Guidance and control requirements for high-speed Rollout and Turnoff (ROTO)

This report defines the initial requirements for designing a research high-speed rollout and turnoff (ROTO) guidance and control system applicable to transport class aircraft whose purpose is to reduce the average runway occupancy time (ROT) for aircraft operations. The requirements will be used to develop a ROTO system for both automatic and manual piloted operation under normal and reduced visibility conditions. Requirements were determined for nose wheel/rudder steering, braking/reverse thrust, and the navigation system with the aid of a non-real time, three degree-of-freedom MD-11 simulation program incorporating airframe and gear dynamics. The requirements were developed for speeds up to 70 knots using 30 ft exit geometries under dry and wet surface conditions. The requirements were generated under the assumptions that the aircraft landing system meets the current Category III touchdown dispersion requirements and that aircraft interarrival spacing is 2 nautical miles. This effort determined that auto-asymmetric braking is needed to assist steering for aft center-of-gravity aircraft. This report shows various time-history plots of the aircraft performance for the ROTO operation. This effort also investigated the state-of-the-art in the measurement of the runway coefficient of friction for various runway conditions

Graduate views on access to higher education: is it really a case of pulling up the ladder?

Using as a starting point in the recent work of Mountford-Zimdars et al., the authors analyse attitudes towards expanding higher education (HE) opportunities in the UK. The authors propose that the approach of Mountford-Zimdars et al. is flawed not only in its adoption of a multivariate logistic regression but also in its interpretation of results. The authors make a number of adaptations, chief among them being the use of an ordered probit approach and the addition of a time dimension to test for changes in attitudes between 2000 and 2010. The authors find that attitudes towards HE expansion have intensified during the decade 2000–2010, but the authors uncover no evidence that this is due to graduates wanting to ‘pull up the ladder’, as suggested by Mountford-Zimdars et al. The authors argue that evidence of a widespread desire to reduce access to HE can most likely be explained by social congestion theory, internal institutional disaffection and rising tuition fees

Lesions to the mediodorsal thalamus, but not orbitofrontal cortex, enhance volatility beliefs linked to paranoia

Beliefs—attitudes toward some state of the environment—guide action selection and should be robust to variability but sensitive to meaningful change. Beliefs about volatility (expectation of change) are associated with paranoia in humans, but the brain regions responsible for volatility beliefs remain unknown. The orbitofrontal cortex (OFC) is central to adaptive behavior, whereas the magnocellular mediodorsal thalamus (MDmc) is essential for arbitrating between perceptions and action policies. We assessed belief updating in a three-choice probabilistic reversal learning task following excitotoxic lesions of the MDmc (n = 3) or OFC (n = 3) and compared performance with that of unoperated monkeys (n = 14). Computational analyses indicated a double dissociation: MDmc, but not OFC, lesions were associated with erratic switching behavior and heightened volatility belief (as in paranoia in humans), whereas OFC, but not MDmc, lesions were associated with increased lose-stay behavior and reward learning rates. Given the consilience across species and models, these results have implications for understanding paranoia

Lesions to the mediodorsal thalamus but not orbitofrontal cortex enhance volatility beliefs linked to paranoia

Beliefs – attitudes toward some state of the environment – guide action selection and should be robust to variability but sensitive to meaningful change. Beliefs about volatility (expectation of change) are associated with paranoia in humans yet the brain regions responsible for volatility beliefs remain unknown. Orbitofrontal cortex (OFC) is central to adaptive behavior whereas magnocellular mediodorsal thalamus (MDmc) is essential for arbitrating between perceptions and action policies. We assessed belief updating in a three-choice probabilistic reversal-learning task following excitotoxic lesions of MDmc (n=3) or OFC (n=3) and compared performance with that of unoperated rhesus macaques (n=14). Computational analyses indicated that lesions of the MDmc, but not OFC, were associated with erratic switching behavior and heightened volatility belief (as in paranoia in humans). In contrast, OFC lesions were associated with increased lose-stay behavior and reward learning rates. Given the consilience across species and models these results have implications for understanding paranoia