Comparison of Interval and Aerial Count Methods for Estimating Fisher Boating Effort

Interval and aerial angler creel survey counting methods were compared for a statistical district of Lake Michigan (MM‐6) to evaluate potential underestimation of the interval method. Two 0.5‐h boat (i.e., interval) counts were made per sample day at five access ports within MM‐6, and on the same day, boats in 3 out of 18 MM‐6 grids were counted from aircraft. Seasonal and monthly day‐type (weekday or weekend day) estimates of boating effort by count method were compared. Seasonal boating effort estimates during open‐water periods were not significantly different for aerial versus interval counts: 250,387 versus 247,117 in 2000 and 177,532 versus 219,097 in 2001. Similarly, comparisons of boating effort by monthly day type (i.e., weekday or weekend day) within each year did not indicate significant differences. Aerial precision estimates (2 SEs/estimate; 14.84% in 2000 and 15.53% in 2001) were more precise than interval estimates (21.42% in 2000 and 24.54% in 2001). Similarly, predicted power (1 − β) was greater for aerial estimates than for interval estimates. The potential power of future interval estimates to detect a 25% change in boating effort with α = 0.05 was 0.38 for 2000 data and 0.30 for 2001 data. Aerial estimates provided power estimates of 0.66 for 2000 data and 0.62 for 2001 data. At least four interval counts per sample day are needed to match the precision and power of three aerial counts. Although both count types were made on the same sample days and at approximately the same (random) times each sample day, each method relied on unique estimation methods. Comparable, independent estimates establish the reliability of these two methods.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141023/1/nafm1331.pd

Millennial-scale sustainability of the Chesapeake Bay Native American oyster fishery

Estuaries around the world are in a state of decline following decades or more of overfishing, pollution, and climate change. Oysters (Ostreidae), ecosystem engineers in many estuaries, influence water quality, construct habitat, and provide food for humans and wildlife. In North America\u27s Chesapeake Bay, once-thriving eastern oyster (Crassostrea virginica) populations have declined dramatically, making their restoration and conservation extremely challenging. Here we present data on oyster size and human harvest from Chesapeake Bay archaeological sites spanning similar to 3,500 y of Native American, colonial, and historical occupation. We compare oysters from archaeological sites with Pleistocene oyster reefs that existed before human harvest, modern oyster reefs, and other records of human oyster harvest from around the world. Native American fisheries were focused on nearshore oysters and were likely harvested at a rate that was sustainable over centuries to millennia, despite changing Holocene climatic conditions and sea-level rise. These data document resilience in oyster populations under long-term Native American harvest, sea-level rise, and climate change; provide context for managing modern oyster fisheries in the Chesapeake Bay and elsewhere around the world; and demonstrate an interdisciplinary approach that can be applied broadly to other fisheries

Empirical performance assessment using soft-core processors on reconfigurable hardware

Simulation has been the de facto standard method for per-formance evaluation of newly proposed ideas in computer architecture for many years. While simulation allows for theoretically arbitrary delity (at least to the level of cycle accuracy) as well as the ability to monitor the architecture without perturbing the execution itself, it suers from low eective delity and long execution times. We (and others) have advocated the use of empirical ex-perimentation on recongurable hardware for computer ar-chitecture performance assessment. In this paper, we de-scribe an empirical performance assessment subsystem im-plemented in recongurable hardware and illustrate its use. Results are presented that demonstrate the need for the types of performance assessment that recongurable hard-ware can provide

Chem-prep PZT95/5 for neutron generator applications : the effect of pore former type and density on the depoling behavior of chemically prepared PZT 95/5 ceramics.

The hydrostatically induced ferroelectric(FE)-to-antiferroelectric(AFE) phase transformation for chemically prepared niobium modified PZT 95/5 ceramics was studied as a function of density and pore former type (Lucite or Avicel). Special attention was placed on the effect of different pore formers on the charge release behavior associated with the FE-to-AFE phase transformation. Within the same density range (7.26 g/cm3 to 7.44 g/cm3), results showed that ceramics prepared with Lucite pore former exhibit a higher bulk modulus and a sharper polarization release behavior than those prepared with Avicel. In addition, the average transformation pressure was 10.7% greater and the amount of polarization released was 2.1% higher for ceramics with Lucite pore former. The increased transformation pressure was attributed to the increase of bulk modulus associated with Lucite pore former. Data indicated that a minimum volumetric transformational strain of -0.42% was required to trigger the hydrostatically induced FE-to-AFE phase transformation. This work has important implications for increasing the high temperature charge output for neutron generator power supply units

Proceedings of the Thirteenth International Society of Sports Nutrition (ISSN) Conference and Expo

Meeting Abstracts: Proceedings of the Thirteenth International Society of Sports Nutrition (ISSN) Conference and Expo Clearwater Beach, FL, USA. 9-11 June 201

Toughening mechanisms in composites of miscible polymer blends with rigid filler particles

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 2006.Vita.Includes bibliographical references (leaves 97-98).Fillers are often added to polymers improve stiffness at the cost of reduced toughness, but this tradeoff is not universal. Well-dispersed microscopic particles have been shown to improve toughness and stiffness simultaneously in some cases. The effect depends on interparticle distance as well as interfacial adhesion. This type of toughening has been more successful in semicrystalline than in amorphous systems. An amorphous polymer blend was chosen to elucidate the effect of matrix properties on the toughening mechanism. The ternary blend of PMMA, PVC, and DOP (a common plasticizer) was characterized using TEM, and was found to be miscible over much of the PVC-rich domain. The blend Tg's fit well to an empirical model, which was used to predict a constant-Tg ([approx.] 40°C) blend series. Mechanical testing showed a wide, systematic variation in properties among these blends, although all were brittle in tension. The blend 90% PVC / 10% DOP was mixed with barium sulfate filler and evaluated for toughness in slow tension. In general, the composites showed decreasing toughness with increasing filler content. However, several specimens at 5 vol% filler exhibited a large increase in ductility and toughness ([approx.] 19-fold).(cont.) SEM examination of tough specimens revealed several important findings: (1) Filler is present both as micron-scale agglomerates and as well dispersed particles. (2) Well-dispersed particles remain bonded to the matrix even for large deformations. (3) Filler agglomerates are prone to debonding and internal fracture, creating void space and enabling deformation. Base blend properties significantly affect the response to filler. The blend 8% PMMA / 80% PVC / 12% DOP showed small increases in ductility for 5 and 10 vol% filler, with the best result being a 10 vol% specimen showing a 6-fold toughness increase over the neat-blend average. This specimen showed similar microscopic behavior to the 90/10 blend, i.e. agglomerate debonding and fracture, but to a lesser degree. The blend 16% PMMA / 70% PVC / 14% DOP, showed no significant toughening. Also investigated were high-Tg ([approx.] 70°C) blends, which were brittle and became weaker with filler, and low-Tg ([approx.] 30°C) blends, which were intrinsically ductile and were not toughened by filler.by Roger Lockwood Aronow.Ph.D