Controls on geothermal heat recovery from a hot sedimentary aquifer in Guardbridge, Scotland:Field measurements, modelling and long term sustainability

Geothermal heat from Hot Sedimentary Aquifers represents a promising intermediate (30°C) resource for district heating systems. A key control on the geothermal productivity of these aquifers is the architecture of faults, which can significantly enhance or reduce the natural permeability of these systems. We present the first three-dimensional coupled groundwater flow and heat transport numerical model, combining multiple data from field mapping and fracture surveys, of two intersecting major fault systems in Central-East Scotland. This includes fault-zone fracture permeability modelling, depth-dependent permeability modelling, geo-mechanical facies assessment and heat productivity estimates for single well and multiple well extraction scenarios. Simulations indicate that with careful location of extraction wells within permeable fault systems, production is sustainable for over 50 years for multiple-well extraction scenarios in this region

State Behavioral Scale (SBS) A Sedation Assessment Instrument for Infants and Young Children Supported on Mechanical Ventilation

Objective: To develop and test the reliability and validity of the State Behavioral Scale for use in describing sedation/agitation levels in young intubated patients supported on mechanical ventilation. Design: In this prospective, psychometric evaluation, pairs of trained pediatric critical care nurse evaluators simultaneously and independently assessed a convenience sample of pediatric intensive care unit patients along eight state/behavioral dimensions and a numeric rating scale (NRS) of 0 (extremely sedated) to 10 (extremely agitated). The eight dimensions were derived from the sedation/agitation literature and expert opinion and included respiratory drive, response to ventilation, coughing, best response to stimulation, attentiveness to careprovider, tolerance to care, consolability, and movement after consoled, each with 3–5 levels. Setting: An 18-bed pediatric medical–surgical intensive care unit and 26-bed pediatric cardiovascular intensive care unit in a university-affiliated academic children’s hospital. Patients: A total of 91 intubated mechanically ventilated patients 6 wks to 6 yrs of age provided a median of two observations (interquartile range, 1–3) for a total of 198 sets of observations. Excluded were postoperative patients or those receiving neuromuscular blockade. Interventions: Patients were observed for 1 min, and then incremental levels of stimulation were applied until patient response. After 2 mins of consoling, the state behavioral assessment and NRS were completed. Measurements: Weighted kappa and intraclass coefficients were generated to assess interrater reliability of the eight dimension and NRS ratings. Distinct state behavior profiles were empirically identified from the dimension ratings using hierarchical cluster analysis using a squared Euclidean distance measure and between-groups linkage. Construct validity of these profiles was assessed by comparing group mean NRS scores using one-way analysis of variance. Main Results: Weighted kappa scores for all 198 dimension ratings ranged from .44 to .76, indicating moderate to good interrater reliability. The intraclass coefficient of .79 was high for NRS ratings. Cluster analysis revealed five distinct state profiles, with mean NRS ratings of 1.1, 2.5, 4.0, 5.3, and 7.6, all of which differed significantly from each other (F = 75.8, p \u3c .001), supporting the profiles’ construct validity. Conclusions: Based on empirically derived state behavior profiles, we have constructed the State Behavioral Scale to allow systematic description of the sedation–agitation continuum in young pediatric patients supported on mechanical ventilation. Further studies including prospective validation and describing the effect of State Behavioral Scale implementation on clinical outcomes, including the quality of sedation and length of mechanical ventilation, are warranted

A novel palaeoaltimetry proxy based on spore and pollen wall chemistry

Understanding the uplift history and the evolution of high altitude plateaux is of major interest to a wide range of geoscientists and has implications for many disparate fields. Currently the majority of palaeoaltimetry proxies are based on detecting a physical change in climate in response to uplift, making the relationship between uplift and climate difficult to decipher. Furthermore, current palaeoaltimetry proxies have a low degree of precision with errors typically greater than 1 km. This makes the calculation of uplift histories and the identification of the mechanisms responsible for uplift difficult to determine. Here we report on advances in both instrumentation and our understanding of the biogeochemical structure of sporopollenin that are leading to the establishment of a new proxy to track changes in the flux of UV-B radiation over geological time. The UV-B proxy is based on quantifying changes in the concentration of UV-B absorbing compounds (UACs) found in the spores and pollen grains of land plants, with the relative abundances of UACs increasing on exposure to elevated UV-B radiation. Given the physical relationship between altitude and UV-B radiation we suggest that the analysis of sporopollenin chemistry, specifically changes in the concentration of UACs, may offer the basis for the first climate independent palaeoaltimetry proxy. Owing to the ubiquity of spores and pollen in the fossil record our proposed proxy has the potential to enable the reconstruction of the uplift history of high altitude plateaux at unprecedented levels of fidelity, both spatially and temporally

Modal noise mitigation in a photonic lantern fed near-IR spectrograph

Recently we have demonstrated the potential of a hybrid astrophotonic device, consisting of a multi-core fiber photonic lantern and a 3D waveguide reformatting component, to efficiently reformat the multimode point spread function of a telescope to a diffracted limited pseudo-slit. Here, we report on an investigation into the potential of this device to mitigate modal noise-one of the main hurdles of multi-mode fiber-fed spectrographs. The modal noise performance of the photonic reformatter and other fiber feeds was assessed using a bench-Top spectrograph based on an echelle grating. In a first method of modal noise quantification, we used broadband light as the input, and assessed the modal noise performance based on the variations in the normalized spectrum as the input coupling to the fiber feed is varied. In a second method, we passed the broadband light through an etalon to generate a source with spectrally narrow peaks. We then used the spectral stability of these peaks as the input coupling to the fiber feed was varied as a proxy for the modal noise. Using both of these approaches we found that the photonic reformatter could significantly reduce modal noise compared to the multi-mode fiber feed, demonstrating the potential of photonic reformatters to mitigate modal noise for applications such as near-IR radial velocity measurements of M-dwarf stars. </p

Solid-phase crystallization of Si films in contact with Al layers

Low-temperature (400–540 °C) crystallization of amorphous and polycrystalline Si films deposited on SiO2 and covered with an evaporated Al layer has been studied using SEM, TEM, electron diffraction, electron channeling, and MeV 4He + backscattering. Silicon deposited by evaporation and chemical vapor deposition (CVD) at 640 °C (both amorphous) was found to crystallize into islands of polycrystalline aggregates. Silicon deposited by CVD at 900 °C (polycrystalline with ~2000-Å grains) produced relatively large (~10 µm) single-crystal islands. In both cases island size increased with annealing time, and the rate of crystallization increased with temperature. Crystallization rates were observed to be the same for both sources of amorphous Si, while 900 °C CVD Si was noticeably slower, consistent with the postulate that the driving force for the reaction is the free-energy difference between initial and final states. The crystallization rate for 900 °C CVD Si decreased when the Al layer thickness was reduced to a value less than the initial Si grain size. The inclusion of a native oxide layer between the deposited Si and Al layers greatly retarded the crystallization process

‘Slappers like you don’t belong in this school’: the educational inclusion/exclusion of pregnant schoolgirls

Policy in England identifies pregnant schoolgirls as a particularly vulnerable group and emphasises the importance of education as a way of improving the life chances of those who become pregnant while young. This paper draws on repeat interviews conducted over a twelve-month period to compare and contrast the stories of four young women. The narratives show that despite a common policy framework, there is great variability between schools in staff attitudes towards and responses to pupil pregnancy which produce different accommodations and support for pregnant girls, and seem likely to produce very different outcomes. We mobilise Iris Marion Young’s five faces of oppression to conduct a second reading of the stories. This situates the specificity of the girls’ school experiences into a wider socio-cultural and economic framing and indicates what might be involved in actually initiating and implementing the kinds of changes that the first ‘face value’ reading suggests are necessary

Applying laboratory thermal desorption data in an interstellar context: sublimation of methanol thin films

Methods by which experimental measurements of thermal desorption can be applied in astrophysical environments have been developed, using the sublimation of solid methanol as an example. The temperature programmed desorption of methanol from graphitic, amorphous silica and polycrystalline gold substrates was compared, with the kinetic parameters of desorption extracted by either a leading edge analysis or by fitting using a stochastic integration method. At low coverages, the desorption shows a substrate-dependent fractional order. However, at higher coverages methanol desorption is zeroth order with kinetic parameters independent of substrate. Using a kinetic model based on the stochastic integration analyses, desorption under astrophysically relevant conditions can be simulated. We find that the chemical and morphological nature of the substrate has relatively little impact on the desorption temperature of solid methanol, and that the substrate independent zeroth-order kinetics can provide a satisfactory model for desorption in astrophysical environments. Uncertainties in the heating rate and the distribution of grain sizes will have the largest influence on the range of desorption temperature. These conclusions are likely to be generally applicable to all species in dust grain ice mantles