Over-expressing the C3 photosynthesis cycle enzyme Sedoheptulose-1-7 Bisphosphatase improves photosynthetic carbon gain and yield under fully open air CO2fumigation (FACE)

Abstract Background Biochemical models predict that photosynthesis in C3 plants is most frequently limited by the slower of two processes, the maximum capacity of the enzyme Rubisco to carboxylate RuBP (Vc,max), or the regeneration of RuBP via electron transport (J). At current atmospheric [CO2] levels Rubisco is not saturated; consequently, elevating [CO2] increases the velocity of carboxylation and inhibits the competing oxygenation reaction which is also catalyzed by Rubisco. In the future, leaf photosynthesis (A) should be increasingly limited by RuBP regeneration, as [CO2] is predicted to exceed 550 ppm by 2050. The C3 cycle enzyme sedoheptulose-1,7 bisphosphatase (SBPase, EC 3.1.3.17) has been shown to exert strong metabolic control over RuBP regeneration at light saturation. Results We tested the hypothesis that tobacco transformed to overexpressing SBPase will exhibit greater stimulation of A than wild type (WT) tobacco when grown under field conditions at elevated [CO2] (585 ppm) under fully open air fumigation. Growth under elevated [CO2] stimulated instantaneous A and the diurnal photosynthetic integral (A') more in transformants than WT. There was evidence of photosynthetic acclimation to elevated [CO2] via downregulation of Vc,max in both WT and transformants. Nevertheless, greater carbon assimilation and electron transport rates (J and Jmax) for transformants led to greater yield increases than WT at elevated [CO2] compared to ambient grown plants. Conclusion These results provide proof of concept that increasing content and activity of a single photosynthesis enzyme can enhance carbon assimilation and yield of C3 crops grown at [CO2] expected by the middle of the 21st century. </jats:sec

Impacts of human hunting on spatial behavior of white-tailed deer (Odocoileus virginianus)

This study was funded by The Samuel Roberts Noble Foundation, Inc., and the Department of Wildlife, Fisheries and Aquaculture at Mississippi State University.Predators can influence populations through top-down effects, but most large predators have been extirpated from the white-tailed deer’s (Odocoileus virginianus) range. Hunters have filled this predatory role, but also can indirectly influence prey species. Indirect behavioral responses can include altered resource selection, space use, or movement patterns. Herein, we developed a controlled study that contained both temporal and spatial risk levels to assess how deer behavior changes in space relative to temporal periods of risk. Total distance travelled (m) and micro-range area (m²) were calculated over two-day periods to determine the general effects of hunting season on deer spatial behavior. Generally, distance travelled, micro-range area, and exploratory behavior decreased during the course of the study, with the greatest decrease occurring during the active 16-day hunting period. Despite potential risk and disturbance from hunters, deer maintained site fidelity to previously established ranges and did not expand micro-range areas. These data indicate that deer recognize threats from humans on the landscape and adapt behavioral strategies by minimizing movement and exhibiting high residency times in well-established ranges, factors known to influence harvest susceptibility. This information can be used to assess potential impacts from hunting for management purposes, but also to test the adaptive ability of animals to risk.Publisher PDFPeer reviewe

A COGNITIVE COMPENSATION MECHANSIM FOR DEFORMABLE ANTENNAS

This thesis presents the design, theory, and measurement of a linearly polarized microstrip patch antenna with a novel substrate-integrated mechanism that can compensate the detuning effects from a physical deformation. Specifically, this antenna bends sharply through the center up to 90 (pivoted about the ground plane) and retuning (compensation) occurs by displacing electromagnetically functionalized colloidal dispersions (EFCDs) through a capillary in the substrate (parallel to the radiating edge). The displacement of a high permittivity EFCD by a low permittivity EFCD acts as a net length reduction (shown mathematically using perturbation theory). This mitigates the physical length extension from the deformation and stretching of the conductors. The design can be considered cognitive (conceptually in this thesis) by allowing the deformation and resulting compressive forces in the substrate to actuate displacement. The antennas to demonstrate this concept have been chosen to operate at 3 GHz and use a Sylgard 184 (a flexible silicone-based elastomer) substrate material with a height of 4 mm. Simulations of an HFSS model demonstrate a stable VSWR 2:1 bandwidth of 141 MHz across the entire range of bending. Currently available fabrication methods and EFCD material systems provide some limitations. Therefore, proof-of-concept is provided using 2 microstrip patch antennas (one flat patch and one patch bent 90) designed using 4 mm thick Rochelle Foam substrates and rigid copper sheets. A flexible patch was fabricated using Sylgard 184 and SEC 1233 (a conductive elastomer) but bending created several tears in the material and delaminating of the flexible conductor. However, the comparison of trends between simulated and measured results show good agreement and are used to validate this compensation mechanism

Laser Ablation System for Solid Sample Analysis by Inductively Coupled Plasma Atomic Emission Spectrometry

A laser ablation sample introduction system, based on a Nd : YAG laser with an X-Y-Zdirectional sampling head, has been designed and constructed for use with inductively coupled plasma optical emission spectrometry. A study has been made of a number of parameters which affect the performance of the system to establish the optimum operating conditions. South African Reference Material (SARM) rock samples have been analysed using the system, and the results obtained have been compared with the certificate values. The importance of using closely matrix-matched samples and standards is demonstrated. Precision studies on SARM 5 (pyroxenite) show that both intra- and inter-sample precisions are typically 10% (relative standard deviation )

Variation in acclimation of photosynthesis in Trifolium repens after eight years of exposure to Free Air CO2 Enrichment (FACE)

The initial stimulation of photosynthesis observed on elevation of [CO2] in grasslands has been predicted to be a transient phenomenon constrained by the loss of photosynthetic capacity due to other limitations, notably nutrients and sinks for carbohydrates. Legumes might be expected partially to escape these feedbacks through symbiotic N2 fixation. The Free‐Air Carbon dioxide Enrichment (FACE) experiment at Eschikon, Switzerland, has been the longest running investigation of the effects of open‐air elevation of [CO2] on vegetation. The prediction of a long‐term loss of photosynthetic capacity was tested by analysing photosynthesis in Trifolium repens L. (cv. Milkanova) in the spring and autumn of the eighth, ninth and tenth years of treatment. A high and low N treatment also allowed a test of the significance of exogenous N‐supply in maintaining a stimulation of photosynthetic capacity in the long‐term. Prior work in this Free Air CO2 Enrichment (FACE) experiment has revealed that elevated [CO2] increased both vegetative and reproductive growth of T. repens independent of N treatment. It is shown here that the photosynthetic response of T. repens was also independent of N fertilization under both current ambient and elevated (600 µmol mol-1) [CO2]. There was a strong effect of season on photosynthesis, with light‐saturated rates (Asat) 37% higher in spring than in autumn. Higher Asat in the spring was supported by higher maximum Rubisco carboxylation rates (Vc,max) and maximum rates of electron transport (Jmax) contributing to RuBP regeneration. Elevated [CO2] increased Asat by 37% when averaged across all measurement periods and both N fertilization levels, and decreased stomatal conductance by 25%. In spring, there was no effect of elevated [CO2] on photosynthetic capacity of leaves, but in autumn both Vc,max and Jmax were reduced by approximately 20% in elevated [CO2]. The results show that acclimation of photosynthetic capacity can occur in a nitrogen‐fixing species, in the field where there are no artificial restrictions on sink capacity. However, even with acclimation there was a highly significant increase in photosynthesis at elevated [CO2

Progress Toward Future Runway Management

The runway is universally acknowledged as a constraining factor to capacity in the National Airspace System (NAS). It follows that investigation of the effective use of runways, both in terms of selection and assignment, is paramount to the efficiency of future NAS operations. The need to address runway management is not a new idea; however, as the complexities of factors affecting runway selection and usage increase, the need for effective research in this area correspondingly increases. Under the National Aeronautics and Space Administration s Airspace Systems Program, runway management is a key research area. To address a future NAS which promises to be a complex landscape of factors and competing interests among users and operators, effective runway management strategies and capabilities are required. This effort has evolved from an assessment of current practices, an understanding of research activities addressing surface and airspace operations, traffic flow management enhancements, among others. This work has yielded significant progress. Systems analysis work indicates that the value of System Oriented Runway Management tools is significantly increased in the metroplex environment over that of the single airport case. Algorithms have been developed to provide runway configuration recommendations for a single airport with multiple runways. A benefits analysis has been conducted that indicates the SORM benefits include supporting traffic growth, cost reduction as a result of system efficiency, NAS optimization from metroplex operations, fairness in aircraft operations, and rational decision making

Attitudes and Beliefs of African-Americans Toward Genetics, Genetic Testing, and Sickle Cell Disease Education and Awareness

Research among African-Americans indicates this population perceives sickle cell (SCD) to be a serious disease and sickle cell trait (SCT) screening an important intervention. However, studies have consistently demonstrated a lower than desired uptake of SCD education, inadequate knowledge regarding personal and family trait status, and a low perceived susceptibility of giving birth to a child with the disease. We examined general attitudes and beliefs regarding genetics and genetic testing including prenatal testing and newborn screening; we used this information as the foundation to more specifically assess attitudes and beliefs regarding SCD and perceived barriers to SCD education and awareness. Thirty-five African-American adult men and women participated in one of four focus groups. Thematic analysis identified that both prenatal testing and newborn screening are acceptable forms of genetic testing. Based largely on their personal experiences, participants possessed an understanding of the natural progression of SCD but had a limited understanding of the inheritance and probable risk of giving birth to a child with the disease. Barriers to education and greater awareness of SCD were classified as personal, familial, and societal. Community based interventions focused on sharing the stories of individuals with first-hand experiences with SCD should be considered

Seeking Sunlight: Rapid Phototactic Motility of Filamentous Mat-Forming Cyanobacteria Optimize Photosynthesis and Enhance Carbon Burial in Lake Huron’s Submerged Sinkholes

We studied the motility of filamentous mat-forming cyanobacteria consisting primarily ofOscillatoria-like cells growing under low-light, low-oxygen, and high-sulfur conditions in Lake Huron’s submerged sinkholes using in situ observations, in vitro measurements and time-lapse microscopy. Gliding movement of the cyanobacterial trichomes (100–10,000 μm long filaments, composed of cells ~10 μm wide and ~3 μm tall) revealed individual as well as group-coordinated motility. When placed in a petri dish and dispersed in ground water from the sinkhole, filaments re-aggregated into defined colonies within minutes, then dispersed again. Speed of individual filaments increased with temperature from ~50 μm min-1 or ~15 body lengths min-1 at 10∘C to ~215 μm min-1 or ~70 body lengths min-1 at 35∘C – rates that are rapid relative to non-flagellated/ciliated microbes. Filaments exhibited precise and coordinated positive phototaxis toward pinpoints of light and congregated under the light of foil cutouts. Such light-responsive clusters showed an increase in photosynthetic yield – suggesting phototactic motility aids in light acquisition as well as photosynthesis. Once light source was removed, filaments slowly spread out evenly and re-aggregated, demonstrating coordinated movement through inter-filament communication regardless of light. Pebbles and pieces of broken shells placed upon intact mat were quickly covered by vertically motile filaments within hours and became fully buried in the anoxic sediments over 3–4 diurnal cycles – likely facilitating the preservation of falling debris. Coordinated horizontal and vertical filament motility optimize mat cohesion and dynamics, photosynthetic efficiency and sedimentary carbon burial in modern-day sinkhole habitats that resemble the shallow seas in Earth’s early history. Analogous cyanobacterial motility may have played a key role in the oxygenation of the planet by optimizing photosynthesis while favoring carbon burial

Technologies to deliver food and climate security through agriculture

Acknowledgements D.J.B. and S.A.B. acknowledge funding from the Leverhulme Trust through a Leverhulme Research Centre Award (RC-2015-029). S.P.L. acknowledges funding from the DOE Center for Advanced Bioenergy and Bioproducts Innovation (US Department of Energy, Office of Science, Office of Biological and Environmental Research under award number DE-SC0018420). The input of P.S. contributes to the DEVIL (NE/M021327/1) and Soils‐R‐GRREAT (NE/P019455/1) projects.Peer reviewedPostprin

System Oriented Runway Management: A Research Update

The runway configuration used by an airport has significant implications with respect to its capacity and ability to effectively manage surface and airborne traffic. Aircraft operators rely on runway configuration information because it can significantly affect an airline's operations and planning of their resources. Current practices in runway management are limited by a relatively short time horizon for reliable weather information and little assistance from automation. Wind velocity is the primary consideration when selecting a runway configuration; however when winds are below a defined threshold, discretion may be used to determine the configuration. Other considerations relevant to runway configuration selection include airport operator constraints, weather conditions (other than winds) traffic demand, user preferences, surface congestion, and navigational system outages. The future offers an increasingly complex landscape for the runway management process. Concepts and technologies that hold the potential for capacity and efficiency increases for both operations on the airport surface and in terminal and enroute airspace are currently under investigation. Complementary advances in runway management are required if capacity and efficiency increases in those areas are to be realized. The System Oriented Runway Management (SORM) concept has been developed to address this critical part of the traffic flow process. The SORM concept was developed to address all aspects of runway management for airports of varying sizes and to accommodate a myriad of traffic mixes. SORM, to date, addresses the single airport environment; however, the longer term vision is to incorporate capabilities for multiple airport (Metroplex) operations as well as to accommodate advances in capabilities resulting from ongoing research. This paper provides an update of research supporting the SORM concept including the following: a concept of overview, results of a TRCM simulation, single airport and Metroplex modeling effort and a benefits assessment