstatite Chondrite Meteorites as Potential Analogs to Mercury

The MESSENGER (MErcury Sur-face, Space ENvironment, GEochemistry and Ranging) orbiter measured the Mercurian surface abundances of key rock-forming elements to help us better understand the planet's surface and bulk geochemistry. A major discovery is that the Mercurian surface and interior are characterized by an extremely low oxygen fugacity (O2; Iron-Wstite (IW) -7.3 to IW-2.6. This is supported by low Fe and high S abundances on the surface. This low O2 causes a different elemental partioning from what is observed on Earth. Using surface composition, it was shown that the Mercurian surface mainly consists of normative plagioclase, pyroxene, olivine, and exotic sulfides, such as niningerite ((Mg,Mn, Fe)S) and oldhamite (CaS)

Aubrite and Enstatite Chondrite Impact Melt Meteorites: Analogs to Mercury?

New data obtained during the MESSENGER mission has allowed us to better contrain the composition and mineralogy of the mercurian surface. One unique feature of Mercury is its extremely low oxygen fugacity (O2) (Iron Wustite (IW) -7.3 to IW-2.6). At such extreme conditions, elements that exhibit lithophile behavior on Earth can exhibit chalcophile or siderophile behavior, leading to the formation of exotic sulfides and metals. As no samples have been returned from Mercury, it is critical to study meteorite analogs to better under-stand the formation conditions of the minerals present at the mercurian surface, as well as mercurian magmatic processes. Given the low fO2 on Mercury, we have selected to investigate potential meteoritic analogs for Mercury among the most reduced meteorite types, including the aubrites and enstatite chondrite impact melts. The aubrites are differentiated meteorites that show varying degrees of brecciation, have a similar O2 to the mercurian surface and interior, and contain exotic sulfides that have been inferred to be present on the mercurian surface. The enstatite chondrite impact melts are from undifferentiated parent bodies, have a similar O2 to the mercurian surface and interior, and contain exotic sulfides that have been inferred to be present on the mercurian surface. In this study, we present a comprehensive analysis of a representative suite of aubrites and enstatite chondrite impact melts and assess their relevance to under-standing magmatic processes on Mercury