An avionics sensitivity study. Volume 1: Operational considerations

Equipment and operational concepts affecting aircraft in the terminal area are reported. Curved approach applications and modified climb and descent procedures for minimum fuel consumption are considered. The curved approach study involves the application of MLS guidance to enable execution of the current visual approach to Washington National Airport under instrument flight conditions. The operational significance and the flight path control requirements involved in the application of curved approach paths to this situation are considered. Alternative flight path control regimes are considered to achieve minimum fuel consumption subject to constraints related to air traffic control requirements, flight crew and passenger reactions, and airframe and powerplant limitations

Deep tillage of non-Solenetzic soils to enhance snow-melt infiltration

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Stubble height and fertilizer N requirements for maximizing canola yield in the semiarid Canadian prairie

Non-Peer ReviewedCanola is becoming a viable crop when grown under fallow in the semiarid prairie, but is also grown in longer rotations, most often direct seeded into standing stubble. Taller standing stubble provides the canola seedlings with a more favorable micro-climate promoting more efficient use of water and increased yields compared to canola grown without the protection of standing stubble. When grown under the more limited moisture conditions of extended rotations but in the moisture conserving characteristics of taller standing stubble, we found canola yielded best with fertilizer N rates similar to those of the moister Black soil zone. Canola yields were consistently highest when fertilized with > 100 kg N ha-1

Plant temperature of canola direct seeded into standing stubble

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The effect of pulse crop rotation and controlled-release urea on the N accumulation and end-use quality of CWRS wheat

Non-Peer ReviewedSpring wheat was grown at Carman in 2000 and 2001, and at Brandon, MB, in 2001, on field pea and flax stubble at three rates of N (0, 30, and 90 kg N ha-1) supplied as ammonium nitrate (AN) or controlled release urea (CRU), a polyurethane-coated urea. Wheat was grown in 2000 and 2001 at Swift Current, SK, on field pea and durum stubble at three rates of urea N (34, 50, and 78 kg N ha-1) based on soil test recommendations. Wheat grown on field pea stubble (P-W) had higher protein content (PC) than wheat grown on flax/durum stubble (F-W) at four of the five sites evaluated. Contrary to expectations, post-anthesis apparent net mineralized N and proportion of total N uptake were higher for F-W compared to P-W at the Carman 2000 and Brandon 2001 sites. Differences between fertilizer N sources were minor. Breadmaking quality of the wheat end-use quality was also assessed. At the same flour protein content (FPC), P-W had a shorter Mixograph dough development time, work input-to-peak, dough strength index, and breakdown resistance, and also tended to be more extensible than F-W

A quantitative model of the initiation of DNA replication in Saccharomyces cerevisiae predicts the effects of system perturbations.

BackgroundEukaryotic cell proliferation involves DNA replication, a tightly regulated process mediated by a multitude of protein factors. In budding yeast, the initiation of replication is facilitated by the heterohexameric origin recognition complex (ORC). ORC binds to specific origins of replication and then serves as a scaffold for the recruitment of other factors such as Cdt1, Cdc6, the Mcm2-7 complex, Cdc45 and the Dbf4-Cdc7 kinase complex. While many of the mechanisms controlling these associations are well documented, mathematical models are needed to explore the network's dynamic behaviour. We have developed an ordinary differential equation-based model of the protein-protein interaction network describing replication initiation.ResultsThe model was validated against quantified levels of protein factors over a range of cell cycle timepoints. Using chromatin extracts from synchronized Saccharomyces cerevisiae cell cultures, we were able to monitor the in vivo fluctuations of several of the aforementioned proteins, with additional data obtained from the literature. The model behaviour conforms to perturbation trials previously reported in the literature, and accurately predicts the results of our own knockdown experiments. Furthermore, we successfully incorporated our replication initiation model into an established model of the entire yeast cell cycle, thus providing a comprehensive description of these processes.ConclusionsThis study establishes a robust model of the processes driving DNA replication initiation. The model was validated against observed cell concentrations of the driving factors, and characterizes the interactions between factors implicated in eukaryotic DNA replication. Finally, this model can serve as a guide in efforts to generate a comprehensive model of the mammalian cell cycle in order to explore cancer-related phenotypes

Long-term straw management and N fertilizer rate effects on soil organic C and N, and some chemical properties in a Gray Luvisol

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