Companion cropping for organic field vegetables (OF0181)

Typical organic crop rotations are extensive with at least one year in four as a fertility building crop. However, the economic viability of organic systems may be compromised by having 75% or less of the farm productive at one time, limited further by the absence of the Arable Area Payments Scheme, particularly Set-aside, for vegetable crops. In addition, the system gives rise to a high fertility/low fertility sequence which is inefficient in terms of nutrient management (particularly nitrogen). To try to address this, the use of permanent beds of companion crop grown alongside the vegetable crops has been developed under various conditions around the world and is perceived as a possible alternative in organic husbandry. Companion crops also have the potential to reduce the impact of pests and weeds. A potential disadvantage of companion crops is competition with crop plants for space, light, water and nutrients. The companion crop, therefore, is likely to have to be mown or grazed to control competition and encourage nutrient transfer. On the positive side, companion crops have the potential to reduce the impact of pests, and weeds. The challenge is, therefore, to develop appropriate crop layouts and machinery to balance these interactions and result in profitable crop production. Project OF0181 was delivered with Elm Farm Research Centre and was guided by a Steering Group. The core of the project was the further development and evaluation of a seven-crop companion crop system initially developed by Professor Martin Wolfe at Wakelyns Agroforesty, Fressingfield, Suffolk, a Soil Association registered organic farm. The system was based on 1.5 m beds, with three 20 cm vegetable rows alternating with 30 cm leguminous companion strips. Within each bed, there was a seven-course crop rotation: potatoes, alliums, Umbellifers, spring oats, legumes, brassicas and spring wheat. To establish and manage this system, Martin Wolfe and his co-workers (P. J. & M. J. Wards) had by spring 1999 developed a range of purpose-built machinery including a strip rotavator, 3 row precision seed drill, straight tine or L-blade strip cultivator with/without discs, rotary strip mower, strip irrigator and a strip compost spreader. Two large experiments were established at Wakelyns in spring 1999; it was planned that these be continued for the full three years of the project. One experiment compared a factorial combination of a) three companion crops: white clover, vetch and nil, b) companion crop mowings left to fall, or deflected onto the vegetable rows, and c) the presence or absence of added composted manure. A second experiment compared factorial combinations of winter cover crops of rye and vetch grown in the vegetable rows with additional approved inputs of phosphorus and potassium. All seven crops were grown but assessments were made only on brassicas, alliums and carrots. Conclusions Companion cropping has the potential to improve economic viability, and pest, disease and annual weed control in organic cropping systems, particularly in field vegetables which are not supported by the Arable Area Payment Scheme. However, in practice, in project OF0181 these benefits were not realised: • Grass weeds were favoured and were difficult to control once established. • There were problems with seedbed preparation and crop establishment; these may be less on lighter soils. • Some crop species were better suited to companion cropping. In 2000 and 2001, there was: - a high yield in both years from beetroot, spinach, chard and kale; - a high yield in one year from Brassicas (some cabbage, swede, turnip), endive, lettuce, parsley and parsnip; - a low yield in both years from Allium crops (leeks, onions), Brassica (sprouts, some cabbage, calabrese), carrots, celeriac, broad and dwarf beans. • Clover used soil available nitrogen in preference to fixed nitrogen, starving less competitive crops such as alliums of the nutrient and resulting in very low yields. • Even with reliable yields, companion cropping in the form tested may only be suited to small-scale labour-intensive production. A system with greater spatial separation of companion and vegetable crops, with vegetables and companion crops grown alone in separate beds or strips, may give the reported benefits of companion cropping with less competition and be practical for large scale production

Understanding the measurement of hunger and food insecurity in the elderly

The elderly are one of the population subgroups at greatest risk for hunger and food insecurity. To date, no accurate measures of this problem have been developed. What is needed are a thorough understanding of the phenomenon, and an assessment of how the elderly perceive and answer items commonly used to measure hunger and food insecurity in other subgroups. In-depth, open-ended interviews were conducted with forty-one low-income urban black and rural white residents of upstate New York. Results suggest a conceptual framework of food insecurity in the elderly with two significant differences from frameworks proposed for younger families: the major role of health problems and physical disabilities, and the impact of personal history on perceptions of food insecurity. In a telephone follow-up (approximately six months after the initial interviews) twenty-four respondents were asked commonly used food insecurity questionnaire items from six different sources. Results suggest that hunger and food insecurity among the elderly can be measured directly. The commonly used measures tested here will help categorize the stages of food insecurity. However, these direct measures might underestimate the prevalence of food insecurity because of a perceived reluctance to report problems with food.

Comparing Segmentation by Time and by Motion in Visual Search: An fMRI Investigation

Abstract Brain activity was recorded while participants engaged in a difficult visual search task for a target defined by the spatial configuration of its component elements. The search displays were segmented by time (a preview then a search display), by motion, or were unsegmented. A preparatory network showed activity to the preview display, in the time but not in the motion segmentation condition. A region of the precuneus showed (i) higher activation when displays were segmented by time or by motion, and (ii) correlated activity with larger segmentation benefits behaviorally, regardless of the cue. Additionally, the results revealed that success in temporal segmentation was correlated with reduced activation in early visual areas, including V1. The results depict partially overlapping brain networks for segmentation in search by time and motion, with both cue-independent and cue-specific mechanisms.</jats:p

Biotic Interactions Shape the Ecological Distributions of Staphylococcus Species.

Many metagenomic sequencing studies have observed the presence of closely related bacterial species or genotypes in the same microbiome. Previous attempts to explain these patterns of microdiversity have focused on the abiotic environment, but few have considered how biotic interactions could drive patterns of microbiome diversity. We dissected the patterns, processes, and mechanisms shaping the ecological distributions of three closely related Staphylococcus species in cheese rind biofilms. Paradoxically, the most abundant species (S. equorum) is the slowest colonizer and weakest competitor based on growth and competition assays in the laboratory. Through in vitro community reconstructions, we determined that biotic interactions with neighboring fungi help resolve this paradox. Species-specific stimulation of the poor competitor by fungi of the genus Scopulariopsis allows S. equorum to dominate communities in vitro as it does in situ Results of comparative genomic and transcriptomic experiments indicate that iron utilization pathways, including a homolog of the S. aureus staphyloferrin B siderophore operon pathway, are potential molecular mechanisms underlying Staphylococcus-Scopulariopsis interactions. Our integrated approach demonstrates that fungi can structure the ecological distributions of closely related bacterial species, and the data highlight the importance of bacterium-fungus interactions in attempts to design and manipulate microbiomes.ImportanceDecades of culture-based studies and more recent metagenomic studies have demonstrated that bacterial species in agriculture, medicine, industry, and nature are unevenly distributed across time and space. The ecological processes and molecular mechanisms that shape these distributions are not well understood because it is challenging to connect in situ patterns of diversity with mechanistic in vitro studies in the laboratory. Using tractable cheese rind biofilms and a focus on coagulase-negative staphylococcus (CNS) species, we demonstrate that fungi can mediate the ecological distributions of closely related bacterial species. One of the Staphylococcus species studied, S. saprophyticus, is a common cause of urinary tract infections. By identifying processes that control the abundance of undesirable CNS species, cheese producers will have more precise control on the safety and quality of their products. More generally, Staphylococcus species frequently co-occur with fungi in mammalian microbiomes, and similar bacterium-fungus interactions may structure bacterial diversity in these systems

Coal Miners and Third-Party Politics in Illinois, 1880-1924: A Statistical Analysis of Voting Behavior

http://deepblue.lib.umich.edu/bitstream/2027.42/50857/1/76.pd

Hysteresis in the Mott Transition between Plasma and Insulating Gas

We show that hysteresis can occur in the transition between a neutral plasma and the insulating gas consisting of neutral pairs bound by Coulomb attraction. Since the transition depends sensitively on the screening length in the plasma, regions of bistability occur in density--temperature phase space. We present numerical results which indicate where these regions occur for systems such as spin-polarized hydrogen, positronium gas, and excitons in a semiconductor.Comment: 9 pages (Latex/RevTex), 6 postscript figures which are in compressed and uuencoded file, prepared using the utility "uufiles" and separately submitted. They should be automatically included with the text when it is downloaded. Figures also available in hard copy from the authors ([email protected]; [email protected]); paper submitted to Phys. Rev.

Inflation-Produced Magnetic Fields in R^n F^2 and I F^2 models

We re-analyze the production of seed magnetic fields during Inflation in (R/m^2)^n F_{\mu \nu}F^{\mu \nu} and I F_{\mu \nu}F^{\mu \nu} models, where n is a positive integer, R the Ricci scalar, m a mass parameter, and I \propto \eta^\alpha a power-law function of the conformal time \eta, with \alpha a positive real number. If m is the electron mass, the produced fields are uninterestingly small for all n. Taking m as a free parameter we find that, for n \geq 2, the produced magnetic fields can be sufficiently strong in order to seed dynamo mechanism and then to explain galactic magnetism. For \alpha \gtrsim 2, there is always a window in the parameters defining Inflation such that the generated magnetic fields are astrophysically interesting. Moreover, if Inflation is (almost) de Sitter and the produced fields almost scale-invariant (\alpha \simeq 4), their intensity can be strong enough to directly explain the presence of microgauss galactic magnetic fields.Comment: 5 pages, 2 figures. Minor revisions. References added. Accepted for publication in Phys. Rev.

Vertex similarity in networks

We consider methods for quantifying the similarity of vertices in networks. We propose a measure of similarity based on the concept that two vertices are similar if their immediate neighbors in the network are themselves similar. This leads to a self-consistent matrix formulation of similarity that can be evaluated iteratively using only a knowledge of the adjacency matrix of the network. We test our similarity measure on computer-generated networks for which the expected results are known, and on a number of real-world networks

Preliminary catalog of pictures taken on the lunar surface during the Apollo 15 mission

Catalog of all pictures taken from lunar module or lunar surface during Apollo 15 missio

Prospective Comparison of Ultrasound-Guided Versus Palpation Techniques for Arterial Line Placement by Residents in a Teaching Institution

Background: Arterial line insertion is traditionally done by blind palpation. Residents may need multiple attempts for successful insertion, leading to longer procedure times and many failed attempts. Objective: We hypothesized that ultrasound guidance (USG) would be faster and more successful than traditional blind palpation (TBP) for radial artery line placement by residents. Methods: Patients undergoing elective surgery requiring a radial arterial line were randomized to either the USG or TBP groups. Exclusion criteria included a need for arterial line placement in an awake patient, emergent surgery, or American Society of Anesthesiologists (ASA) physical status class VI. After the induction of anesthesia, a postgraduate year 3 (PGY-3) or PGY-4 anesthesia resident placed an arterial line by either USG or TBP. Results: A total of 412 patients and 85 of 106 residents (80%) in the training program were included. The 2 groups were similar with respect to sex, weight, height, ASA class, baseline systolic blood pressure, and baseline heart rate. USG was faster than TBP (mean times 171.1 ± 16.7 seconds versus 243.6 ± 23.5 seconds, P = .012), required fewer attempts (mean 1.78 ± 0.11 versus 2.48 ± 0.15, P = .035), and had an improved success rate (96% versus 90%, P = .012). Conclusions: We found that residents using USG in an academic institution resulted in significantly faster placement of the arterial lines, fewer attempts, and fewer catheters used