Working out of the ‘toolbox’: an exploratory study with complementary therapists in acute cancer care

Aims: The aim of this research was to explore and capture therapists’ experiences of and preparation for working with patients in an acute cancer care setting. Method: Semi structured interviews with therapists (n=18) in an acute cancer hospital in the North West of England. The interviews were transcribed and analysed using thematic coding. Results: Key themes identified included; the need for a ‘tool box’ that goes beyond initial training, building confidence with adapting these new skills in practice, helping patients to become empowered, the need to support carers, research evidence and resources issues, and the role of supervision. Conclusion: This study was limited by being set in a single acute cancer site. Therapists valued having a ‘tool box’ but needed confidence and support to navigate the challenges of clinical practice.The authors would like to acknowledge the support of ‘Walk the Walk’ Charity, who help fund the complementary therapy services in the Radiotherapy and Chemotherapy Departments

Fixed-Point Posets in Theories of Truth

We show that any coherent complete partial order is obtainable as the fixed-point poset of the strong Kleene jump of a suitably chosen first-order ground model. This is a strengthening of Visser’s result that any finite ccpo is obtainable in this way. The same is true for the van Fraassen supervaluation jump, but not for the weak Kleene jump

He abundances in disc galaxies. I. Predictions from cosmological chemodynamical simulations

Accepted for publication in A&AWe investigate how the stellar and gas-phase He abundances evolve as a function of time within simulated star-forming disc galaxies with different star formation histories. We make use of a cosmological chemodynamical simulation for galaxy formation and evolution, which includes star formation as well as energy and chemical enrichment feedback from asymptotic giant branch stars, core-collapse supernovae, and Type Ia supernovae. The predicted relations between the He mass fraction, Y, and the metallicity, Z, in the interstellar medium of our simulated disc galaxies depend on the galaxy star formation history. In particular, dY/dZ is not constant and evolves as a function of time, depending on the specific chemical element that we choose to trace Z; in particular, dY/dX O and dY/dX C increase as a function of time, whereas dY/dX N decreases. In the gas-phase, we find negative radial gradients of Y, due to the inside-out growth of our simulated galaxy discs as a function of time; this gives rise to longer chemical enrichment timescales in the outer galaxy regions, where we find lower average values for Y and Z. Finally, by means of chemical-evolution models, in the galactic bulge and inner disc, we predict steeper Y vs. age relations at high Z than in the outer galaxy regions. We conclude that for calibrating the assumed Y-Z relation in stellar models, C, N, and C+N are better proxies for the metallicity than O because they show steeper and less scattered relations.Peer reviewedFinal Published versio

The stellar mass of the Gaia-Sausage/Enceladus accretion remnant

The \textit{Gaia}-Sausage/Enceladus (GS/E) structure is an accretion remnant which comprises a large fraction of the Milky Way's stellar halo. We study GS/E using high-purity samples of kinematically selected stars from APOGEE DR16 and \textit{Gaia}. Employing a novel framework to account for kinematic selection biases using distribution functions, we fit density profiles to these GS/E samples and measure their masses. We find that GS/E has a shallow density profile in the inner Galaxy, with a break between 15--25~kpc beyond which the profile steepens. We also find that GS/E is triaxial, with axis ratios 1:0.55:0.45 (nearly prolate), and the major axis is oriented about 80~degrees from the Sun--Galactic centre line and 16 degrees above the plane. We measure a stellar mass for GS/E of $1.45\,^{+0.92}_{-0.51}\,\mathrm{(stat.)}\,^{+0.13}_{-0.37} \mathrm{(sys.)}\ \times10^{8}~\Msun. Our mass estimate is lower than others in the literature, a finding we attribute to the excellent purity of the samples we work with. We also fit a density profile to the entire Milky Way stellar halo, finding a mass in the range of 6.7-8.4 \times 10^{8}$~\Msun, and implying that GS/E could make up as little as 15-25~per~cent of the mass of the Milky Way stellar halo. Our lower stellar mass combined with standard stellar-mass-to-halo mass relations implies that GS/E constituted a minor 1:8 mass-ratio merger at the time of its accretion.Comment: Accepted in MNRA

Evaluating various classification strategies for identifying tree species for tree inventory creation from a hyperspectral image : a thesis presented in the partial fulfilment of the requirements for the degree of Master of Science in Agriculture at Massey University, Manawatū, New Zealand

An inventory showing tree species locations is a valuable tool for urban forest managers to support a healthy ecosystem. Urban areas offer harsh environmental conditions for these trees. This intensifies the value of a tree inventory to make sure the urban forest provides environmental, social and economic benefits. But the frequency and coverage of an inventory can be limited due to cost, time, level of expertise and poor access to private property. This study aims to overcome this limitation by using hyperspectral remote sensing and analysis to create cost effective and relatively fast tree inventories that cover both private and public land. This research tests if this technology accumulates enough information to separate and classify twenty tree species within a diverse canopy. To classify this image, this study used two stages. The first stage removed areas of the map that did not represent trees while the second stage separated twenty tree species from each other. This study used the aisaFENIX airborne imaging spectrometer to gather reflected light in the visible-shortwave infra-red (SWIR) range (400-2500 nm) over Palmerston North, New Zealand. The image has a 1 m2 spatial resolution, 3.5-11 nm spectral resolution of 448 spectral bands. Then ground sampling of tree species locations collected correct training and accuracy testing data for the classifiers. The classification compared 45 different strategies (9 pre-processing methods and five supervised classifiers). These combinations identified the best method to pre-process and classify the image at each stage. The pre-processing methods included band selection, and the noise reducing techniques of minimum noise fraction (MNF) and derivative reflectance (DR). While the classifiers used included the support vector machine (SVM), binary encoding (BE), Mahalanobis distance (MHD), maximum likelihood (ML), and minimum distance (MD) classifiers. The strategies produced vastly different results. In the first stage the MD classifier together with DR, MNF, and band selection pre-processing produced the best results when removing the non-tree surfaces from the image. In the second stage the SVM classifier together with MNF and band selection pre-processing achieved the best overall accuracy of 94.85% to separate twenty specific tree species. (Other tree species are misclassified as one of the twenty tree species). Therefore, this accuracy means that pixels representing each of the twenty tree species will be correctly classified within their own class 94.85% of the time. Evaluating multiple strategies led to combination producing a high overall accuracy in being able to separate twenty tree species from each other. This shows that hyperspectral remote sensing could be an effective tool to create tree inventories in urban environments

Unveiling the History and Nature of the Milky Way with Galactic Surveys and Numerical Simulations

The galaxy within which we reside, the Milky Way, offers perhaps the highest fidelity training ground for models of galaxy formation, providing insights into its history of formation and evolution on a star-by-star basis. Such insights are only truly useful for constraining disc galaxy formation models if we properly understand the wider context of the Milky Way among the plethora of galaxies in the Universe. This thesis aims to make progress toward answering the question of whether the Milky Way is a typical disc galaxy. Through the effort to answer this question, this thesis presents new measurements of the structure of our Galaxy and new insights into aspects of its history of assembly and evolution which have a strong influence on its α-element abundances. Providing a baseline constraint on future models for the formation of the Galaxy, I present a dissection of the Milky Way disc spatial structure as a function of [Fe/H], [α/Fe] and stellar ages (based on the surface abundances of Carbon and Nitrogen), as measured by the APOGEE survey. I measure the disc density profile, fitting the scale heights and lengths of mono-age, mono-[Fe/H] sub-populations in the high and low [α/Fe] disc. The fitted disc vertical scale height distribution is smooth when weighted by surface-mass density, suggesting that the high and low [α/Fe] populations are not vertically distinct at the solar radius, as would be expected if they were interchangeable with the geometric thin and thick disc components. I find that the surface density profile of low [α/Fe] mono-age, mono-[Fe/H] populations is best fit by a broken exponential, such that their density increases with R to a peak radius, and declines thereafter, whereas the high [α/Fe] populations are better described by a single, declining exponential within the range of Galactocentric radii observed by APOGEE. The trends of the density profile parameters as a function of age and metallicity provide insights into the structural evolution of the Galaxy, and provide strong constraints on future models of its formation and evolution. In particular, a main finding of this study is that the high and low [α/Fe] discs have a relatively distinct radial structure. To understand the origin of the structures found in the above study, and to generate novel and predictive models for the formation of the Galaxy, I perform an analysis of element abundances in Milky Way like galaxy discs in the EAGLE simulation. I concentrate on the abundance of α-elements in these galaxies, with a view to understanding the origin of the bimodality in [α/Fe] at fixed [Fe/H] which is apparent in both the Milky Way and in EAGLE Galactic analogues. I show that EAGLE reproduces broad expectations for the production of α-elements from simple chemical evolution models, namely that stars with enhanced [α/Fe] are born from gas in rapidly star forming environments at high density. These environments are conducive to forming α-enhanced stars because their gas consumption timescale is considerably shorter than the characteristic delay timescale for Type Ia supernovae. I further show that such environments are only achieved in EAGLE haloes when the rate of dark matter accretion is faster at early times than the majority of galaxies with similar stellar mass at z=0. The necessity for this atypical and rapid early assembly means that galaxies hosting discs with [α/Fe] bimodality are extremely rare, forming in ≈ 6% of galaxies at the Milky Way stellar mass range. Following the prediction of EAGLE that galaxies which host [α/Fe] bimodality like that of the Milky Way should have atypical histories of assembly, I then perform a study of Milky Way halo stars in common between APOGEE and Gaia DR2, with a view to placing constraints on the accretion history of the Galaxy. I present a detailed characterisation of the kinematics and abundances of the recently discovered Gaia-Enceladus association, which is proposed to be the debris of a singular and massive accretion event. By comparing the kinematics and abundances of Gaia-Enceladus to the debris of satellites accreted onto Milky Way analogues in the EAGLE simulations, I make a quantitative prediction of the stellar mass of the Milky Way satellite to be 10^8.5 < M* < 10^9 Msun and predict its earliest possible time of accretion to be z≈1.5. I also show that such mergers are uncommon in the simulations, in agreement with the prediction that the Milky Way assembly history should be atypical. The above results outline a new view of the Galaxy in which it is potentially not a good example of a `typical' disc galaxy, playing host to structural components which are linked to its chemistry in a complex manner, which may indicate that its history of assembly is not in common with other galaxies at the same stellar mass. In finding that the Galaxy is atypical in this way, this thesis has uncovered new aspects of the evolutionary history of the Milky Way, which pave the way for future work towards the goal of fully reconstructing the history of our Galaxy and using that understanding to formulate robust and general models for the formation of disc galaxies

A variational encoder-decoder approach to precise spectroscopic age estimation for large Galactic surveys

Constraints on the formation and evolution of the Milky Way Galaxy require multi-dimensional measurements of kinematics, abundances, and ages for a large population of stars. Ages for luminous giants, which can be seen to large distances, are an essential component of studies of the Milky Way, but they are traditionally very difficult to estimate precisely for a large dataset and often require careful analysis on a star-by-star basis in asteroseismology. Because spectra are easier to obtain for large samples, being able to determine precise ages from spectra allows for large age samples to be constructed, but spectroscopic ages are often imprecise and contaminated by abundance correlations. Here we present an application of a variational encoder-decoder on cross-domain astronomical data to solve these issues. The model is trained on pairs of observations from APOGEE and Kepler of the same star in order to reduce the dimensionality of the APOGEE spectra in a latent space while removing abundance information. The low dimensional latent representation of these spectra can then be trained to predict age with just $\sim$ 1,000 precise seismic ages. We demonstrate that this model produces more precise spectroscopic ages ($\sim$ 22% overall, $\sim$ 11% for red-clump stars) than previous data-driven spectroscopic ages while being less contaminated by abundance information (in particular, our ages do not depend on [$\alpha$/M]). We create a public age catalog for the APOGEE DR17 data set and use it to map the age distribution and the age-[Fe/H]-[$\alpha$/M] distribution across the radial range of the Galactic disk