A review of knowledge: inter-row hoeing & its associated agronomy in organic cereal & pulse crops

The aim of this project was to establish the “state of the art” for inter-row hoeing and its associated agronomic practices in organic cereal and pulse crops. To achieve this a detailed review of literature was undertaken. • To facilitate inter-row cultivation in cereal and pulse crops, some adjustment of row spacing may be required. For cereals, drilling crops in 25 cm rows can reduce yield compared with normal drilling practice, primarily due to greater intra-specific competition amongst the crop (i.e. competition between crop plants). • The yield penalty resulting from widely spaced crop rows can be minimised using a number of approaches, depending on the drill: 1. Reducing the seed rate in widely spaced crop rows can help to minimise excessive intra-specific competition. 2. Band sowing the crop in wide rows can also help to minimise intra-specific competition as the seed is distributed over a greater area. 3. Using a twin-row arrangement can completely overcome the yield penalty. • The recommended row spacing for peas (up to 20 cm) and beans (up to 35 cm) does not require any further adjustment for inter-row hoeing. • Recent developments in automated guidance of inter-row hoeing equipment mean that weeding operations can now be conducted a much higher speeds (10 km h-1). This has highlighted the limitations of some of the cultivators currently used (e.g. ‘A’ blades), as excessive soil throw can occur at this high speed. Rolling cultivators may prove to be the most suitable at high forward speeds. For manually guided hoes working at slower speeds (5 km h-1), ‘A’ and ‘L’ blades offer an effective low cost solution. • In terms of the timing of inter-row hoeing, it is suggested that weeding operations should be conducted at an early stage in the growing season, as the weeds that emerge with or shortly after the crop are the ones that pose the most significant threat for crop yield. Weeding on two occasions can provide better levels of weed control than weeding once, but weeding more frequently offered little additional benefit. Reductions of weed biomass of up to 99 % have been reported as a result of inter-row hoeing, although this has not always resulted in a positive crop yield response. This is probably due to crop damage resulting from inaccurate hoeing, a problem that can be overcome with automated guidance. • There is some evidence to suggest that mechanical weeding operations can mineralise soil bound nitrogen. • The impact of inter-row hoeing on ground nesting birds is uncertain. Early indications suggest that skylarks prefer to nest directly adjacent to or in the crop row rather than between rows. The information contained within this review should enable farmers to make best use of inter-row hoeing in their arable crops. There are a number of areas that require further research and development: • The interaction of seed rate and row spacing needs to be confirmed in organic systems. • Relatively little is known about the mechanisms of weed kill and the detailed interaction between the cultivator blade, the weed and the soil. This is particularly important with the new automated guidance equipment that allows weeding at high forward speeds. • The timing and frequency of inter-row hoeing has received very little attention. The optimum weed control timings are based on small-plot crop:weed competition studies and need to be verified under field scale management with inter-row hoeing equipment. • Finally, the impact of inter-row hoeing and widely spaced crop rows on ground-nesting birds has not been looked at directly, but is of importance. Please see the main report for a more detailed summary before the full text

Applying mesh conformation on shape analysis with missing data

A mesh conformation approach that makes use of deformable generic meshes has been applied to establishing correspondences between 3D shapes with missing data. Given a group of shapes with correspondences, we can build up a statistical shape model by applying principal component analysis (PCA). The conformation at first globally maps the generic mesh to the 3D shape based on manually located corresponding landmarks, and then locally deforms the generic mesh to clone the 3D shape. The local deformation is constrained by minimizing the energy of an elastic model. An algorithm was also embedded in the conformation process to fill missing surface data of the shapes. Using synthetic data, we demonstrate that the conformation preserves the configuration of the generic mesh and hence it helps to establish good correspondences for shape analysis. Case studies of the principal component analysis of shapes were presented to illustrate the successes and advantages of our approach

Effects of Fluctuating Environments on the Selection of High Yielding Microalgae

Microalgae have the potential of producing biomass with a high content of lipids at high productivities using seawater or saline ground water resources. Microalgal lipids are similar to vegetable oils and suitable for processing to liquid fuels. Engineering cost analysis studies have concluded that, at a favorable site, microalgae cultivation for fuel production could be economically viable. The major uncertainties involve the microalgae themselves: biomass and lipid productivity and culture stability

Measurements of thorium and uranium daughters in radioenvironmental samples using γγ-coincidence spectrometry

We present the performance of a γγ-coincidence spectrometer for measuring the activities of thorium and uranium daughters in environmental samples. The spectrometer consists of two NaI(Tl) detectors facing each other inside a low-background passive shield. We present coincidence gating schemes for achieving the best signal-to-noise ratios, coincidence detection efficiencies, background levels, and minimum detectable activities. The spectrometer is simulated using Geant4 to correct sample efficiencies for self-absorption effects. The device is used to measure thorium and uranium daughter activities in Brazil nuts, potting mix, and magazine paper. Our results for Brazil nuts agree with some, but not all, previous measurements. Thorium or uranium daughter activities have previously not been reported for commercial potting mix. For magazine paper, our measured activities are lower than most previously determined values

An investigation into the design of cultivation systems for inter- and intra-row weed control

The aim of this study was to investigate the factors that influence the design of soil engaging systems to mechanically control weeds between plants within the crop row in widely spaced field vegetables. A mass flow soil dynamics model based on particle dynamics was developed to aid designers in determining the lateral and forward displacement of soil as it is undercut by shallow working wide blades. The model was validated in soil bin laboratory experiments and used to design a novel mechanical inter- and intra-row weeding system.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Associations between Delta-8 THC and Four Loko retail availability in Fort Worth, Texas

Alcohol and cannabis are two of the most widely used substances among young people, and availability and price are two of the most significant determinants of use. Four Loko products contain up to 5.5 standard alcoholic drinks in a single can, are one of the least expensive ready-to-drink alcohol products on the market and are commonly consumed by underage drinkers. Delta-8 THC is a psychoactive substance with no federal regulations regarding minimum purchase age, ingredients and synthesis, marketing, and testing for potency or contaminants. Delta-8 THC products can be inexpensively synthesized and are sold for low prices. Given that young people often use both products, and use of these products can result in negative consequences, it is important to understand whether these products are being sold in the same stores, which would indicate the presence of niche stores marketing high-risk, youth-oriented substances. This study included 360 locations with off-premise beer or beer/wine licenses in Fort Worth, Texas. Locations were called and asked whether they sold Delta-8 THC. Four Loko’s availability was determined using the manufacturer’s website. A logistic regression model examined associations between the availability of Delta-8 THC and Four Loko. Of the 360 locations, 38% sold Four Loko and 9% sold Delta-8 THC. Delta-8 THC availability was significantly associated with higher odds of Four Loko availability (OR=2.15,95%CI=1.05,4.43). Given the associations between the retail availability of Delta-8 THC and Four Loko, policies that limit access to such products, including near schools and in stores that youth patronize, may be warranted

Sporobolus stapfianus: Insights into desiccation tolerance in the resurrection grasses from linking transcriptomics to metabolomics

Predominant clusters of SDATs that share distinct patterns of abundance during dehydration: A. Predominant patterns of abundance for transcripts in clusters that exhibited increased abundance during dehydration. B. Predominant patterns of abundance for transcripts in clusters that exhibited a decreased abundance during dehydration. (PDF 226 kb

Lobster Attack Induces Sensitization In the Sea Hare, Aplysia Californica

Studies of the neural mechanisms of learning, especially of sensitization, have benefitted from extensive research on the model species, Aplysia californica (hereafter Aplysia). Considering this volume of literature on mechanisms, it is surprising that our understanding of the ecological context of sensitization in Aplysia is completely lacking. Indeed, the widespread use of strong electric shock to induce sensitization (an enhancement of withdrawal reflexes following noxious stimulation) is completely unnatural and leaves unanswered the question of whether this simple form of learning has any ecological relevance. We hypothesized that sublethal attack by a co-occurring predator, the spiny lobster, Panulirus interruptus, might be a natural sensitizing stimulus. We tested reflex withdrawal of the tail-mantle and head of individual Aplysia before and after attack by lobsters. Lobster attack significantly increased the amplitude of both reflexes, with a temporal onset that closely matched that observed with electric shock. This result suggests that electric shock may indeed mimic at least one naturally occurring sensitizing stimulus, suggesting, for the first time, an ecological context for this well studied form of learning