Distribution and causes of high fluoride groundwater in the western Bushveld area of South Africa

Includes bibliography.Dental fluorosis is endemic in the western Bushveld of South Africa. This study investigated the occurrence of fluoride (Fˉ) in groundwater in the area. It was hypothesised that fluoride in groundwater originated from the dissolution of fluorine-bearing minerals, principally fluorite, mica, amphibole and apatite, and that high F- groundwater would be hosted in rocks with a high fluorine (F) content. It was further hypothesised . that groundwater residence time, rare F-bearing minerals, ion exchange reactions and evaporation affected the Fˉ concentration of groundwater. These hypotheses were investigated by analysing data on Fˉ concentrations in groundwater, paired rock and soil samples, and selected minerals. Three hundred and thirty eight samples of groundwater from the field area were analysed for Fˉ by both Fluoride Ion Selective Electrode and High Pressure Ion Chromatography. The results were added to a database of three thousand water samples covering the western Bushveld and together provide the first complete picture of the distribution of high Fˉ groundwater in the area

Interpreting syndepositional sediment remobilization and deformation beneath submarine gravity flows; a kinematic boundary layer approach

Turbidite sandstones and related deposits commonly contain deformation structures and remobilized sediment that might have resulted from post-depositional modification such as downslope creep (e.g. slumping) or density-driven loading by overlying deposits. However, we consider that deformation can occur during the passage of turbidity currents that exerted shear stress on their substrates (whether entirely pre-existing strata, sediment deposited by earlier parts of the flow itself or some combination of these). Criteria are outlined here, to avoid confusion with products of other mechanisms (e.g. slumping or later tectonics), which establish the synchronicity between the passage of overriding flows and deformation of their substrates. This underpins a new analytical framework for tracking the relationship between deformation, deposition and the transit of the causal turbidity current, through the concept of kinematic boundary layers. Case study examples are drawn from outcrop (Miocene of New Zealand, and Apennines of Italy) and subsurface examples (Britannia Sandstone, Cretaceous, UK Continental Shelf). Example structures include asymmetric flame structures, convolute lamination, some debritic units and injection complexes, together with slurry and mixed slurry facies. These structures may provide insight into the rheology and dynamics of submarine flows and their substrates, and have implications for the development of subsurface turbidite reservoirs

Investigating the Impact of Work Integrated Learning on Science Students’ Professional Identity

Australian science graduates have among the lowest full-time professional employment of all undergraduate courses (GOS-L 2018). It is hypothesised that professionally open-ended science degrees do not currently create significant opportunities to develop professional identity, leading to poor professional employment outcomes. Work Integrated Learning (WIL) has been proposed as a means to develop professional identity among business students (Jackson 2016), however little evidence demonstrates the impact of WIL on science students’ professional identity. We investigated the impact of WIL on Nutrition Science and Biomedical Science students' professional identity. Employing a mixed-methods approach, students were surveyed pre- (N=52) and post- (N=22) placement, and in a focus group (N=6). Thematic analysis was conducted to identify convergent themes. We find evidence to suggest that WIL may help science students develop professional identity, although barriers remain. Students responded that WIL helped to develop their professional identity, and identified more strongly as ‘general professionals’ after placement. Exposure to professional environments, interaction with placement supervisors and work-related tasks were the top enablers to building professional identity. These findings help to inform science educators about the role of WIL in developing graduate employability by better understanding complex notions of science students’ professional identity

Time-to-Event Modeling for Hospital Length of Stay Prediction for COVID-19 Patients

Providing timely patient care while maintaining optimal resource utilization is one of the central operational challenges hospitals have been facing throughout the pandemic. Hospital length of stay (LOS) is an important indicator of hospital efficiency, quality of patient care, and operational resilience. Numerous researchers have developed regression or classification models to predict LOS. However, conventional models suffer from the lack of capability to make use of typically censored clinical data. We propose to use time-to-event modeling techniques, also known as survival analysis, to predict the LOS for patients based on individualized information collected from multiple sources. The performance of six proposed survival models is evaluated and compared based on clinical data from COVID-19 patients

Air and Steam Gasification of Almond Biomass

Experiments were performed on a laboratory scale fluidized bed gasifier to characterize the gasification products of almond shell and hull removed in nut processing operations and to determine the effect of gasifying media on bed agglomeration. The higher heating value of syngas during air gasification of almond biomass ranged from 4 to 6 MJ m(-3) while gas concentrations ranged from 14 to 18% H-2, 3-4% CH4, 43-50% N-2, 16-19% CO, and 16-17% CO2. For steam gasification, higher heating value was 10-12 MJ m(-3) and gas concentrations were 35-40% H-2, 5-7% CH4, 17-21% N-2, 18-21% CO, and 16-18% CO2. The high level of potassium in the almond shells led to strong corrosion and bed agglomeration due to flue gas transport of potassium compounds. These resulting pervasive kalsilite reactions were significantly worse under air gasification than under steam gasification. As a result of prolonged duration and elevated temperature approaching 1,000 degrees C, the corrosinal reaction changes to formation of an adhesive potassium distillate melt locally forming strong bonds. This latter is interpreted as a result of aerosol transported of melt particles.California Energy Commission [PIR-07-002, PIR-11-008]; Almond Board of California; USDA-NIFA/UC Agricultural Experiment Station; California Almond Hullers and Processors AssociationThis work was supported by the California Energy Commission [PIR-07-002 and PIR-11-008]. We also acknowledge the generous support of the Almond Board of California, the California Almond Hullers and Processors Association, and USDA-NIFA/UC Agricultural Experiment Station

Experimental application to a water delivery canal of a distributed MPC with stability constraints

In this work, a novel distributed MPC algorithm, denoted D-SIORHC, is applied to upstream local control of a pilot water delivery canal. The D-SIORHC algorithm is based on MPC control agents that incorporate stability constraints and communicate only with their adjacent neighbors in order to achieve a coordinated action. Experimental results that show the effect of the parameters configuring the local controllers are presented

ANGPTL4 variants E40K and T266M are associated with lower fasting triglyceride levels in Non-Hispanic White Americans from the Look AHEAD Clinical Trial

Background: Elevated triglyceride levels are a risk factor for cardiovascular disease. Angiopoietin-like protein 4 (Angptl4) is a metabolic factor that raises plasma triglyceride levels by inhibiting lipoprotein lipase (LPL). In nondiabetic individuals, the ANGPTL4 coding variant E40K has been associated with lower plasma triglyceride levels while the T266M variant has been associated with more modest effects on triglyceride metabolism. The objective of this study was to determine whether ANGPTL4 E40K and T266M are associated with triglyceride levels in the setting of obesity and T2D, and whether modification of triglyceride levels by these genetic variants is altered by a lifestyle intervention designed to treat T2D. Methods: The association of ANGPTL4 E40K and T266M with fasting triglyceride levels was investigated in 2,601 participants from the Look AHEAD Clinical Trial, all of whom had T2D and were at least overweight. Further, we tested for an interaction between genotype and treatment effects on triglyceride levels. Results: Among non-Hispanic White Look AHEAD participants, ANGPTL4 K40 carriers had mean triglyceride levels of 1.61 +/- 0.62 mmol/L, 0.33 mmol/L lower than E40 homozygotes (p = 0.001). Individuals homozygous for the minor M266 allele (MAF 30%) had triglyceride levels of 1.75 +/- 0.58 mmol/L, 0.24 mmol/L lower than T266 homozygotes (p = 0.002). The association of the M266 with triglycerides remained significant even after removing K40 carriers from the analysis (p = 0.002). There was no interaction between the weight loss intervention and genotype on triglyceride levels. Conclusions: This is the first study to demonstrate that the ANGPTL4 E40K and T266M variants are associated with lower triglyceride levels in the setting of T2D. In addition, our findings demonstrate that ANGPTL4 genotype status does not alter triglyceride response to a lifestyle intervention in the Look AHEAD study

Rotation and plate locking at the southern Cascadia subduction zone

Global Positioning System vectors and surface tilt rates are inverted simultaneously for the rotation of western Oregon and plate locking on the southern Cascadia subduction thrust fault. Plate locking appears to be largely offshore, consistent with earlier studies, and is sufficient to allow occasional great earthquakes inferred from geology. Clockwise rotation of most of Oregon about a nearby pole is likely driven by collapse of the Basin and Range and results in shortening in NW Washington State. The rotation pole lies along the Olympic - Wallowa lineament and explains the predominance of extension south of the pole and contraction north of it