Revealing the Ionization Properties of the Magellanic Stream using Optical Emission

The Magellanic Stream, a gaseous tail that trails behind the Magellanic Clouds, could replenish the Milky Way with a tremendous amount of gas if it reaches the Galactic disk before it evaporates into the halo. To determine how the Magellanic Stream's properties change along its length, we have conducted an observational study of the H-alpha emission, along with other optical warm ionized gas tracers, toward 39 sight lines. Using the Wisconsin H-alpha Mapper telescope, we detect H-alpha emission brighter than 30 - 50 mR in 26 of our 39 sight lines. This H-alpha emission extends more than 2-degree away from the HI emission. By comparing H-alpha and [OI] intensities, we find that regions with log NHI = 19.5 - 20.0 are 16 - 67% ionized. Most of the H-alpha intensities along the Magellanic Stream are much higher than expected if the primary ionization source is photoionization from Magellanic Clouds, the Milky Way, and the extragalactic background. We find that the additional contribution from self ionization through a "shock cascade" that results as the Stream plows through the halo might be sufficient to reproduce the underlying level of H-alpha emission along the Stream. In the sparsely sampled region below the South Galactic Pole, there exists a subset of sight lines with uncharacteristically bright emission, which suggest that gas is being ionized further by an additional source that could be a linked to energetic processes associated with the Galactic center.Comment: Accepted for publication in the Astrophysical Journal on Nov 8, 201

The Emotional Impact of Testing Positive for High-Risk HPV: an Exploration of Cis-Women’s Experiences Following a Positive Test Result in the UK

Aims: High-risk HPV is often stigmatised and feminised. Testing positive for high-risk HPV is associated with a range of distressing emotional and relational responses. The aims of this study were to explore the emotional experience of cis-gender women testing positive for high-risk HPV in the UK. Specifically, it explored sense making and meaning making. Method: Six semi-structured interviews were conducted with cis-gender women who had tested positive for, or were diagnosed with, high-risk HPV at routine cervical screening. The interviews were analysed using Interpretative Phenomenological Analysis. Results: Four Group Experiential Themes were identified showing the extent of emotional and psychological distress associated with testing positive for high-risk HPV. Ten sub-themes were identified. These showed the impact of high-risk HPV at several levels from societal through to individual. The themes highlighted the impact of stigma and feminisation, emotional distress associated with interactions with NHS systems, and experiences of connection and disconnection. Finally, the themes highlighted this process as an emotional journey, and the impact on identity and control. Implications: Findings of this study were discussed alongside relevant theory and literature with careful consideration of clinical implications. The implications suggested a need to consider language and narratives when high-risk HPV is discussed both within the NHS and wider services (e.g. schools), the impact of assigned female at birth only testing, the delivery of positive test results, and better integration of physical and mental health in relation to high-risk HPV

Probing the Gamma-ray Emission from HESS Source RX J1713.7-3946

The origin of Cosmic Rays (CRs) from our the galaxy remains a major mystery in high energy astrophysics. Astronomy techniques, such as -ray astronomy, have assisted us in coming closer to solving the problem, but many questions still remain unsolved. CRs are believed to produce -rays via interactions with the interstellar medium (ISM) in high energy situations. For this reason -rays are often used as a tracer for the parent CRs. The hadronic ( interactions) and leptonic processes (IC scattering, synchrotron processes and relativistic Bremsstrahlung) involved in the production of the -rays are complex and at times intertwined. Hadronic processes are often favoured as the dominant production channel when there is spatially correlated ISM gas surrounding a source. RX J1713.7- 3946 is a bright source of -rays, but is also visible in the radio and X-ray regime. The morphology of the radiation seen from this source is shell like, which leads us to believe that it resembles a supernova remnant (SNR). The high energy environment provided by SNRs is believed to be a great way to accelerate CRs to the energies we observe. In this study we attempt to determine whether the -ray production is dominated by hadronic and/or leptonic processes towards RX J1713.7-3946. Using the latest high resolution -ray observations from the High Energy Stereoscopic System (HESS) along with X-ray and radio observations from Suzaku and the Southern Galactic Plane Survey (SGPS) respectively, we are able to model the broadband spectra from 29 distinct regions across the SNR. We investigate the resultant parameter space and begin to gain an idea of how the -rays are produced in some of these regions. Additionally, using the latest high resolution Mopra CO data we are able to estimate the density of the ISM in each region. This allows us to more accurately model the spectra and to uncover some regions where the often-negligible Bremsstrahlung emission is of significance. In addition to this spectral study, we use the high resolution -ray and CO data to perform a 2D correlation study between the -rays and ISM. Spatial correlation is found in 7 regions, suggesting the -rays are produced predominantly by hadronic processes. On the other hand, 5 regions display anti-correlation, leading us to favour the leptonic scenario for the -ray production. We also find observable and modeled differences between the correlated regions and anti-correlated regions, e.g. the radio synchrotron emission. These differences are investigated and discussed within the scope of the literature.Thesis (MPhil) -- University of Adelaide, School of Physical Sciences, 201

Rapid, metal-free and aqueous synthesis of imidazo[1,2-a]pyridine under ambient conditions

A novel, rapid and efficient route to imidazo[1,2-a]pyridines under ambient, aqueous and metal-free conditions is reported. The NaOH-promoted cycloisomerisations of N-propargylpyridiniums give quantitative yield in a few minutes (10 g scale). A comparison of common green metrics to current routes showed clear improvements, with at least a one order of magnitude increase in space-time-yield

A laboratory-scale annular continuous flow reactor for UV photochemistry using excimer lamps for discrete wavelength excitation and its use in a wavelength study of a photodecarboxlyative cyclisation

This paper describes a new annular reactor for continuous UV photochemistry, which uses easily interchangeable excimer lamps of different wavelengths. The reactor has narrow clearance to form thin films of material for efficient irradiation of molecules. Its use is demonstrated by investigating the effect of discrete wavelength lamps (222, 282 and 308 nm) on the reaction of potassium N-phthalimidobutanoate 1. The ability of the reactor to be integrated into multistep processes is illustrated by combining it with an Amberlyst scavenger and a solid acid catalyst, NbOPO4, to access a second product 3 that is obtained in a single telescoped process. The tricyclic scaffold in 3 is a motif found in several biologically active compounds and has possibilities as a synthon for new pharmaceutical products

Using metrics and sustainability considerations to evaluate the use of bio-based and non-renewable Brønsted acidic ionic liquids to catalyse Fischer esterification reactions

Background Ionic liquids have found uses in many applications, one of which is the joint solvation and catalysis of chemical transformations. Suitable Brønsted acidic ionic liquids can be formed by combining lactams with sulphonic acids. This work weighs up the relative benefits and disadvantages of applying these Brønsted acidic ionic liquid catalysts in esterifications through a series of comparisons using green chemistry metrics. Results A new bio-based ionic liquid was synthesised from N-methyl pyrrolidinone and p-cymenesulphonic acid, and tested as a catalyst in three Fischer esterifications under different conditions. An evaluation of the performance of this Brønsted acidic ionic liquid was made through the comparison to other ionic liquid catalysts as well as conventional homogeneous Brønsted acids. Conclusion Extending the argument to feedstock security as well as mass utilisation, ultimately in most instances traditional mineral acids appear to be the most sensible option for Brønsted acid esterification catalysts. Ester yields obtained from Brønsted acidic ionic liquid catalysed procedures were modest. This calls into question the diversity of research exploring esterification catalysis and the role of ionic liquids in esterifications

Tools and techniques for solvent selection: green solvent selection guides

Driven by legislation and evolving attitudes towards environmental issues, establishing green solvents for extractions, separations, formulations and reaction chemistry has become an increasingly important area of research. Several general purpose solvent selection guides have now been published with the aim to reduce use of the most hazardous solvents. This review serves the purpose of explaining the role of these guides, highlighting their similarities and differences. How they can be used most effectively to enhance the greenness of chemical processes, particularly in laboratory organic synthesis and the pharmaceutical industry, is addressed in detail

The large-scale ionization cones in the Galaxy

There is compelling evidence for a highly energetic Seyfert explosion (10^{56-57} erg) that occurred in the Galactic Centre a few million years ago. The clearest indications are the x-ray/gamma-ray "10 kpc bubbles" identified by the Rosat and Fermi satellites. In an earlier paper, we suggested another manifestation of this nuclear activity, i.e. elevated H-alpha emission along a section of the Magellanic Stream due to a burst (or flare) of ionizing radiation from Sgr A*. We now provide further evidence for a powerful flare event: UV absorption line ratios (in particular CIV/CII, SiIV/SiII) observed by the Hubble Space Telescope reveal that some Stream clouds towards both galactic poles are highly ionized by a source capable of producing ionization energies up to at least 50 eV. We show how these are clouds caught in a beam of bipolar, radiative "ionization cones" from a Seyfert nucleus associated with Sgr A*. In our model, the biconic axis is tilted by about 15 deg from the South Galactic Pole with an opening angle of roughly 60 deg. For the Stream at such large Galactic distances (D > 75 kpc), nuclear activity is a plausible explanation for all of the observed signatures: elevated H-alpha emission and H ionization fraction (X_e > 0.5), enhanced CIV/CII and SiIV/SiII ratios, and high CIV and SiIV column densities. Wind-driven "shock cones" are ruled out because the Fermi bubbles lose their momentum and energy to the Galactic corona long before reaching the Stream. The nuclear flare event must have had a radiative UV luminosity close to the Eddington limit (f_E ~ 0.1-1). Our time-dependent Seyfert flare models adequately explain the observations and indicate the Seyfert flare event took place T_o = 3.5 +/- 1 Myr ago. The timing estimates are consistent with the mechanical timescales needed to explain the x-ray/gamma-ray bubbles in leptonic jet/wind models (2-8 Myr).Comment: 21 pages; 15 figures; 2 movies (this version matches published version

Comparison of depression and anxiety symptom networks in reporters and non-reporters of lifetime trauma in two samples of differing severity

Background: Reported trauma is associated with differences in the course and outcomes of depression and anxiety. However, no research has explored the association between reported trauma and patterns of clinically relevant symptoms of both depression and anxiety. / Methods: We used network analysis to investigate associations between reported trauma and depression and anxiety symptom interactions in affected individuals from the Genetic Links to Anxiety and Depression (GLAD) Study (n = 17720), and population volunteers from the UK Biobank (n = 11120). Participants with current moderate symptoms of depression or anxiety were grouped into reporters and non-reporters of lifetime trauma. Networks of 16 depression and anxiety symptoms in the two groups were compared using the network comparison test. / Results: In the GLAD Study, networks of reporters and non-reporters of lifetime trauma did not differ on any metric. In the UK Biobank, the symptom network of reporters had significantly greater density (7.80) than the network of non-reporters (7.05). / Limitations: The data collected in the GLAD Study and the UK Biobank are self-reported with validated or semi-validated questionnaires. / Conclusions: Reported lifetime trauma was associated with stronger interactions between symptoms of depression and anxiety in population volunteers. Differences between reporters and non-reporters may not be observed in individuals with severe depression and/or anxiety due to limited variance in the presentation of disorder