Pump thrombosis is the epitome of left ventricular assist device dysfunction for end-stage heart failure patients. With the increased utilization of implantable, long-term, left ventricular assist devices (LVADs), understanding the implications associated with device orientation and interaction with the body is exceedingly important. Components associated with pump thrombosis in the Thoratec© HeartMate II™ (HMII) and the HeartWare© HVAD® devices include the inflow cannula, the outflow graft, and the pump elements as well as pump pocket depth for the HMII specifically. Several studies have been conducted to analyze these interactions with the HMII, however there is minimal to no data available analyzing how the device orientation of the HeartWare HVAD affects hemodynamics and a patient’s risk for developing pump thrombosis. Therefore, the purpose of this pilot study is the simulate the hemodynamic implications associated with Sub-optimal cannula angulation of the HVAD. Using Solidworks 2016 Ed., a simplified, hemo-static model of the left side of the heart was created. Dimensions for the atria, ventricle, and mitral valve were determined through the combination of Trans-Esophageal Echo cardiogram data as well as literature references. Three different inflow cannula angle scenarios were developed including a Control, a Clinically Optimal, and a Sub-optimal. Assumptions included body temperature, no accumulation within the ventricle, and no ejection or contraction. The model consists of static continuous flow set to 5 liters per minute with the assumption that the HeartWare HVAD is completely supporting the left ventricle. The results include both qualitative and quantitative data. Flow trajectory plots for each cannula scenario depict the hemodynamic flow patterns for different time points. Results show visible changes in the Sub-optimal orientation when compared to both the Control and the Clinically Optimal scenario. Additionally, it was determined that there were no statistically significant differences in the velocity vectors for any of the scenarios however, the shear stress values were determined to be significantly different for all time points, p < 0.001 for all scenarios when compared to Control. Though there are several limitations of this study, with sub-optimal inflow cannula angulation, there is a potential increased risk of hemolysis due to increased shear stress.

This study explores the use of early warning scores (EWS) in deteriorating patients. These are widely used tools to measure vital signs and highlight abnormal physiology in acutely unwell patients. Measurements of the process in the management of the deteriorating patient includes time to first assessment of such patients. The level of clinician involved in the subsequent management is also investigated to determine whether escalation of care was appropriate. This work is a retrospective case note analysis of the recognition and management of deteriorating patients prior to critical care admission. Research Questions 1. What violations in the optimum process are associated with sub-optimal recognition and management of deteriorating patients and delayed critical care admission in patients triggering early warning scores in acute care wards? 2. Are there independent variables which can predict the delay in the recognition and management of deteriorating patients and subsequent critical care admission? Methods The literature was reviewed to determine the optimum process of recognition and management of deteriorating patients in acute care wards. A data collection tool was then specifically designed and locally validated to extract objective data from the case records. A sample of 157 patients admitted to critical care from acute wards over a 6 month period were included in the study. The case records were then retrospectively reviewed and information was extracted using the data collection tool. Results The accuracy and frequency of early warning scores were measured and findings demonstrated that 59% of Early Warning Scores (EWS) were miscalculated. The most frequent of those miscalculated were the intermediate scores (4 or 5) (error rate - 52%) followed by the higher scores (6 or more) (error rate - 32%). The least frequently miscalculated were the lower scores (0 -3) (error rate 15%). Descriptive data from the sample such as age, ward, diagnosis, time of hospital admission, time and day of transfer / EWS triggering were included. From the total case records reviewed, 110 patients had abnormal Early Warning Scores (4 or more) and were included in the inferential data analysis. The independent variables related to the processes objectively measurable in the recognition and management of deteriorating patients were included. After descriptive analysis the independent variables were cross-tabulated with the dependent variable using Pearson chi-square. The dependent variable was identified from the literature. This was whether time from triggering an abnormal EWS to critical care admission was delayed more than 6 hours. The subsequent predictor variables were then entered in to a binary logistic regression model for statistical analysis using SPSS version 21 software. Binominal Logistic Regression Analysis identified three significant variables predicting delay of the recognition and management of deteriorating patients. • Frequency of EWS measurement not increased appropriately • Length of stay prior to critical care admission 12-36 hours • If no consultant review during 6 hours of abnormal EWS Implications for Future Practice This study highlights areas of risk in the detection of patients’ clinical deterioration in acute wards. These findings should guide quality improvement to prevent unnecessary morbidity and mortality. As a key area of patient risk included the lack of frequency and accuracy of EWS measurements, staff education is required to ensure staff are given the appropriate knowledge to understand the use of the tool. Regular review of the frequency of measurement is also required as this was statistically significant in the delay to critical care admission. The high risk time from admission of 12-36 hours needs further investigation. This study also highlights the need for senior decision makers to be involved in the care of deteriorating patients to improve outcomes.

Detection of sub-optimal effort is a critical element of all psychological assessment procedures. Failure to consider the validity of the client's performance and symptom reporting may result in inaccurate conclusions about the degree of impairment. Because the American with Disabilities Act requires colleges to provide accommodations for students with documented disabilities, providing resources for students feigning impairment may ultimately drain university resources intended to help those students with disabilities. This study sought to examine the relationship between two different types of measures of effort and variables related to academic ability. De-identified archival data was gathered from the University Accessibility Center (UAC) at Brigham Young University (BYU) which provided psychological assessments for accommodation seeking students (N = 602) for a reduced fee. Measures used to detect sub-optimal effort included the Test of Memory Malingering (TOMM), Word Memory Test (WMT), Validity Indicator Profile (VIP), California Verbal Learning Test-Second Edition (CVLT-II), Reliable Digit Span (RDS), and the Integrated Visual and Auditory Continuous Performance Advanced Edition (IVA-AE). Measures indicating academic ability included select subtests from the Woodcock Johnson Test of Achievement Third Edition (WJ-III). Additionally, Matrix Reasoning of the Wechsler Adult Intelligence Scale Fourth Edition (WAIS-IV) was included as a cognitive measure of nonverbal IQ. Two point biserial correlations were conducted. Results indicated that the nonverbal portion of the VIP had a significant relationship with writing fluency. The TOMM also had a significant relationship with writing fluency. Additionally, results demonstrated that Reliable Digit Span had a significant relationship with Academic Fluency, Writing Fluency, Letter Word Identification, and Math Fluency. Data suggests that university disability service offices may wish to include the RDS, TOMM, and VIP in their considerations of effort.

The content of this dissertation consists of three parts. In the first part, optimal control strategies are developed for Unified Power Flow Controller (UPFC) following the clearance of fault conditions. UPFC is one of the most versatile Flexible AC Transmission devices (FACTs) that have been implemented thus far. The optimal control scheme is composed of two parts. The first is an optimal stabilization control, which is an open-loop ‘Bang’ type of control. The second is an suboptimal damping control, which consists of segments of ‘Bang’ type control with switching functions the same as those of a corresponding approximate linear system. Simulation results show that the proposed control strategy is very effective in maintaining stability and damping out transient oscillations following the clearance of the fault. In the second part, a new power market structure is proposed. The new structure is based on a two-level optimization formulation of the market. It is shown that the proposed market structure can easily find the optimal solutions for the market while takeing factors such as demand elasticity into account. In the last part, a mathematical programming problem is formulated to obtain the maximum value of the loadibility factor, while the power system is constrained by steady-state dynamic security constraints. An iterative solution procedure is proposed for the problem, and the solution gives a slightly conservative estimate of the loadibility limit for the generation and transmission system.

Ultra-wide Band (UWB) has sparked a lot of interest lately from the industry and academia. The growing capacity of the wireless industry is requires a new communication system that satisfies the high data rate which does not interfere with existing RF systems. UWB promises to be this new technology. UWB also promises low power, low cost and flexibility. The UWB Channel opens up a huge new wireless channel with Giga Hertz Capacities as well as the highest spatial capacities measured in bits per hertz per square meter. When properly implemented UWB channel can share spectrum with traditional radio systems without causing harmful interference. In this thesis we studied and compared several reduced complexity sub-optimal Ultra-Wide Band receivers. These receivers include auto correlation receiver, the square value detector and the absolute value detector are studied. We consider OOK and PPM modulation schemes. We examine these schemes and the receivers on Gaussian and UWB indoor channels. We compare the performance with optimal receivers. A transmitter receiver system using 0.1us pulses implemented using existing hardware. A packet consisting of 24 bits were transmitted and the received signal could be verified in real time using a vector signal analyzer. The results show sub-optimal receivers provide a better trade off between robust, complexity and performance.

No description available.

Title: Sub-optimal algorithms for solving sliding puzzles Author: Petr Michalík Department: Department of Theoretical Computer Science and Mathematical Logic Supervisor: RNDr. Pavel Surynek, Ph.D. Supervisor's e-mail address: Pavel.Surynek@mff.cuni.cz In the present work techniques for solving the so-called sliding tiles puzzles, which generate optimal or sub-optimal solution, are studied. This thesis focuses especially on a specific variant of the puzzle: the (n^2-1)-puzzle. This work shows and compares current methods for solving this type of problem. A choosen method is a subject to a close analysis of complexity and is also implemented so that theoretical and experimental results could be confronted. An alternative sub-optimal algorithm is proposed and its theoretical analysis is presented. This algorithm is implemented as well and is compared with the existing algorithm. Both the theoretical analysis and the test results show that better (shorter) solutions can often be obtained using this alternative algorithm.

There is a considerable scope for improving the temperature control of exothermic processes. In this thesis, a sub-optimal control strategy is developed through utilizing the dynamic, simulation tool. This scheme is built around easily obtained knowledge of the system and still retains flexibility. It can be applied to both exothermic batch and fed-batch processes. It consists of servo and regulatory modes, where a Generalized Predictive Controller (GPC) was used to provide self-tuning facilities. The methods outlined allow for limited thermal runaway whilst keeping some spare cooling capacity to ensure that operation at constraints are not violated. A special feature of the method proposed is that switching temperatures and temperature profiles can be readily found from plant trials whilst the addition rate profile Is capable of fairly straightforward computation. The work shows that It is unnecessary to demand stability for the whole of the exothermic reaction cycle, permitting a small runaway has resulted in a fast temperature response within the given safety margin. The Idea was employed for an exothermic single Irreversible reaction and also to a set of complex reactions. Both are carried out in a vessel with a heating/cooling coil. Two constraints are Imposed; (1) limited heat transfer area, and (11) a maximum allowable reaction temperature Tmax. The non-minimum phase problem can be considered as one of the difficulties in managing exothermic fed-batch process when cold reactant Is added to vessel at the maximum operating temperature. The control system coped with this within limits, a not unexpected result. In all cases, the new strategy out-performed the conventional controller and produced smoother variations in the manipulated variable. The simulation results showed that batch to batch variations and disturbances In cooling were successfully handled. GPC worked well but can be susceptible to measurement noise.

There is a considerable scope for improving the temperature control of exothermic processes. In this thesis, a sub-optimal control strategy is developed through utilizing the dynamic, simulation tool. This scheme is built around easily obtained knowledge of the system and still retains flexibility. It can be applied to both exothermic batch and fed-batch processes. It consists of servo and regulatory modes, where a Generalized Predictive Controller (GPC) was used to provide self-tuning facilities. The methods outlined allow for limited thermal runaway whilst keeping some spare cooling capacity to ensure that operation at constraints are not violated. A special feature of the method proposed is that switching temperatures and temperature profiles can be readily found from plant trials whilst the addition rate profile Is capable of fairly straightforward computation. The work shows that It is unnecessary to demand stability for the whole of the exothermic reaction cycle, permitting a small runaway has resulted in a fast temperature response within the given safety margin. The Idea was employed for an exothermic single Irreversible reaction and also to a set of complex reactions. Both are carried out in a vessel with a heating/cooling coil. Two constraints are Imposed; (1) limited heat transfer area, and (11) a maximum allowable reaction temperature Tmax. The non-minimum phase problem can be considered as one of the difficulties in managing exothermic fed-batch process when cold reactant Is added to vessel at the maximum operating temperature. The control system coped with this within limits, a not unexpected result. In all cases, the new strategy out-performed the conventional controller and produced smoother variations in the manipulated variable. The simulation results showed that batch to batch variations and disturbances In cooling were successfully handled. GPC worked well but can be susceptible to measurement noise. / Higher Education Ministry and Scientific Research

This research project explores the contribution of prenatal stress to the pathogenesis of autism as a neurobiological developmental disorder. The neurobiological impact of stress prior to the 28th week of gestation might produce structural neural changes, specifically regarding the cerebellum, the brain stem and limbic pathways, including the hippocampal area, which concept relates closely to the pathogenesis of autism. In this research project a significant focus is placed on prenatal hipothalamic-pituary-adrenal (HPA) activity due to the HPA axis’ interactivity with cortisol, digoxin and serotonin, as these biochemicals are significantly implicated in programmed foetal development, postnatal cortical behaviour, postnatal learning, as well as in functional impairment of socialization, communication and imagery associated with autism. Based upon the rationale of this research project and the conceptualisation of the topic of interest, the research problem was formulated as follows: In what unique ways does prenatal stress contribute to the pathogenesis of autism as a neurobiological developmental disorder? Sub questions included: Did the mother of the dizygotic twins experience significant stress during the period of gestation? What structural brain differences can be observed among the dizygotic twins at hand of MR-imaging? To which periods of prenatal development can these structural differences be related? How do these differences account for sensory, motor, cognitive, and affective behavioural differences among the dizygotic twins? What plasma differences can be observed among the dizygotic twins at hand of blood sampling? How does elevation of pre- and postnatal glucocorticoids relate to plasma difference among the dizygotic twins? How do these plasma differences account for sensory, motor, cognitive, and affective behavioural differences among the dizygotic twins? This research project represents quantitative research. The mode of inquiry is non-experimental at hand of a single dizygotic twin study. The following data generating strategies were employed: clinical intake interviews, administration of a diagnostic stress inventory and the 16-PF Questionnaire, MR-imaging, and the collection of blood plasma pathology results. / Dissertation (M.Ed)--University of Pretoria, 2006. / Educational Psychology / unrestricted