Multi-Maneuver Clohessy-Wiltshire Targeting

Orbital rendezvous involves execution of a sequence of maneuvers by a chaser vehicle to bring the chaser to a desired state relative to a target vehicle while meeting intermediate and final relative constraints. Intermediate and final relative constraints are necessary to meet a multitude of requirements such as to control approach direction, ensure relative position is adequate for operation of space-to-space communication systems and relative sensors, provide fail-safe trajectory features, and provide contingency hold points. The effect of maneuvers on constraints is often coupled, so the maneuvers must be solved for as a set. For example, maneuvers that affect orbital energy change both the chaser's height and downrange position relative to the target vehicle. Rendezvous designers use experience and rules-of-thumb to design a sequence of maneuvers and constraints. A non-iterative method is presented for targeting a rendezvous scenario that includes a sequence of maneuvers and relative constraints. This method is referred to as Multi-Maneuver Clohessy-Wiltshire Targeting (MM_CW_TGT). When a single maneuver is targeted to a single relative position, the classic CW targeting solution is obtained. The MM_CW_TGT method involves manipulation of the CW state transition matrix to form a linear system. As a starting point for forming the algorithm, the effects of a series of impulsive maneuvers on the state are derived. Simple and moderately complex examples are used to demonstrate the pattern of the resulting linear system. The general form of the pattern results in an algorithm for formation of the linear system. The resulting linear system relates the effect of maneuver components and initial conditions on relative constraints specified by the rendezvous designer. Solution of the linear system includes the straight-forward inverse of a square matrix. Inversion of the square matrix is assured if the designer poses a controllable scenario - a scenario where the the constraints can be met by the sequence of maneuvers. Matrices in the linear system are dependent on selection of maneuvers and constraints by the designer, but the matrices are independent of the chaser's initial conditions. For scenarios where the sequence of maneuvers and constraints are fixed, the linear system can be formed and the square matrix inverted prior to real-time operations. Example solutions are presented for several rendezvous scenarios to illustrate the utility of the method. The MM_CW_TGT method has been used during the preliminary design of rendezvous scenarios and is expected to be useful for iterative methods in the generation of an initial guess and corrections

Periodic cruise of a hypersonic cruiser for fuel minimization

Aerospace Engineerin

A Measure of Success in an Alternative Junior High School

This project examined three aspects of the Alternative Junior High School program at Plymouth Christian Youth Center (PCYC), a social service agency in North Minneapolis. One aspect was this program\u27s ability to retain students at risk of dropping-out of the educational system. A second was to examine whether the program increased the academic performance and attendance rates of these students. Finally, aspects of the program that students described as helpful are reported, as well as those that they described as needing improvement. The study compared the academic performance and attendance rates of the students in their last semester of public school to their academic performance and attendance rates in the first semester of school at PCYC. This data was collected from a sample of eight students of the 24 enrolled in the program at PCYC. It indicated that the program at PCYC increased academic performance, attendance rates, number of classes passed and credits earned for these students

Wholeheartedness and Acquaintance with God

In this thesis, I demonstrate that wholeheartedness is a constitutive intellectual virtue. Wholeheartedness consists of a definite and unified volitional structure in which one’s desires are integrated around union with God and which contributes to one’s personal intellectual worth by positively orienting her toward acquaintance with God. Since wholeheartedness consists of a hierarchy of the will that prioritizes a desire for union with God, wholeheartedness aims towards the epistemic good of acquaintance. By desiring that one have a will that wills union with God, she cooperates with God toward wholeheartedness. As one becomes aware of her volitional structure changing, she also becomes aware of God’s presence. This sanctification produces a pattern of interactions with God overtime that constitute an acquaintance with God, where acquaintance is an aptitude of recognition, belief formation, and understanding carried via memory and other faculties that is consequent on and subsequent to an earlier immediate cognitive contact or awareness of an object of knowledge. It is in and through one becoming wholehearted that she comes to know God

Grieving the violent death of a child: synthesizing the private and public response

Accidents, suicides, and homicides are the leading causes of death in the young. These are all modes of violent deaths. Although the response to loss has been a prevalent area of inquiry, limited research exists how or whether the context of violent death affects the response of parents to the loss of a child. The purpose of this grounded theory study was to enhance the theoretical understanding of the parent\u27s bereavement response to the violent death of the child. Twelve parents whose children were murdered participated in the in-depth interviews. With the constant comparison and analysis of data, the public response to the death emerged as the most troublesome and unique issue when a child is murdered. Parents contended with this problem by synthesizing their own response to the death with that of the public in an attempt to recreate the scenario surrounding the death. The ability of the parents to synthesize the public response with their own accounts for the variance in the outcome of the process. When parents attain synthesis, they integrate both and attain a culmination in the process. Parents who are unable to synthesize the two do not attain this reprieve. As the number of violent deaths continues to increase, more children will be murdered. The substantive theory developed from this research extends the foundation for nursing caring for parents bereaved under these circumstances

Generating Improved RNA Localization Reporters Using the U1hp-U1A System

Generating Improved RNA Localization Reporters Using the U1hp-U1A System Ryan Dannemiller, Rebecca Adams, PhD. Belmont University, Nashville, TN. Messenger mRNA (mRNA) is genetic material that is used to bridge between DNA in the nucleus and protein-making machinery in the cytoplasm of eukaryotic cells. The processes of transcription and translation are physically separated, so the localization of mRNA dictates whether the encoded protein can be generated. In order to observe the localization of specific transcripts in response to stimuli, tools are needed to track location of mRNA. For example, in response to heat shock and ethanol stress, most mRNA is retained in the nucleus while select transcripts are permitted to export, allowing the cell to drastically reprogram its gene expression. The goal of this project is to develop an updated method to track the location of specific mRNA in live cells by building off previous tools. In this approach, the transcript of interest is engineered to include the mRNA hairpins found in the U1A snRNA (U1hp), and green fluorescent protein (GFP) is fused to the RNA binding domain of the U1A protein that binds U1hp with high affinity. While previous studies have demonstrated the utility of this approach, plasmid-based expression of the U1A-GFP reporter results in variable expression among cells, limiting its utility and reproducibility. In order to limit the amount of variability in the production of the reporter protein, I have cloned the U1A-GFP protein into an integrative plasmid with promoters of different strengths. This allows for even expression of the reporter among all cells in a population. This collection of integrative plasmids have been generated by a step-wise cloning process. We are currently performing experiments to test whether selective mRNA export can be recapitulated using this updated reporter. The tests will show how accurate the reporter is at localizing mRNA within a cell under different stress conditions

Effects of Deepwater Horizon oil on feather structure and thermoregulation in gulls: Does rehabilitation work?

Impacts of large-scale oil spills on avian species are far-reaching.While media attention often focuses on lethal impacts, sub-lethal effects and the impacts of rehabilitation receive less attention. The objective of our study was to characterize effects of moderate external oiling and subsequent rehabilitation on feather structure and thermoregulation in gulls. We captured 30 wild ring-billed gulls (Larus delawarensis) and randomly assigned each individual to an experimental group: 1) controls, 2) rehabilitated birds (externally oiled, rehabilitated by washing), or 3) oiled birds (externally oiled, not rehabilitated). We externally oiled birds with weathered MC252 Deepwater Horizon oil (water for controls) and collected feathers and thermography imagery (FLIR) approximately weekly for four weeks to investigate feather structure (quantified using a barbule clumping index) and thermoregulatory ability (characterized by internal body temperature and external surface temperature). Post-oiling feather clumping was significantly higher in oiled and rehabilitated birds compared to controls, but steadily declined over time in both groups. However, feather microstructure in rehabilitated birds was indistinguishable from controls within three weeks of washing whereas the feathers of oiled birds were still significantly clumped a month post oiling. Internal body temperatures didn\u27t differ in any of the groups, suggesting birds maintain thermoregulatory homeostasis in spite of moderate external oiling. External temperatures for rehabilitated birds didn\u27t differ from controls within a week of rehabilitation. Overall, rehabilitation procedures were effective and washed birds were in better condition compared to non-rehabilitated, oiled birds. This study provides evidence that the benefits of rehabilitation for moderately oiled birds likely outweigh the costs with regard to feather structure and thermoregulation.While feather preening and time were insufficient to reestablish baseline fine scale feather structure in moderately oiled birds, the significant clumping reduction over time may indicate that rehabilitation of lightly oiled birds may not be necessary and deserves further study

Diagnostic agreement between three point-of-care glucose and β-hydroxybutyrate meters and reference laboratory methods in stingrays

Point-of-care (POC) glucose and β-hydroxybutyrate (β-HB) meters can potentially provide rapid insight into an elasmobranch’s metabolic state in clinical and field research settings. This study evaluated the diagnostic agreement of three commercial POC meters against reference laboratory methods for glucose and β-HB concentrations in stingrays. Blood was collected during anesthetized exams from 28 stingrays representing four species: cownose rays (Rhinoptera bonasus), Atlantic stingrays (Hypanus sabina), southern stingrays (Hypanus americanus), and yellow stingrays (Urobatis jamaicensis). Glucose and β-HB concentrations were measured with each POC meter using whole blood and plasma; in parallel, plasma glucose and β-HB concentrations were measured via reference laboratory methods. Agreement between POC meters and reference laboratory methods was assessed using Bland–Altman methods, Passing-Bablok regression, observed total error, percent relative error, and linear mixed effect models. Plasma glucose and β-HB concentrations determined by reference laboratory methods ranged from <20–63 mg/dL to 0.05–5.38 mmol/L, respectively. One human POC meter—the Precision Xtra—showed the greatest agreement with reference laboratory methods when measuring glucose with whole blood [mean bias and 95% CI: 0 (−3–4) mg/dL] and β-HB with plasma [mean bias and 95% CI: 0.1 (−0.04–0.2) mmol/L]. Stingray sex, weight, buffy coat, and packed cell volume did not significantly affect the agreement between POC meters and reference laboratory methods. Across all three POC meters, mean bias and imprecision for plasma β-HB concentrations were relatively small (0–0.1 mmol/L and 0%, respectively). Utilizing POC meters to measure glucose and β-HB in stingrays may be viable when reference methods are unavailable