Evaluation of a Pound Net Leader Designed to Reduce Sea Turtle Bycatch

Offshore pound net leaders in the southern portion of Chesapeake Bay in Virginia waters were documented to incidentally take protected loggerhead, Caretta caretta, and Kemp’s ridley, Lepidochelys kempii, sea turtles. Because of these losses, NOAA’s National Marine Fisheries Service (NMFS) in 2004 closed the area to offshore pound net leaders annually from 6 May to 15 July and initiated a study of an experimental leader design that replaced the top two-thirds of the traditional mesh panel leader with vertical ropes (0.95 cm) spaced 61 cm apart. This experimental leader was tested on four pound net sites on the eastern shore of Chesapeake Bay in 2004 and 2005. During the 2 trial periods, 21 loggerhead and Kemp’s ridley sea turtles were found interacting with the control leader and 1 leatherback turtle, Dermochelys coriacea, was found interacting with the experimental leader. Results of a negative binomial regression analysis comparing the two leader designs found the experimental leader significantly reduced sea turtle interactions (p=0.03). Finfish were sampled from the pound nets in the study to assess finfish catch performance differences between the two leader designs. Although the conclusions from this element of the experiment are not robust, paired t-test and Wilcoxon signed rank test results determined no significant harvest weight difference between the two leaders. Kolmogorov-Smirnov tests did not reveal any substantive size selectivity differences between the two leaders

Studies Toward the Synthesis of a Novel Diastereomerically Pure Cyclopropyl N-Heterocyclic Carbene Ligand for Asymmetric Catalysis

This M.S. Thesis research objective is designed towards the racemic synthesis of a novel diastereoselectively pure, sterically bulky, cyclopropyl-containing, N-heterocyclic carbene (NHC) ligand. It is hypothesized that introduction of the sterically bulky cyclopropyl moiety at the N-substituent position of the imidazolium backbone will cause the self-assembly to develop a well defined C2-symmetric N-heterocyclic ligand, thereby limiting the free rotation about the C-N bond and creating a well-defined chiral pocket. It was discovered through utilizing classic synthetic methods that a diastereomeric imidazolium salt product was yielded, which can be attributed to the racemic synthesis of a diastereomeric cyclopropane starting material

Initial Assessment of a Rapid Method of Calculating CEV Environmental Heating

An innovative method for rapidly calculating spacecraft environmental absorbed heats in planetary orbit is described. The method employs reading a database of pre-calculated orbital absorbed heats and adjusting those heats for desired orbit parameters. The approach differs from traditional Monte Carlo methods that are orbit based with a planet centered coordinate system. The database is based on a spacecraft centered coordinated system where the range of all possible sun and planet look angles are evaluated. In an example case 37,044 orbit configurations were analyzed for average orbital heats on selected spacecraft surfaces. Calculation time was under 2 minutes while a comparable Monte Carlo evaluation would have taken an estimated 26 hour

Trajectory generation for road vehicle obstacle avoidance using convex optimization

This paper presents a method for trajectory generation using convex optimization to find a feasible, obstacle-free path for a road vehicle. Consideration of vehicle rotation is shown to be necessary if the trajectory is to avoid obstacles specified in a fixed Earth axis system. The paper establishes that, despite the presence of significant non-linearities, it is possible to articulate the obstacle avoidance problem in a tractable convex form using multiple optimization passes. Finally, it is shown by simulation that an optimal trajectory that accounts for the vehicle’s changing velocity throughout the manoeuvre is superior to a previous analytical method that assumes constant speed

The Impact of Stress Management on Nurse Productivity and Retention

Throughout the history of nursing there is a seeming legacy of personnel shortage, lack of funds, and, based on the nature of the role and related services, heightened levels of stress involved in patient care.The future of the profession and more imminently, patient care and the health of nurses, may be significantly impacted by repeated challenges where current levels of stress and burnout are contributing to organizational problems, burnout, and attrition.Employee stress and burn out commonly lead to myriad health-related problems that result in significant organizational consequences.There are many methods of stress management, and sometimes the best and most effective begin with simple recognition, validation, and visible and committed efforts by the nurse executive.Regardless of the technique or approach, what is clear is that there is a need for nurse executives to include the development and enhancement of comprehensive stress-management programming for employees as a priority item to avoid burnout and attrition

Equilibration between edge states in the fractional quantum Hall effect regime at high imbalances

We experimentally study equilibration between edge states, co-propagating at the edge of the fractional quantum Hall liquid, at high initial imbalances. We find an anomalous increase of the conductance between the fractional edge states at the filling factor $\nu=2/5$ in comparison with the expected one for the model of independent edge states. We conclude that the model of independent fractional edge states is not suitable to describe the experimental situation at $\nu=2/5$.Comment: 4 page

Application of fluvial scaling relationships to reconstruct drainage-basin evolution and sediment routing for the Cretaceous and Paleocene of the Gulf of Mexico

This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.Fluvial systems represent a key component in source-to-sink analysis of ancient sediment-dispersal systems. Modern river channels and channel-related deposits possess a range of scaling relationships that reflect drainage-basin controls on water and sediment flux. For example, channel-belt sand-body thicknesses scale to bankfull discharge, and represent a reliable first-order proxy for contributing drainage-basin area, a proxy that is more robust if climatic regimes can be independently constrained. A database of morphometrics from Quaternary channel belts provides key modern fluvial system scaling relationships, which are applied to Cretaceous- to Paleocene-age fluvial deposits. This study documents the scales of channel-belt sand bodies within fluvial successions from the northern Gulf of Mexico passive-margin basin fill from well logs, and uses scaling relationships developed from modern systems to reconstruct the scale of associated sediment-routing systems and changes in scale through time. We measured thicknesses of 986 channel-belt sand bodies from 248 well logs so as to estimate the scales of the Cretaceous (Cenomanian) Tuscaloosa-Woodbine, Paleocene–early Eocene Wilcox, and Oligocene Vicksburg-Frio fluvial systems. These data indicate that Cenozoic fluvial systems were significantly larger than their Cenomanian counterparts, which is consistent with Cretaceous to Paleocene continental-scale drainage reorganization that routed water discharge and sediment from much of the continental United States to the Gulf of Mexico. At a more detailed level, Paleocene–early Eocene Wilcox fluvial systems were larger than their Oligocene counterparts, which could reflect decreases in drainage-basin size and/or climatic change within the continental interior toward drier climates with less runoff. Additionally, these data suggest that the paleo–Tennessee River, which now joins the Ohio River in the northernmost Mississippi embayment of the central United States, was an independent fluvial system, flowing southwest to the southern Mississippi embayment, or directly to the Gulf of Mexico, through the early Eocene. Changes in scaling relationships through time, and interpreted changes in the scales of contributing drainage basins, are generally consistent with previously published regional paleogeographic maps, as well as with newly published maps of paleodrainage from detrital-zircon provenance and geochronological studies. As part of a suite of metrics derived from modern systems, scaling relationships make it possible to more fully understand and constrain the scale of ancient source-to-sink systems and their changes through time, or cross-check interpretations made by other means

The channels of technology acquisition in commercial firms, and the NASA dissemination program

Technology acquisition in commercial firms, and NASA dissemination progra

State resolved vibrational relaxation modeling for strongly nonequilibrium flows

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/98747/1/PhysFluids_23_057101.pd

Channel-belt scaling relationship and application to early Miocene source-to-sink systems in the Gulf of Mexico basin

In past decades, numerous studies have focused on the alluvial sedimentary record of basin fill. Paleo–drainage basin characteristics, such as drainage area or axial river length, have received little attention, mostly because the paleo–drainage system underwent erosion or bypass, and its record is commonly modified and overprinted by subsequent tectonism or erosional processes. In this work, we estimate the drainage areas of early Miocene systems in the Gulf of Mexico basin by using scaling relationships between drainage area and river channel dimensions (e.g., depth) developed in source-to-sink studies. Channel-belt thickness was used to estimate channel depth and was measured from numerous geophysical well logs. Both lower channel-belt thickness and bankfull thickness were measured to estimate the paleo–water depth at low and bankfull stages. Previous paleogeographic reconstruction using detrital zircon and petrographic provenance analysis and continental geomorphic synthesis constrains independent estimates of drainage basin extent. Comparison of results generated by the two independent approaches indicates that drainage basin areas predicted from channel-belt thickness are reasonable and suggests that bankfull thickness correlates best with drainage basin area. The channel bankfull thickness also correlates with reconstructed submarine fan dimension. This work demonstrates application to the deep-time stratigraphic archive, where records of drainage basin characteristics are commonly modified or lost