4,337 research outputs found

    ASSOCIATING SNPS WITH BINARY TRAITS

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    Association mapping uses statistical analyses to test for relationships between genomic markers called single nucleotide polymorphisms (SNPs) and traits. This research focuses on the use of logistic regression to assess the additive, dominance, and epistatic effects when investigating associations between SNPs and binary traits, such as disease status. A very specific phenomenon that results in infinite maximum likelihood estimates (MLEs) of logistic regression parameters, called quasi-separation of points (QSP), is investigated. We provide a solution that relies on the use of Firth’s MLE to estimate logistic regression parameters. Simulated and real data are utilized to investigate the use of Firth’s MLE in a QSP setting

    An investigation into the fertilizer potential of slaughterhouse cattle paunch

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    In Australia, the red meat processing industry actively seeks approaches to improve the management of solid waste from processing operations and enhance the environmental performance. Recycling of paunch waste to farmland could be a cost-effective and practicable environmental option. However, little is known about the agronomic value of fresh and composted paunch, and the associated requirements for land application. Therefore, a short-term experimental work was undertaken to assess potential risks due to weed seed contamination and determine the agronomic response of ryegrass (Lolium perenne L.) to soil incorporation of paunch. The risk of weed contamination from soil application of paunch appeared to be low; however, methods that account for viability of seeds may be required to fully discard such a risk. Soil application of paunch at field equivalent rates of 150-300 kg ha-1 of N increased dry matter yield by ≈30% on average compared with untreated grass, but was approximately 35% lower than a mineral fertilizer treatment applied at the same rates. Dry matter yield of paunch-treated grass was between 2000 and 3000 kg per ha over four consecutive cuts at 25-day intervals. Nitrogen use-efficiency of paunch was approximately 10% (range: 3% to 20%, depending on paunch type), and total N in harvested plant material showed values, which were between 2% and 3%. Overall, there appears to be potential for paunch-derived products to be used as a source of carbon and nutrients in crop production. Areas that merit a research priority within this space are also outlined in this paper. Such work is required to inform soil-, climate- and crop-specific land application rates, optimize agronomic performance, and minimize environmental concerns. There is also a requirement for the value proposition to industry to be determined, including reduced cost of disposal of material via gate fees and fertilizer replacement value

    Knowledge of late-life depression : an empirical investigation of aged care staff

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    Objectives: This study examined knowledge of late-life depression among staff working in residential and community aged care settings, as well as their previous training in caring for older people with depression. Method: A sample of 320 aged care staff (mean age = 42 years) completed a survey questionnaire. Participants included direct care staff, registered nurses and Care Managers from nursing and residential homes and community aged care services. Results: Less than half of the participating aged care staff had received any training in depression, with particularly low rates in residential care. Although aware of the importance of engaging with depressed care recipients and demonstrating moderate knowledge of the symptoms of depression, a substantial proportion of staff members saw depression as a natural consequence of bereavement, aging or relocation to aged care. Conclusion: Experience in aged care appears to be insufficient for staff to develop high levels of knowledge of depression. Specific training in depression is recommended for staff working in aged care settings in order to improve the detection and management of late-life depression, particularly among direct carers, who demonstrated least knowledge of this common disorder. <br /

    Staff-focused interventions to increase referrals for depression in aged care facilities: a cluster randomized controlled trial

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    Objective:&nbsp;While there is evidence that depression training can improve the knowledge of staff in residential care facilities, there is an absence of research determining whether such training translates into practice change. This study aimed to evaluate the impact of staff training and the introduction of a protocol for routine screening and referral for depression on the numbers of residents detected and referred by care staff for further assessment.Method: A cluster randomized controlled design was used to compare the referral rates for residents in seven facilities randomly allocated into one of three conditions: staff training, staff training plus a screening and referral protocol and wait-list control. Participants were 216 aged care residents (M age&thinsp;=&thinsp;87 years), who agreed to a 12-month audit of their facility file.Results: Staff training on its own did not increase the rate of referrals for depression; however, staff training plus the screening protocol and referral guidelines did lead to a significant increase in the number of residents who were referred to a medical practitioner for further assessment. However, this increase in care staff referrals did not result in substantial changes in the treatment prescribed for residents.Conclusion: Staff training in depression, supplemented with a protocol for routine screening and guidelines on referring residents, can improve pathways to care. However, strategies to overcome barriers to appropriate subsequent treatment of depression are required for staff-focused initiatives to translate into better outcomes for depressed older adults. Methodological limitations of this study are discussed.</div

    Determination of 3D Trajectories of Knots in Solar Prominences Using MSDP Data

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    In this paper we present a new method of restoration of the true thee-dimensional trajectories of the prominence knots based on ground-based observations taken with a single telescope, which is equipped with a Multi-Channel Subtractive Double Pass imaging spectrograph. Our method allows to evaluate true three-dimensional trajectories of the prominence knots without any assumptions concerning the shape of the trajectories or dynamics of the motion. The reconstructed trajectories of several knots observed in three prominences are presented.Comment: 14 pages, 9 figures, accepted for publication in Solar Physic

    Practical long-distance quantum key distribution system using decoy levels

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    Quantum key distribution (QKD) has the potential for widespread real-world applications. To date no secure long-distance experiment has demonstrated the truly practical operation needed to move QKD from the laboratory to the real world due largely to limitations in synchronization and poor detector performance. Here we report results obtained using a fully automated, robust QKD system based on the Bennett Brassard 1984 protocol (BB84) with low-noise superconducting nanowire single-photon detectors (SNSPDs) and decoy levels. Secret key is produced with unconditional security over a record 144.3 km of optical fibre, an increase of more than a factor of five compared to the previous record for unconditionally secure key generation in a practical QKD system.Comment: 9 page

    Evaluation of Wildlife Reflectors in Reducing Vehicle-Deer Collisions on Indiana Interstate 80/90

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    The Indiana Department of Transportation is committed to reducing vehicle-deer collision incidents on the Indiana Interstate I-80/90 as well as on the other roads. Very few of the studies to reduce vehicle-deer collisions incorporated any sound and complete statistical design. Some states (California, Colorado, Maine, Ontario-Canada, Washington State and Wyoming) have found that the use of wildlife reflectors did not reduce vehicle-deer collisions. However, some other states (British Columbia-Canada, Iowa, Minnesota, Oregon, Washington State and Wisconsin) found that the use of wildlife reflectors did reduce vehicle-deer collisions. The main objective of this experimental study is to evaluate the effectiveness of the Reflectors in reducing vehicledeer collisions. The experimental design uses one-mile long road sections for each combination of reflector colors (red and blue/green), reflector spacing (30 m and 45 m), reflector design (single and dual reflectors), and median (one with and one without reflectors). In this design there are sixteen treatment combinations. A complete set of treatment combinations is called a replicate and the design had two replicates. Two one-mile control sections were placed at each end of each replicate. Data for the peak months of April, May, October and November was used in the data analyses. Poisson Regression models were used to analyze the data. No statistically significant differences among reflectors combinations or between reflectors and controls were found. When comparing all combined reflector sites with all combined control sites, the Poisson Regression Analyses indicate that the difference between the Poisson Mean (μ) of the all reflectors sections and all the control sections is statistically significant. The use of reflectors provides an expected reduction in deer-vehicle collisions of 19% with 95% confidence limits of 5% to 30%. Maximum reduction is associated with 100 ft spacing regardless of the reflector color, median with or without reflectors, single or double reflectors. The cost effectiveness of this reduction will be behind any decision to use reflectors to reduce vehicle-deer collisions

    Biomass burning and urban air pollution over the Central Mexican Plateau

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    Observations during the 2006 dry season of highly elevated concentrations of cyanides in the atmosphere above Mexico City (MC) and the surrounding plains demonstrate that biomass burning (BB) significantly impacted air quality in the region. We find that during the period of our measurements, fires contribute more than half of the organic aerosol mass and submicron aerosol scattering, and one third of the enhancement in benzene, reactive nitrogen, and carbon monoxide in the outflow from the plateau. The combination of biomass burning and anthropogenic emissions will affect ozone chemistry in the MC outflow

    Dryland ecohydrology and climate change: critical issues and technical advances

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    Drylands cover about 40% of the terrestrial land surface and account for approximately 40% of global net primary productivity. Water is fundamental to the biophysical processes that sustain ecosystem function and food production, particularly in drylands where a tight coupling exists between ecosystem productivity, surface energy balance, biogeochemical cycles, and water resource availability. Currently, drylands support at least 2 billion people and comprise both natural and managed ecosystems. In this synthesis, we identify some current critical issues in the understanding of dryland systems and discuss how arid and semiarid environments are responding to the changes in climate and land use. The issues range from societal aspects such as rapid population growth, the resulting food and water security, and development issues, to natural aspects such as ecohydrological consequences of bush encroachment and the causes of desertification. To improve current understanding and inform upon the needed research efforts to address these critical issues, we identify some recent technical advances in terms of monitoring dryland water dynamics, water budget and vegetation water use, with a focus on the use of stable isotopes and remote sensing. These technological advances provide new tools that assist in addressing critical issues in dryland ecohydrology under climate change
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