A survey of anticyclonic mesoscale eddies, within the Southern Ocean, and their propagation south from the South West Indian Ridge

Eddies within oceans act as vehicles, transporting smaller bodies of water, with certain oceanographic characteristics, from one place to another within a larger body of water. The South West Indian Ridge [SWIR] is a topographically complex bathymetric feature which amplifies the production of mesoscale eddies in and around the Antarctic Circumpolar Current [ACC]. Within the Southern Ocean [SO], a section of this ridge - the Andrew Bain Fracture Zone [ABFZ] - has been found to be the starting line of an eastward extending eddy corridor. Earlier research shows an area of diminishing mesoscale variability within this corridor which extends down from 45°S to approximately 60S. A recent study focused on a southward extending anticyclonic eddy corridor and proved its existence. The anticyclonic [warm core] eddies which are propagating south, not previously investigated through in situ means, were observed during the 2014 Marion Island Relief Cruise [MIRC2014] aboard the SA Agulhas II. Two anticyclonic mesoscale eddies [one juvenile and one mature] were bisected with transects of conductivity, temperature and depth stations and expendable bathythermograph deployments. This paper used the in situ data captured during the MIRC2014 to study the internal structure of the two eddies. The objectives of this study were also to examine both the recent and the historical trajectory characteristics of the southward advecting anticyclonic eddies, to confirm the origin of the two sampled eddies, and to assess the structural differences between the two anticyclonic eddies. This paper plots the behaviour of the anticyclonic mesoscale eddies found within the area of the southward eddy corridor, firstly using website available data collected over a two year period [May 2012 - May 2014] and then utilizing a previously compiled data set to plot the historical dynamics [October 1992 - April 2012]. The trajectories of the southward anticyclones during that time period were found to be predominantly southward, typically following the south west slope of the SWIR. The two MIRC2014 eddies were confirmed to originate from the ABFZ section of the SWIR. Each eddy had a similar grouping of water masses; Antarctic Bottom Water, Circumpolar Deep Water, Antarctic Intermediate Water, Winter Water and Sub-Antarctic Surface Water: water masses characteristic of the Antarctic Polar Frontal Zone [APFZ]. The in situ measurement and analysis of these eddies allowed the first comparison between a juvenile and a mature anticyclonic eddy in the recently discovered southward extending eddy corridor. Thermal section comparisons of these two sampled anticyclonic eddies showed that, over time, these anticyclonic eddies appear to shrink in surface diameter, deepen and lose heat to host waters. This loss of heat occurs due to the degradation of water mass boundary integrity over time and is theorised to accelerate as time passes. This study shows that the southward extending eddy corridor is a means of shifting heat and salt further south within the SO, large sections of which are sink areas for atmospheric CO₂. This poleward heat transport influences the capability of the SO to absorb atmospheric CO₂, since higher temperatures negatively affect the ocean's CO₂ uptake capability. The results of this study are proposed to be a catalyst for future in situ sampling across eddies in this area, in order that heat and salt transport, through this southward anticyclonic eddy corridor, can be monitored for fluctuations. As this carbon sink is vitally important with regards to climate change, the quantification of the heat and salt sources of the SO, which alter the SO's ability to absorb CO₂, is imperative

Interprofessional partnerships in chronic illness care: a conceptual model for measuring partnership effectiveness

Introduction: Interprofessional health and social service partnerships (IHSSP) are internationally acknowledged as integral for comprehensive chronic illness care. However, the evidence-base for partnership effectiveness is lacking. This paper aims to clarify partnership measurement issues, conceptualize IHSSP at the front-line staff level, and identify tools valid for group process measurement. <br><br> Theory and methods: A systematic literature review utilizing three interrelated searches was conducted. Thematic analysis techniques were supported by NVivo 7 software. Complexity theory was used to guide the analysis, ground the new conceptualization and validate the selected measures. Other properties of the measures were critiqued using established criteria. <br><br> Results: There is a need for a convergent view of what constitutes a partnership and its measurement. The salient attributes of IHSSP and their interorganizational context were described and grounded within complexity theory. Two measures were selected and validated for measurement of proximal group outcomes. <br><br> Conclusion: This paper depicts a novel complexity theory-based conceptual model for IHSSP of front-line staff who provide chronic illness care. The conceptualization provides the underpinnings for a comprehensive evaluative framework for partnerships. Two partnership process measurement tools, the PSAT and TCI are valid for IHSSP process measurement with consideration of their strengths and limitations

Peer learning beyond the curriculum in university statistics courses

Peer learning in statistics can occur in a variety of settings, including class collaborations and assessment in the form of group projects. Most reports indicate that it has positive effects on learning. However, peer learning can also be organised by students themselves outside course requirements, to similar positive effect. In this paper, we investigate this second form, sometimes referred to as ‘peer learning beyond the curriculum’. The parameters of the project were derived from a similar study in the discipline of music, conceived as an action research collaboration between students and academics. A series of focus group interviews was carried out with students in a range of university statistics classes, introductory and later-year, majoring in statistics or studying statistics as a component of another discipline. These were arranged and run by a group of statistics students participating as researchers and peer learners in a ‘vertical’ research team that also included more experienced academics from statistics and other disciplines. The team found that first-year students were well aware of the academic and social benefits of forming study groups to support each other’s statistics learning, and they gave clear advice to future students to do so. By contrast, peer learning in later-year classes played a more nuanced role that seemed to depend on the major discipline in which statistics was being studied – possibly due to the particular aspects of statistics that were in focus. Comparisons with peer learning in other disciplines shed more light on the various ways that peer learning in statistics can be utilised in different contexts, and suggest various implications for improving statistics pedagogy

Effects of correlated turbulent velocity fields on the formation of maser lines

The microturbulent approximation of turbulent motions is widely used in radiative transfer calculations. Mainly motivated by its simple computational application it is probably in many cases an oversimplified treatment of the dynamical processes involved. This aspect is in particular important in the analysis of maser lines, since the strong amplification of radiation leads to a sensitive dependence of the radiation field on the overall velocity structure. To demonstrate the influence of large scale motions on the formation of maser lines we present a simple stochastic model which takes velocity correlations into account. For a quantitative analysis of correlation effects, we generate in a Monte Carlo simulation individual realizations of a turbulent velocity field along a line of sight. Depending on the size of the velocity correlation length we find huge deviations between the resulting random profiles in respect of line shape, intensity and position of single spectral components. Finally, we simulate the emission of extended maser sources. A qualitative comparison with observed masers associated with star forming regions shows that our model can reproduce the observed general spectral characteristics. We also investigate shortly, how the spectra are effected when a systematic velocity field (simulating expansion) is superposed on the fluctuations. Our results convincingly demonstrate that hydrodynamical motions are of great importance for the understanding of cosmic masers.Comment: Accepted for publication in A&A. 8 pages, 8 figure

Availability and utilisation of physician-based pre-hospital critical care support to the NHS ambulance service in England, Wales and Northern Ireland

Background: Every day throughout the UK, ambulance services seek medical assistance in providing critically ill or injured patients with pre-hospital care. Objective: To identify the current availability and utilisation of physician-based pre-hospital critical care capability across England, Wales and Northern Ireland. Design: A postal and telephone survey was undertaken between April and December 2009 of all 13 regional NHS ambulance services, 17 air ambulance charities, 34 organisations affiliated to the British Association for Immediate Care and 215 type 1 emergency departments in England, Wales and Northern Ireland. The survey focused on the availability and use of physician-basedpre-hospital critical care support. Results: The response rate was 100%. Although nine NHS ambulance services recorded physician attendance at 6155 incidents, few could quantify doctor availability and utilisation. All but one of the British Association for Immediate Care organisations deployed ‘only when available’ and only 45% of active doctors could provide critical care support. Eleven air ambulance services (65%) operated with a doctor but only 5 (29%) operated 7 days a week. Fifty-nine EDs (27%) had a pre-hospital team but only 5 (2%) had 24 h deployable critical care capability and none were used regularly. Conclusion: There is wide geographical and diurnal variability in availability and utilisation of physician-based pre-hospital critical care support. Only London ambulance service has access to NHS-commissioned 24 h physician-based pre-hospital critical care support. Throughout the rest of the UK, extensive use is made of volunteer doctors and charity sector providers of varying availability and capability

A novel optical microscope for imaging large embryos and tissue volumes with sub-cellular resolution throughout

Current optical microscope objectives of low magnification have low numerical aperture and therefore have too little depth resolution and discrimination to perform well in confocal and nonlinear microscopy. This is a serious limitation in important areas, including the phenotypic screening of human genes in transgenic mice by study of embryos undergoing advanced organogenesis. We have built an optical lens system for 3D imaging of objects up to 6 mm wide and 3 mm thick with depth resolution of only a few microns instead of the tens of microns currently attained, allowing sub-cellular detail to be resolved throughout the volume. We present this lens, called the Mesolens, with performance data and images from biological specimens including confocal images of whole fixed and intact fluorescently-stained 12.5-day old mouse embryos

Rusty old stars: a source of the missing interstellar iron?

Iron, the Universe's most abundant refractory element, is highly depleted in both circumstellar and interstellar environments, meaning it exists in solid form. The nature of this solid is unknown. In this Letter, we provide evidence that metallic iron grains are present around oxygen-rich AGB stars, where it is observationally manifest as a featureless mid-infrared excess. This identification is made using Spitzer Space Telescope observations of evolved globular cluster stars, where iron dust production appears ubiquitous and in some cases can be modelled as the only observed dust product. In this context, FeO is examined as the likely carrier for the 20-micron feature observed in some of these stars. Metallic iron appears to be an important part of the dust condensation sequence at low metallicity, and subsequently plays an influential role in the interstellar medium. We explore the stellar metallicities and luminosities at which iron formation is observed, and how the presence of iron affects the outflow and its chemistry. The conditions under which iron can provide sufficient opacity to drive a wind remain unclear.Comment: 7 pages. 4 figures, accepted ApJ

Continuous and Burst-like Accretion onto Substellar Companions in Mira Winds

We present numerical hydrodynamical modeling of the effects of a giant planet or brown dwarf companion orbiting within the extended atmosphere and wind formation zone of an approximately solar-mass Mira variable star. The large-scale, time-dependent accretion flows within the radially oscillating and outflowing circumstellar gas around Miras are related to Bondi-Hoyle-Lyttleton flows, but have not, to our knowledge, been previously modelled. The new models presented in this paper illustrate the changes in accretion and wake dynamics as the companion mass is varied over a range from 10 to 50 Jupiter masses ($M_J$). The character of the accretion onto the companion changes greatly as the companion mass is increased. At the lowest companion masses considered here, a low continuous rate of mass accretion is punctuated by large, nearly periodic bursts of accretion. When the companion mass is large, the mass accretion has both a continuous part, and a rapidly varying, nearly stochastic part. These trends can be understood as the result of the interplay between the shocks and radial oscillations in the circumstellar gas, and the wake flow behind the companion. Models with accretion bursts may produce observable optical brightenings, and may affect SiO maser emission. (Abridged)Comment: 16 pgs., 10 figures with low resolution versions of Figs. 1, 9. Accepted for publication in MNRA

Dynamical Opacity-Sampling Models of Mira Variables. II: Time-Dependent Atmospheric Structure and Observable Properties of 4 M-Type Model Series

We present 4 model series of the CODEX dynamical opacity-sampling models of Mira variables with solar abundances, designed to have parameters similar to $o$ Cet, R Leo and R Cas. We demonstrate that the CODEX models provide a clear physical basis for the molecular shell scenario used to explain interferometric observations of Mira variables. We show that these models generally provide a good match to photometry and interferometry at wavelengths between the near-infrared and the radio, and make the model outputs publicly available. These model also demonstrate that, in order to match visible and infrared observations, the Fe-poor silicate grains that form within 3 continuum radii must have small grain radii and therefore can not drive the winds from O-rich Mira variables.Comment: 16 pages, 18 figures, accepted for MNRA