132 research outputs found

    Attitude Design for the LADEE Mission

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    The Lunar Atmosphere and Dust Environment Explorer (LADEE) satellite successfully completed its 148-day science investigation in a low-altitude, near-equatorial lunar orbit on April 18, 2014. The LADEE spacecraft was built, managed and operated by NASA's Ames Research Center (ARC). The Mission Operations Center (MOC) was located at Ames and was responsible for activity planning, command sequencing, trajectory and attitude design, orbit determination, and spacecraft operations. The Science Operations Center (SOC) was located at Goddard Space Flight Center and was responsible for science planning, data archiving and distribution. This paper details attitude design and operations support for the LADEE mission. LADEE's attitude design was shaped by a wide range of instrument pointing requirements that necessitated regular excursions from the baseline one revolution per orbit "Ram" attitude. Such attitude excursions were constrained by a number of flight rules levied to protect instruments from the Sun, avoid geometries that would result in simultaneous occlusion of LADEE's two star tracker heads, and maintain the spacecraft within its thermal and power operating limits. To satisfy LADEE's many attitude requirements and constraints, a set of rules and conventions was adopted to manage the complexity of this design challenge and facilitate the automation of ground software that generated pointing commands spanning multiple days of operations at a time. The resulting LADEE Flight Dynamics System (FDS) that was developed used Visual Basic scripts that generated instructions to AGI's Satellite Tool Kit (STK) in order to derive quaternion commands at regular intervals that satisfied LADEE's pointing requirements. These scripts relied heavily on the powerful "align and constrain" capability of STK's attitude module to construct LADEE's attitude profiles and the slews to get there. A description of the scripts and the attitude modeling they embodied is provided. One particular challenge analysts faced was in the design of LADEE maneuver attitudes. A flight rule requiring pre-maneuver verification of in-flight maneuver conditions by ground operators prior to burn execution resulted in the need to accommodate long periods in the maneuver attitude. This in turn complicated efforts to satisfy star tracker interference and communication constraints in lunar orbit. In response to this challenge, a graphical method was developed and used to survey candidate rotation angles about the thrust vector. This survey method is described and an example of its use on a particular LADEE maneuver is discussed. Finally, the software and methodology used to satisfy LADEE's attitude requirements are also discussed in the context of LADEE's overall activity planning effort. In particular, the way in which strategic schedules of instrument and engineering activities were translated into actual attitude profiles at the tactical level, then converted into precise quaternion commands to achieve those pointing goals is explained. In order to reduce the risk of time-consuming re-planning efforts, this process included the generation of long-term projections of constraint violation predictions for individual attitude profiles that could be used to establish keep-out time-frames for particular attitude profiles. The challenges experienced and overall efficacy of both the overall LADEE ground system and the attitude components of the Flight Dynamics System in meeting LADEE's varied pointing requirements are discussed

    Preliminary statewide projections of county-level water demands in Illinois: Draft project completion report

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    Illinois State Water Survey and Southern Illinois University CarbondaleOpe

    Everything is INTERRELATED:Teaching Software Engineering for Sustainability

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    Sustainability has become an important concern across many disciplines,and software systems play an increasingly central role in addressing it. However, teaching students from software engineering and related disciplines to effectively act in this space requires interdisciplinary courses that combines the concep to of sustainability with software engineering practice and principles. Yet, presently little guidance exist on which subjects and materials to cover in such courses and how, combined with a lack of reusable learning objects. This paper describes a summer school course on Software Engineering for Sustainability (SE4S). We provide a blueprint for this course, in the hope that it can help the community develop a shared approach and methods to teaching SE4S. Practical lessons learned from delivery of this course are also reported here, and could help iterate over the course materials, structure, and guidance for future improvements. The course blueprint, availability of used materials and report of the study results make this course viable for replication and further improvement

    Severe progressive scoliosis due to huge subcutaneous cavernous hemangioma: A case report

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    Cavernous hemangioma consists mainly of congenital vascular malformations present before birth and gradually increasing in size with skeletal growth. A small number of patients with cavernous hemangioma develop scoliosis, and surgical treatment for the scoliosis in such cases has not been reported to date. Here we report a 12-year-old male patient with severe progressive scoliosis due to a huge subcutaneous cavernous hemangioma, who underwent posterior correction and fusion surgery. Upon referral to our department, radiographs revealed a scoliosis of 85° at T6-L1 and a kyphosis of 58° at T4-T10. CT and MR images revealed a huge hemangioma extending from the subcutaneous region to the paraspinal muscles and the retroperitoneal space and invading the spinal canal. Posterior correction and fusion surgery using pedicle screws between T2 and L3 were performed. Massive hemorrhage from the hemangioma occurred during the surgery, with intraoperative blood loss reaching 2800 ml. The scoliosis was corrected to 59°, and the kyphosis to 45° after surgery. Seven hours after surgery, the patient suffered from hypovolemic shock and disseminated intravascular coagulation due to postoperative hemorrhage from the hemangioma. The patient developed sensory and conduction aphasia caused by cerebral hypoxia during the shock on the day of the surgery. At present, two years after the surgery, although the patient has completely recovered from the aphasia. This case illustrates that, in correction surgery for scoliosis due to huge subcutaneous cavernous hemangioma, intraoperative and postoperative intensive care for hemodynamics should be performed, since massive hemorrhage can occur during the postoperative period as well as the intraoperative period

    Multicenter Trial of a Combination Probiotic for Children with Gastroenteritis.

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    Background Gastroenteritis accounts for approximately 1.7 million visits to the emergency department (ED) by children in the United States every year. Data to determine whether the use of probiotics improves outcomes in these children are lacking. Methods We conducted a randomized, double-blind trial involving 886 children 3 to 48 months of age with gastroenteritis who presented to six pediatric EDs in Canada. Participants received a 5-day course of a combination probiotic product containing Lactobacillus rhamnosus R0011 and L. helveticus R0052, at a dose of 4.0×10 Results Moderate-to-severe gastroenteritis within 14 days after enrollment occurred in 108 of 414 participants (26.1%) who were assigned to probiotics and 102 of 413 participants (24.7%) who were assigned to placebo (odds ratio, 1.06; 95% confidence interval [CI], 0.77 to 1.46; P=0.72). After adjustment for trial site, age, detection of rotavirus in stool, and frequency of diarrhea and vomiting before enrollment, trial-group assignment did not predict moderate-to-severe gastroenteritis (odds ratio, 1.06; 95% CI, 0.76 to 1.49; P=0.74). There were no significant differences between the probiotic group and the placebo group in the median duration of diarrhea (52.5 hours [interquartile range, 18.3 to 95.8] and 55.5 hours [interquartile range, 20.2 to 102.3], respectively; P=0.31) or vomiting (17.7 hours [interquartile range, 0 to 58.6] and 18.7 hours [interquartile range, 0 to 51.6], P=0.18), the percentages of participants with unscheduled visits to a health care provider (30.2% and 26.6%; odds ratio, 1.19; 95% CI, 0.87 to 1.62; P=0.27), and the percentage of participants who reported an adverse event (34.8% and 38.7%; odds ratio, 0.83; 95% CI, 0.62 to 1.11; P=0.21). Conclusions In children who presented to the emergency department with gastroenteritis, twice-daily administration of a combined L. rhamnosus-L. helveticus probiotic did not prevent the development of moderate-to-severe gastroenteritis within 14 days after enrollment. (Funded by the Canadian Institutes of Health Research and others; PROGUT ClinicalTrials.gov number, NCT01853124 .)

    Prospectus, October 6, 1982

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    PROSPECTUS FOCUS ON VILLA GROVE; News Digest; Villa Grove looks ahead to future; Voter turnout appreciated; What\u27s your opinion on draft revitalization?: Draft dialogue wanted by student; Listeners available for PC students; Christian humorist appears; Guides needed; Addition bids out, construction to begin this fall; C-U Happenings...; Voter turnout doubled since last election; Loan funding may increase; Can you picture this?; Winter is comin, are you ready?; Three-year restoration project for historic \u27Sunnyside\u27; Growth and tradition mark Villa Grove\u27s 150 years; Classified; Places and Faces in Villa Grove; \u27Wouldn\u27t trade my life for the world,\u27 says bear trainer; Newton-John gives \u27love-filled performace\u27; Live sound makes for smokin\u27 rock; \u27Playboy\u27 sued over photo; Students, instructors cast in fall play; Security does more than give tickets; New seminar offers transfer; Community Calendar; Voices join in \u27Messiah\u27; Convocations sponsors films; Cougar has two in top ten; Are the NFL players holding fans for ransom?; Area seniors to visit PC Campus; Reps to appear at PC; Women\u27s team looking good, may reach finals; Fast Freddy Contest; More participation expected; Golf Scores; Cross Countryhttps://spark.parkland.edu/prospectus_1982/1009/thumbnail.jp

    A randomized trial evaluating virus-specific effects of a combination probiotic in children with acute gastroenteritis

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    Gastroenteritis accounts for nearly 500,000 deaths in children younger than 5 years annually. Although probiotics have been touted as having the potential to expedite diarrhea resolution, recent clinical trials question their effectiveness. A potential explanation is a shift in pathogens following the introduction of a rotavirus vaccine. Here, we report the results of a multi-center, double-blind trial of 816 children with acute gastroenteritis who completed follow-up and provided multiple stool specimens. Participants were randomized to receive a probiotic containing Lactobacillus rhamnosus and Lactobacillushelveticus or placebo. We report no virus-specific beneficial effects attributable to the probiotic, either in reducing clinical symptoms or viral nucleic acid clearance from stool specimens collected up to 28 days following enrollment. We provide pathophysiological and microbiologic evidence to support the clinical findings and conclude that our data do not support routine probiotic administration to children with acute gastroenteritis, regardless of the infecting virus

    Optimized parameter search for large datasets of the regularization parameter and feature selection for ridge regression

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    In this paper we propose mathematical optimizations to select the optimal regularization parameter for ridge regression using cross-validation. The resulting algorithm is suited for large datasets and the computational cost does not depend on the size of the training set. We extend this algorithm to forward or backward feature selection in which the optimal regularization parameter is selected for each possible feature set. These feature selection algorithms yield solutions with a sparse weight matrix using a quadratic cost on the norm of the weights. A naive approach to optimizing the ridge regression parameter has a computational complexity of the order with the number of applied regularization parameters, the number of folds in the validation set, the number of input features and the number of data samples in the training set. Our implementation has a computational complexity of the order . This computational cost is smaller than that of regression without regularization for large datasets and is independent of the number of applied regularization parameters and the size of the training set. Combined with a feature selection algorithm the algorithm is of complexity and for forward and backward feature selection respectively, with the number of selected features and the number of removed features. This is an order faster than and for the naive implementation, with for large datasets. To show the performance and reduction in computational cost, we apply this technique to train recurrent neural networks using the reservoir computing approach, windowed ridge regression, least-squares support vector machines (LS-SVMs) in primal space using the fixed-size LS-SVM approximation and extreme learning machines

    The Heat Shock Response of Mycobacterium Tuberculosis: Linking Gene Expression, Immunology and Pathogenesis

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    The regulation of heat shock protein (HSP) expression is critically important to pathogens such as Mycobacterium tuberculosis and dysregulation of the heat shock response results in increased immune recognition of the bacterium and reduced survival during chronic infection. In this study we use a whole genome spotted microarray to characterize the heat shock response of M. tuberculosis. We also begin a dissection of this important stress response by generating deletion mutants that lack specific transcriptional regulators and examining their transcriptional profiles under different stresses. Understanding the stimuli and mechanisms that govern heat shock in mycobacteria will allow us to relate observed in vivo expression patterns of HSPs to particular stresses and physiological conditions. The mechanisms controlling HSP expression also make attractive drug targets as part of a strategy designed to enhance immune recognition of the bacterium
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