ANALYSIS AND PREDICTION OF WATER TREATMENT COSTS AT THE DV HARRIS PLANT IN THE UMGENI CATCHMENT AREA.

This paper has two objectives: first, to identify the main contaminants responsible for high treatment costs in the Umgeni catchment area, and second, to predict treatment costs from observed levels of contaminants. A partial adjustment model of treatment costs is estimated for the DV Harris plant, which draws water from Midmar Dam, using ordinary least squares regression and principal component analysis. The model highlights important policy issues and explains 61% of the variation in chemical treatment costs. Environmental contaminants have a marked impact on treatment costs. Treatment costs increase when levels of alkalinity, sodium and turbidity fall. Conversely, costs rise with higher levels of dissolved oxygen and water stability. Paradoxically, clean water - typical of Midmar Dam - is expensive to treat. Treatment costs also rise when concentrations of the algae, Chlorella, decline. Apparently the level of Chlorella varies inversely with the level of other, more harmful, contaminants.Resource /Energy Economics and Policy,

ANALYSIS AND PREDICTION OF WATER TREATMENT COSTS AT THE DV HARRIS PLANT IN THE UMGENI CATCHMENT AREA.

This paper has two objectives: first, to identify the main contaminants responsible for high treatment costs in the Umgeni catchment area, and second, to predict treatment costs from observed levels of contaminants. A partial adjustment model of treatment costs is estimated for the DV Harris plant, which draws water from Midmar Dam, using ordinary least squares regression and principal component analysis. The model highlights important policy issues and explains 61% of the variation in chemical treatment costs. Environmental contaminants have a marked impact on treatment costs. Treatment costs increase when levels of alkalinity, sodium and turbidity fall. Conversely, costs rise with higher levels of dissolved oxygen and water stability. Paradoxically, clean water - typical of Midmar Dam - is expensive to treat. Treatment costs also rise when concentrations of the algae, Chlorella, decline. Apparently the level of Chlorella varies inversely with the level of other, more harmful, contaminants

Metal-carbon fiber composite femoral stems in hip replacements a randomized controlled parallel group study with mean ten year follow-up

Background: Attempts to improve proximal load transfer and minimize stress shielding have included reducing the stiffness of femoral stems and using alternative stem materials, including carbon fiber composites. An uncemented implant (SR71) composed of a carbon-fiber-composite distal section and a porous-coated titanium-alloy proximal section, designed to improve proximal load transfer and provide good fixation, was clinically evaluated in a prospective randomized study.Methods: Sixty patients were enrolled and randomized to receive either the SR71 stem or an all-metal stem (Stability). All patients received a cemented all-polyethylene acetabular component and a 28-mm metal femoral head. All uncemented stems were implanted by the same surgeon. Patients were followed for up to ten years with repeated assessments of bone mineral density, radiographs, Harris hip scores (HHS), and visual analog scale (VAS) pain scores.Results: Ten years postoperatively, nineteen patients who had been treated with the SR71 stem and not lost to follow-up showed a significantly greater increase in proximal bone mineral density (Gruen zones 1 [p = 0.003] and 7 [p = 0.0007]) from baseline than did the twenty-two who had been treated with the Stability stem and not lost to follow-up. In contrast, the Stability group showed a significantly greater increase in distal bone mineral density (Gruen zones 2 [p = 0.0004], 3 [p = 0.0001], and 5 [p = 0.0035]) compared with the SR71 group. Radiographs demonstrated one case of progressive migration of an acetabular component used with an SR71 stem and one case of bone resorption in Gruen zones 7 and 14 in a patient treated with a Stability stem. There was no significant difference between the SR71 and Stability stems in terms of changes in the total HHS, HHS for pain, HHS for range of motion, or VAS pain scores ten years postoperatively relative to preoperative levels. There was one reported revision of an SR71 femoral stem at the ten-year review.Conclusions: The investigational SR71 implant provided increased proximal bone density and reduced distal bone density. The implant showed promising results at the time of early follow-up, and the clinical outcomes were similar to those of an all-metal stem at the time of a ten-year follow-up

Child protection system involvement in children of incarcerated mothers: A linked data study

Background: Women prisoners are a growing portion of the prison population. Health and social outcomes of their children have been studied and found to be poor, but little is known about child protection outcomes. Objectives: Ascertain child protection system contact of children exposed to maternal incarceration. Participants and setting: All children born between 1985 and 2011 exposed to the incarceration of their mothers in a Western Australian correctional facility and a matched comparison group. Methods: A matched cohort study using linked administrative data on 2637 mothers entering prison between 1985 and 2015 and their 6680 children. We estimated hazard ratios (HRs) and incidence rate ratios (IRRs) of child protection service (CPS) contact post maternal incarceration (four concern levels), comparing rates for children exposed to maternal incarceration with a matched non-exposed group, adjusting for maternal and child factors. Findings: Exposure to maternal incarceration increased risk of CPS contact. Unadjusted HRs exposed vs unexposed children were 7.06 (95%CI = 6.49–7.69) for substantiated child maltreatment and 12.89 (95%CI = 11.42–14.55) for out-of-home care (OOHC). Unadjusted IRRs were 6.04 (95%CI = 5.57–6.55) for number of substantiations and 12.47 (95%CI = 10.65–14.59) for number of removals to OOHC. HRs and IRRs were only slightly attenuated in adjusted models. Conclusions: Maternal incarceration is a warning flag for a child at high risk of serious child protection concerns. Family-friendly rehabilitative women’s prisons, incorporating support for more nurturing mother-child relationships could provide a placed-based public health opportunity for disrupting distressing life trajectories and intergenerational pathways of disadvantage of these vulnerable children and their mothers. This population should be a priority for traumainformed family support services.Leonie Segal, Sharon Dawe, Ha Nguyen, Susan Dennison, Emmanuel S. Gnanamanickam, Megan Bell, Matthew Spittal, Stuart Kinner, David B. Pree