Polarized Self-Absorption: A potential new method for probing excited states of nuclei

Photon strength functions are some of the most important and useful properties of nuclei. Their uses range from modeling the synthesis of light and heavy elements in supernovae to the production of medical isotopes to be used in imaging and therapy. However, complete knowledge of all possible decay modes of a nucleus is required before these functions can be calculated. Current methods of probing nuclei, such as nuclear resonance fluorescence (NRF), often fail to find low-energy decays due to exponentially increasing background radiation at low energies. As a result, current knowledge of all possible decays of a nucleus results in a lower limit rather than a definitive value. I seek to probe the reliability of Polarized Self Absorption, a new method proposed for probing nuclei that takes advantage of the quasi-monochromatic and linearly polarized photon beam produced at the High Intensity gamma-ray Source, by examining the 10.71-MeV excited state in 24Mg. Specifically, I work towards finding the full and partial widths of this state in 24Mg. As a first result, this work found new decay paths out of the 10.71-MeV state and determined its spin and parity to be 1^+. The difference between the experimental asymmetry, A_{Ex} = 0.644(5), and the mass-weighed asymmetry, A_{MW} = 0.457(5), indicates that self absorption is taking place, as required for this method to work. However, the final determination of the resonance width will have to await resolution of an issue discussed further in the text.Bachelor of Scienc

Gaia transient detection efficiency: hunting for nuclear transients

We present a study of the detectability of transient events associated with galaxies for the Gaia European Space Agency astrometric mission. We simulated the on-board detections, and on-ground processing for a mock galaxy catalogue to establish the properties required for the discovery of transient events by Gaia, specifically tidal disruption events (TDEs) and supernovae (SNe). Transients may either be discovered by the on-board detection of a new source or by the brightening of a previously known source. We show that Gaia transients can be identified as new detections on-board for offsets from the host galaxy nucleus of 0.1--0.5,arcsec, depending on magnitude and scanning angle. The Gaia detection system shows no significant loss of SNe at close radial distances to the nucleus. We used the detection efficiencies to predict the number of transients events discovered by Gaia. For a limiting magnitude of 19, we expect around 1300 SNe per year: 65% SN Ia, 28% SN II and 7% SN Ibc, and ~20 TDEs per year.Comment: 17 pages, 10 figures, accepted by MNRA

MI5 and the Cold War in South-East Asia: Examining the Performance of Security Intelligence Far East (SIFE), 1946-1963

From 1946–1963, MI5 operated a South-East Asian regional headquarters in Singapore: Security Intelligence Far East (SIFE). This article responds to growing interest in theatre-level intelligence organisation and the importance of intelligence to Britain’s Cold War and decolonisation by examining the performance of SIFE. On the organisational level, SIFE was strongest when it remained wedded to its charter functions and closely adhered to the priorities of its principal consumer: the Commissioner-General for South-East Asia. Its assessments were influential in shaping decision-makers’ understandings of key regional developments, although this did not always translate into public policy. Lastly, SIFE enjoyed success in developing lasting liaison relationships to cement British influence, but failed to utilise these to improve its intake of raw intelligence

Evaluating Total Environmental Impact for a Computing Infrastructure

In this paper we outline the results of a project to evaluate the total climate/carbon impact of a digital research infrastructure for a defined snapshot period. We outline the carbon model used to calculate the impact and the data collected to quantify that impact for a defined set of resources. We discuss the variation in potential impact across both the active and embodied carbon for computing hardware and produce a range of estimates on the amount of carbon equivalent climate impact for the snapshot period

Assessment of the Environmental Impact of Food Consumption in Ireland-Informing a Transition to Sustainable Diets

Dietary changes are required to mitigate the climatic impact of food consumption. Food consumption databases can support the development of sustainable food based dietary guidelines (SFBDG) when linked to environmental indicators. An improved knowledge base is crucial to the transition to sustainable diets, and multiple environmental indicators should be considered to ensure this transition is evidence based and accounts for trade-offs. The current study aimed to quantify the environmental impact of daily diets across population groups in Ireland. Nationally representative food consumption surveys for Irish children (NCFSII; 2017-2018), teenagers (NTFSII; 2019-2020), and adults (NANS; 2008-2010) were used in this analysis. Blue water use (L) and greenhouse gas emissions (GHGe; kgCO2eq) were assigned at food level to all surveys. Cropland (m2), nitrogen (kgN/t), and phosphorous use (kgP/t) were assigned at the agricultural level for adults. Multiple linear regressions, Spearman correlations, and ANCOVAs with Bonferroni corrections were conducted. Higher environmental impact diets were significantly associated with demographic factors such as age, education status, residential location, and sex, but these associations were not consistent across population groups. The median greenhouse gas emissions were 2.77, 2.93, and 4.31 kgCO2eq, and freshwater use per day was 88, 144, and 307 L for children, teenagers, and adults, respectively. The environmental impact of the Irish population exceeded the planetary boundary for GHGe by at least 148% for all population groups, however the boundary for blue water use was not exceeded. Meat and meat alternatives (27-44%); eggs, dairy, and dairy alternatives (15-21%); and starchy staples (10-20%) were the main contributors to GHGe. For blue water use, the highest contributors were meat and meat alternatives in children; savouries, snacks, nuts, and seeds in teenagers; and eggs, dairy, and dairy alternatives in adults (29-52%). In adults, cropland use, nitrogen use, and phosphorous use exceeded planetary boundaries by 277-382%. Meat, dairy, and grains were the main contributors to cropland, nitrogen, and phosphorous use (79-88%). The quantified environmental impact of Irish diets provides a baseline analysis, against which it will be possible to track progress towards sustainable diets, and the basis for the development of Sustainable Food Based Dietary Guidelines in Ireland

The real foundation of fictional worlds

I argue that judgements of what is ‘true in a fiction’ presuppose the Reality Assumption: the assumption that everything that is (really) true is fictionally the case, unless excluded by the work. By contrast with the more familiar Reality Principle, the Reality Assumption is not a rule for inferring implied content from what is explicit. Instead it provides an array of real-world truths that can be used in such inferences. I claim that the Reality Assumption is essential to our ability to understand stories, drawing on a range of empirical evidence that demonstrates our reliance on it in narrative comprehension. However, the Reality Assumption has several unintuitive consequences, not least that what is fictionally the case includes countless facts that neither authors nor readers could (or should) ever consider. I argue that such consequences provide no reason to reject the Reality Assumption. I conclude that we should take fictions, like non-fictions, to be about the real world