4,317 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

    Extended scope of nursing practice: a multicentre randomised controlled trial of appropriately trained nurses and pre-registration house officers in pre-operative assessment in elective general surgery

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    Aim/ Principal Research Question:1) To determine whether pre-operative assessment carried out by an appropriately trained nurse (ATN) is equivalent in quality to that carried out by a pre-registration house officer (PRHO).2) To assess whether pre-assessments carried out by ATNs and PRHOs are equivalent in terms of cost.3) To determine whether assessments carried out by ATNs are acceptable to patients.4) To investigate the quality of communication between senior medical staff and ATNs.Factors of Interest:The extended role of appropriately trained nurses and pre-registration house officers in pre-operative assessment in elective general surgery.Methods:The study design was principally a prospective randomised equivalence trial but was accompanied by additional qualitative assessment of patient and staff perceptions, and an economic evaluation.The intervention consisted of a pre-operative assessment carried out by either an ATN or a PRHO. Of the patients who completed the study with a full evaluation, 926 patients were randomised to the PRHO arm of the trial and 948 to the ATN arm. Three ATNs took part in the study, one from each centre, together with a total of 87 PRHOs.Immediately following the initial assessment of a patient by a PRHO or an ATN, one of a number of clinical research fellows, all specialist registrars in anaesthetics, repeated the assessment and recorded it on a study form, together with a list of investigations required. The clinical research fellow then evaluated the competency of the initial assessor by comparing the quality of their assessment with their own. Any deficiencies in ordering of investigations and referral to other specialities were met in order to maximise patient care.Sample groups:All patients attending at one site for assessment prior to general anaesthetic for elective general, vascular, urological or breast surgery were potentially included in the study. Of 1907 patients who were randomised, 1874 completed the study with a full evaluation.The study was carried out at four NHS hospitals, three of which were teaching hospitals, in three NHS Trusts in Southampton, Sheffield and Doncaster.Outcome measures:Three areas of ATN and PRHO performance were judged separately, history taking, examination and ordering of tests, and each was graded into one of four categories, the most important of which was under-assessment, which would possibly have affected peri-operative management. In the case of ordering of tests, it was possible to have both over- and under-assessed a patient on different tests.Findings:The pre-operative assessments carried out by the ATNs were essentially equivalent to those performed by the PRHOs in terms of under-assessment that might possibly have affected peri-operative management, although there was variation between the ATNs in terms of the quality of history taking. This may be related to the low number of patients seen at one study site.PRHOs ordered significantly more unnecessary tests than the ATNs. The substitution of ATNs for PRHOs was calculated to be cost neutral.The results of the qualitative assessment showed that the use of ATNs for pre-operative assessment was acceptable to patients; however, there was no evidence that communication between senior medical staff and those carrying out pre-operative assessments was improved by their introduction.Conclusions:This study demonstrated no reason to inhibit the development of fully nurse-led pre-operative assessment, provided that the nurses are appropriately trained and maintain sufficient workload to retain skills.Implications for Further Research:Further research is needed in the following areas:1) the extent and type of training needed for nurses undertaking the pre-operative assessment role2) the use, costs and benefits of routine pre-operative testing.<br/
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