Current Performance Characteristics of NASA Langley Research Center's Cockpit Motion Base and Standardized Test Procedure for Future Performance Characterization

This report documents the updated performance characteristics of NASA Langley Research Center's (LaRC) Cockpit Motion Base (CMB) after recent revisions that were made to its inner-loop, feedback control law. The modifications to the control law will be briefly described. The performance of the Cockpit Motion Facility (CMF) will be presented. A short graphical comparison to the previous control law can be found in the appendix of this report. The revised controller will be shown to yield reduced parasitic accelerations with respect to the previous controller. Metrics based on the AGARD Advisory Report No. 144 are used to assess the overall system performance due to its recent control algorithm modification. This report also documents the standardized simulator test procedure which can be used in the future to evaluate potential updates to the control law

Current Performance Characteristics of NASA Langley Research Center's Cockpit Motion Base and Standardized Test Procedure for Future Performance Characterization

This report documents the updated performance characteristics of NASA Langley Research Center's (LaRC) Cockpit Motion Base (CMB) after recent revisions that were made to its inner-loop, feedback control law. The modifications to the control law will be briefly described. The performance of the CMF will be presented. A short graphical comparison to the previous control law can be found in the appendix of this report. The revised controller will be shown to yield reduced parasitic accelerations with respect to the previous controller. Metrics based on the AGARD Advisory Report No. 144 are used to assess the overall system performance due to its recent control algorithm modification. This report also documents the standardized simulator test procedure which can be used in the future to evaluate potential updates to the control law

Piloted Simulation Assessment of the Impact of Flexible Structures on Handling Qualities of Generic Supersonic Aircraft

The NASA Langley Research Center Cockpit Motion Facility (CMF) was used to conduct a piloted simulation assessment of the impact of flexible structures on flying qualities. The CMF was used because of its relatively high bandwidth, six degree-of-freedom motion capability. Previous studies assessed and attempted to mitigate the effects of multiple dynamic aeroservoelastic modes (DASE). Those results indicated problems existed, but the specific cause and effect was difficult to ascertain. The goal of this study was to identify specific DASE frequencies, damping ratios, and gains that cause degradation in handling qualities. A generic aircraft simulation was developed and designed to have Cooper-Harper Level 1 handling qualities when flown without DASE models. A test matrix of thirty-six DASE modes was implemented. The modes had frequencies ranging from 1 to 3.5 Hz and were applied to each axis independently. Each mode consisted of a single axis, frequency, damping, and gain, and was evaluated individually by six subject pilots with test pilot backgrounds. Analysis completed to date suggests that a number of the DASE models evaluated degrade the handling qualities of this class of aircraft to an uncontrollable condition

Previous reproductive history and post-natal family planning among HIV-infected women in Ukraine

BACKGROUND: Ukraine has the highest antenatal HIV prevalence in Europe. The national prevention of mother-to-child transmission (MTCT) programme has reduced the MTCT rate, but less attention has been given to the prevention of unintended pregnancy among HIV-positive women. Our objectives were to describe the reproductive health, condom use and family planning (FP) practices of HIV-positive childbearing Ukrainian women and to identify factors associated with different methods of post-natal contraception. METHODS: HIV-infected childbearing women, diagnosed before or during pregnancy, were enrolled prospectively in a post-natal cohort study in four regional HIV/AIDS centres in Ukraine from December 2007. Logistic regression models were used to identify factors associated with post-natal FP practices. RESULTS: Data were available for 371 women enrolled by March 2009; 82% (n = 303) were married or cohabiting, 27% (97 of 363) reported a current HIV-negative sexual partner and 69% were diagnosed with HIV during their most recent pregnancy. Overall, 21% (75 of 349) of women were not using contraception post-natally (of whom 80% reported no current sexual activity), 50% (174 of 349) used condoms, 20% (74 of 349) relied solely/partially on coitus interruptus and 4% used hormonal methods or intrauterine device. Among married/cohabiting women, consistent use of condoms in the previous pregnancy [AOR 1.96 (95%CI 1.06–3.62)], having an HIV-positive partner [AOR 0.42 (0.20–0.87)], current sexual activity [AOR 4.53 (1.19–17.3)] and study site were significantly associated with post-natal condom use; 16% of those with HIV-negative partners did not use condoms. Risk factors for non-use of FP were lack of affordability [AOR 6.34 (1.73–23.2)] and inconsistent use of condoms in the previous pregnancy [AOR 7.25 (1.41–37.2)]. CONCLUSIONS: More than 40% of HIV-positive women in this population are at risk of unintended pregnancy and the one in six women in HIV-discordant couples not using barrier methods risk transmitting HIV to their partners. Our study results are limited by the observational nature of the data and the potential for both measured and unmeasured confounding

Russia-UK collaboration in paleontology: past, present, and future

There is a long history of collaboration between Russia and the United Kingdom in paleontology. This began, arguably, in 1821, with the seminal work by William Fox-Strangways, who produced a geological map of the area around St Petersburg. Most famously, Roderick Murchison carried out extensive surveying and observations throughout European Russia in 1840 and 1841, and published a major monograph on geology and paleontology of European Russia in 1845. Since then, and continuing today, there have been many fruitful collaborations on Precambrian life, Paleozoic marine organisms, terrestrialization of plants and vertebrates, the Permian–Triassic mass extinction, fossil mammals, human evolution, and conservation paleobiology

The purpose of mess in action research: building rigour though a messy turn

Mess and rigour might appear to be strange bedfellows. This paper argues that the purpose of mess is to facilitate a turn towards new constructions of knowing that lead to transformation in practice (an action turn). Engaging in action research - research that can disturb both individual and communally held notions of knowledge for practice - will be messy. Investigations into the 'messy area', the interface between the known and the nearly known, between knowledge in use and tacit knowledge as yet to be useful, reveal the 'messy area' as a vital element for seeing, disrupting, analysing, learning, knowing and changing. It is the place where long-held views shaped by professional knowledge, practical judgement, experience and intuition are seen through other lenses. It is here that reframing takes place and new knowing, which has both theoretical and practical significance, arises: a 'messy turn' takes place

Exceptional 20th Century Shifts in Deep-Sea Ecosystems Are Spatially Heterogeneous and Associated With Local Surface Ocean Variability

Traditionally, deep-sea ecosystems have been considered to be insulated from the effects of modern climate change, but with the recognition of the importance of food supply from the surface ocean and deep-sea currents to sustaining these systems, the potential for rapid response of benthic systems to climate change is gaining increasing attention. However, very few ecological time-series exist for the deep ocean covering the twentieth century. Benthic responses to past climate change have been well-documented using marine sediment cores on glacial-interglacial timescales, and ocean sediments have also begun to reveal that planktic species assemblages are already being influenced by global warming. Here, we use benthic foraminifera found in mid-latitude and subpolar North Atlantic sediment cores to show that, in locations beneath areas of major surface water change, benthic ecosystems have also changed significantly over the last ∼150 years. The maximum benthic response occurs in areas which have seen large changes in surface circulation, temperature, and/or productivity. We infer that the observed surface-deep ocean coupling is due to changes in the supply of organic matter exported from the surface ocean and delivered to the seafloor. The local-to-regional scale nature of these changes highlights that accurate projections of changes in deep-sea ecosystems will require (1) increased spatial coverage of deep-sea proxy records, and (2) models capable of adequately resolving these relatively small-scale oceanographic features

Concerted involvement of Cdx/Hox genes and Wnt signaling in morphogenesis of the caudal neural tube and cloacal derivatives from the posterior growth zone

Decrease in Cdx dosage in an allelic series of mouse Cdx mutants leads to progressively more severe posterior vertebral defects. These defects are corrected by posterior gain of function of the Wnt effector Lef1. Precocious expression of Hox paralogous 13 genes also induces vertebral axis truncation by antagonizing Cdx function. We report here that the phenotypic similarity also applies to patterning of the caudal neural tube and uro-rectal tracts in Cdx and Wnt3a mutants, and in embryos precociously expressing Hox13 genes. Cdx2 inactivation after placentation leads to posterior defects, including incomplete uro-rectal septation. Compound mutants carrying one active Cdx2 allele in the Cdx4-null background (Cdx2/4), transgenic embryos precociously expressing Hox13 genes and a novel Wnt3a hypomorph mutant all manifest a comparable phenotype with similar uro-rectal defects. Phenotype and transcriptome analysis in early Cdx mutants, genetic rescue experiments and gene expression studies lead us to propose that Cdx transcription factors act via Wnt signaling during the laying down of uro-rectal mesoderm, and that they are operative in an early phase of these events, at the site of tissue progenitors in the posterior growth zone of the embryo. Cdx and Wnt mutations and premature Hox13 expression also cause similar neural dysmorphology, including ectopic neural structures that sometimes lead to neural tube splitting at caudal axial levels. These findings involve the Cdx genes, canonical Wnt signaling and the temporal control of posterior Hox gene expression in posterior morphogenesis in the different embryonic germ layers. They shed a new light on the etiology of the caudal dysplasia or caudal regression range of human congenital defects.AICR project grant: (08-0199); Dutch Earth and Life Sciences grant: (820.02.005); 6th Framework Programme Network of Excellence `Cells into Organs'; Dutch government grant: (Bsik Program 03038); Fundação para a Ciência e Tecnologia grant: (PTDC/BIA-BCM/110638/2009); Centro de Biologia do Desenvolvimento grant: (POCTI-ISFL-4-664)