The effect of flight line spacing on radioactivity inventory and spatial feature characteristics of airborne gamma-ray spectrometry data

Airborne Gamma Spectrometry (AGS) is well suited to the mapping of radioactivity in the environment. Flight parameters (e.g. speed and line spacing) directly affect the rate of area coverage, cost, and data quality of any survey. The influences of line spacing have been investigated for data from inter‐tidal, coastal and upland environments with a range of <sup>137</sup>Cs activity concentrations and depositional histories. Estimates of the integrated <sup>137</sup>Cs activity (‘inventory’) within specified areas and the shapes of depositional features were calculated for subsets of the data at different line spacings. Features with dimensions greater than the line spacing show variations in inventory and area of less than 3%, and features with dimensions less than the line spacing show larger variations and a decreased probability of detection. The choice of line spacing for a task is dependent on the dimensions of the features of interest and required edge definition. Options for line spacing for different tasks are suggested. It is noted that for regional mapping, even 5–10 km line spacing can produce useful data

Chapter 2 - Luminescence analysis (OSL and TL) from Karabai I

This chapter reports a pilot study by two luminescence laboratories on samples from the 2004 excavations of Karabai I. The Scottish Universities Environmental Research Centre (SUERC) examined the optical stimulated luminescent (OSL) properties of the sediments using a method called luminescence profiling (Burbidge et al. 2007); the Max-Planck-Institute for Evolutionary Anthropology, Leipzig attempted to analyse the thermoluminescence (TL) age of a small collection of heated stones. Luminescence profiling is a rapid survey method for assessing the suitability of sediments for full dating based on the presence of particular minerals, grain-sizes and luminescence signals. At Karabai I the study revealed many factors that would complicate a subsequent full dating study, however a tentative age range of 60-115 ka was obtained using the ‘IRSL’ and ‘post IR & OSL TL’ signal from the polymineral coarse fraction. Luminescence signals based on quartz were found to be saturating and so could provide only minimum ages. Only one heated rock of sufficient mass, recovered in square 4H archaeological layer 2, exhibited acceptable properties for successful dating. The resulting TL age, 142 ± 23 ka (EVA-LUM-06/01), places Karabai I within MIS 6. This contrasts with the luminescence profile study that suggested sedimentary deposition within MIS 4-5. In both studies it is important to recognise the tentative nature of these conclusions

Evaluation of prediagnosis emergency department presentations in patients with active tuberculosis:the role of chest radiography, risk factors and symptoms

Introduction London has a high rate of tuberculosis (TB) with 2572 cases reported in 2014. Cases are more common in non-UK born, alcohol-dependent or homeless patients. The emergency department (ED) presents an opportunity for the diagnosis of TB in these patient groups. This is the first study describing the clinico-radiological characteristics of such attendances in two urban UK hospitals for pulmonary TB (PTB) and extrapulmonary TB (EPTB). Methods We conducted a retrospective cohort study using the London TB Register (LTBR) and hospital records to identify patients who presented to two London ED's in the 6 months prior to their ultimate TB diagnosis 2011–2012. Results 397 TB cases were identified. 39% (154/397) had presented to the ED in the 6 months prior to diagnosis. In the study population, the presence of cough, weight loss, fever and night sweats only had prevalence rates of 40%, 34%, 34% and 21%, respectively. Chest radiography was performed in 76% (117/154) of patients. For cases where a new diagnosis of TB was suspected, 73% (41/56) had an abnormal radiograph, compared with 36% (35/98) of patients where it was not. There was an abnormality on a chest radiograph in 73% (55/75) of PTB cases and also in 40% (21/52) of EPTB cases where a film was requested. Conclusions A large proportion of patients with TB present to ED. A diagnosis was more likely in the presence of an abnormal radiograph, suggesting opportunities for earlier diagnosis if risk factors, symptoms and chest radiograph findings are combined

Luminescence Analyses of Samples from Thailand and Laos

Prior investigation of cover sands in Thailand and Vietnam identified two distinct materials present; material containing high sensitivity quartz with robust SAR-OSL luminescence ages <35ka, and material containing lower sensitivity quartz with OSL signals in excess of the ~50ka saturation limit of the SAR method. Thermal transfer methods were developed to extend the range of equivalent dose determination for these older materials. In the work reported here, additional samples of older materials from three sites have been analysed to extend the extent of these observations. An additional set of profile samples (SUTL3002) and a dating sample (SUTL3003) were collected below the previous samples at Huai Om, Thailand. Laboratory profile measurements give similar sensitivities and apparent doses for quartz grains from the gravel layer to the earlier analyses from the sands immediately above these, with the sandy layer (associated with tektites) and weathered basement samples yielding quartz with even lower sensitivity. The tube sample from immediately above the weathered basement gives an age of 120 ± 10 ka, slightly older than the sample previously measured immediately above the gravel layer (95 ± 15 ka). A sample from the granule layer at Pakse, Laos (SUTL3004) gives an age of 150 ± 25 ka. A breccia sample from Tad Huakhon, Laos, (SUTL3005) taken from a layer between the basement and a basalt layer gives luminescence sensitivities two orders of magnitude higher than the lower sand and granule layer samples, potentially a result of heating from the lava flow above, and gives an age of 80 ± 20 ka

Ehrlichia chaffeensis Infection in the Reservoir Host (White-Tailed Deer) and in an Incidental Host (Dog) Is Impacted by Its Prior Growth in Macrophage and Tick Cell Environments

Citation: Nair, A. D. S., Cheng, C., Jaworski, D. C., Willard, L. H., Sanderson, M. W., & Ganta, R. R. (2014). Ehrlichia chaffeensis Infection in the Reservoir Host (White-Tailed Deer) and in an Incidental Host (Dog) Is Impacted by Its Prior Growth in Macrophage and Tick Cell Environments. PLOS ONE, 9(10), e109056. https://doi.org/10.1371/journal.pone.0109056Ehrlichia chaffeensis, transmitted from Amblyomma americanum ticks, causes human monocytic ehrlichiosis. It also infects white-tailed deer, dogs and several other vertebrates. Deer are its reservoir hosts, while humans and dogs are incidental hosts. E. chaffeensis protein expression is influenced by its growth in macrophages and tick cells. We report here infection progression in deer or dogs infected intravenously with macrophage- or tick cell-grown E. chaffeensis or by tick transmission in deer. Deer and dogs developed mild fever and persistent rickettsemia; the infection was detected more frequently in the blood of infected animals with macrophage inoculum compared to tick cell inoculum or tick transmission. Tick cell inoculum and tick transmission caused a drop in tick infection acquisition rates compared to infection rates in ticks fed on deer receiving macrophage inoculum. Independent of deer or dogs, IgG antibody response was higher in animals receiving macrophage inoculum against macrophage-derived Ehrlichia antigens, while it was significantly lower in the same animals against tick cell-derived Ehrlichia antigens. Deer infected with tick cell inoculum and tick transmission caused a higher antibody response to tick cell cultured bacterial antigens compared to the antibody response for macrophage cultured antigens for the same animals. The data demonstrate that the host cell-specific E. chaffeensis protein expression influences rickettsemia in a host and its acquisition by ticks. The data also reveal that tick cell-derived inoculum is similar to tick transmission with reduced rickettsemia, IgG response and tick acquisition of E. chaffeensis

An Axial Time-of-flight Mass Spectrometer for Upper Atmospheric Measurements

As the “shoreline” of the Earth’s atmosphere, the mesosphere/lower thermosphere (MLT) region is home to many interesting and important phenomena, the most visible of which are the auroras. Geomagnetic storms, in addition to causing very intense auroral activity, also deposit large amounts of energy into the earth’s ionosphere. Recent analysis of data from the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument aboard the Thermosphere-Ionosphere-Mesosphere Energetics and Dynamics (TIMED) satellite suggests that 5.3μm emission from vibrationally excited NO is the main method of energy dissipation from energy deposited by geomagnetic storms. Additionally, NO+ has been shown to be the major contributor to geomagnetic storm induced 4.3μm nighttime emission. In order to better physically understand these two large sources of geomagnetic storm energy dissipation, a sounding rocket mission, ROCKet-borne Storm Energetics of Auroral Dosing in the E-region (ROCK-STEADE) is being proposed. The ROCK-STEADE instrument suite consists of several photometers, an interferometer, an IR spectrometer, and two time-of-flight mass spectrometers (TOFMS). The TOFMS will measure the ion and neutral compositions in the atmosphere as the sounding rocket travels through the MLT. Due to the use of microchannel plate (MCP) detectors in TOFMS, one of the major challenges to making measurements in the MLT is the high ambient pressure. Other challenges and sources of error and background include stray UV photons, scattering of gas molecules from the interior surfaces of the instrument, dissociation of molecules in the bow shock caused by the supersonic rocket flight, and reactive recombination at the surfaces of the instrument. Methods of dealing with these challenges include: • Recent advances in MCP technology allowing MCP operation into the mtorr range • Cooling the front surface of the TOFMS using liquid He to eliminate the bow shock (thus making possible the direct sampling of the ambient atmosphere) • Cryogenically cooling the interior of the instrument to eliminate scattering of gas from instrument walls and therefore also reducing the contribution of reactive recombination • Rigorous error analysis to account for the background contribution of stray U