Modelling tidal changes within the wash and Morecambe bay during the Holocene

Palaeotidal changes are one of the least known factors of the sea-level record variation at the local scale (Shennan, 1986a; Devoy, 1987). This thesis extends knowledge of tidal alterations with sea-level change by means of an approach integrating numerical tidal models with geological stratigraphic data recording former tidal heights. The last 10,000 years (the Holocene period) were chosen for study due to the sedimentary sequence available recording sea-level changes. Two macro-tidal embayments, the Wash and Morecambe Bay, are examined for palaeotidal changes by running a series of seven numerical tidal models from the scale of the north-east Atlantic to that of the bays. In order to obtain results to the required resolution to carry out the work, two new tidal models were developed for the Wash. Tidal model simulations for lowering of sea depths from current bathymetric values without coastline shape changes showed reductions of a maximum of 10% of the sea-level reductions in the bays. Changes to tidal altitudes were not so great for alterations to coastal shape alone, where no modification of present sea depth values was included. A combination of sea depth and coastline changes used in the reconstruction of former tidal height patterns within the embayments showed differences corresponding broadly to the variations in altitude of sea-level index points within the Wash Fenlands, although altitudinal differences are within the model error band for tidal predictions. For Morecambe Bay, however, tidal inundation does not occur to altitudes predicted by sea-level index points and it is suggested, following Tooley (1978, 1987), that neotectonic movements may well have influenced the Holocene sea-level record in this area. Better palaeogeographic data are required for more accurate palaeotidal simulations in embayments. Sediment compaction is also identified as an area requiring further research in the attempt to explain altitudinal variation of sea-level index points within local areas and so enable regional comparisons of sea-level change to be made

Comparative effectiveness and harms of antibiotics for outpatient diverticulitis two nationwide cohort studies

Background: Outpatient diverticulitis is commonly treated with either a combination of metronidazole and a fluoroquinolone (metronidazole-with-fluoroquinolone) or amoxicillin-clavulanate alone. The U.S. Food and Drug Administration advised that fluoroquinolones be reserved for conditions with no alternative treatment options. The comparative effectiveness of metronidazole-with-fluoroquinolone versus amoxicillin-clavulanate for diverticulitis is uncertain. Objective: To determine the effectiveness and harms of metronidazole-with-fluoroquinolone versus amoxicillin-clavulanate for outpatient diverticulitis. Design: Active-comparator, new-user, retrospective cohort studies. Setting: Nationwide population-based claims data on U.S. residents aged 18 to 64 years with private employer-sponsored insurance (2000 to 2018) or those aged 65 years or older with Medicare (2006 to 2015). Participants: Immunocompetent adults with diverticulitis in the outpatient setting. Intervention: Metronidazole-with-fluoroquinolone or amoxicillin-clavulanate. Measurements: 1-year risks for inpatient admission, urgent surgery, and Clostridioides difficile infection (CDI) and 3-year risk for elective surgery. Results: In MarketScan (IBM Watson Health), new users of metronidazole-with-fluoroquinolone (n = 106 361) and amoxicillin-clavulanate (n = 13 160) were identified. There were no differences in 1-year admission risk (risk difference, 0.1 percentage points [95% CI, -0.3 to 0.6]), 1-year urgent surgery risk (risk difference, 0.0 percentage points [CI, -0.1 to 0.1]), 3-year elective surgery risk (risk difference, 0.2 percentage points [CI, -0.3 to 0.7]), or 1-year CDI risk (risk difference, 0.0 percentage points [CI, -0.1 to 0.1]) between groups. In Medicare, new users of metronidazole-with-fluoroquinolone (n = 17 639) and amoxicillin-clavulanate (n = 2709) were identified. There were no differences in 1-year admission risk (risk difference, 0.1 percentage points [CI, -0.7 to 0.9]), 1-year urgent surgery risk (risk difference, -0.2 percentage points [CI, -0.6 to 0.1]), or 3-year elective surgery risk (risk difference, -0.3 percentage points [CI, -1.1 to 0.4]) between groups. The 1-year CDI risk was higher for metronidazole-with-fluoroquinolone than for amoxicillin-clavulanate (risk difference, 0.6 percentage points [CI, 0.2 to 1.0]). Limitation: Residual confounding is possible, and not all harms associated with these antibiotics, most notably drug-induced liver injury, could be assessed. Conclusion: Treating diverticulitis in the outpatient setting with amoxicillin-clavulanate may reduce the risk for fluoroquinolone-related harms without adversely affecting diverticulitis-specific outcomes

A stacked analysis of brightest cluster galaxies observed with the Fermi Large Area Telescope

We present the results of a search for high-energy γ-ray emission from a large sample of galaxy clusters sharing the properties of three existing Fermi Large Area Telescope detections (in Perseus, Virgo and A3392), namely a powerful radio source within their brightest cluster galaxy (BCG). From a parent, X-ray flux-limited sample of 863 clusters, we select 114 systems with a core-dominated BCG radio flux above 50/75 mJy (in the National Radio Astronomy Observatory Very Large Array Sky Survey and the Sydney University Molonglo Sky Survey, respectively), stacking data from the first 45 months of the Fermi mission in three energy bands, to determine statistical limits on the γ-ray fluxes of the ensemble of candidate sources. For a >300 MeV selection, the distribution of detection significance across the sample is consistent with that across control samples for significances 4σ signals which are not associated with previously identified γ-ray emission. Modelling of the data in these fields results in the detection of four non-2FGL Fermi sources, though none of these appear to be unambiguously associated with the BCG candidate. Only one is sufficiently close to be a plausible counterpart (RXC J0132.6−0804) and the remaining three appear to be background active galactic nuclei. A search at energies >3 GeV hints at emission from the BCG in A2055, which hosts a BL Lac object. There is no evidence for a signal in the stacked data, and the upper limit derived on the γ-ray flux of an average radio-bright BCG in each band is at least an order of magnitude more constraining than that calculated for individual objects. F1 GeV/F1.4 GHz for an average BCG in the sample is <15, compared with ≈120 for NGC 1275 in Perseus, which might indicate a special case for those objects detected at high energies. The tentative suggestion that point-like beamed emission from member galaxies comprise the dominant bright γ-ray sources in clusters implies searches for evidence of dark matter annihilation or large-scale merger shock signatures, for example, need to account for a significant level of contamination from within each cluster that is both highly stochastic and varies significantly over time

A non-thermal study of the brightest cluster galaxy NGC 1275 - the Gamma-Radio connection over four decades

Emission from the active nucleus in the core of the brightest cluster galaxy of the Perseus cluster, NGC 1275, has varied dramatically over the past four decades. Prompted by the Fermi detection of flaring in the γ-ray band, we present the recent increased activity of this source in the context of its past radio and γ-ray output. The broad correspondence between the high-frequency radio data and the high-energy (HE) emission is striking. However, on short time-scales this correlation breaks down and the 1.3 mm Submillimeter Array flux is apparently unaffected during Fermi -detected flaring activity. The fact that NGC 1275 is also detected at TeV energies during the periods of HE γ-ray flaring suggests that the short-time-scale variation might be primarily related to changes in the inverse Compton scattering of photons by the electron population in the jet. The longer-time-scale changes suggest a 30–40 year variation in the fuelling of the black hole that affects the power of the inner jet. NCG 1275 is a laboratory for the class of brightest cluster galaxies, and its variability on these time-scales has implications for our understanding of massive galaxies in cooling-core clusters. The case of NGC 1275 highlights the need for wide coverage across the radio band to correctly account for the contribution to emission from a synchrotron self-absorbed core (for example when considering contamination of Sunyaev–Zel'dovich effect observations), and the danger of variability biases in radio surveys of galaxies

Prevalence and implications of gambling problems among firefighters

Firefighting is a high-risk occupation that accounts for vulnerability to a range of mental health problems and addictive behaviours. However, no research has addressed whether this vulnerability extends to gambling problems, and the aim of this study was thus to provide new data on frequency and implications of such problems in this occupational context. The sample consisted of n = 566 career and retained firefighters who participated in a cross-sectional survey of an Australian metropolitan fire service. The Problem Gambling Severity Index (PGSI) was used to operationalise both clinically significant levels of problem gambling (PGSI ≥ 5), and 'at-risk' gambling (PGSI 1-4); alongside measures of major depression (PHQ-9), anxiety (GAD-7), Posttraumatic Stress Disorder (PCL-5) and alcohol problems (AUDIT), as well as other addictive behaviours, wellbeing and psychosocial issues. Results indicated 12.3% of firefighters that reported any gambling problems across a continuum of severity (PGSI ≥ 1), including 2.3% that were problems gamblers, and 10.0% reporting at-risk gambling. The weighted prevalence of problem gambling was comparable to other significant mental health conditions including depression and PTSD, while the rate of any gambling problems was high relative to other addictive behaviours. Gambling problems were associated with poor mental health and wellbeing, but not psychosocial indicators (e.g., financial difficulties). The findings suggest that gambling problems across a spectrum of severity may be significant yet hidden issues among emergency service workers, and thus require increased recognition and responses at the organisational level.S. Cowlishaw, J. Little, A. Sbisa, A.C. McFarlane, M. Van Hooff, E. Lawrence-Wood, M. O'Donnell, M. Hinton, N. Sadler, A. Savic, D. Forbes, O. Metcal