Design and flight testing of a nullable compressor face rake

A compressor face rake with an internal valve arrangement to permit nulling was designed, constructed, and tested in the laboratory and in flight at the NASA Flight Research Center. When actuated by the pilot in flight, the nullable rake allowed the transducer zero shifts to be determined and then subsequently removed during data reduction. Design details, the fabrication technique, the principle of operation, brief descriptions of associated digital zero-correction programs and the qualification tests, and test results are included. Sample flight data show that the zero shifts were large and unpredictable but could be measured in flight with the rake. The rake functioned reliably and as expected during 25 hours of operation under flight environmental conditions and temperatures from 230 K (-46 F) to greater than 430 K (314 F). The rake was nulled approximately 1000 times. The in-flight zero-shift measurement technique, as well as the rake design, was successful and should be useful in future applications, particularly where accurate measurements of both steady-state and dynamic pressures are required under adverse environmental conditions

Breast feeding practices and views among diabetic women: a retrospective cohort study

Objective: to explore the pattern and experiences of breast-feeding practices among diabetic women. Design: retrospective cohort study using maternal records and postal questionnaires in a Baby-Friendly hospital. Participants: diabetic mothers including women with gestational diabetes, and type 1 and 2 diabetes mellitus. Findings: from the total group of respondents, 81.9% intended to breast feed. The actual breast feeding rates were 81.9% at birth, 68.1% at 2 weeks and 28.7% at 6 months postpartum. Major themes that were identified from women's experiences included information and advice, support vs. pressure, classification and labelling, and expectations. Conclusions: more than two-thirds of the diabetic women intended to breast feed and actually did breast feed in this study. For both the total study population and the type 1 and 2 diabetics alone, more than half were still breast feeding at 2 weeks postpartum, and approximately one-third were still breast feeding at 6 months postpartum. Implications for practice: structured support, provided for women through Baby-Friendly initiatives, was appreciated by the diabetic women in this study. The extent to which this support influenced the highly successful breast feeding practices in this group of women needs focused investigation. The need for a delicate balancing act between pressure and advice in order to prevent coercion was noted.</p

Adapting clinical guidelines to take account of multimorbidity

Most people with a chronic condition have multimorbidity, but clinical guidelines almost entirely focus on single conditions. It will never be possible to have good evidence for every possible combination of conditions, but guidelines could be made more useful for people with multimorbidity if they were delivered in a format that brought together relevant recommendations for different chronic conditions and identified synergies, cautions, and outright contradictions. We highlight the problem that multimorbidity poses to clinicians and patients using guidelines for single conditions and propose ways of making them more useful for people with multimorbidity

Superluminal propagation of an optical pulse in a Doppler broadened three-state, single channel active Raman gain medium

Using a single channel active Raman gain medium we show a $(220\pm 20)$ns advance time for an optical pulse of $\tau_{FWHM}=15.4 \mu$s propagating through a 10 cm medium, a lead time that is comparable to what was reported previously. In addition, we have verified experimentally all the features associated with this single channel Raman gain system. Our results show that the reported gain-assisted superluminal propagation should not be attributed to the interference between the two frequencies of the pump field.Comment: 4 pages, 3 figure

A study to define an in-flight dynamics measurement and data applications program for space shuttle payloads

Data measurement and interpretation techniques were defined for application to the first few space shuttle flights, so that the dynamic environment could be sufficiently well established to be used to reduce the cost of future payloads through more efficient design and environmental test techniques. It was concluded that: (1) initial payloads must be given comprehensive instrumentation coverage to obtain detailed definition of acoustics, vibration, and interface loads, (2) analytical models of selected initial payloads must be developed and verified by modal surveys and flight measurements, (3) acoustic tests should be performed on initial payloads to establish realistic test criteria for components and experiments in order to minimize unrealistic failures and retest requirements, (4) permanent data banks should be set up to establish statistical confidence in the data to be used, (5) a more unified design/test specification philosophy is needed, (6) additional work is needed to establish a practical testing technique for simulation of vehicle transients

Understanding performance under pressure: anxiety, attention, cognitive biases and the perception of failure

It is consistently found that heightened anxiety leads to poorer performance in sport environments, with the majority of research reporting that disrupted attentional mechanisms explain the negative anxiety-performance relationship. However, there has been little exploration of why sports performers might become anxious in the first instance. Additionally, the effect these different interpretations of pressure might have on attentional control and performance has not been explored. These two issues drove the main aims of the current thesis, which sought to test the predictions of a new theory developed by researchers in the anxiety-performance area. First, the thesis systematically collated the evidence in regards to the attentional mechanisms underpinning the anxiety-performance relationship to determine the consensus in the sporting literature, including the challenges and areas of emergent or current research. Second, the thesis addressed the research challenges highlighted in the review by exploring the Attentional Control Theory Sport (ACTS; Eysenck & Wilson, 2016) with the aim to understand what initiates the anxiety response in individuals, in particular through the interpretation of pressure. The first experimental study examined the cognitive biases element of ACTS and investigated whether attention and interpretive bias as moderating variables of state anxiety are related to trait anxiety and attentional control, with the intention of better understanding what pre-empts experiencing cognitive biases. The second experimental study examined the perception of failure by determining whether perceived probability and cost of failure influenced the experience of state anxiety. Finally, the third experimental study built upon the aims from the previous studies and examined the hypothesised relationships between cognitive biases, perception of failure and state anxiety, attentional control and performance. This work is the first to empirically examine the theoretically derived predictions of ACTS, through exploring attentional and interpretive biases, perceived probability and cost of failure and the influence on momentary state anxiety, attentional control and performance

Viking dynamics experience with application to future payload design

Analytical and test techniques are discussed. Areas in which hindsight indicated erroneous, redundant, or unnecessarily severe design and test specifications are identified. Recommendations are made for improvements in the dynamic design and criteria philosophy, aimed at reducing costs for payloads