Manitoba field survey of herbicide-resistant weeds

Non-Peer ReviewedIn 2002, 150 fields were randomly selected throughout the ecoregions of Manitoba and surveyed for grass and broadleaf weeds resistant to Group 1 (ACCase inhibitor) or Group 2 (ALS inhibitor) herbicides. One-third of surveyed fields had a herbicide-resistant weed biotype. Two biotypes new to western Canada are Group 2-resistant green foxtail and redroot pigweed. Of producers with resistant biotypes, 10% or fewer were aware of their occurrence

Antiflow of kaons in relativistic heavy ion collisions

We compare relativistic transport model calculations to recent data on the sideward flow of neutral strange K^0_s mesons for Au+Au collisions at 6 AGeV. A soft nuclear equation of state is found to describe very well the positive proton flow data measured in the same experiment. In the absence of kaon potential, the K^0 flow pattern is similar to that of protons. The kaon flow becomes negative if a repulsive kaon potential determined from the impulse approximation is introduced. However, this potential underestimates the data which exhibits larger antiflow. An excellent agreement with the data is obtained when a relativistic scalar-vector kaon potential, that has stronger density dependence, is used. We further find that the transverse momentum dependence of directed and elliptic flow is quite sensitive to the kaon potential in dense matter.Comment: 5 pages, Revtex, 4 figure

Herbicide-use trends in prairie canola production systems

Non-Peer Reviewe

Effect of Structure on Strength of Agglomerates using Distinct Element Method

Knowledge of agglomerate strength is highly desirable for compression and tableting, dissolution and dispersion and mitigation of dust formation. The behaviour of agglomerates is affected by parameters such as density, agglomerate size, primary particle size, and interparticle bond strength. The method of agglomeration influences the evolution of structure, and this in turn affects its strength. Furthermore, the methods of strength characterisation, i.e. quasi-static or impact produce different results. To understand the role of structure and the influence of test method, agglomerate failure behaviour has been analysed by the use of the Distinct Element Method (DEM). We report on our work on the simulation of the breakage of the agglomerates for different porosities and impact conditions, where the role of impact speed and angle and type of contact bonding model have been evaluated. The adhesive contact model of JKR is used to form an agglomerate. The effect of the bonding level on the strength and size distribution of the clusters released as a result of failure has been investigated. This work also evaluates the effect of structure (porosity) on the strength of the agglomerates

Sedimentary ancient DNA from Lake Skartjorna, Svalbard: assessing the resilience of arctic flora to Holocene climate change

Reconstructing past vegetation and species diversity from arctic lake sediments can be challenging because of low pollen and plant macrofossil concentrations. Information may be enhanced by metabarcoding of sedimentary ancient DNA (sedaDNA). We developed a Holocene record from Lake Skartjørna, Svalbard, using sedaDNA, plant macrofossils and sediment properties, and compared it with published records. All but two genera of vascular plants identified as macrofossils in this or a previous study were identified with sedaDNA. Six additional vascular taxa were found, plus two algal and 12 bryophyte taxa, by sedaDNA analysis, which also detected more species per sample than macrofossil analysis. A shift from Salix polaris-dominated vegetation, with Koenigia islandica, Ranunculaceae and the relatively thermophilic species Arabis alpina and Betula, to Dryas octopetala-dominated vegetation ~6600–5500 cal. BP suggests a transition from moist conditions 1–2°C warmer than today to colder/drier conditions. This coincides with a decrease in runoff, inferred from core lithology, and an independent record of declining lacustrine productivity. This mid-Holocene change in terrestrial vegetation is broadly coincident with changes in records from marine sediments off the west coast of Svalbard. Over the Holocene sedaDNA records little floristic change, and it clearly shows species persisted near the lake during time intervals when they are not detected as macrofossils. The flora has shown resilience in the presence of a changing climate, and, if future warming is limited to 2°C or less, we might expect only minor floristic changes in this region. However, the Holocene record provides no analogues for greater warming

Evolution of particle breakage studied using x-ray tomography and the discrete element method

Particle breakage can significantly change the fabric (size and shape of particles and contact network) of a granular material, affecting highly the material's macroscopic response. In this paper, oedometric compression tests are performed on zeolite specimens and x-ray computed micro-tomography is employed, to acquire high resolution 3D images of the specimens throughout the test. The images are processed, to describe breakage spatially and quantify it throughout the test and gain information about the mechanisms leading to particle breakage. In addition to the image processing, the discrete element method (DEM) is used to study the initiation and likelihood of particle breakage, by simulating the experimental test during the early stages of loading and using quantitative results from the images to inform and validate the DEM model. A discrete digital image correlation is used, in order to incrementally identify intact grains and simultaneously get results about the strain field within the specimen, as well as the kinematics of individual grains and fragments. In the initial stages of breakage, there is a clear boundary effect on the spatial distribution of breakage, as it is concentrated at the moving boundary (more than 90% of total breakage) and circumferentially (more than 70% of total breakage) close to the apparatus cell. The DEM model can reproduce the bulk response of the material until the point where substantial breakage governs the macroscopic response and it starts to soften. Additionally, there is an initial indication that the spatial distribution of the force network matches the localisation of breakage radially, but it does not seem to localise close to the loading platen. This analysis will enrich our understanding of the mechanisms and evolution of particle breakage

Self-Structuring of Granular material under Capillary Bulldozing

An experimental observation of the structuring of a granular suspension under the progress of a gas/liquid meniscus in a narrow tube is reported here. The granular material is moved and compactifies as a growing accumulation front. The frictional interaction with the confining walls increases until the pore capillary entry pressure is reached. The gas then penetrates the clogged granular packing and a further accumulation front is formed at the far side of the plug. This cyclic process continues until the gas/liquid interface reaches the tube’s outlet, leaving a trail of plugs in the tube. Such 1D pattern formation belongs to a larger family of patterning dynamics observed in 2D Hele-Shaw geometry. The cylindrical geometry considered here provides an ideal case for a theoretical modelling for forced granular matter oscillating between a long frictional phase and a sudden viscous fluidization

keynote 412 phase iii study of pembrolizumab plus chemoradiation vs chemoradiation alone for locally advanced head and neck squamous cell carcinoma hnscc

n/

Development and initial psychometric properties of the Warwick–Edinburgh Mental Wellbeing Scale‐Intellectual Disability version

Background The Warwick–Edinburgh Mental Wellbeing Scale (WEMWBS; Tennant et al., 2007) is yet to be validated in the intellectual disability (ID) population. The aim of this study was to report the development process and assess the psychometric properties of a newly adapted version of the WEMWBS and the Short WEMWBS for individuals with mild to moderate IDs (WEMWBS-ID/SWEMWBS-ID). Method The WEMWBS item wordings and response options were revised by clinicians and researchers expert in the field of ID, and a visual aid was added to the scale. The adapted version was reviewed by 10 individuals with IDs. The measure was administered by researchers online using screenshare, to individuals aged 16+ years with mild to moderate IDs. Data from three UK samples were collated to evaluate the WEMWBS-ID (n = 96). A subsample (n = 22) completed the measure again 1 to 2 weeks later to assess test–retest reliability, and 95 participants additionally completed an adapted version of the adapted Rosenberg Self-Esteem Scale to examine convergent validity. Additional data from a Canadian sample (n = 27) were used to evaluate the SWEMWBS-ID (n = 123). Results The WEMWBS-ID demonstrated good internal consistency (ω = 0.77–0.87), excellent test–retest reliability [intraclass correlation coefficient (ICC) = .88] and good convergent validity with the self-esteem scale (r = .48–.60) across samples. A confirmatory factor analysis for a single factor model demonstrated an adequate fit. The SWEMWBS-ID showed poor to good internal consistency (ω = 0.36–0.74), moderate test–retest reliability (ICC = .67) and good convergent validity (r = .48–.60) across samples, and a confirmatory factor analysis indicated good model fit for a single factor structure. Conclusions The WEMWBS-ID and short version demonstrated promising psychometric properties, when administered virtually by a researcher. Further exploration of the scales with larger, representative samples is warranted