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Field studies were conducted to determine the possible rate and timing of nicosulfuron to suppress annual ryegrass (ARG) seeded as a cover crop at the time of corn planting without affecting corn performance near Ridgetown, ON, Canada, in 2016 and 2017. Nicosulfuron was applied at rates from 0.8 to 50 g ai ha–1 when the ARG was at the two- to three- or four- to five-leaf stages, or approximately 3 or 4 wk after emergence of both corn and ARG. There were no differences between the two application timings in grain yield responses or ARG suppression. As the rate of nicosulfuron increased from 0.8 to 50 g ai ha–1, ARG was suppressed 6% to 76% and 5% to 96%, at 1 and 4 wk after application (WAA), respectively. At 4 WAA, ARG biomass decreased from 29 to 1 g m–2 as the rate of nicosulfuron increased from 0.8 to 50 g ai ha–1, compared to 36 g m–2 in the untreated control. Where nicosulfuron was not applied to ARG, grain corn yield was reduced by 6% compared to the ARG-free control; similar effects on corn yield were observed with nicosulfuron at the lowest rate applied at 0.8 g ai ha–1. Grain corn yield was reduced by 2.5% with the application of nicosulfuron at 25 g ai ha–1 (label rate for corn) compared to no ARG control, but this was not statistically significant. This study identified rates of nicosulfuron that suppressed ARG when emerged approximately the same day as corn, but there was evidence that grain corn yields were lowered because of interference, possibly during the critical weed control period. Based on this study, an ARG cover crop should not be seeded at the same time as corn unless one is willing to accept a risk for corn grain yield losses for the sake of the cover crop.
Glyphosate-resistant (GR) and multiple herbicide–resistant (groups 2 and 9) Canada fleabane have been confirmed in 30 and 23 counties in Ontario, respectively. The widespread incidence of herbicide-resistant Canada fleabane highlights the importance of developing integrated weed management strategies. One strategy is to suppress Canada fleabane using cover crops. Seventeen different cover crop monocultures or polycultures were seeded after winter wheat harvest in late summer to determine GR Canada fleabane suppression in corn grown the following growing season. All cover crop treatments seeded after wheat harvest suppressed GR Canada fleabane in corn the following year. At 4 wk after cover crop emergence (WAE), estimated cover crop ground cover ranged from 31% to 68%, a density of 124 to 638 plants m–2, and a range of biomass from 29 to 109 g m–2, depending on cover crop species. All of the cover crop treatments suppressed GR Canada fleabane in corn grown the following growing season from May to September compared to the no cover crop control. Among treatments evaluated, annual ryegrass (ARG), crimson clover (CC)/ARG, oilseed radish (OSR)/CC/ARG, and OSR/CC/cereal rye (CR) were the best treatments for the suppression of GR Canada fleabane in corn. ARG alone or in combination with CC provided the most consistent GR Canada fleabane suppression, density reduction, and biomass reduction in corn. Grain corn yields were not affected by the use of the cover crops evaluated for Canada fleabane suppression.
We present an overview of the survey for radio emission from active stars that has been in progress for the last six years using the observatories at Fleurs, Molonglo, Parkes and Tidbinbilla. The role of complementary optical observations at the Anglo-Australian Observatory, Mount Burnett, Mount Stromlo and Siding Spring Observatories and Mount Tamborine are also outlined. We describe the different types of star that have been included in our survey and discuss some of the problems in making the radio observations.
Field trials were conducted in Ontario in 2013 and 2014 in soybean to determine the efficacy of POST herbicides on common ragweed resistant to group 2 and group 9 herbicides. Glyphosate dose-response experiments were conducted in the field on two resistant common ragweed populations and one susceptible population. None of the POST herbicides evaluated provided 80% control of glyphosate-resistant (GR) common ragweed. The most effective POST herbicide mixture was glyphosate (Monsanto Canada Inc., 67 Scurfield Blvd., Winnipeg, Manitoba, Canada) plus fomesafen(Syngenta Canada Inc., 140 Research Lane, Research Park Guelph, Ontario, Canada), which provided 68 to 98% control of GR common ragweed. Chlorimuron, cloransulam, imazethapyr, and thifensulfuron provided control similar to glyphosate alone. An application of glyphosate/fomesafen reduced biomass by as much as 95%. Glyphosate plus acifluorfen reduced GR common ragweed biomass by as much as 92%. The remaining POST herbicide tank mixes evaluated reduced GR common ragweed biomass by less than 80%. Glyphosate plus bentazon, glyphosate plus chlorimuron, and glyphosate plus thifensulfuron resulted in soybean yields similar to the weedy control, with yield reductions of 70, 62, and 73%, respectively. An application of glyphosate plus fomesafen or glyphosate/fomesafen had the lowest soybean yield reductions of 29 and 34%, respectively. The resistant biotype required a 2- to 28-fold increase in glyphosate dose compared to the susceptible population to achieve 50% control.
Like many of the social sciences, sociology is a multi-paradigm science (Ritzer, 1975). Different approaches explain social phenomena at different scales (from the individual to the world system) and focus on different aspects of social reality (e.g. the distinction between the objective world and the subjective world). Another distinction is between descriptive and normative analysis. Descriptive analyses focus on explanation and understanding cause and effect relationships. Normative analyses focus on moral dimensions of issues and what we ‘ought to do’. While sociological approaches often entail elements of both of these approaches, most work tends to emphasise one or the other. Also, there is a distinction between sociological work that has further theoretical explanation as a primary goal and work that is more applied – that is, work that applies past theory and research to practical empirical problems.
In sociology, there are a variety of views about conflict, and the orientation of any given analysis depends upon the theoretical framework and objectives of the researcher. Thus, the approach that a sociologist might take regarding conflict depends on where her work is situated with regard to these different considerations. Some sociologists might focus primarily on explaining social conflict, such as someone studying the causes of a revolution, while others might focus on trying to resolve it, such as those supporting a land management planning process. In some instances sociologists might actually be interested in facilitating conflict, such as those who work to mobilise collective action among members of an oppressed group. Some sociologists might focus on the mechanisms that generate conflict (descriptive analysis) – such as the factors that might underlie a conflict over clear-cut logging, while others might focus primarily on the moral dimensions of conflict (e.g. how can gender inequality be reduced in forest-dependent communities). Some sociologists might focus primarily on ‘objective’ indicators of conflict (e.g. the size of a social protest, and its political outcomes), while others might focus on subjective dimensions, such as how conflict is socially constructed (e.g. such as perceptions about the social values that underlie the conflict).
1/f noise in semiconductor devices and circuits provides important information regarding quality of the interface as well as the transport mechanism. In 1D and 2D channel materials, 1/f noise also provides information on stability under ambient conditions, including effects of contaminants adsorbed on the surface. In addition, noise levels are important in evaluating suitability of the device for analog and digital applications. In this work, we have fabricated back-gated field-effect transistors (FETs) using various thicknesses of mechanically exfoliated MoS2 flakes (bilayer and 15 layer flakes) and studied the 1/f noise under ambient conditions. The on-current of the devices scales with the number of layers. The Hooge parameters inferred from the measured noise amplitudes and calculated carrier densities are comparable to prior reports on devices such as CNTs and graphene FETs, even when measured under ambient conditions. The effect of channel and contacts on both the conductance and noise can be inferred from bias-dependent current and noise measurements.