Numerical Modeling of Coupled Groundwater and Surface Water Interactions in an Urban Setting

The Dominguez Channel Watershed (DCW), located in the southern portion of Los Angeles County (Figure A.1), drains about 345 square miles into the Los Angeles Harbor. The cities and jurisdictions in DCW are shown in Figure A.2. The largest of these include the cities of Los Angeles, Carson, and Torrance. This watershed is unique in that 93% of its land area is highly developed (i.e. urbanized). The watershed boundaries are defined by a complex network of storm drains and flood control channels, rather than being defined by natural topography. Table (1) shows a summary of different land uses in the Dominguez Channel Watershed (MEC, 2004). The Dominguez Watershed has the highest impervious area of all watersheds in the Los Angeles region. The more impervious the surface, the more runoff is generated during a storm. Storm water runoff can carry previously accumulated contaminants and transport them into receiving water systems. Point sources such as industrial wastewater and municipal sewage as well as urban runoff from commercial, residential, and industrial areas are all recognized as contributors to water quality degradation at DWC. Section 303(d) of the 1972 Federal Clean Water Act (CWA) requires states to identify and report all waters not meeting water quality standards and to develop action plans to pursue the water quality objectives. These plans specify the maximum amount of a given pollutant that the water body of concern can receive and still meet water quality standards. Such plans are called Total Maximum Daily Loads (TMDLs). TMDLs also specify allocations of pollutant loadings to point and non-point sources taking into account natural background pollutant levels. This demonstrates the importance of utilizing scientific tools, such as flow and transport models, to identify contaminant sources, understand integrated flow paths, and assess the effectiveness of water quality management strategies. Since overland flow is a very important component of the water balance and hydrology of DCW, a parallel, distributed watershed model that treats flow in groundwater and surface water in a dynamically coupled manner will be used to build a flow model of the watershed. This coupled model forms the basis for modeling and understanding the transport of contaminants through the Dominguez Channel Watershed, which can be used in designing and implementing TMDLs to manage the water quality in this basin. In this report, the coupled surface water-groundwater flow model of DCW will be presented. This flow model was calibrated against a storm that occurred in February 21st, 2004. The model and approach are explained further in the following sections

Adherence to 6-Mercaptopurine in children and adolescents with Acute Lymphoblastic Leukemia

OBJECTIVE: Studies on children with Acute Lymphoblastic Leukemia (ALL) reported non-adherence in 2–54% of cases. The primary objective of this study was to assess rates of adherence to 6-MP using two different methods in children and adolescents with ALL. Secondary aim was to identify factors that influence adherence to 6-MP in children with ALL. METHODS: All eligible children with ALL who are (≤ 19) years old and receive 6-MP therapy for at least 1 month were approached to participate in the study. A total of 52 children with ALL and their primary caregivers were recruited. Adherence measures included an objective method (measuring 6-MP metabolites in packed Red Blood Cells (RBCs)) and a subjective method (using parent and child self-report via the Medication Adherence Report Scale; MARS; Adherence was defined as 90% or greater). RESULTS: Rates of adherence varied across the measurement methods. Packed RBCs sample analysis indicated forty-four patients (84.6%) to be adherent. Using the MARS questionnaires, a total of 49 children (94.2%) were classified as being adherent according to the parental MARS questionnaire scores, while all the 15 children (100%) who answered the MARS (child) questionnaire were classified as adherent. Overall adherence rate was 80.8% within the studied population. CONCLUSION: MARS scale was shown to overestimate adherence compared to measurement of 6-MP metabolites in the blood. A combination of both methods led to increased detection of non-adherence to thiopurine in children with ALL

Can international health programmes be sustained after the end of international funding? The case of eye care interventions in Ghana

There is general agreement amongst major international policy makers that sustainability is a key component of health interventions in developing countries. However, there is little evidence on the factors enabling or constraining sustainability. Diffusion of innovation theory can help explain how the continuation of activities is related to the attributes of innovations. Innovations are characterised by five attributes: (i) relative advantage; (ii) compatibility; (iii) complexity; (iv) triability; and (v) observability. An eye care programme was selected as a case study. The programme was implemented in the Brong Ahafo region of Ghana and had been funded over a ten-year period by an international organisation

Spectroscopic Ellipsometry Analysis of Rapid Thermal Annealing Effect on MBE Grown GaAs1-x-Nx

We report on the effect of rapid thermal annealing (RTA) on GaAs1-x-Nx layers, grown by molecular beam epitaxy (MBE), using room temperature spectroscopic ellipsometry (SE). A comparative study was carried out on a set of GaAs1-x-Nx as-grown and the RTA samples with small nitrogen content (x = 0.1%, 0.5% and 1.5%). Thanks to the standard critical point model parameterization of the GaAs1-x-Nx extracted dielectric functions, we have determined the RTA effect, and its nitrogen dependence. We have found that RTA affects more samples with high nitrogen content. In addition, RTA is found to decrease the E1 energy nitrogen blueshift and increase the broadening parameters of E1, E1+?1, E'0 and E2 critical points