1,293 research outputs found

    RELATIVE CROSS TRACK ERROR CALCULATIONS IN ASABE/ISO 12188-2:2012 AND POWER/ENERGY ANALYSIS USING A 20 HP TRACTOR ON A FULLY ELECTRIC DRIVETRAIN

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    ASABE/ISO Standard 12188-2 provides test procedures for positioning and guidance systems in agricultural vehicles during straight and level travel. The standard provides excellent descriptions of test procedures, however it does not provide detail on methods to carry out the calculations necessary to calculate relative cross-track error (XTE), which is the primary measurement used to judge accuracy of the system. The standard was used to estimate the guidance accuracy of a relatively low-accuracy vehicle at 1.25 and 0.5 m s-1. At 1.25 m s-1, a nearest point calculation overestimated mean XTE by 0.8 cm, or 8.2%. The location sampling density was much higher with a 0.5 m s-1 travel speed, and mean XTE was only overestimated by 0.1 cm with the nearest point method. Power and energy data were recorded using a sled with a known weight to vary the drawbar force on asphalt. This will allow a comparison between the electric and conventional tractor over a range of forces applicable to a 20 HP tractor. The electric tractor was found to consume less than half the energy compared to a Kubota L5030 in a common configuration and a custom configuration to match the weight distribution of the electric tractor. Finger weeding tasks were recorded throughout the year capturing the duration and frequency of these tasks at the University of Kentucky (UK) consumer supported agriculture (CSA) farm. Power and energy data were recorded from the electric tractor while finger weeding. Diesel consumption was also recorded from a conventional tractor while finger weeding. Field data shows that the electric tractor needs approximately 0.532 kWh of energy while a conventional tractor requires approximately 1.258 kWh or energy to finger weed each row of vegetables. Conventional electric bills were compiled for the University of Kentucky CSA establishing an average monthly electric need. Historic NREL data was compiled establishing an average potential solar resource for central Kentucky. It was determined that a 15 kW photovoltaic array could meet the conventional electric needs of the UK CSA and supply the net energy allowing the electric tractor to meet the finger weeding need

    INVASION DYNAMICS OF THE EXOTIC LIANA \u3cem\u3eEUONYMUS FORTUNEI\u3c/em\u3e (TURCZ.) HAND.-MAZZ. (WINTERCREEPER)

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    Elevated atmospheric CO2 has been implicated as a driver of increased liana abundance worldwide. Known as disturbance creators and beneficiaries, lianas possess the potential to significantly influence forest ecosystems. I investigated the early-invasion dynamics of Euonymus fortunei (wintercreeper), an evergreen liana that is invading forests in eastern North America, disrupting native plant communities and ecosystem functions. Wintercreeper is widely cultivated as an ornamental groundcover, frequently invading natural areas via asexual stem growth. Invasion of remote natural areas is dependent upon seed transport and may occur less frequently. I examined the mechanisms of seed dormancy by conducting a ‘move-along’ experiment using fresh and after-ripened seeds. Additionally, I sought to characterize the nature of seed dispersal by birds by deploying seed traps within an invaded forest in central Kentucky. Wintercreeper seeds displayed conditional nondeep physiological dormancy. Although germination occurs at high velocity following cold stratification, a cold period was only facultative to break dormancy. While fresh seeds had greater germination rates (98.6%) compared to after-ripened seeds (85.7%), after-ripened seeds experienced earlier germination (41 days across all treatments). My findings also indicate that bird-mediated seed dispersal occurs throughout the winter from seeds that after-ripen on maternal liana phanerophytes. Overall, these data suggest wintercreeper seeds are capable of dispersing and recruiting in areas with mild to non-existent winters. The invasion of natural areas by exotic invaders is regulated by biotic and abiotic processes, which influence the invader’s success or failure. I studied the vegetation and soil effects of paired invaded (INV), uninvaded (NAT), and ‘restored’ (RES) sites on the germination and survival of wintercreeper seeds and seedlings. The effect of aril (with vs. without) was also tested, both in the field and in vitro. In the field, total germination and first year survival were 55.6% and 24.2%, respectively, across treatments. Total germination was unaffected by treatments, yet vegetation (P = 0.0016) and aril (P = 0.001) treatments significantly influenced germination rates over time, including delayed germination of seeds with arils. The proportion of germinated seedlings that survived was significantly different based on vegetation (P = 0.054) and aril (P = 0.071) treatments after the first winter of growth, but not prior to the first winter. The proportion of seedling survival was significantly lower among seeds dispersed with an aril and seeds sown within INV treatments; there were no interactive effects. Finally, I examined how seedling density and growth habit (horizontal vs. vertical) influenced plant survival, growth, and allometry. I also tested extractable soil C, N, P, K, Ca, and Mg prior to planting and after 17 months of soil conditioning. I found evidence that increased planting density negatively influenced growth among individual plants (lower survival, basal diameter, shoot mass, root mass). At the plot level, high-density plantings yielded greater stem length, and shoot, root, and combined biomass, indicating positive frequency dependence for this species. Soil analyses indicated C, N, P, Ca, and Mg significantly increased (P \u3c 0.05) over the course of the experiment. I conclude that in wintercreeper, prominent asexual propagation leads to aggregate populations whose total contributions to above- and belowground biomass are positively correlated with density, even though individual plant fitness is not. Altogether, this work provides insight into how wintercreeper invasions occur at broad and fine scales. This information will provide a foundation for future wintercreeper studies and aid land managers in their prevention and control strategies

    Empowerment and ownership in effective internationalisation of the higher education curriculum

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    Internationalising the curriculum (IOC) in order to produce graduates with global citizenship skills is a common strategic goal in modern higher education. The extent to which this is achieved and the level of understanding amongst staff and students of what IOC involves and the benefits it imparts are varied. In this study, activities and attitudes across 15 subject disciplines delivered in a modern UK university were surveyed through an analysis of official course documentation, and semi-structured interviews with a range of academic staff. The outcomes are discussed in relation to the level of understanding and ownership that staff have of IOC. Through the modification of a process control model Barnett (European Journal of Education, 29(2), 165–179, 1994), suggestions are made as to how to move this top-down strategic imperative forward through empowerment of the academic staff involved in course delivery

    The mental status of 1090 heroin addicts at entry into treatment: should depression be considered a 'dual diagnosis'?

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    <p>Abstract</p> <p>Background</p> <p>Mental symptoms are common in heroin addiction and may arise from issues of addiction and withdrawal, raising doubts about the patients truly having co-morbid psychiatric diagnoses.</p> <p>Methods</p> <p>We studied the mental status of 1090 heroin addicts (831 males and 259 females aged between 16 and 51 years) at the beginning of treatment, and its relationship to relevant demographic and clinical data through the use of standardised instruments.</p> <p>Results</p> <p>A total of 506 (46.42%) heroin addicts showed depressive-anxious symptomatology, 421 (38.62%) had psychomotor excitement and 163 (14.95%) demonstrated a psychotic state. Patients with depressive-anxious symptomatology on the whole had a less severe addictive illness compared to those demonstrating excited and psychotic symptoms. The presence of depressive-anxious features was felt to not necessarily be indicative of the presence of a dual diagnosis.</p> <p>Conclusion</p> <p>The presence of depressive-anxious symptomatology in the clinical presentation in heroin addicts appears to be unrelated to 'dual diagnosis'.</p

    Methods for Calculating Relative Cross-Track Error for ASABE/ISO Standard 12188-2 from Discrete Measurements

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    ASABE/ISO Standard 12188-2 provides test procedures for positioning and guidance systems in agricultural vehicles during straight and level travel. While the standard provides excellent descriptions of test procedures, it does not provide detail on methods to carry out the calculations necessary to calculate relative cross-track error (XTE), which is the primary error statistic used to judge accuracy. Given the travel speed and sampling constraints provided by the standard, the difference between a method based on nearest points or one based on path interpolation could hypothetically be as large as 25 cm. In this project, the standard was used to estimate the guidance accuracy of a relatively low-accuracy vehicle at 1.25 and 0.5 m s-1. At 1.25 m s-1, a basic nearest point calculation overestimated mean XTE by 0.8 cm, or 8.2%. The location sampling density was much higher with a 0.5 m s-1 travel speed, and mean XTE was only overestimated by 0.1 cm with the nearest point method. There are clearly situations where the calculation method will affect results, and the use of the more complicated methods explained in this article are suggested when using this standard

    Where should I study? : international students’ perceptions of higher education in the UK, Ireland, and the U.S.

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    In the thesis I examine international student decision-making arguing that there is a gap in knowledge about the theoretical frameworks which have been applied to understanding this issue. A comprehensive review of the literature showed that thus far the foremost theory utilised for explaining international student decision-making is the Push-Pull Theory of Migration, a theory which is primarily quantitative. This research innovatively uses a theoretical framework combining three influential capital theories based on a qualitative methodology. Using this theoretical framework, I sought a deeper, and potentially new and different understanding of why international students choose to study abroad and why they select particular host countries – the two questions traditional Push-Pull Theory seeks to answer. The three capital theories used are Human, Cultural and Social Capital. Using these to understand the decision-making of international students begins with the premise that individuals invest in international education in the hope of achieving some aim or reaping some benefit. As these theories originate from two different disciplines, I argue that such an approach provides a more multifaceted perspective for understanding students’ decision-making. Each of these theories, including their strengths and weaknesses, is discussed in detail in the thesis. The context for the study is provided through an examination of the impact of globalisation and neo-liberalism on the political, economic, socio-cultural, and technological trends of recent decades. It also considers the growing internationalisation and marketisation of higher education, including a greater emphasis on and expansion of international student recruitment and mobility. The research notes that individuals are increasingly responsible for their own success in the global knowledge economy. International education is one way in which students can make themselves competitive in the labour market as well as obtain valuable socio-cultural benefits. The research emphasises that higher education is becoming a privately rather than publicly-funded activity in which individual students (and often their families)make the decisions about whether or not to study abroad and where. Host country, source country, and student perspectives are considered. The research focused on international postgraduates originating from five Asian source countries, studying in six disciplines, and enrolled at universities in three different English-speaking host countries. Data on why students decided to study abroad and why they selected their host country was gathered using questionnaires and face-to-face interviews. The student participants in the research were already enrolled in their host universities at the time of data collection thus enabling me to investigate post-enrolment the reasons for their decisions. The combined theoretical framework was used to analyse and categorise the data based on whether students’ answers referred primarily to human, cultural or social capital. The analysis revealed that for each form of capital, the decisions made by these students were based on both the capital they possessed and had access to prior to international study (existing capital) and the capital they hoped to gain from going abroad (potential capital). Existing and potential capital were broken down further into relevant themes and sub-themes. The analyses also showed that human capital factors were most influential, followed by cultural capital and then social capital factors. In addition there was significant overlap among the forms of capital. Finally, the implications and limitations of the research are considered along with recommendations for further research

    Efficacy of an intensive outpatient rehabilitation program in alcoholism: Predictors of outcome 6 months after treatment

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    Treatment of alcohol-dependent patients was primarily focused on inpatient settings in the past decades. The efficacy of these treatment programs has been evaluated in several studies and proven to be sufficient. However, with regard to the increasing costs in public healthcare systems, questions about alternative treatment strategies have been raised. Meanwhile, there is growing evidence that outpatient treatment might be comparably effective as inpatient treatment, at least for subgroups of alcohol dependents. On that background, the present study aimed to evaluate the efficacy of a high-structured outpatient treatment program in 103 alcohol-dependent patients. 74 patients (72%) terminated the outpatient treatment regularly. At 6 months' follow-up, 95% patients were successfully located and personally re-interviewed. Analyses revealed that 65 patients (64%) were abstinent at the 6-month follow-up evaluation and 37 patients ( 36%) were judged to be non-abstinent. Pretreatment variables which were found to have a negative impact (non-abstinence) on the 6-month outcome after treatment were a higher severity of alcohol dependence measured by a longer duration of alcohol dependence, a higher number of prior treatments and a stronger alcohol craving (measured by the Obsessive Compulsive Drinking Scale). Further patients with a higher degree of psychopathology measured by the Beck Depression Inventory (depression) and State-Trait Anxiety Inventory (anxiety) relapsed more often. In summary, results of this study indicate a favorable outcome of socially stable alcohol-dependent patients and patients with a lower degree of depression, anxiety and craving in an intensive outpatient rehabilitation program

    Naltrexone and combined behavioral intervention effects on trajectories of drinking in the COMBINE study

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    Objective—COMBINE is the largest study of pharmacotherapy for alcoholism in the United States to date, designed to answer questions about the benefits of combining behavioral and pharmacological interventions. Trajectory-based analyses of daily drinking data allowed identification of distinct drinking trajectories in smaller studies and demonstrated significant naltrexone effects even when primary analyses on summary drinking measures were unsuccessful. The objective of this study was to replicate and refine trajectory estimation and to assess effects of naltrexone, acamprosate and therapy on the probabilities of following particular trajectories in COMBINE. It was hypothesized that different treatments may affect different trajectories of drinking. Methods—We conducted exploratory analyses of daily indicators of any drinking and heavy drinking using a trajectory-based approach and assessed trajectory membership probabilities and odds ratios for treatment effects. Results—We replicated the trajectories (“abstainer”, “sporadic drinker”, “consistent drinker”) established previously in smaller studies. However, greater numbers of trajectories better described the heterogeneity of drinking over time. Naltrexone reduced the chance to follow a “nearly daily” trajectory and Combined Behavioral Intervention (CBI) reduced the chance to be in an “increasing to nearly daily” trajectory of any drinking. The combination of naltrexone and CBI increased the probability of membership in a trajectory in which the frequency of any drinking declined over time. Trajectory membership was associated with different patterns of treatment compliance. Conclusion—The trajectory-analyses identified specific patterns of drinking that were differentially influenced by each treatment and provided support for hypotheses about the mechanisms by which these treatments work
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