Description and calibration of the Langley unitary plan wind tunnel

The two test sections of the Langley Unitary Plan Wind Tunnel were calibrated over the operating Mach number range from 1.47 to 4.63. The results of the calibration are presented along with a a description of the facility and its operational capability. The calibrations include Mach number and flow angularity distributions in both test sections at selected Mach numbers and tunnel stagnation pressures. Calibration data are also presented on turbulence, test-section boundary layer characteristics, moisture effects, blockage, and stagnation-temperature distributions. The facility is described in detail including dimensions and capacities where appropriate, and example of special test capabilities are presented. The operating parameters are fully defined and the power consumption characteristics are discussed

Grand Designs: a study of student midwives' use of a 'Room Planner' App to create a normal birthing environment

The environment within which women give birth has a direct effect upon their birthing experience (RCM 2008, Hodnett et al 2009, Walsh 2010, RCM 2010a, Igarashi et al 2014, Hammond et al 2013). Due to the shift from home to hospital birth most women now birth in an environment which is highly medicalised and one that affects her privacy and sense of control (Walsh 2010a). If a woman does not choose to give birth at home a ‘home from home’ modified type birth setting is the next preferable environment and has been demonstrated to lead to positive outcomes. (Hodnett et al 2009). From the evidence it is vital that midwives and student midwives provide the most positive birthing environment they can for the women they are caring for. In view of this student midwives were asked to design an optimum birthing environment using a free ‘Room Planner’ App which was downloaded onto I-pads. The App contained no medical appliances or equipment thus the students could only design a ‘home like’ birth environment. The students’ use of the App was explored in relation to birthing environment and as an educational tool. Methodology The study design was mixed methods and data was collected by a 10 point Questionnaire (n=17) focus group (n=6) and printouts of the birth environment designs. Data was analysed manually for the questionnaire, by thematic analysis for the focus group and via critical visual analysis in relation to the designs. Results The students placed great emphasis on the birthing ‘triad’ of woman, birth partner(s) and midwife when designing their rooms, which featured three main themes: comfort, usefulness and aesthetics. Comfort was strongly aligned to the psychological nature of labour and birth, with an emphasis on reducing anxiety. Lighting, space and privacy were paramount for the woman. This also included space and privacy for the midwife to observe labour and to make records, and for the birthing partner(s) to relax and rejuvenate themselves. Usefulness was very much focused on the physical process of labour and birth, with water featuring in all of the rooms (shower or bath) and furniture that would aid an upright position. L-shaped sofas were often included in order for the woman, birth partner and midwife to be together. Aesthetics were additions that were often personal to the students enabling them to have some ‘ownership’ of the birth environment, and promote familiarity. From an educational perspective the students felt that using the app aided their visual learning, increased retention of knowledge, made them ‘think outside the box’ and prepared them for clinical practice. Discussion It is evident the students viewed the design of an optimum birthing environment as one that needed to be inclusive of the birthing ‘triad’ of woman, birth partner and midwife. In addition the room design was aligned to practical, psychological and physical needs. Birthing rooms design needs to consider those supporting a woman during labour and birth, and their individual requirements in order to maximise care and outcome

Vapor-screen technique for flow visualization in the Langley Unitary Plan Wind Tunnel

The vapor-screen technique for flow visualization, as developed for the Langley Unitary Plan Wind Tunnel, is described with evaluations of light sources and photographic equipment. Test parameters including dew point, pressure, and temperature were varied to determine optimum conditions for obtaining high-quality vapor-screen photographs. The investigation was conducted in the supersonic speed range for Mach numbers from 1.47 to 4.63 at model angles of attack up to 35 deg. Vapor-screen photographs illustrating various flow patterns are presented for several missile and aircraft configurations. Examples of vapor-screen results that have contributed to the understanding of complex flow fields and provided a basis for the development of theoretical codes are presented with reference to other research

Computational psychiatry: a Rosetta Stone linking the brain to mental illness.

PCF is supported by the Bernard Wolfe Health Neuroscience Fund and the Wellcome Trust. This work was carried out within the Wellcome- and MRC-funded Behavioural and Clinical Neuroscience Institute and the Cambridge and Peterborough NHS Foundation Trust.This is the accepted manuscript. The final version is available from the Lancet Psychiatry at: http://www.thelancet.com/journals/lanpsy/article/PIIS2215-0366%2814%2970298-6/fulltex

Why Do Delusions Persist?

Delusions are bizarre and distressing beliefs that characterize certain mental illnesses. They arise without clear reasons and are remarkably persistent. Recent models of delusions, drawing on a neuroscientific understanding of learning, focus on how delusions might emerge from abnormal experience. We believe that these models can be extended to help us understand why delusions persist. We consider prediction error, the mismatch between expectancy and experience, to be central. Surprising events demand a change in our expectancies. This involves making what we have learned labile, updating and binding the memory anew: a process of memory reconsolidation. We argue that, under the influence of excessive prediction error, delusional beliefs are repeatedly reconsolidated, strengthening them so that they persist, apparently impervious to contradiction

Pavlovian conditioning-induced hallucinations result from overweighting of perceptual priors

Some people hear voices that others do not, but only some of those people seek treatment. Using a Pavlovian learning task, we induced conditioned hallucinations in four groups of people who differed orthogonally in their voice-hearing and treatment-seeking statuses. People who hear voices were significantly more susceptible to the effect. Using functional neuroimaging and computational modeling of perception, we identified processes that differentiated voice-hearers from non-voice-hearers and treatment-seekers from non-treatment-seekers and characterized a brain circuit that mediated the conditioned hallucinations. These data demonstrate the profound and sometimes pathological impact of top-down cognitive processes on perception and may represent an objective means to discern people with a need for treatment from those without

Illusions and Delusions: Relating Experimentally-Induced False Memories to Anomalous Experiences and Ideas

The salience hypothesis of psychosis rests on a simple but profound observation that subtle alterations in the way that we perceive and experience stimuli have important consequences for how important these stimuli become for us, how much they draw our attention, how they embed themselves in our memory and, ultimately, how they shape our beliefs. We put forward the idea that a classical memory illusion – the Deese–Roediger–McDermott (DRM) effect – offers a useful way of exploring processes related to such aberrant belief formation. The illusion occurs when, as a consequence of its relationship to previous stimuli, a stimulus that has not previously been presented is falsely remembered. Such illusory familiarity is thought to be generated by the surprising fluency with which the stimulus is processed. In this respect, the illusion relates directly to the salience hypothesis and may share common cognitive underpinnings with aberrations of perception and attribution that are found in psychosis. In this paper, we explore the theoretical importance of this experimentally-induced illusion in relation to the salience model of psychosis. We present data showing that, in healthy volunteers, the illusion relates directly to self reported anomalies of experience and magical thinking. We discuss this finding in terms of the salience hypothesis and of a broader Bayesian framework of perception and cognition which emphasizes the salience both of predictable and unpredictable experiences

Effects of methamphetamine administration on information gathering during probabilistic reasoning in healthy humans.

Jumping to conclusions (JTC) during probabilistic reasoning is a cognitive bias repeatedly demonstrated in people with schizophrenia and shown to be associated with delusions. Little is known about the neurochemical basis of probabilistic reasoning. We tested the hypothesis that catecholamines influence data gathering and probabilistic reasoning by administering intravenous methamphetamine, which is known to cause synaptic release of the catecholamines noradrenaline and dopamine, to healthy humans whilst they undertook a probabilistic inference task. Our study used a randomised, double-blind, cross-over design. Seventeen healthy volunteers on three visits were administered either placebo or methamphetamine or methamphetamine preceded by amisulpride. In all three conditions participants performed the "beads" task in which participants decide how much information to gather before making a probabilistic inference, and which measures the cognitive bias towards jumping to conclusions. Psychotic symptoms triggered by methamphetamine were assessed using Comprehensive Assessment of At-Risk Mental States (CAARMS). Methamphetamine induced mild psychotic symptoms, but there was no effect of drug administration on the number of draws to decision (DTD) on the beads task. DTD was a stable trait that was highly correlated within subjects across visits (intra-class correlation coefficients of 0.86 and 0.91 on two versions of the task). The less information was sampled in the placebo condition, the more psychotic-like symptoms the person had after the methamphetamine plus amisulpride condition (p = 0.028). Our results suggest that information gathering during probabilistic reasoning is a stable trait, not easily modified by dopaminergic or noradrenergic modulation.This was supported by a Clinical Scientist Award to Dr. Murray from the Medical Research Council (G0701911); by the University of Cambridge Behavioural and Clinical Neuroscience Institute, funded by a joint award from the Medical Research Council and Wellcome Trust (G1000183 and 093875/Z/10Z); by awards from the Wellcome Trust and the Bernard Wolfe Health Neuroscience Fund to Dr. Fletcher; and by the Wellcome Trust Clinical Research Facility (WTCRF) at Addenbrooke's Hospital. This work was partly conducted at the Clinical Neuroscience Research Unit, Connecticut Mental Health Center. The authors recognize the support of the Connecticut Department of Mental Health and Addiction Services. This publication was also made possible by Clinical and Translational Science Awards grant UL1 RR024139 from the National Center for Research Resources and the National Center for Advancing Translational Science, components of National Institutes of Health, and the NIH Roadmap for Medical Research. Its contents are solely the responsibility of the authors and do not necessarily represent the official view of NIH.This is the final published version, also available from PLOS at http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0102683