The Saskatchewan integrated noxious weeds management program

Non-Peer ReviewedThe distribution of scentless chamomile was mapped for highways and municipal roads throughout the province. The weed grows on 867 miles of provincial highway and 2814 miles of municipal roads. In Saskatchewan, 98 rural municipalities do not have the weed. Scentless chamomile was reported in 199 rural municipalities. The weed should be controlled to prevent further spread throughout the province. The scentless chamomile seed weevil (Omphalapion hookeri) and gall midge (Rhopalomyia tripleurospermi) have successfully established in the province. Their populations are increasing

Diagnostics from polarization of scattered optical light from Galactic infrared cirrus

We propose polarization of scattered optical light from intermediate Galactic latitude infrared cirrus as a new diagnostic to constrain models of interstellar dust and the anisotropic interstellar radiation field (aISRF). For single scattering by a sphere, with Mie scattering phase functions for intensity and polarized intensity for a dust model at a given wavelength (Sloan $r$ and $g$ bands), and with models of anisotropic illumination from the entire sky (represented in HEALPix), we develop the formalism for calculating useful summary parameters for an integrated flux nebula (IFN): average of the phase function weighted by the illumination, polarization angle ($\psi$), and polarization fraction ($p$). To demonstrate the diagnostic discrimination of polarization from scattered light, we report on the effects of different anisotropic illumination models and different dust models on the summary parameters for the Spider IFN. The summary parameters are also sensitive to the IFN location, as we illustrate using FRaNKIE illumination models. For assessing the viability of dust and aISRF models, we find that observations of $\psi$ and $p$ of scattered light are indeed powerful new diagnostics to complement joint modeling of the intensity of scattered light (related to the average phase function) and the intensity of thermal dust emission. However, optically thin IFNs that can be modelled using single scattering are faint and $p$ is not large, as it could be with Rayleigh scattering, and so these observations need to be carried out with care and precision. Results for the Draco nebula compared to the Spider illustrate the challenge.Comment: 14 pages, 8 figures; Accepted for publication in Ap

Letters and accounts from George Bowes to GF Story, 8 Sept 1829 and May 14 1838

Two letters with accounts sent to GF Story in Tasmania, from George Bowes, London, 8 September 1829 and 14 May 1838. The first letter is concerned with Story's house in Critchell Place, London, which was leased to Mrs Townsend at 45 pounds per annum. Accounts concerning the lease are included, while the second letter (1838) speculates as to the value of the house. From Cotton Family Papers C7/160, 16

Learning About Development at A-Level

Young people’s interest in development issues has been the focus of numerous studies but there has been little research that looks at the impact of learning of a specific educational course. This research paper looks at the impact of studying A-level World Development on young people in England and Wales. It summarises the outcomes of research by Bowes in 2011 and a further survey in 2012 with students who have completed the course. This study looks specifically at the relevance, effectiveness and impact of the course on students. The evidence suggests that the A-level is popular and seen as relevant to young people’s lives and views about the world. Both teachers and students state that the themes discussed are up-to-date and accessible to study. In terms of effectiveness of the course overall, there is evidence of understanding of the key issues in development, although the priorities given to particular themes varied from school and college. Programmes and projects on learning about development have often been promoted because there is an assumption that mere engagement with these themes has an impact on young people’s learning in terms of changing their behaviour and attitudes towards taking action to reduce global poverty. The evidence from this research shows a complex picture of impact with the emphasis appearing to be more on the social and moral aspects of development than the political. The research indicates positive changes in perceptions of global poverty and inequality in the world, but less so on the more social and political aspects. There is evidence that studying the A-level has had an impact upon the students’ future learning in higher education with Geography and Development Studies becoming more popular. The first full World Development A-level began in 2008 so the examination is still relatively new. The sample taken for this study and the research by Bowes covered a relatively small number of students. However, what is clear from this research is that an A-level of this type can play an important contribution in deepening a young person’s learning and understanding about development and that it is a subject that is seen as popular and relevant to their lives

Flight Envelope Assessment of SmallSat Aerocapture Trajectories at Venus and Mars

Aerocapture is an increasingly studied orbit insertion concept for small satellite (SmallSat) missions beyond low Earth orbit (LEO). Compared to fully propulsive methods, aerocapture reduces the orbit-insertion propellant mass by approaching on a hyperbolic path and using the planetary atmosphere to reduce the vehicle’s velocity such that the final target orbit is achieved. This allows for an increase in payload mass delivered to orbit and a reduction in launch-to -orbit time. To analyze the feasibility at Venus and Mars, aerocapture flight envelope analysis is conducted by assessing the guidable trajectory space during atmospheric flight given entry conditions, vehicle properties, target parameters, and planet-dependent trajectory dispersions. The Program to Optimize Simulated Trajectories II (POST2) is used to simulate both ballistic and lifting aerocapture trajectories with SmallSat-compatible aeroshell designs. The entry flight path angle is optimized to achieve a final target orbit for lift up/down and max/min control configurations. When plotted, the resulting area between the steep and shallow trajectories forms a flight envelope with planet-dependent ±3σ atmospheric, aerodynamic, and delivery state dispersion profiles applied. The results presented in this paper show that SmallSat aerocapture is feasible for lifting aeroshell designs at Mars and Venus as well as ballistic vehicle designs at Mars

Small Satellite-Sized Hypersonic Inflatable Aerodynamic Decelerators for Interplanetary Science Missions

To make the most of ridesharing opportunities, small satellite (SmallSat) mission designers endeavor to pack as much payload into a SmallSat-class form factor as possible. The mass and volume constraints of this smaller vehicle class present a challenge for interplanetary mission sets that require a means of achieving orbit insertion at their destination of interest. For a fully propulsive orbit insertion design, this may translate to the propellant mass being a significant fraction of the overall vehicle mass and prolonged insertion time. Aerocapture is a single quick maneuver that can significantly reduce the required propellant mass for orbit insertion. Because aerocapture uses a planet’s atmosphere to achieve the necessary change in velocity, a protective aeroshell is needed. The constraints imposed on secondary payloads render traditional rigid aeroshells mass and space prohibitive for the SmallSat class of vehicles; thus, warranting consideration of deployable designs that can be stowed compactly until needed for atmospheric entry. The Hypersonic Inflatable Aerodynamic Decelerator (HIAD) is a deployable aeroshell that leverages inflatable toroids to achieve the large drag area needed for aerodynamic deceleration. While the technology is currently being analyzed for Mars human-scale missions, it has the potential applicability for interplanetary SmallSat-scale missions as well. This paper highlights a study conducted during an internship at NASA Langley Research Center to investigate the feasibility of using a scaled-down HIAD design in SmallSat aerocapture missions. Several scaling methodologies are investigated including use of parametric models and direct computer-aided design (CAD) model scaling. Candidate HIAD configurations that conform to secondary payload adapter requirements are identified. The Program to Optimize Simulated Trajectories II (POST2) is utilized to conduct orbit insertion performance and trajectory sensitivity studies using the candidate configurations at Earth, Venus, and Mars. The results of the study indicate that multiple SmallSat-sized HIAD designs, targeting a range of SmallSat payload classes, are feasible for planetary aerocapture missions to Mars and Venus as well as Earth-based aerocapture missions

Mapping eutrophication risk from climate change: future phosphorus concentrations in English rivers

Climate change is expected to increase eutrophication risk in rivers yet few studies identify the timescale or spatial extent of such impacts. Phosphorus concentration, considered the primary driver of eutrophication risk in English rivers, may increase through reduced dilution particularly if river flows are lower in summer. Detailed models can indicate change in catchment phosphorus concentrations but targeted support for mitigation measures requires a national scale evaluation of risk. In this study, a load apportionment model is used to describe the current relationship between flow and total reactive phosphorus (TRP) at 115 river sites across England. These relationships are used to estimate TRP concentrations for the 2050s under 11 climate change driven scenarios of future river flows and under scenarios of both current and higher levels of sewage treatment. National maps of change indicate a small but inconsistent increase in annual average TRP concentrations with a greater change in summer. Reducing the TRP concentration of final sewage effluent to 0.5 mg/L P for all upstream sewage treatment works was inadequate to meet existing P standards required through the EU Water Framework Directive, indicating that more needs to be done, including efforts to reduce diffuse pollution

Impact of Oxidation State on Reactivity and Selectivity Differences between Nickel(III) and Nickel(IV) Alkyl Complexes

Described is a systematic comparison of factors impacting the relative rates and selectivities of C(sp3)−C and C(sp3)−O bond‐forming reactions at high‐valent Ni as a function of oxidation state. Two Ni complexes are compared: a cationic octahedral NiIV complex ligated by tris(pyrazolyl)borate and a cationic octahedral NiIII complex ligated by tris(pyrazolyl)methane. Key features of reactivity/selectivity are revealed: 1) C(sp3)−C(sp2) bond‐forming reductive elimination occurs from both centers, but the NiIII complex reacts up to 300‐fold faster than the NiIV, depending on the reaction conditions. The relative reactivity is proposed to derive from ligand dissociation kinetics, which vary as a function of oxidation state and the presence/absence of visible light. 2) Upon the addition of acetate (AcO−), the NiIV complex exclusively undergoes C(sp3)−OAc bond formation, while the NiIII analogue forms the C(sp3)−C(sp2) coupled product selectively. This difference is rationalized based on the electrophilicity of the respective M−C(sp3) bonds, and thus their relative reactivity towards outer‐sphere SN2‐type bond‐forming reactions.The high point: This report describes a systematic comparison of factors impacting the relative rates and selectivities of C(sp3)−C and C(sp3)−O bond‐forming reactions at high‐valent Ni centers as a function of oxidation state (NiIII versus NiIV). Two Ni complexes are compared: a cationic octahedral NiIV complex ligated by tris(pyrazolyl)borate and a cationic octahedral NiIII complex ligated by tris(pyrazolyl)methane.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/150547/1/anie201903638.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/150547/2/anie201903638-sup-0001-misc_information.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/150547/3/anie201903638_am.pd