Efficacy of metabarcoding for identification of fish eggs evaluated with mock communities.

There is urgent need for effective and efficient monitoring of marine fish populations. Monitoring eggs and larval fish may be more informative than that traditional fish surveys since ichthyoplankton surveys reveal the reproductive activities of fish populations, which directly impact their population trajectories. Ichthyoplankton surveys have turned to molecular methods (DNA barcoding & metabarcoding) for identification of eggs and larval fish due to challenges of morphological identification. In this study, we examine the effectiveness of using metabarcoding methods on mock communities of known fish egg DNA. We constructed six mock communities with known ratios of species. In addition, we analyzed two samples from a large field collection of fish eggs and compared metabarcoding results with traditional DNA barcoding results. We examine the ability of our metabarcoding methods to detect species and relative proportion of species identified in each mock community. We found that our metabarcoding methods were able to detect species at very low input proportions; however, levels of successful detection depended on the markers used in amplification, suggesting that the use of multiple markers is desirable. Variability in our quantitative results may result from amplification bias as well as interspecific variation in mitochondrial DNA copy number. Our results demonstrate that there remain significant challenges to using metabarcoding for estimating proportional species composition; however, the results provide important insights into understanding how to interpret metabarcoding data. This study will aid in the continuing development of efficient molecular methods of biological monitoring for fisheries management

Measuring Confidentiality Risks in Census Data

Two trends have been on a collision course over the recent past. The first is the increasing demand by researchers for greater detail and flexibility in outputs from the decennial Census of Population. The second is the need felt by the Census Offices to demonstrate more clearly that Census data have been explicitly protected from the risk of disclosure of information about individuals. To reconcile these competing trends the authors propose a statistical measure of risks of disclosure implicit in the release of aggregate census data. The ideas of risk measurement are first developed for microdata where there is prior experience and then modified to measure risk in tables of counts. To make sure that the theoretical ideas are fully expounded, the authors develop small worked example. The risk measure purposed here is currently being tested out with synthetic and a real Census microdata. It is hoped that this approach will both refocus the census confidentiality debate and contribute to the safe use of user defined flexible census output geographies

Measuring Confidentiality Risks in Census Data

Two trends have been on a collision course over the recent past. The first is the increasing demand by researchers for greater detail and flexibility in outputs from the decennial Census of Population. The second is the need felt by the Census Offices to demonstrate more clearly that Census data have been explicitly protected from the risk of disclosure of information about individuals. To reconcile these competing trends the authors propose a statistical measure of risks of disclosure implicit in the release of aggregate census data. The ideas of risk measurement are first developed for microdata where there is prior experience and then modified to measure risk in tables of counts. To make sure that the theoretical ideas are fully expounded, the authors develop small worked example. The risk measure purposed here is currently being tested out with synthetic and a real Census microdata. It is hoped that this approach will both refocus the census confidentiality debate and contribute to the safe use of user defined flexible census output geographies

Development of a flight test maneuver autopilot for an F-15 aircraft

An autopilot can be used to provide precise control to meet the demanding requirements of flight research maneuvers with high-performance aircraft. This paper presents the development of control laws for a flight test maneuver autopilot for an F-15 aircraft. A linear quadratic regulator approach is used to develop the control laws within the context of flight test maneuver requirements by treating the maneuver as a finite time tracking problem with regulation of state rates. Results are presented to show the effectiveness of the controller in insuring acceptable aircraft performance during a maneuver

Development of control laws for a flight test maneuver autopilot for an F-15 aircraft

An autopilot can be used to provide precise control to meet the demanding requirements of flight research maneuvers with high-performance aircraft. The development of control laws within the context of flight test maneuver requirements is discussed. The control laws are developed using eigensystem assignment and command generator tracking. The eigenvalues and eigenvectors are chosen to provide the necessary handling qualities, while the command generator tracking enables the tracking of a specified state during the maneuver. The effectiveness of the control laws is illustrated by their application to an F-15 aircraft to ensure acceptable aircraft performance during a maneuver

Tunneling Anisotropic Magnetoresistance of Helimagnet Tunnel Junctions

We theoretically investigate the angular and spin dependent transport in normal-metal/helical-multiferroic/ferromagnetic heterojunctions. We find a tunneling anisotropic magnetoresistance (TAMR) effect due to the spiral magnetic order in the tunnel junction and to an effective spin-orbit coupling induced by the topology of the localized magnetic moments in the multiferroic spacer. The predicted TAMR effect is efficiently controllable by an external electric field due to the magnetoelectric coupling

Responses of Hyalella azteca and Ceridaphnia dubia to reservoir sediments following Chelated Copper Herbicide Applications

In response to nuisance growths of algae and vascular plants, such as dioecious hydrilla ( Hydrilla verticillata L.f. Royle), copper formulations have been applied in lakes and reservoirs for a number of years. Concerns have arisen regarding the long-term consequences of copper applications and those concerns have appropriately focused on sediment residues. In this study, we evaluated the toxicity of sediments from treated (for a decade) and untreated areas in Lake Murray, South Carolina and estimated the capacity of those sediments to bind additional copper. Two sentinel aquatic invertebrates, Hyalella azteca Saussure and Ceriodaphnia dubia Richard, were used to measure residual toxicity of treated and untreated sediments from the field and after laboratory amendments. (PDF has 5 pages.

Decision Analysis Using Value Focused Thinking to Select Renewable Energy Sources

The United States is heavily dependent on fossil fuels to produce electricity. Renewable energy can provide an alternative source of energy for electricity production as well as reduce fossil fuel consumption. The executive agencies in the U.S. must also reduce greenhouse gas emissions by 2010 based on 1990 emission levels as directed by Executive Order. However, there is currently no analysis model to provide guidance toward which renewable energy to select as a course of action. This research effort used value-focused thinking decision analysis to create a model based on inputs from the Air Force Civil Engineer Support Agency. This model allows a decision-maker to easily alter weights and value functions related to renewable energy sources as needed to correspond to the personal values of that person. These values combined with the objective scores obtained from the generated alternatives results in a suggested course of action. The sensitivity analysis shows the changes of the output based on the alterations of the weighting of each measure. All measures were varied to study their influence on the final outcome. Application of the model at three bases showed this model appears to work based on the influencing weights and values of the decision-maker

From Model Systems To Real Catalysts: Bridging The Pressure And Materials Gaps

For decades a fundamental understanding of heterogeneous catalysts has been pursued for rational catalyst design using model systems under ultrahigh vacuum (UHV) conditions; however, there exist stark differences between the simplified models investigated under UHV and the industrial catalysts used at high pressures. To bridge these gaps, it becomes essential to utilize progressively more complex materials and to correlate their surface structure and activity using incrementally higher pressure techniques. In this work, both model Pt-Re catalysts and powdered metal-organic frameworks (MOFs) were studied using a suite of traditional UHV surface science techniques in addition to ambient pressure X-ray photoelectron spectroscopy (APXPS) and UHV-coupled ambient pressure cells. CO oxidation and methanol oxidation were investigated by APXPS on Pt(111), Re films on Pt(111), and on Pt−Re alloy model surfaces. Pt-Re alloy surfaces were found to dissociate oxygen more readily than Pt surfaces, and CO was found to desorb at lower temperatures from Pt−Re alloy surfaces than from Pt. Pt and Pt-Re surfaces were found to have similar product formation with Pt-Re alloys having higher activity and maintaining greater selectivity than Pt to CO2 formation. Model Pt-Re systems were also studied for methanol oxidation in a UHV-coupled microreactor where products were determined via GC-TCD, and pre- and post-reaction surfaces were characterized by XPS without exposure to air. The Pt-Re alloy surface initially showed less activity than Pt; but over extended time periods, the alloy maintained higher activity than Pt, which deactivated due to accumulation of atomic carbon. Re films were unstable since they form volatile Re2O7, but alloying Re with Pt made it less susceptible to sublimation. Water-gas shift was also performed in the microreactor on TiO2(110)-supported Pt, Re, and Pt-Re bimetallic clusters. Surface ReOx appears to block Pt active sites, but Re underneath Pt shows higher activity than Pt alone as Re modifies Pt. A separate UHV XPS-coupled high pressure cell was used to study the generation of mixed valence Cu+1/+2 sites in a powdered MOF before and after extensive heating and exposure to H2, O2, CO, and air, which corresponded to changes in the valence band, indicating tunability of the MOF’s electronic properties