Multiple curved descending approaches and the air traffic control problem

A terminal area air traffic control simulation was designed to study ways of accommodating increased air traffic density. The concepts that were investigated assumed the availability of the microwave landing system and data link and included: (1) multiple curved descending final approaches; (2) parallel runways certified for independent and simultaneous operation under IFR conditions; (3) closer spacing between successive aircraft; and (4) a distributed management system between the air and ground. Three groups each consisting of three pilots and two air traffic controllers flew a combined total of 350 approaches. Piloted simulators were supplied with computer generated traffic situation displays and flight instruments. The controllers were supplied with a terminal area map and digital status information. Pilots and controllers also reported that the distributed management procedure was somewhat more safe and orderly than the centralized management procedure. Flying precision increased as the amount of turn required to intersect the outer mark decreased. Pilots reported that they preferred the alternative of multiple curved descending approaches with wider spacing between aircraft to closer spacing on single, straight in finals while controllers preferred the latter option. Both pilots and controllers felt that parallel runways are an acceptable way to accommodate increased traffic density safely and expeditiously

Performer Experience on a Continuous Keyboard Instrument

On several keyboard instruments the produced sound is not always dependent exclusively on a discrete key-velocity parameter, and minute gestural details can affect the final sonic result. By contrast, variations in articulation beyond velocity have normally no effect on the produced sound when the keyboard controller uses the MIDI standard, used in the vast majority of digital keyboards. In this article, we introduce a novel keyboard-based digital musical instrument that uses continuous readings of key position to control a nonlinear waveguide flute synthesizer with a richer set of interaction gestures than would be possible with a velocity-based keyboard. We then report on the experience of six players interacting with our instrument and reflect on their experience, highlighting the opportunities and challenges that come with continuous key sensing

Access to condoms for female sex workers in Andhra Pradesh.

BACKGROUND: Condoms are an essential part of comprehensive HIV prevention and care programmes. We report the accessibility of male condoms for female sex workers (FSWs) and the associated characteristics that may play a major role in determining access to condoms for FSWs. METHODS: Confidential interviews of 6509 street- and home-based FSWs in 13 districts of the Indian state of Andhra Pradesh provided data on the number of paying clients and various aspects of access to free condoms and purchase of condoms. Access to condoms was defined as having ever obtained condoms either through free distribution or through purchase. Multivariate analyses were done separately for street- and home-based FSWs to describe correlates of their access to condoms. The requirement of condoms was assessed based on the number of paying clients during the past 15 days. RESULTS: Data on condom access were available for 6465 (99.3%) FSWs. A total of 2850 (44.1%; 95% CI: 36.2%-52.0%) reported accessing free condoms ever and 2336 (36.1%; 95% CI: 30.6%-41.6%) had purchased condoms ever (not mutually exclusive). The primary sources for condoms were non-governmental organization facilities (73.8%) and pharmacies (79.7%) for free and purchased condoms, respectively. A total of 3510 (54.3%; 95% CI: 48.5%-60.1%) FSWs reported no access to free or purchased condoms during the past 15 days, and this no access was significantly higher for those > 30 years of age, with no schooling, street-based FSWs, and with no participation in a FSW support group (p < 0.001 for each in univariate analysis). Participation in a FSW support group was the main predictor of access to free condoms for both types of FSWs during the past 15 days with multivariate analysis. Condom requirements during the past 15 days were met for 67.5% of FSWs who had accessed only free condoms and for 33.8% of those who had accessed only purchased condoms. CONCLUSIONS: One-fourth of FSWs had never accessed condoms, and a little over half of those who had ever accessed reported no access during the past 15 days. Condom requirements were not met for three-fifths of the FSWs. HIV prevention programmes need to Increase access to free condoms for FSWs in Andhra Pradesh as access to condoms is a necessary prerequisite for condom use

Classroom Listening Conditions in Indian Primary Schools: A Survey of Four Schools

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A climatological analysis of heatbursts in Oklahoma (1994–2009)

Heatbursts are characterized by a sudden and highly localized increase in air temperature, a simultaneous decrease in relative humidity and dewpoint temperature, and strong gusty winds, typically associated with decaying thunderstorms. The small spatial extent and short duration of most heatbursts makes detailed study of these events difficult using the standard federal observation network (e.g. hourly observations) established in most countries. Thus, many discussions of heatbursts note that they are ‘rare’ phenomena. However, observations from the Oklahoma Mesonet indicate that although heatbursts are meso-alpha scale phenomena, they are not rare. Using multi-criteria analysis, 207 heatburst events of various magnitudes, areal coverage and duration were identified between 1994 and 2009 across Oklahoma. Significantly more heatbursts were detected in the western two-thirds of the state as compared to the eastern third. Heatbursts were primarily nocturnal events, with 70% of heatburst events initiated between 0000 and 0800 UTC (i.e. between 6 p.m. and 2 a.m. Central Standard Time). With 62 of the 207 events, June was the most active month for heatbursts. At the other extreme, no heatbursts were detected during February and November, and only one was observed during January and December. Almost all of the heatbursts occurred underneath or adjacent to weak radar echoes at the time of the event. Four basic radar patterns were associated with the events: (1) radar echoes associated with rapidly weakening convection, (2) weak reflectivity not produced by or associated with deep moist convection, (3) weak radar echoes to the rear of a dissipating mesoscale convective system (MCS) and (4) weak reflectivity along the periphery of intense convection that did not appear to be weakening

HIV testing among female sex workers in Andhra Pradesh, India.

Of 6648 female sex workers (FSW) in 13 districts of Andhra Pradesh state in India, only 7.9% reported having undergone HIV testing, and three-quarters of the rest were unwilling to undergo HIV testing in the future. The risk of HIV infection as a result of the non-use of condoms was higher among FSW who reported not having been tested and were also unwilling to get tested, and they also held significantly more negative beliefs about HIV/AIDS