Assessing Simulated Transmissivity in Numerical Flow Models of Complex Hydrogeology

Accurately extracting a meaningful transmissivity, a target value within one order of magnitude of field estimates, in numerical models poses a significant challenge when modeling complex groundwater systems. Aquifer transmissivity is directly proportional to the aquifer thickness and the estimated aquifer hydraulic conductivity. In complex geologic conditions (especially in fractured systems) with multiple heterogeneous and anisotropic hydrogeologic units, transmissivity can vary over several orders of magnitude. To extract a meaningful value of transmissivity from a numerical model, a simple five-layer MODFLOW model was constructed. Each layer in the model was assigned a fixed hydraulic conductivity and thickness. The model simulates multiple pumping scenarios with varying combinations of hydraulic conductivity, aquifer thicknesses, and locations of the well screen to simulate aquifer tests. Two extraction methods, the Screen Interval and Layer Summation, were used to extract transmissivity values from the five-layer model, and first compared to model-assigned transmissivity values and then to transmissivity estimated from simulated pumping tests using the Cooper-Jacob Approximation. A similar process was repeated with a more complex groundwater model, the Death Valley regional groundwater-flow system v. 2.0 numerical model. However, in the Death Valley regional groundwater-flow system v. 2.0 numerical model analysis, the Screen Interval and Layer Summation values were compared to field estimated values, not model-assigned transmissivity values. The results of these comparisons show that transmissivity values extracted from a numerical model can vary many orders of magnitude from model assigned transmissivity values, and in the case of the Death Valley regional groundwater-flow system v. 2.0 numerical model, field estimated transmissivity. However, out of the 30 pumping scenarios run, the Screen Interval method transmissivity values were all within half an order of magnitude with the model input transmissivity and was found to be the most sensitive to the variation in transmissivity in both the simple five-layer model and Death Valley regional groundwater-flow system v. 2.0 numerical model. The Screen Interval extraction method may provide the most meaningful comparison of transmissivity between model results and field estimate

Optimum protein-excipient interactions using molecular docking simulations

This article was published in the Spring 2014 issue of the Journal of Undergraduate Researc

Development of Model Vaccination Initiative in Detroit

The distribution of vaccines to Detroit residents faced significant challenges during the COVID-19 health crisis. Vaccine distribution was slow, ineffective, and resulted in significant disparities in vaccine coverage among various racial and ethnic populations. This study examines existing data barriers to vaccination efforts in the United States, including common factors associated with vaccine hesitancy and attempts to identify factors that impact racial and ethnic disparities in vaccine coverage. Finally, this study examines successful vaccination initiatives from other cities in the United States to discuss a model vaccination initiative in Detroit

Inaugural Address

At the outset let me thank Professor Hashmi for his kind words about me in the welcome address. It is a matter of great pleasure for me to inaugurate this conference. I congratulate the Pakistan Society of Development Economists on organising its 16th Annual Conference with such wide and distinguished participation. The conference’s theme “Growth, Poverty and Decentralisation” is highly relevant for Pakistan in view of the urgent need to pull the country out of the vicious circle of poverty and indebtedness. I hope this Conference will come up with concrete recommendations to strengthen the economy by addressing the issues confronting us in this matter. The importance of economy in the emerging global scene cannot be overemphasised. A country’s sovereignty, political stability and diplomatic weightage largely depend upon its state of economy. Pakistan can take genuine pride in its achievements since 1947. We started from the scratch and today we are proud to be the first Islamic country and 7th in the world to become a nuclear power. Our industrial sector, communication infrastructure and agriculture have attained reasonable levels of development. However today when we look back at our achievements, we see that we have not made judicious use of our scarce resources. We borrowed heavily and went on a spending spree without proper planning. Wastage and injudicious use of resources coupled with lop-sided planning have now landed us in economic crises. Our debts have become difficult to service, our population growth rate outpaces our economic growth, and disparities in incomes have increased the gap between the rich and the poor

Expression of hepatitis B virus chimeric proteins in prokaryotic and eukaryotic systems

The particulate form of the core antigen of hepatitis B virus (HBcAg), is highly immunogenic. It has been used as a carrier molecule, for expression and presentation of heterologous viral epitopes on the surface of hybrid core particles, in immunogenicity studies. The aim of this project was to produce a hybrid antigen comprising HBcAg and an immunogenic epitope of human cytomegalovirus (HCMV). A direct comparison was made of amino and carboxyl terminal fusions, by investigating the influence of position of the foreign epitope on antigenicity, immunogenicity and hybrid core particle formation. A part of the HCMV genome, encoding a neutralizing glycoprotein epitope gp58, was inserted at the amino terminus or fused to the truncated carboxyl terminus of HBcAg in separate constructs and expressed in a prokaryotic system (E.coli). At the same time, in order to express the same fusion proteins in a eukaryotic system, the baculovirus expression vector system (BEVS) was selected and as an initial control two recombinant baculoviruses, containing genes encoding HBcAg and hepatitis B surface antigen were isolated by dot blot hybridization. It was realized that work in BEVS would require more time than previously expected therefore further work was only carried out on the prokaryotic system. The HBcAg carboxyl terminal fusion (HBC 3 - 1 4 4 -HCMV) was expressed in high yields in E.coli and assembled into core like particles resembling native HBcAg. A similar fusion in the amino terminus of HBcAg (HCMV-HBC1-183) could not be purified or characterized immunologically, although it formed core like particles. HBc3-144-HCMV displayed HBc antigenicity but HCMV antigenicity could not be detected. Following immunization of rabbits with HBC3-144-HCMV, a high level of anti-HBc specific antibody was produced along with HCMV/gp58 specific antibody. The data presented here provide evidence that the HCMV/gp58 region can be used as a candidate immunogen for an HCMV subunit vaccine and that HBcAg can effectively present this foreign epitope joined to its carboxyl terminus, to the immune system

Student Union Handbook 2016-17

Annual Handbook Publication of the OCAD Student Unio

Application of Smooth Transition autoregressive (STAR) models for Exchange Rate

This study evaluates the suitability of the Smooth transition autoregressive (STAR) models specification for real exchange rate Modeling. Our paper investigates the stationarity of real exchange rates which assume linearity in it; we also apply the tests to check stationarity that assume nonlinearity in a particular time series. The focus of this study is to explain the simple matter of time series stationarity or non-stationarity regarding modeling; its principle aim is application of logistic Smooth transition autoregressive (LSTAR) and exponential Smooth transition autoregressive (ESTAR) modeling to Exchange rate series to find the model which better explain its deviation from mean. We found ESTAR adjustment for our data series

Review of Gravity Model Derivations

The gravity model of international trade flows is a common approach to modeling bilateral trade flows. But it is criticized on the ground of weak theoretical base and poor micro-foundation. The gravity equation for describing trade flows first appeared in the empirical literature without much serious attempt to justify it theoretically. The theoretical support for the gravity model was originally very poor, but after the second half of the 1970s, several theoretical developments have filled this gap .In this study we also endeavor to justify the Gravity model specification and derive gravity equation from different perspective. We infer from literature and find it a strong empirical tool of analysis for international trade flows even though of some weakness it innate. Moreover, multilateral trade resistance factors may be added in the empirical estimation to correctly estimate theoretical gravity model. Keywords: Gravity Model, Anderson Gravity Model, Tinbergen Gravity Model, Newton’s Basic