547 research outputs found
A review of knowledge: inter-row hoeing & its associated agronomy in organic cereal & pulse crops
The aim of this project was to establish the āstate of the artā 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.
ā¢ 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).
ā¢ 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.
ā¢ 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.
ā¢ 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. āAā 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), āAā and āLā blades offer an effective low cost solution.
ā¢ 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.
ā¢ There is some evidence to suggest that mechanical weeding operations can mineralise soil bound nitrogen.
ā¢ 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:
ā¢ The interaction of seed rate and row spacing needs to be confirmed in organic systems.
ā¢ 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.
ā¢ 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.
ā¢ 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
Does ultrasound screening for abdominal aortic aneurysm reduce mortality?
Screening reduces mortality in men, although it's unclear whether it has the same effect in women. Screening for aortic abdominal aneurysm (AAA) with ultrasound in men 65 to 79 years of age reduces AAA-specific mortality (number needed to screen [NNS] to prevent one death from AAA=769 men over 3 years). However, a trend toward reduced all-cause mortality doesn't reach significance, possibly because of the low incidence of AAA (strength of recommendation [SOR]: A, systematic review of 4 population-based randomized controlled trials [RCTs]). Evidence is inadequate to demonstrate benefits of screening in women
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
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
Tissue-specific mRNA expression profiling in grape berry tissues
<p>Abstract</p> <p>Background</p> <p>Berries of grape (<it>Vitis vinifera</it>) contain three major tissue types (skin, pulp and seed) all of which contribute to the aroma, color, and flavor characters of wine. The pericarp, which is composed of the exocarp (skin) and mesocarp (pulp), not only functions to protect and feed the developing seed, but also to assist in the dispersal of the mature seed by avian and mammalian vectors. The skin provides volatile and nonvolatile aroma and color compounds, the pulp contributes organic acids and sugars, and the seeds provide condensed tannins, all of which are important to the formation of organoleptic characteristics of wine. In order to understand the transcriptional network responsible for controlling tissue-specific mRNA expression patterns, mRNA expression profiling was conducted on each tissue of mature berries of <it>V. vinifera </it>Cabernet Sauvignon using the Affymetrix GeneChip<sup>Ā® </sup><it>Vitis </it>oligonucleotide microarray ver. 1.0. In order to monitor the influence of water-deficit stress on tissue-specific expression patterns, mRNA expression profiles were also compared from mature berries harvested from vines subjected to well-watered or water-deficit conditions.</p> <p>Results</p> <p>Overall, berry tissues were found to express approximately 76% of genes represented on the <it>Vitis </it>microarray. Approximately 60% of these genes exhibited significant differential expression in one or more of the three major tissue types with more than 28% of genes showing pronounced (2-fold or greater) differences in mRNA expression. The largest difference in tissue-specific expression was observed between the seed and pulp/skin. Exocarp tissue, which is involved in pathogen defense and pigment production, showed higher mRNA abundance relative to other berry tissues for genes involved with flavonoid biosynthesis, pathogen resistance, and cell wall modification. Mesocarp tissue, which is considered a nutritive tissue, exhibited a higher mRNA abundance of genes involved in cell wall function and transport processes. Seeds, which supply essential resources for embryo development, showed higher mRNA abundance of genes encoding phenylpropanoid biosynthetic enzymes, seed storage proteins, and late embryogenesis abundant proteins. Water-deficit stress affected the mRNA abundance of 13% of the genes with differential expression patterns occurring mainly in the pulp and skin. In pulp and seed tissues transcript abundance in most functional categories declined in water-deficit stressed vines relative to well-watered vines with transcripts for storage proteins and novel (no-hit) functional assignments being over represented. In the skin of berries from water-deficit stressed vines, however, transcripts from several functional categories including general phenypropanoid and ethylene metabolism, pathogenesis-related responses, energy, and interaction with the environment were significantly over-represented.</p> <p>Conclusion</p> <p>These results revealed novel insights into the tissue-specific expression mRNA expression patterns of an extensive repertoire of genes expressed in berry tissues. This work also establishes an extensive catalogue of gene expression patterns for future investigations aimed at the dissection of the transcriptional regulatory hierarchies that govern tissue-specific expression patterns associated with tissue differentiation within berries. These results also confirmed that water-deficit stress has a profound effect on mRNA expression patterns particularly associated with the biosynthesis of aroma and color metabolites within skin and pulp tissues that ultimately impact wine quality.</p
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 Lokoās availability was determined using the manufacturerās 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
Evaluation of a patient self-stratification methodology to identify those in need of shielding during COVID-19
The logistical challenges of rapidly and accurately identifying those patients who needed to shield during the COVID-19 pandemic were unprecedented. We report our experiences of meeting this challenge for >9,000 patients with rheumatic and musculoskeletal disease at our centre, incorporating an element of guided patient self-stratification. Our results indicate that patients are able to stratify their own risk accurately using the BSR COVID-19 risk stratification guidance.</p
Alcopops Disproportionately Consumed by Minors in Sexual Assault Cases
Alcohol is present in a large proportion of sexual assault cases. However, research largely overlooks the role that providing alcoholic beverages ā particularly those with high-alcohol- content and/or whose flavors mask the taste of alcohol ā may have in making young people more vulnerable to being assaulted. This research is especially important given the rise in the availability of sugar-sweetened alcopops and their high-alcohol-content counterparts āsupersized alcopops,ā which contain up to 5.5 standard alcoholic drinks. In the current study, we examined whether alcopops and supersized alcopops, relative to beer, were involved in disproportionately more sexual assault cases involving victims who were minors (\u3c 18 years old) rather than adults. In this secondary data analysis, we used Nexis Uni to search legal documents for the brands of supersized alcopop (Four Loko), alcopop (Smirnoff Ice), and beer (Bud Light) most commonly consumed by underage drinkers. Inclusion criteria were U.S. sexual assault cases occurring from 2010 to 2019 and involving victims who consumed one of these three alcohol brands. Two researchers coded information from the case facts, compared coding, and reaching consensus. Thirty-six cases were included for analyses. Compared to victims of sexual assault who consumed beer, victims who consumed supersized alcopops or alcopops were significantly more likely to be minors. Similar results were observed after adjusting for the victim being given the alcohol by the perpetrator, which was strongly associated with the victim being a minor. This study provides initial evidence that sexual assault perpetrators may disproportionately use alcopops and supersized alcopops for the sexual victimization of minors
Preserving Bibliographic Relationships in Mappings from FRBR to BIBFRAME 2.0
In the environment of the World Wide Web large volumes of library data have been pub-lished following different conceptual models. The navigation through these volumes and the data interlinking require the development of mappings between the conceptual models. Library conceptual models provide constructs for the representation of bibliographic families and the relationships between Works. A key requirement for successful map-pings between different conceptual models is to preserve such content relationships. This paper studies a set of cases (Work with single Expression, Work with multiple Expres-sions, translation, adaptation) to examine if and how bibliographic content relationships and families could be preserved in mappings from FRBR to BIBFRAME 2.0. Even though, relationships between Works of the same bibliographic family may be preserved, the progenitor Work is not always represented in BIBFRAME after mappings
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