375 research outputs found

    Recommendations For Improvement Of Collegiate Flight Training Operational Efficiency Through Guided-Inquiry Inductive Learning

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    Efficiency in higher education has increasingly come under scrutiny as student debt levels continue to increase and the quantification of the value provided to students by colleges remains elusive. Collegiate flight training operations are especially subject to such scrutiny, due to their expense and to continued below-average entry-level salaries in the airline industry. This research examines an inductive learning approach combined with a flipped classroom, whereby aviation management students in a large Midwestern collegiate aviation program analyzed the operational efficiency of their primary flight training operation and recommend potential solutions and means of implementation. Such an approach provides multiple benefits. The resulting improvement in scheduling efficiency results in better use of existing capacity, and can be utilized to allow additional students to matriculate in the program, subsequently reducing student fees for all enrolled students by spreading fixed costs over a wider customer base. In addition, the management students participated in the development and implementation planning of empirical solutions to the problem, thereby addressing a call from industry to incorporate practical projects in the classroom to achieve greater comprehension and retention of subject matter. A number of alternative assessment methods (Frank & Barzilai, 2004), including semi-structured student interviews, surveys, peer evaluations, and analysis of deliverables, were utilized, and these indicated that classroom engagement and subject matter retention was improved by the delivery methods that were employed

    Leveraging Aircraft Transponder Signals for Measuring Aircraft Fleet Mix at Non-Towered Airports

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    The general aviation sector has contributed significantly to the overall growth of the aviation industry. Fleet mix and operations information is important for the analysis of both the safety and the environmental and economic impact of general aviation activity. Factual data on the impact of environment and safety is particularly important, given the scarcity of airport improvement funds and the strong stakeholder engagement that often occurs when airport investments are evaluated. The research presented herein evaluates Mode S short and extended squitter data collected from three general aviation airports over a one-month period. This article demonstrates that by utilizing the unique ICAO code present in Mode S records in the United States, ICAO identification can be used as a primary key for retrieving information from publicly available databases, permitting the determination of aircraft type and engine models. An aircraft operation type with the corresponding fleet mix information can thus be estimated at non-towered airports. The techniques reported here are also useful in monitoring the increase in aircraft compliant with the FAA’s January 1, 2020 mandate for ADS-B out to operate in large portions of the national airspace system. For the three Indiana airports studied, the proportion of ADS-B transponder messages received ranged from approximately 29% at the Terre Haute Regional Airport (KHUF) to 79% at the Purdue University Airport (KLAF)

    Leveraging Aircraft Avionics

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    Airport operations count data are used for a variety of purposes ranging from allocation of Airport Improvement Program (AIP) funding to environmental assessments and budget justification. Operations counts are hard to obtain at small, non-towered airports, which constitute the majority of airports in the United States, and are frequently estimated unscientifically by airport managers. Current acoustic and video counting technology is limited, but with the FAA NextGen mandate for installation of ADS-B Out transponders by Jan. 1, 2020, transponder data is rapidly emerging as a viable data source beyond traditional NextGen applications. To date, the NextGen literature has focused on the use of this technology for navigation, safety, and airspace management. This paper introduces a method of applying ADS-B data to fleet management and airport operations. With a 1090 MHz receiver and appropriate signal processing hardware and software, Mode S and Mode S Extended data can be used to track runway operations and fleet usage in an accurate and cost-effective manner

    Atmospheric Pressure Calibration to Improve Accuracy of Transponder-Based Aircraft Operations Counting Technology

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    In the United States, over 2,400 of the 2,941 non-primary National Plan of Integrated Airport System airports have limited means of establishing operations counts due to lack of available personnel. Precise counts of airport operations are helpful for allocating airport improvement funds, as well as for local and system planning. An emerging technology utilizing ADS-B position data to calibrate signal strength received from Mode C transponders, thereby capturing location information from over 90% of the aircraft operating in the National Airspace System, has successfully estimated operations counts at these non-towered airports with reasonable levels of accuracy. This paper evaluates the impact of further calibration of the model using an atmospheric pressure-based calibration method to improve the accuracy of operations counts. Over 10 million aircraft transponder records collected during 58 days at Purdue University Airport and Terre Haute Regional Airport were analyzed. Uncorrected operations counts and corrected counts using atmospheric pressures averaged both monthly and daily were compared with those obtained from tower-reported figures from the Air Traffic Activity Data System (ATADS) database. The overall accuracy of operations counts from uncorrected heuristics ranged from 5.5% to 13.6% as compared to ATADS over different time periods ranging from 55 to 58 days. Incorporating monthly and daily average pressures improved the count accuracy from 3.2% to 8.7% and from 2.6% to 9.3%, respectively. The test results suggest that the barometric correction method using monthly average pressures results in a modest improvement in overall percentage error and mean average error over the uncorrected method

    Characterisation of cationic amphiphilic cyclodextrins for neuronal delivery of siRNA: effect of reversing primary and secondary face modifications

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    Significant research is focused on the development of non-viral vectors for delivery of siRNA to neurons and the central nervous system. Cyclodextrins (CDs) have shown great promise as efficient and low toxicity gene delivery vectors in various cell types. Here, we investigate two CDs for siRNA delivery in a neuronal cell model. These CDs were substituted on opposite faces (primary and secondary) with amphiphilic and cationic groups. Physical properties of CD.siRNA complexes, including size, charge and stability were measured. In vitro investigations were carried out in immortalised hypothalamic neurons. Neuronal cell uptake was measured by flow cytometry and cytotoxicity was assessed by MTT assay. Knockdown of a luciferase reporter gene was used as a measure of gene silencing efficiency. Both CDs interacted with siRNA, yielding nanosized cationic complexes which exhibited good stability on storage. A favourable toxicity profile was demonstrated for the CD.siRNA complexes. However, only one of the two CDs mediated high levels of neuronal uptake and efficient gene silencing, equivalent to those achieved with a commercial lipid-based vector. Despite the suitability of both CDs as siRNA delivery vectors in terms of their ability to complex siRNA and the properties of the complexes yielded, only one CD achieved good transfection efficiency. This was likely due to the differences in their chemical structures. The effective CD offers great potential as a novel non-toxic vector for neuronal siRNA delivery

    Increasing Collegiate Flight Training Fleet Utilization Through the Use of an Aircraft Assignment Algorithm

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    The operational efficiency of fleet aircraft employed for student flight training in collegiate aviation programs is strongly influenced by scheduling, among other factors. The average utilization rate for the fleet operated by the Purdue University School of Aviation and Transportation Systems was found to be 24% (Avery, 2014), and there is no data to suggest that that this rate is atypical in similar institutional programs. Mott and Bullock (2015) identified several means by which the utilization rate could be increased, and improvements in the dispatch and scheduling process were a key component of those recommendations. This article describes a scheduling algorithm that was implemented at Purdue University in the fall semester of 2015. The algorithm is a linear programming technique that incorporates optimization constraints unique to collegiate flight training operations. The resulting improvements in aircraft utilization will facilitate an increased matriculation rate of students into the flight program, thereby allowing the allocation of fixed costs over a wider user base and the reduction of overall program fees for all students. Those improvements are validated through measurement of the reduction of the cumulative turn times between aircraft operations

    Cationic and PEGylated amphiphilic cyclodextrins: co-formulation opportunities for neuronal siRNA delivery

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    Optimising non-viral vectors for neuronal siRNA delivery presents a significant challenge. Here, we investigate a co-formulation, consisting of two amphiphilic cyclodextrins (CDs), one cationic and the other PEGylated, which were blended together for siRNA delivery to a neuronal cell culture model. Co-formulated CD-siRNA complexes were characterised in terms of size, charge and morphology. Stability in salt and serum was also examined. Uptake was determined by flow cytometry and toxicity was measured by MTT assay. Knockdown of a luciferase reporter gene was used as a measure of gene silencing efficiency. Incorporation of a PEGylated CD in the formulation had significant effects on the physical and biological properties of CD. siRNA complexes. Co-formulated complexes exhibited a lower surface charge and greater stability in a high salt environment. However, the inclusion of the PEGylated CD also dramatically reduced gene silencing efficiency due to its effects on neuronal uptake. The co-formulation strategy for cationic and PEGylated CDs improved the stability of the CD. siRNA delivery systems, although knockdown efficiency was impaired. Future work will focus on the addition of targeting ligands to the co-formulated complexes to restore transfection capabilities

    Therapeutic targeting in the silent era: advances in non-viral siRNA delivery

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    Gene silencing using RNA-interference, first described in mammalian systems almost a decade ago, is revolutionizing therapeutic target validation efforts both in vitro and in vivo. Moreover, the potential for using short interfering RNA (siRNA) as a therapy in its own right is also progressing at a significant pace. However, the widespread use of such approaches is contingent on having appropriate systems to achieve clinically appropriate, safe, and efficient delivery of siRNA. There are many physicochemical and biological barriers to such delivery, and a growing emphasis on the design and characterisation of non-viral technologies that will overcome these barriers and expedite targeted delivery. This review discusses the considerations and challenges associated with use of siRNA-based therapeutics, including stability and off-target effects. Speculation is made on the properties of an ideal delivery system and the non-viral delivery approaches used to date, both in vitro and in vivo, are classified and discussed. Moreover, the ability of cyclodextrin-based delivery vectors to fulfil many of the criteria of an ideal delivery construct is also elaborated

    Provider Self-Report and Practice: Reassessment and Referral of Emergency Department Patients With Elevated Blood Pressure

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    Background We attempted to identify patient factors associated with blood pressure (BP) reassessment and to compare health-care provider self-reported reassessment and referral to actual practice in an emergency department (ED) setting. Methods Provider reassessment and referral practices were determined through systematic review of 1,250 medical records at five EDs. Medical records were included if patients were ≥18 years, nonpregnant, presented with a systolic (SBP) ≥140 or diastolic BP (DBP) ≥90 mm Hg, and discharged. A separate questionnaire obtained self-reported practice patterns of health-care providers. Multivariate logistic regression identified factors associated with patient BP reassessment and referral. Results Of 1,250 patients, only 57% underwent BP reassessment and 9% received a referral for outpatient management. The most significant independent variables related to a reassessment were as follows: treatment of elevated BP in the ED (odds ratio (OR): 6.05; 95% confidence interval (CI): 1.80-20.31), chest pain (OR: 3.90; 95% CI: 2.37-6.42), and presence of an ED reassessment protocol (OR: 2.49; 95% CI: 1.77-3.50). The most significant factors associated with a referral included treatment of elevated BP in the ED (OR: 5.55; 95% CI: 2.72-11.32), presence of a reassessment protocol (OR: 2.58; 95% CI: 1.32-5.05), and a BP reassessment (OR: 2.56; 95% CI: 1.34-4.89). For self-reported practice patterns, 379 (72%) health-care providers completed questionnaires. Providers consistently overestimated their referral practices, yet the mean referral threshold values reported (SBP, 150 mm Hg; DBP, 93 mm Hg) were lower than the mean BP values of patients who actually received a directed referral (SBP, 170 mm Hg; DBP, 97 mm Hg, P < 0.0001). Conclusions Reassessment and referral of discharged ED patients with elevated BP was infrequent and health-care providers overestimate their reassessment and referral effort

    A click chemistry route to 2-functionalised PEGylated and cationic beta-cyclodextrins: co-formulation opportunities for siRNA delivery

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    A new approach to the synthesis of amphiphilic beta-cyclodextrins has used 'click' chemistry to selectively modify the secondary 2-hydroxyl group. The resulting extended polar groups can be either polycationic or neutral PEGylated groups and these two amphiphile classes are compatible in dual cyclodextrin formulations for delivery of siRNA. When used alone with an siRNA, a cationic cyclodextrin was shown to have good transfection properties in cell culture. Co-formulation with a PEGylated cyclodextrin altered the physicochemical properties of nanoparticles formed with siRNA. Improved particle properties included lower surface charges and reduced tendency to aggregate. However, as expected, the transfection efficiency of the cationic vector was lowered by co-formulation with the PEGylated cyclodextrin, requiring future surface modification of particles with targeting ligands for effective siRNA delivery
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