Attitude Determination from Single-Antenna Carrier-Phase Measurements

A model of carrier phase measurement (as carried out by a satellite navigation receiver) is formulated based on electromagnetic theory. The model shows that the phase of the open-circuit voltage induced in the receiver antenna with respect to a local oscillator (in the receiver) depends on the relative orientation of the receiving and transmitting antennas. The model shows that using a {\it single} receiving antenna, and making carrier phase measurements to seven satellites, the 3-axis attitude of a user platform (in addition to its position and time) can be computed relative to an initial point. This measurement model can also be used to create high-fidelity satellite signal simulators that take into account the effect of platform rotation as well as translation.Comment: 12 pages, and one figure. Published in J. Appl. Phys. vol. 91, No. 7, April 1, 200

A close-pair binary in a distant triple supermassive black-hole system

Galaxies are believed to evolve through merging, which should lead to multiple supermassive black holes in some. There are four known triple black hole systems, with the closest pair being 2.4 kiloparsecs apart (the third component is more distant at 3 kiloparsecs), which is far from the gravitational sphere of influence of a black hole with mass $\sim$10$^9$ M$_\odot$ (about 100 parsecs). Previous searches for compact black hole systems concluded that they were rare, with the tightest binary system having a separation of 7 parsecs. Here we report observations of a triple black hole system at redshift z=0.39, with the closest pair separated by $\sim$140 parsecs. The presence of the tight pair is imprinted onto the properties of the large-scale radio jets, as a rotationally-symmetric helical modulation, which provides a useful way to search for other tight pairs without needing extremely high resolution observations. As we found this tight pair after searching only six galaxies, we conclude that tight pairs are more common than hitherto believed, which is an important observational constraint for low-frequency gravitational wave experiments.Comment: 21 pages, 6 figures. Published online by Nature on 25 June 2014. Extremely minor differences with published version exis

Hydroxyferroroméite, a new secondary weathering mineral from Oms, France

Hydroxyferroroméite, ideally (Fe2+ 1.5[]0.5)Sb5+ 2O6(OH), is a new secondary mineral from the Correc d'en Llinassos, Oms, Pyrénées-Orientales Department, France. Hydroxyferroroméite occurs as yellow to yellow-brown powdery boxwork replacements up to about 50μm across after tetrahedrite in a siderite–quartz matrix. No distinct crystals have been observed. The empirical formula (based on 7 (O + OH) per formula unit, pfu) is (Fe2+ 1.07Cu2+ 0.50Zn0.03Sr0.03Ca 0.01[]0.36)Σ2 (Sb5+ 1.88Si0.09Al0.02As0.01)Σ2 O6 ((OH)0.86 O0.14). X-ray photoelectron spectroscopy was used to determine the valence states of Sb, Fe and Cu. Hydroxyferroroméite crystallises in the space group Fd3 m with the pyrochlore structure and hence is a new Fe2+ -dominant member of the roméite group of the pyrochlore supergroup. It has the unit-cell parameters: a = 10.25(3) Å, V = 1077(6) Å3 and Z = 8. A model, based on bond-valence theory, for incorporation of the small Fe2+ cation into a displaced variant of the A site of the pyrochlore structure is proposed.The attached document is the author(’s’) final accepted/submitted version of the journal article. You are advised to consult the publisher’s version if you wish to cite from it

Midwifery capacity building in Papua New Guinea: Key achievements and ways forward

© 2015 Australian College of Midwives. Background: Papua New Guinea has some of the poorest health outcomes in the Asia-Pacific region. Maternal mortality is unacceptably high and there is a severe midwifery shortage requiring a quadrupling of the workforce. Aim: This paper outlines the findings of an evaluation of the Maternal Child Health Initiative (MCHI) (2012-2013) to determine key factors contributing to maternal health workforce strengthening. Method: A descriptive mixed methods study was undertaken. Data were gathered through interviews, focus group discussions and surveys with clinicians, midwifery students and staff from nursing and midwifery schools and National Department of Health staff. Documentation from stakeholder meetings and regular site reports were reviewed. Each data set was analysed separately and meta-inferences were drawn across all data. Findings: Learning opportunities were found to have increased for midwifery educators and improvements were described in midwifery educators teaching capacity and student clinical education experience. There was an increase in the number of midwifery graduates and improvements were noted in the working environment and skills of clinical staff. Education challenges were described including the lack of clinical preceptoring and limited continuing education for clinical educators. Participants recommended increasing clinical education hours and extending the length of the midwifery program. Ongoing efforts to accredit the midwifery curricula and regulate midwifery graduates were noted. Conclusion: The MCHI has contributed to strengthening the midwifery workforce nationally. However, scaling-up and sustaining these achievements requires leadership and funding commitments from the midwifery schools and government alongside the accreditation of midwifery curricula and regulation of new graduates

Pacific Islands Emergency Management Alliance (PIEMA) Project Mid-Term Review Report

This report presents findings of the Mid-Term Review of the Pacific Islands Emergency Management Alliance (PIEMA) project

Grid-Adapted FUN3D Computations for the Second High Lift Prediction Workshop

Contributions of the unstructured Reynolds-averaged Navier-Stokes code FUN3D to the 2nd AIAA CFD High Lift Prediction Workshop are described, and detailed comparisons are made with experimental data. Using workshop-supplied grids, results for the clean wing configuration are compared with results from the structured code CFL3D Using the same turbulence model, both codes compare reasonably well in terms of total forces and moments, and the maximum lift is similarly over-predicted for both codes compared to experiment. By including more representative geometry features such as slat and flap brackets and slat pressure tube bundles, FUN3D captures the general effects of the Reynolds number variation, but under-predicts maximum lift on workshop-supplied grids in comparison with the experimental data, due to excessive separation. However, when output-based, off-body grid adaptation in FUN3D is employed, results improve considerably. In particular, when the geometry includes both brackets and the pressure tube bundles, grid adaptation results in a more accurate prediction of lift near stall in comparison with the wind-tunnel data. Furthermore, a rotation-corrected turbulence model shows improved pressure predictions on the outboard span when using adapted grids

Appearance concerns in ophthalmic patients

Aims: This study aimed to determine the psychosocial and appearance-related concerns of a sample of ophthalmic patients by measuring a range of psychological, social, and demographic factors. Methods: Standardized psychological measures including anxiety, depression, appearance-related distress, self-discrepancy, appearance salience and valence were administered to 98 participants attending ophthalmic outpatient clinics in either London, Bristol, Sheffield or Bradford. Differences between groups were explored using t-tests and ANOVA, relationships between all variables were investigated using Pearson's correlation coefficient. Results: Although mean scores for psychological adjustment were within the normal range, some participants were experiencing considerable levels of generalized anxiety. Being older, male, and married or living with a partner was related to significantly better adjustment. Better adjustment was also related to a less visible area of concern, greater disguisability of the affected area, a more positive evaluation of their own appearance, less engagement in comparing themselves with others, greater feelings of being accepted by others, appearance being less important to their self-concept, and a smaller discrepancy between the persons ideal and actual appearance. Conclusions: A majority of ophthalmic patients adjust positively to the demands placed on them. By identifying the variables that are associated with successful adaptation, the specific psychological interventions and appropriate systems of support can be put in place to help those who are adversely affected

On Planetary Companions to the MACHO-98-BLG-35 Microlens Star

We present observations of microlensing event MACHO-98-BLG-35 which reached a peak magnification factor of almost 80. These observations by the Microlensing Planet Search (MPS) and the MOA Collaborations place strong constraints on the possible planetary system of the lens star and show intriguing evidence for a low mass planet with a mass fraction $4\times 10^{-5} \leq \epsilon \leq 2\times 10^{-4}$. A giant planet with $\epsilon = 10^{-3}$ is excluded from 95% of the region between 0.4 and 2.5 $R_E$ from the lens star, where $R_E$ is the Einstein ring radius of the lens. This exclusion region is more extensive than the generic "lensing zone" which is $0.6 - 1.6 R_E$. For smaller mass planets, we can exclude 57% of the "lensing zone" for $\epsilon = 10^{-4}$ and 14% of the lensing zone for $\epsilon = 10^{-5}$. The mass fraction $\epsilon = 10^{-5}$ corresponds to an Earth mass planet for a lensing star of mass \sim 0.3 \msun. A number of similar events will provide statistically significant constraints on the prevalence of Earth mass planets. In order to put our limits in more familiar terms, we have compared our results to those expected for a Solar System clone averaging over possible lens system distances and orientations. We find that such a system is ruled out at the 90% confidence level. A copy of the Solar System with Jupiter replaced by a second Saturn mass planet can be ruled out at 70% confidence. Our low mass planetary signal (few Earth masses to Neptune mass) is significant at the $4.5\sigma$ confidence level. If this planetary interpretation is correct, the MACHO-98-BLG-35 lens system constitutes the first detection of a low mass planet orbiting an ordinary star without gas giant planets.Comment: ApJ, April 1, 2000; 27 pages including 8 color postscript figure