1,928 research outputs found

    Departmental Review: Department of Agricultural Education

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    1. Schedule for Review of Departmental Program 2. Overview of Agricultural Education Department: Functions; Budgets; Where Ag. Ed. Graduates Go; Advisory Council 3. University Administration: UN-L Organization Chart; IANR Administrative Chart 4. Agricultural Education Faculty: Staff and Assignments; Appointments, status and experience; Professional Activities during last two calendar years 5. Instructional Program: Teaching &Advisement; mEnrollment History; Undergraduate Curriculum; Graduate Program; Departmental Self Survey 6. Research and Writing: Project Descriptions; Accomplishments; Planned Objectives; Recent Publications 7. Extension Activities 8. Special Programs: In-Service Education; Curriculum Modification Project 9. Future Directions: Instructional; Research; Extension; Continuing/In-Servic

    AC transmission system planning choosing lines from a discrete set

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    Transmission system planning (TSP) is a difficult nonlinear optimization problem involving non-convex quadratic terms, as well as discrete variables. We extend prior results for linear relaxations, drawing on a preliminary notional model of the power grid for the State of Florida. Realistic line choices necessitate a binary formulation, which is at the same time substantially more expensive than the mixed-integer counterpart and more accurate. In many cases, our relaxation directly generates a feasible solution; where it does not, we apply a practical load-deflation heuristic to recover strong solutions.United States. Office of Naval Research (Grant N00014-02-1-0623

    Sharp Phase Change in Shape Memory Alloy Thermal Actuators for Subsea Flow Control

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    Gas-lifted oil wells are susceptible to failure through malfunction of gas lift valves (GLV). One failure mode occurs when the GLV check valve fails and product passes into the well annulus, potentially reaching the wellhead. This is a growing concern as offshore wells are drilled thousands of meters below the ocean floor in extreme temperature and pressure conditions and repair and monitoring become difficult. The authors have previously developed a thermally-actuated safety valve to prevent product backflow into the annulus in the event of check valve failure. The safety valve uses shape memory alloy (SMA) wires to translate a temperature change into a displacement and, based on commercially available SMA wire material properties, requires a 6°C temperature change to fully actuate. In some wells, however, check valve failure may result in less than 6°C temperature change. In this paper a new concept is developed to sharpen the austenitic phase change in SMA actuators. The concept has broad practical implications because it will allow thermally-activated devices, such as fluid control valves, to become much more precise, i.e., translating a small temperature change into a large displacement. The new concept uses the fact that SMA transition temperatures are stress dependent. By specifically controlling stress in the wire, the temperature difference required for austenitic transition can be decreased. This is achieved with a negative-differential spring — a spring that exerts a decreasing amount of force as it is displaced. The concept is tested experimentally by conductively and electrically heating SMA wires connected to a negative-differential spring. Results show a 2.9°C-5°C reductions, respectively, in the temperature difference required for austenitic transition.Chevron Corporation (MIT-Chevron University Partnership Program

    Failure Mode and Sensitivity Analysis of Gas Lift Valves

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    Gas-lifted oil wells are susceptible to failure through malfunction of gas lift valves. This is a growing concern as offshore wells are drilled thousands of meters below the ocean floor in extreme temperature and pressure conditions and repair and monitoring become more difficult. Gas lift valves and oil well systems have been modeled but system failure modes are not well understood. In this paper a quasi-steady-state fluid-mechanical model is constructed to study failure modes and sensitivities of a gas-lifted well system including the reservoir, two-phase flow within the tubing, and gas lift valve geometry. A set of three differential algebraic equations of the system is solved to determine the system state. Gas lift valve, two-phase flow, and reservoir models are validated with well and experimental data. Sensitivity analysis is performed on the model and sensitive parameters are identified. Failure modes of the system and parameter values that lead to failure modes are identified using Monte Carlo simulation. In particular, we find that the failure mode of backflow through the gas lift valve with a leaky check valve is sensitive to small variations in several design parameters.Chevron Corporation (MIT-Chevron University Partnership Program

    The differential diagnosis of multiple personality disorder from borderline personality disorder

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    p. 041-046Considerable controversy surrounds the relationship between multiple personality disorder (MPD) and borderline personality disorder (BPD). Some authors argue that MPD is a variant of BPD, and most agree that the differential diagnosis of the two is often very difficult. In this article data are presented from a study comparing historical, demographic and psychological testing variables between the two groups. No statistically significant differences were found between the two groups on these variables. However, certain trends emerged which may serve as a catalyst for further research. The relationship between the disorders may be complex; clinicians may need to use more sophisticated research techniques and develop more sensitive diagnostic criteria before it is understood

    The relationship between Hippocampal asymmetry and working memory processing in combat-related PTSD: a monozygotic twin study

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    BACKGROUND: PTSD is associated with reduction in hippocampal volume and abnormalities in hippocampal function. Hippocampal asymmetry has received less attention, but potentially could indicate lateralised differences in vulnerability to trauma. The P300 event-related potential component reflects the immediate processing of significant environmental stimuli and has generators in several brain regions including the hippocampus. P300 amplitude is generally reduced in people with PTSD. METHODS: Our study examined hippocampal volume asymmetry and the relationship between hippocampal asymmetry and P300 amplitude in male monozygotic twins discordant for Vietnam combat exposure. Lateralised hippocampal volume and P300 data were obtained from 70 male participants, of whom 12 had PTSD. We were able to compare (1) combat veterans with current PTSD; (2) their non-combat-exposed co-twins; (3) combat veterans without current PTSD and (4) their non-combat-exposed co-twins. RESULTS: There were no significant differences between groups in hippocampal asymmetry. There were no group differences in performance of an auditory oddball target detection task or in P300 amplitude. There was a significant positive correlation between P300 amplitude and the magnitude of hippocampal asymmetry in participants with PTSD. CONCLUSIONS: These findings suggest that greater hippocampal asymmetry in PTSD is associated with a need to allocate more attentional resources when processing significant environmental stimuli.Timothy Hall, Cherrie Galletly, C.R. Clark, Melinda Veltmeyer, Linda J. Metzger, Mark W. Gilbertson, Scott P. Orr, Roger K. Pitman and Alexander McFarlan

    Design of a Thermally-Actuated Gas Lift Safety Valve

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    Gas-lifted oil wells are susceptible to failure through malfunction of gas lift valve assemblies (GLV). One failure mode occurs when the GLV check valve fails and product passes into the well annulus, potentially reaching the wellhead. This is a growing concern as offshore wells are drilled thousands of meters below the ocean floor in extreme temperature and pressure conditions, and repair and monitoring become difficult. Currently no safeguard exists in the GLV to prevent product passage in the event of check valve failure. In this paper a design and operational procedures are proposed for a thermally-actuated positive-locking safety valve to seal the GLV in the event of check valve failure. A thermal model of the well and GLV system is developed and compared to well data to verify feasibility of a thermally-actuated safety valve. A 3× scale prototype safety valve is built and tested under simulated failure scenarios and well start-up scenarios. Realistic well temperatures in the range of 20C to 70C are used. Results demonstrate valve closure in response to simulated check valve failure and valve opening during simulated well start-up

    Karyomegalic interstitial nephritis with a novel FAN1 gene mutation and concurrent ALECT2 amyloidosis

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    Background: Karyomegalic interstitial nephritis (KIN) is a rare hereditary cause of chronic kidney disease. It typically causes progressive renal impairment with haemoproteinuria requiring renal replacement therapy before 50 years of age. It has been associated with mutations in the Fanconi anaemia-associated nuclease 1 (FAN1) gene and has an autosomal recessive pattern of inheritance. Leukocyte chemotactic factor 2 amyloidosis (ALECT2) is the third most common cause of amyloid nephropathy presenting with chronic kidney disease and variable proteinuria. We report a novel mutation in the FAN1 gene causing KIN and to our knowledge, the first case of concurrent KIN and ALECT. / Case presentation: We describe the case of 44 year old Pakistani woman, presenting with stage four non-proteinuric chronic kidney disease, and a brother on dialysis. Renal biopsy demonstrated KIN and concurrent ALECT2. Genetic sequencing identified a novel FAN1 mutation as the cause of her KIN and she is being managed conservatively for chronic kidney disease. Her brother also had KIN with no evidence of amyloidosis and is being worked up for kidney transplantation. / Conclusion: This case highlights two rare causes of chronic kidney disease considered underdiagnosed in the wider population due to their lack of proteinuria, and may contribute to the cohort of patients reaching end stage renal disease without a renal biopsy. We report a novel mutation of the FAN1 gene causing KIN, and report the first case of concurrent KIN and ALECT2. This case highlights the importance of renal biopsy in chronic kidney disease of unclear aetiology which has resulted in a diagnosis with implications for kidney transplantation and family planning

    Ethical considerations for HIV remission clinical research involving participants diagnosed during acute HIV infection

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    HIV remission clinical researchers are increasingly seeking study participants who are diagnosed and treated during acute HIV infection—the brief period between infection and the point when the body creates detectable HIV antibodies. This earliest stage of infection is often marked by flu-like illness and may be an especially tumultuous period of confusion, guilt, anger, and uncertainty. Such experiences may present added ethical challenges for HIV research recruitment, participation, and retention. The purpose of this paper is to identify potential ethical challenges associated with involving acutely diagnosed people living with HIV in remission research and considerations for how to mitigate them. We identify three domains of potential ethical concern for clinicians, researchers, and ethics committee members to consider: 1) Recruitment and informed consent; (2) Transmission risks and partner protection; and (3) Ancillary and continuing care. We discuss each of these domains with the aim of inspiring further work to advance the ethical conduct of HIV remission research. For example, experiences of confusion and uncertainty regarding illness and diagnosis during acute HIV infection may complicate informed consent procedures in studies that seek to recruit directly after diagnosis. To address this, it may be appropriate to use staged re-consent procedures or comprehension assessment. Responsible conduct of research requires a broad understanding of acute HIV infection that encompasses its biomedical, psychological, social, and behavioral dimensions. We argue that the lived experience of acute HIV infection may introduce ethical concerns that researchers and reviewers should address during study design and ethical approval

    Individual patient data meta-analysis of randomized controlled trials of community occupational therapy for stroke patients

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    <p><b>Background and Purpose:</b> Trials of occupational therapy for stroke patients living in the community have varied in their findings. It is unclear why these discrepancies have occurred.</p> <p><b>Methods:</b> Trials were identified from searches of the Cochrane Library and other sources. The primary outcome measure was the Nottingham Extended Activities of Daily Living (NEADL) score at the end of intervention. Secondary outcome measures included the Barthel Index or the Rivermead ADL (Personal ADL), General Health Questionnaire (GHQ), Nottingham Leisure Questionnaire (NLQ), and death. Data were analyzed using linear or logistic regression with a random effect for trial and adjustment for age, gender, baseline dependency, and method of follow-up. Subgroup analyses compared any occupational therapy intervention with control.</p> <p><b>Results:</b> We included 8 single-blind randomized controlled trials incorporating 1143 patients. Occupational therapy was associated with higher NEADL scores at the end of intervention (weighted mean difference [WMD], 1.30 points, 95% confidence intervals [CI], 0.47 to 2.13) and higher leisure scores at the end of intervention (WMD, 1.51 points; 95% CI, 0.24 to 2.79). Occupational therapy emphasizing activities of daily living (ADL) was associated with improved end of intervention NEADL (WMD, 1.61 points; 95% CI, 0.72 to 2.49) and personal activities of daily living (odds ratio [OR], 0.65; 95% CI, 0.46 to 0.91), but not NLQ. Leisure-based occupational therapy improved end of intervention NLQ (WMD, 1.96 points; 95% CI, 0.27 to 3.66) but not NEADL or PADL.</p> <p><b>Conclusions:</b> Community occupational therapy significantly improved personal and extended activities of daily living and leisure activity in patients with stroke. Better outcomes were found with targeted interventions.</p&gt
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