The state-of-the-art in air transportation demand and systems analysis : a report on the proceedings of a workshop sponsored by the Civil Aeronautics Board, Department of Transportation, and National Aeronautics and Space Administration (June 1975)

August 1975Introduction and summary: Forecasting air transportation demand has indeed become a complex and risky business in recent years, especially in view of unpredictable fuel prices, high inflation rates, a declining rate of aggregate population growth, and an uncertainty with respect to the regulatory structure in the aviation industry. Since the stakes are very high, the need for accurate forecasting and for a more complete understanding of the total system of air transportation continues to grow. Past forecasting methods have become inadequate for at least two reasons. First, the trend extrapolation method of forecasting is no longer appropriate due to the significant changes in both the economic and the operating environments in recent years. Second, the more sophisticated econometric forecasting models are only as good as our understanding of the total air transportation system on the one hand, and the availability of data on the other. In light of these deficiencies, the dual needs for improving forecasting methods and for increasing the reliability of data are more critical now than ever before. In short, there is a compelling need to perform basic research to improve both the forecasting methods and the data in the aviation industry. Among the various types of forecasts of aviation activity desired by the government agencies, the air carriers, the airframe and engine manufacturers, the airport authorities, and the financial community, one component that plays a critical role in long-range planning pertains to the future fleet requirements for the aviation industry. Forecast items needed with respect to future fleet requirements include types, configuration, ranges, and technologies of new aircraft so that the industry and government can coordinate their resources to maximize the interests of the producers, regulators and consumers of future air service. The National Aeronautics and Space Administration (NASA), with its twin missions of both aeronautics and astronautics, has been focusing its attention on the aeronautics component in recent years. In this overall responsibility, the Systems Study Division of NASA-Ames Research Center has as one of its main objectives the development of a better understanding of the civil air transportation system in the United States, with emphasis placed on the proper and timely application of new technology. In order to fulfill this objective, the division has a critical need for projections of the growth of demand and for the determination of the role of technology in the future growth of air transportation. Before undertaking an extensive research effort in the area of air transportation demand analysis and forecasting, NASA-Ames attempted to solicit the views of the industry and other government agencies at a one day informal meeting in San Francisco in December 1974. The meeting was attended by about twenty experts from the carriers, airframe and engine manufacturers, U.S. Department of Transportation, universities and NASA. The goals of this mini-workshop were three-fold: the first objective was to determine the ways in which the NASA-Ames Systems Study Division could play a supportive role in this area; second, it was essential to receive an informal endorsement from the industry and other government agencies; and third, it was necessary to determine the direction for the proposed research. This meeting concluded with a general agreement on a definite need for future research, with the belief that not only could NASA-Ames play a supportive role but, more important, that it could play a catalytic role. However, due to the limited participation in this one-day meeting and the assistance that the proposed research could have provided to a wide variety of users, a more extensive workshop was proposed at that time, possibly to be co-sponsored by other government agencies. Subsequent to the December 1974 meeting, further discussions with the U.S. Civil Aeronautics Board (CAB) and the U.S. Department of Transportation (DOT) resulted in a three-day workshop co-sponsored by the CAB, DOT and NASA. The reasons for the joint sponsorship by the CAB and DOT reflected a desire from these agencies to participate in the search for methodologies and information on the long-range benefits, problems and issues of technological advances in aviation and to assist NASA in deploying its funds on these matters in the most productive and efficient ways. The overall objectives of this workshop were four-fold: first, to investigate the state-of-the-art in air transportation demand forecasting; second, to determine the needs of the various government agencies and the industry; third, to assess the possibility of long-term government sponsorship of basic research to improve the forecasting of air transportation activity; and fourth, to determine the most promising areas of research in air transportation and systems analysis. This workshop was organized by the Flight Transportation Laboratory of the Massachusetts Institute of Technology and the Transportation Center at Northwestern University and was held at the Mayflower Hotel in Washington, D.C. on June 2-4, 1975. The meeting was attended by one hundred experts, thirty-three of whom made extensive presentations. This report then is a summary of the highlights of the presentations delivered at the workshop, with appropriate interjections and editorial comments as perceived by its authors

A review of the role of social cognition in major depressive disorder

BACKGROUND: Social cognition - the ability to identify, perceive, and interpret socially relevant information - is an important skill that plays a significant role in successful interpersonal functioning. Social cognitive performance is recognized to be impaired in several psychiatric conditions, but the relationship with major depressive disorder is less well understood. The aim of this review is to characterize the current understanding of: (i) the different domains of social cognition and a possible relationship with major depressive disorder, (ii) the clinical presentation of social cognition in acute and remitted depressive states, and (iii) the effect of severity of depression on social cognitive performance. METHODS: Electronic databases were searched to identify clinical studies investigating social cognition in a major depressive disorder population, yielding 31 studies for this review. RESULTS: Patients with major depressive disorder appear to interpret social cognitive stimuli differently to healthy controls: depressed individuals may interpret emotion through a mood-congruent bias and have difficulty with cognitive theory of mind tasks requiring interpretation of complex mental states. Social cognitive performance appears to be inversely associated with severity of depression, whilst the bias toward negative emotions persists even in remission. Some deficits may normalize following effective pharmacotherapy. CONCLUSIONS: The difficulties with social interaction observed in major depressive disorder may, at least in part, be due to an altered ability to correctly interpret emotional stimuli and mental states. These features seem to persist even in remission, although some may respond to intervention. Further research is required in this area to better understand the functional impact of these findings and the way in which targeted therapy could aid depressed individuals with social interactions.Michael James Weightman,Tracy Michele Air and Bernhard Theodor Baun

Trajectories of anxiety and health related quality of life during pregnancy

Published: July 24, 2017Anxiety and health related Quality of Life (HRQoL) have emerged as important mental health measures in obstetric care. Few studies have systematically examined the longitudinal trajectories of anxiety and HRQoL in pregnancy. Using a linear growth modeling strategy, we analyzed the course of State-Trait Anxiety Inventory (STAI)- and Short Form (36) Health Survey (SF-36) scores between the 12th and the 36th week of gestation, in a sample of 355 women. We additionally analyzed the impact of depressive symptoms and a chronic medical condition (asthma), on STAI and SF-36 trajectory curves. STAI scores remained stable throughout pregnancy. A previous history of anxiety increased the overall STAI scores. Asthma and depressive symptoms scores had no impact on the STAI trajectory. Physical SF-36 scores decreased over the course of pregnancy, whereas mental SF-36 trended towards improvement. Asthma reduced physical SF-36 overall. While high depressive symptoms decreased the overall mental SF-36, they were also significantly associated with mental SF-36 improvements over time. Anxiety symptoms are stable during pregnancy and are not modulated by depressive symptoms or asthma. Physical HRQoL declines in pregnancy. In contrast, mental HRQoL appears to improve, particularly in women with high initial levels of depressive symptoms.K. Oliver Schubert, Tracy Air, Scott R. Clark, Luke E. Grzeskowiak, Edward Miller, Gustaaf A. Dekker, Bernhard T. Baune, Vicki L. Clifto

Correlation of influenza infection with glycan array

Poster Presentation: SPB1 / SPB2 - Virus Host Interaction/Pathogensis/Transmission: abstract no. B109PINTRODUCTION: The past 6 years has seen the introduction of glycan arrays containing large numbers of sialic acid (Sia) containing compounds and these arrays have been used to demonstrate the relative binding affinity of influenza viruses to different glycans. Though infor...postprin

The prototype HIV-1 maturation inhibitor, bevirimat, binds to the CA-SP1 cleavage site in immature Gag particles

<p>Abstract</p> <p>Background</p> <p>Bevirimat, the prototype Human Immunodeficiency Virus type 1 (HIV-1) maturation inhibitor, is highly potent in cell culture and efficacious in HIV-1 infected patients. In contrast to inhibitors that target the active site of the viral protease, bevirimat specifically inhibits a single cleavage event, the final processing step for the Gag precursor where p25 (CA-SP1) is cleaved to p24 (CA) and SP1.</p> <p>Results</p> <p>In this study, photoaffinity analogs of bevirimat and mass spectrometry were employed to map the binding site of bevirimat to Gag within immature virus-like particles. Bevirimat analogs were found to crosslink to sequences overlapping, or proximal to, the CA-SP1 cleavage site, consistent with previous biochemical data on the effect of bevirimat on Gag processing and with genetic data from resistance mutations, in a region predicted by NMR and mutational studies to have α-helical character. Unexpectedly, a second region of interaction was found within the Major Homology Region (MHR). Extensive prior genetic evidence suggests that the MHR is critical for virus assembly.</p> <p>Conclusions</p> <p>This is the first demonstration of a direct interaction between the maturation inhibitor, bevirimat, and its target, Gag. Information gained from this study sheds light on the mechanisms by which the virus develops resistance to this class of drug and may aid in the design of next-generation maturation inhibitors.</p

Employers and schools: how Mansfield is building a world of work approach

There is a keen interest in encouraging employers to engage with schools so that young people can learn more about careers, understand the skills that employers are interested in, broaden their aspirations and be motivated to succeed. Employer engagement in schools in England however is increasingly fragmented because of a loss of brokering infrastructure. This article describes a partnership approach developed in Mansfield where a consortium of local schools has worked with their business community and public sector organisations. Together they have listened to what young people say they both want and need to know about careers and then responded by providing a strategic careers learning programme. The particular contribution of the Mansfield Learning Partnership which is wholly funded by the town’s secondary schools is detailed in the article alongside elaboration of the Mansfield Framework for Career Learning which provides a work experience programme and several imaginative opportunities for young people to engage in meaningful encounters with employers

Optometric Measurements Predict Performance but Not Comfort on a Virtual Object Placement Task With a Stereoscopic 3D Display

Twelve participants were tested on a simple virtual object precision placement task while viewing a stereoscopic 3D (S3D) display. Inclusion criteria included uncorrected or best corrected vision of 20/20 or better in each eye and stereopsis of at least 40 arc sec using the Titmus stereo test. Additionally, binocular function was assessed, including measurements of distant and near phoria (horizontal and vertical) and distant and near horizontal fusion ranges using standard optometric clinical techniques. Before each of six 30 minute experimental sessions, measurements of phoria and fusion ranges were repeated using a Keystone View Telebinocular and an S3D display, respectively. All participants completed experimental sessions in which the task required the precision placement of a virtual object in depth at the same location as a target object. Subjective discomfort was assessed using the Simulator Sickness Questionnaire (SSQ). Individual placement accuracy in S3D trials was significantly correlated with several of the binocular screening outcomes: viewers with larger convergent fusion ranges (measured at near distance), larger total fusion ranges (convergent plus divergent ranges, measured at near distance), and/or lower (better) stereoscopic acuity thresholds were more accurate on the placement task. No screening measures were predictive of subjective discomfort, perhaps due to the low levels of discomfort induced

A single residue substitution in the receptor-binding domain of H5N1 hemagglutinin is critical for packaging into pseudotyped lentiviral particles

© 2012 Tang et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Background: Serological studies for influenza infection and vaccine response often involve microneutralization and hemagglutination inhibition assays to evaluate neutralizing antibodies against human and avian influenza viruses, including H5N1. We have previously characterized lentiviral particles pseudotyped with H5-HA (H5pp) and validated an H5pp-based assay as a safe alternative for high-throughput serological studies in BSL-2 facilities. Here we show that H5-HAs from different clades do not always give rise to efficient production of H5pp and the underlying mechanisms are addressed. Methodology/Findings: We have carried out mutational analysis to delineate the molecular determinants responsible for efficient packaging of HA from A/Cambodia/40808/2005 (H5Cam) and A/Anhui/1/2005 (H5Anh) into H5pp. Our results demonstrate that a single A134V mutation in the 130-loop of the receptor binding domain is sufficient to render H5Anh the ability to generate H5Anh-pp efficiently, whereas the reverse V134A mutation greatly hampers production of H5Cam-pp. Although protein expression in total cell lysates is similar for H5Anh and H5Cam, cell surface expression of H5Cam is detected at a significantly higher level than that of H5Anh. We further demonstrate by several independent lines of evidence that the behaviour of H5Anh can be explained by a stronger binding to sialic acid receptors implicating residue 134. Conclusions: We have identified a single A134V mutation as the molecular determinant in H5-HA for efficient incorporation into H5pp envelope and delineated the underlying mechanism. The reduced binding to sialic acid receptors as a result of the A134V mutation not only exerts a critical influence in pseudotyping efficiency of H5-HA, but has also an impact at the whole virus level. Because A134V substitution has been reported as a naturally occurring mutation in human host, our results may have implications for the understanding of human host adaptation of avian influenza H5N1 virusesThis work was supported by grants from the Research Fund for the Control of Infectious Diseases of Hong Kong (RFCID#08070972), the Area of Excellence Scheme of the University Grants Committee (grant AoE/M-12/-06 of the Hong Kong Special Administrative Region, China), the French Ministry of Health, and the RESPARI project of the Institut Pasteur International Network

Validation of Proposed Go-Around Criteria Under Various Environmental Conditions

This paper evaluates the effects of environmental conditions on touchdown performance under varying approach states and validates proposed go-around criteria developed using data from a previously conducted study under these various environmental conditions. An experiment was conducted using Boeing 737-800 and Airbus A330-200 Level D full-flight simulators in which 24 pilots flew multiple approaches under different approach conditions and environmental variables. Pilots were instructed to always land the aircraft, even from conditions considered to be an unstable approach. Various touchdown performance metrics were analyzed. In addition, pilots perceptions of risk under the various unstable approach conditions and resulting landings were assessed. The results of the study revealed that wind speed/direction and visibility had a stronger effect on touchdown performance than the approach parameters. Specifically, wind had a highly significant effect on longitudinal and lateral touchdown point, as well as a significant effect on sink-rate at touchdown. Wind and visibility, along with localizer deviation, also had a strong effect on pilots perception of risk and workload ratings. Furthermore, the study confirmed that touchdown performance was similar among the runs with a 300-foot and 500-foot starting gate, as was found in the previously conducted experiment. These results support the previous finding that lowering the go-around decision gate to 300-foot might be acceptable, but suggest that certain environmental conditions might warrant altered thresholds of the proposed go-around criteria at this gate. Finally, the findings of this experiment highlight the importance of environmental factors in the assessment of risk of unwanted outcomes on approach and landing