Can Catfish Aquaculture be Profitable in Farm Ponds?

Extensive channel catfish farming is a means of utilizing farm ponds for aquaculture production for either supplementary income of home use. This involves stocking catfish at sufficiently low densities such that a pond is able to assimilate excess feed and fish wastes without needing supplemental aeration or chemicals to keep water quality from reaching toxic levels. This is "low-tech" aquaculture and requires little producer labor/management inputs. A mathematical model of extensive catfish culture in farm ponds was presented in this paper. This model used data from Kentucky where part-time producers, with a minimum of aquaculture experience and time for pond management, are involved in culturing catfish for retail/live markets. Results of this model showed that the optimal strategy would be to stock fish at densities up to 3,000/ha/yr (1,200/ac/yr). Other results showed that breakeven prices were less than $2.20/kg ($1.00/lb), a popular retail price for whole catfish. Hence, this paper concluded that small-scale aquaculture is both feasible and profitable in farm ponds, provided the producer had access to retail markets for the product.Mathematical programming, catfish, aquaculture, farm ponds, Livestock Production/Industries,

Systems in Legal Education

Until recent years there was but one system of teaching law in the schools. It was the good old system employed in all the professions of introducing the student to text-books of recognized authority and compelling him to commit their contents to memory, under the guidance of an instructor. As shown by Professor Theodore W. Dwight, it was the method advocated in the Roman law of introducting students to their first knowledge of that remarkable system of jurisprudence. In the earlier days, the work of the instructor was limited to ascertaining that the student had properly memorized the text and to oral explanations. The student\u27s memorizing feat being accomplished, he was admitted to the bar. But because law, like medicine, is not an exact science and a working knowledge of law involves knowledge not only of its rules, but of how those rules are applied, only the preliminary stage of a man\u27s legal education was finished when he passed out of the law school into the ranks of the profession. While the swearing in of a law school graduate placed upon him the imprimatur of the court in form notifying the public that he was competent to practice, it, in fact, was little more than a permission to enter upon the second stage of his education in which he would be given the opportunity to learn the application of the rules of law. Before his admission to the bar, he had been studying law only in the abstract, but afterwards he began a voluntary course of delving into the undigested mass of its original sources,--always more or less at the expense of clients, who were compelled to take the consequences of his lack of knowledge

Real-Time Collision Imminent Steering Using One-Level Nonlinear Model Predictive Control

Automotive active safety features are designed to complement or intervene a human driver's actions in safety critical situations. Existing active safety features, such as adaptive cruise control and lane keep assist, are able to exploit the ever growing sensor and computing capabilities of modern automobiles. An emerging feature, collision imminent steering, is designed to perform an evasive lane change to avoid collision if the vehicle believes collision cannot be avoided by braking alone. This is a challenging maneuver, as the expected highway setting is characterized by high speeds, narrow lane restrictions, and hard safety constraints. To perform such a maneuver, the vehicle may be required to operate at the nonlinear dynamics limits, necessitating advanced control strategies to enforce safety and drivability constraints. This dissertation presents a one-level nonlinear model predictive controller formulation to perform a collision imminent steering maneuver in a highway setting at high speeds, with direct consideration of safety criteria in the highway environment and the nonlinearities characteristic of such a potentially aggressive maneuver. The controller is cognizant of highway sizing constraints, vehicle handling capability and stability limits, and time latency when calculating the control action. In simulated testing, it is shown the controller can avoid collision by conducting a lane change in roughly half the distance required to avoid collision by braking alone. In preliminary vehicle testing, it is shown the control formulation is compatible with the existing perception pipeline, and prescribed control action can safely perform a lane change at low speed. Further, the controller must be suitable for real-time implementation and compatible with expected automotive control architecture. Collision imminent steering, and more broadly collision avoidance, control is a computationally challenging problem. At highway speeds, the required time for action is on the order of hundreds of milliseconds, requiring a control formulation capable of operating at tens of Hertz. To this extent, this dissertation investigates the computational expense of such a controller, and presents a framework for designing real-time compatible nonlinear model predictive controllers. Specifically, methods for numerically simulating the predicted vehicle response and response sensitivities are compared, their cross interaction with trajectory optimization strategy are considered, and the resulting mapping to a parallel computing hardware architecture is investigated. The framework systematically evaluates the underlying numerical optimization problem for bottlenecks, from which it provides alternative solutions strategies to achieve real-time performance. As applied to the baseline collision imminent steering controller, the procedure results in an approximate three order of magnitude reduction in compute wall time, supporting real-time performance and enabling preliminary testing on automotive grade hardware.PHDMechanical EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/163063/1/jbwurts_1.pd

Mongolian National Parks: Competing Interests and Institutional Viability in a Still Emerging Protected Areas System

In Mongolia, 17% of the total landmass is designated as one of four kinds of “protected areas”—Strictly protected areas, national parks, nature reserves, and natural historical monuments. This study focuses primarily on national parks as a civil institution, through on the ground interviewing of ten individuals employed in the protected areas system, field-notes and observations, and community surveying totaling 38 respondents at two research locations, Hustai-Nuruu National Park and Lake Khovsgol National Park. Protected areas are constructed civil spaces, and as a result are sites of competing societal interests--the interests of scientists and conservationists, of tourism and business interests, and of local (and many times displaced) peoples, to name a few. This study aims to evaluate national parks in Mongolia--existing in their current legal iteration for about two decades--from the angle of institutional efficacy, the balancing of tourism and conservation interests, and the compensation for losses to national park buffer zone communities. Included with surveying of park operations, successes, challenges and goals as outlined by interviewees and park management plan publication, potential policy suggestions are made in light of research findings. These include suggestions for future policy in each park pertaining to issues of climate change, illegal grazing, buffer zone development, and conservation regulations for tourists--including campsite, boating, and transportation development suggestions

Seen at the Jameson Trial

The great State Trial was on. The witnesses for the Crown had willingly or unwillingly told with fatal certainty the story of Jameson\u27s raid from organization to defeat. The relentlessly exact reports of the testimony had frayed the cloak of chivalry which public opinion had hung upon the shoulders of the accused, and the suspicion was gaining ground that the raid was a bold stroke for wealth planned and carried out in detail by selfishness and greed. The Boer witnesses nightly proclaimed the wrongs of the Transvaal in the smoking-rooms of the hotels. They openly asserted their belief that Jameson and his officers could not be convicted in an English court. Their distrust provoked them, and their self-confidence permitted them, to use the boldest language in discussing the situation in mixed gatherings. The Chief of the Transvaal Mounted Police had exclaimed to a company of Englishmen: I hope Jameson will be acquitted! I hope he will be acquitted! Then the Transvaal will abrogate the Convention, and that will mean war with England! And we can defeat any army that England can send against us

Os desajustados: representações do outsider no cinema juvenil brasileiro e norte americano

Desde a década de 1950, os filmes juvenis figuram como um rentável e versátil ramo da indústria de Hollywood. Sob a forma de diversos subgêneros, esta tradição cinematográfica segue em expansão no início deste milênio. No Brasil, os títulos que retratam os prazeres e os conflitos vividos pela juventude contemporânea também proliferam, revelando maior apelo comercial e variedade temática. Entre os personagens típicos de tais produções, o outsider se destaca por seu posicionamento à margem da interação social com outros jovens, sua identificação com culturas alternativas e, amiúde, seu questionamento do status quo. O objetivo deste trabalho é definir conceitualmente esta figura emblemática (suas idiossincrasias, peculiaridades e inserção na sociedade pós-moderna) e analisar suas manifestações no meio audiovisual, a partir de distintas representações em filmes brasileiros e norte-americanos lançados comercialmente entre 2001 e 2007. O estudo destes temas pouco tratados no país – o cinema juvenil e o outsider – é aprofundado através de um panorama histórico do gênero cinematográfico no Brasil e nos Estados Unidos, uma análise do uso de estereótipos nas narrativas adolescentes e uma reflexão acerca do posicionamento do jovem no circuito de consumo da sociedade contemporânea

As leis de Kepler e a gravitação universal no Ensino Médio

Apresenta propostas de aulas que tratam das leis de Kepler e gravitação universal com a intenção de levar o aluno a compreender com mais clareza o que acontece em nosso sistema solar. A primeira parte deste trabalho tem como ponto de partida um questionário com perguntas básicas dos assuntos relacionados e a análise das respostas nos permitem fazer um trabalho, baseado em conhecimentos adquiridos anteriormente. Este trabalho procura não só apresentar as teorias como algumas noções de tamanho e distância do sistema solar, com expefl6ncias praticas e fáceis de fazer, sem esquecer de abordar noções de física moderna que geralmente são omitidas nos livros de segundo grau, corno a teoria da relatividade de Einstein. A segunda parte deste trabalho dedica-se a definições de alguns conceitos básicos relacionados com as Leis de Kepler e a Gravitação. A terceira parte do trabalho se refere ao estudo da física moderna; nesta seção vamos descrever diversos conceitos de relatividade geral, bem como algumas das suas aplicações. Finalmente apresentamos as conclusões deste trabalho, fazendo uma discussão dos temas abordados de uma forma incentivadora e informativa não só para a vida escolar do aluno e sim para o seu dia a dia

Preferences for Working in Rural Clinics among Trainee Health Professionals in Uganda: A Discrete Choice Experiment

Background: Health facilities require teams of health workers with complementary skills and responsibilities to efficiently provide quality care. In low-income countries, failure to attract and retain health workers in rural areas reduces population access to health services and undermines facility performance, resulting in poor health outcomes. It is important that governments consider health worker preferences in crafting policies to address attraction and retention in underserved areas. Methods We investigated preferences for job characteristics among final year medical, nursing, pharmacy, and laboratory students at select universities in Uganda. Participants were administered a cadre-specific discrete choice experiment that elicited preferences for attributes of potential job postings they were likely to pursue after graduation. Job attributes included salary, facility quality, housing, length of commitment, manager support, training tuition, and dual practice opportunities. Mixed logit models were used to estimate stated preferences for these attributes. Results: Data were collected from 246 medical students, 132 nursing students, 50 pharmacy students and 57 laboratory students. For all student-groups, choice of job posting was strongly influenced by salary, facility quality and manager support, relative to other attributes. For medical and laboratory students, tuition support for future training was also important, while pharmacy students valued opportunities for dual practice. Conclusions: In Uganda, financial and non-financial incentives may be effective in attracting health workers to underserved areas. Our findings contribute to mounting evidence that salary is not the only important factor health workers consider when deciding where to work. Better quality facilities and supportive managers were important to all students. Similarities in preferences for these factors suggest that team-based, facility-level strategies for attracting health workers may be appropriate. Improving facility quality and training managers to be more supportive of facility staff may be particularly cost-effective, as investments are borne once while benefits accrue to a range of health workers at the facility

Flight Demonstration of Novel Atmospheric Satellite Concept

The major focus of the Phase II effort described herein is to develop and demonstrate an aircraft capable of autonomously sailing (i.e., to cruise without propulsion or external assistance), and thereby prove that the dual-aircraft platform (DAP) atmospheric satellite concept is potentially viable. This sailing mode of flight was identified as the number-1 enabling technology required for the stratospheric DAP concept (also known as Stratosat) in the NIAC (NASA Innovative Advanced Concept) Phase I effort. No scientific demonstration of this technology has ever been done or documented to our knowledge. This report describes efforts to take a major step towards the sailing mode of flight capability using a single aircraft connected by cable to a moving ground vehicle which uses sufficient crosswind to cruise without propulsion while "pulling" the ground vehicle forward (i.e., without external assistance). The development of a prototype aircraft is described in terms of novel and key hardware and software elements. A specialized prototype aircraft is described, including a novel cable release mechanism, novel "lateron" control surfaces, and a highly-accurate onboard wind measurement system. Additionally, a novel means to safely connect the aircraft to the moving ground vehicle is described involving a fishing rod/reel and integrated load cell. All of these devices were designed and developed in-house and validated in flight testing. Software is developed to provide look-up tables that give the flight condition targets (i.e., 3-D position relative to ground vehicle, forward speed, aircraft orientation, etc.), based on current wind speed and direction. These tables are successfully validated in flight simulation and used onboard the aircraft. High fidelity analysis of the aircraft aerodynamics are described - required to produce accurate target sailing flight conditions. A novel wind tunnel measurement technique is developed to accurately assess the aerodynamics of the ultra-thin cable. A new specialized flight simulator is described which is utilized to develop and verify the flight software required onboard the aircraft, and to support training of pilots for flying the aircraft while tethered to a ground vehicle. The DAP flight simulator was developed within the Matlab-Simulink framework and included detailed treatment of aircraft/cable aerodynamics, cable dynamics, experimentally-derived propeller-motor thrust curves, actuator responsiveness, and realistic air turbulence. The specialized formation flight controller algorithm, developed using this flight simulator, and onboard the aircraft is described. Finally, a novel auto-tuning software is described and verified within the flight simulator that is shown to refine the sailing flight condition targets during flight using an optimization technique involving doublet maneuvers. Virtual flights using the auto-tuning software indicate that the prototype aircraft should be able to reach and hold sailing conditions despite moderate levels of turbulence provided there is sufficient mean wind available. An overview of the flight testing program is provided. Hundreds of short flights were conducted, primarily using a dead short runway at Deland Municipal Airport which permitted use of a moving ground vehicle. Additional flight tests at Space Floridas Shuttle Landing Facility are also described. First year results from these tests in which the aircraft is controlled manually, demonstrated that excessive flight testing would be required for a pilot to learn to sail with visual cues. However, second year results from autonomous flight these tests included successful demonstration of the closed-loop autonomous formation flight capability (i.e., autonomously determine, reach, and hold the required 3-D location relative to the ground vehicle required for sailing). The next step of using the auto-tune software to autonomously refine the aircraft orientation targets to finally achieve sailing remains the primary goal of future work