Assessment of Surface Water Runoff and Groundwater Recharge Using Mathematical Models

In arid and semi-arid regions, surface water resources are scarce and, in most cases, groundwater is the only natural resource of freshwater. Pumping of groundwater often exceeds natural recharge. Therefore, groundwater levels are declining and its quality is deteriorating. Sustainable management of groundwater is thus a key issue and requires implementation of appropriate technologies to augment groundwater resources. Artificial recharge augments the natural movement of surface water into the underground formations using some means of construction whereby surface water from streams or lakes is made to infiltrate into the ground. The UAE is known by its arid conditions and limited renewable freshwater resources. Surface water in UAE is very limited and of a little significance in the water budget of the country. Despite the construction of many desalination plants, groundwater represents a vital natural resource. Although it may not be suitable, in most cases, for drinking, it represents the main source for irrigation. About 85% of the total water consumption in UAE is from groundwater. The sustainability of this precious resource is of prime concern in the UAE. Many dams have been constructed during the last two decades across the main wadis to harvest surface water runoff and recharge groundwater. The importance of this study evolves from the need to assess surface water and groundwater resources in the main wadis which are of vital role in the sustainable development of UAE, specifically, the agricultural development. The study aims at the simulation and quantitative assessment of surface water runoff and the associated groundwater recharge in Wadi Ham, UAE. HEC-HMS and MODFLOW models were used. Due to data limitation, HEC-HMS was applied for the period 1979 to 1989 and MODFLOW was applied for the period from January, 1990 to December, 1993. The study provides a methodology that can be followed in other sites of similar hydrological and hydrogeological conditions. All the data and facilities were provided through a project entitled Assessment of the effectiveness of AI-Bih, AI-Tawiyaen and Ham Dams in groundwater recharge using numerical models . The project was funded by the Ministry of Agriculture and Fisheries. The catchment area and drainage network were delineated based on the available toposheets and remote sensing images using ArcView GIS and AutoCAD softwares. Different wadi tributaries and properties were identified. Comprehensive analyses were conducted to study the variations of rainfall, surface water flow and groundwater levels based on historical records. Several lithologic cross sections were developed to assess the hydrogeology of the area and identify the aquifer geometry. A rainfall/runoff model (HEC-HMS) was used to study the surface runoff process and quantify the total runoff yields. A three-dimensional groundwater flow model (MODFLOW) was used to quantify groundwater recharge and study flow directions and the water balance. The total catchment area to the Wadi Ham Dam is approximately 195 km2. This includes Wadi Ham itself and the catchment of Wadi AI-Farfar system. Rainfall distribution is intermittent and highly scattered. The mean annual rainfall, estimated for 23 years, is 154 mm. Surface water flow is also variable reflecting the intermittent nature of rainfall. Wadi AI-Farfar system has major contribution to the total runoff and accounts for about 40% of the total runoff yield accumulated at the dam site. The Wadi Ham Dam has an effective role in groundwater recharge and its effect is clearly reflected by rise in groundwater levels. The recharge from the dam ranged from 32% to 43% of the dam storage. The flow of seawater to the aquifer is reduced to very low levels during recharge events from the dam while water losses to the sea appear to be very minor. The study suggests some recommendations including continuity of measurements and additional installations of flow gauges and observation wells. The groundwater model developed in this study can be enhanced and its capabilities can be expanded by conducting field inventory of pumping wells, new drillings and pumping tests of longer durations

The role of MRI in the diagnosis of endometriosis

AbstractAimThe aim of this study is to evaluate the accuracy of the magnetic resonance imaging in diagnosis of endometriosis especially in non-apparent types as tubal and cul de sac endometriosis.Patients and methodsMRI obtained between January 2007 and June 2009 for 34 premenopausal women complaining of dysmenorrhea, menorrhagia and infertility and the diagnosis of endometriosis were included in the differential diagnosis. T1 weighted fat saturated and T2 weighted images were done for every patient, we evaluated the MR images for the presence of T1 bright signal suggesting endometriosis. Transvaginal US was performed in two perpendicular planes for the detection of focal areas with ill defined borders or abnormal echo texture. Suspicious cases which become negative by laparoscopy were excluded from the study.ResultsMRI diagnosed endometriosis in the uterus in 18 patients, ovarian endometriosis in 13 patients, tubal in two patients, and cul de sac in one patient.ConclusionIt is concluded that MRI is superior in the diagnosis of endometriosis than transvaginal ultrasound

Real business cycles in small emerging economies: The role of financial frictions and dollarization

The objective of this thesis is to explain and empirically evaluate real business cycle (RBC) models in small and emerging economies. The focus of the thesis is to explore the role of financial sector in propagation and amplification of real business cycle in these economies. This objective is achieved through self-contained chapters (chapter 2-6) where one or more forms of financial features of interest are incorporated. The thesis makes theoretical and empirical contribution to real business cycle literature on small and emerging economies through methodological innovation used to incorporate financial features and empirical estimation of the models using Bayesian framework. The theoretical and empirical work is direct at establishment of real business cycle properties and processes of the Maldives. As of my knowledge, there are no empirical studies done to document and explain business cycle in the Maldives. One of the reasons for lack of studies are due to scarcity of relevant data. A small but growing literature is emerging in relation to exchange rate regime and the effect of exchange rate on domestic prices. However, to fully understand the impact of exchange rate in a dollarized economy like the Maldives, an appropriate general equilibrium framework with exchange rate is needed. This thesis therefore contributes to such a framework. Furthermore, using Chapter 3, I have addressed the gap in data availability and quality by comparing a database developed using archives with the secondary sources. The literature studying role of financial friction and dollarization in the propagation and amplification of business cycle through RBC framework is a growing area. Empirical work incorporating liability dollarization using RBC framework is scarce. The overall result from thesis is summarised as follows: Maldivian business cycle follows the predictions from the literature; dollarization, real exchange rate and risk premium are the main drivers of business cycles

Outward FDI: National and Regional Policy Implications for Technology Innovation

A significant contributor to China’s growth over the last 20 years is the ‘go-out’ policy, that is, for domestic firms to invest in international firms and has seen it develop a foundation of high technology industries and world leading research. We find that across China, the ‘go-out’ policy needs support from provincial governments in terms of human capital, basic research and infrastructure to ensure that imported technology is effectively absorbed into the local economies. This means a national strategy needs local tuning to the needs of the region. Across all provinces, we find that during the period 2006 to 2016 outward foreign direct investment (OFDI) spillovers have a significant and positive impact on technology innovation as measured by patents. OFDI alone is insufficient and may crowd out local research and development (R&D), as such, those provinces need to get to a threshold of absorptive capacity in basic, applied research supported by human capital and R&D capital stock. When the gap between a province and the rest of the world is large then OFDI could have a crowding out effect without the province supporting basic research. We test for structural changes across all provinces by classifying them by either having large or small frontier technology, the proxy for absorptive capacity. We find that the role of human capital and basic research changes substantially between small gap and large gap provinces indicating that regional policy makers need to ensure that policies are fine tuned to the stage of development in a particular region and will change over time. OFDI effects are diminished as the provinces gap reduces and this may be particularly timely in the face of China being subject to increasing trade and investment pressure internationally

Antibacterial evaluation of synthetic thiazole compounds in vitro and in vivo in a methicillin-resistant staphylococcus aureus (MRSA) skin infection mouse model

The emergence of community-associated methicillin-resistant Staphylococcus aureus (MRSA), including strains resistant to current antibiotics, has contributed to an increase in the number of skin infections reported in humans in recent years. New therapeutic options are needed to counter this public health challenge. The aim of the present study was to examine the potential of thiazole compounds synthesized by our research group to be used topically to treat MRSA skin and wound infections. The broth microdilution method confirmed that the lead thiazole compound and four analogues are capable of inhibiting MRSA growth at concentrations as low as 1.3 μg/mL. Additionally, three compounds exhibited a synergistic relationship when combined with the topical antibiotic mupirocin against MRSA in vitro via the checkerboard assay. Thus the thiazole compounds have potential to be used alone or in combination with mupirocin against MRSA. When tested against human keratinocytes, four derivatives of the lead compound demonstrated an improved toxicity profile (were found to be non-toxic up to a concentration of 20 μg/mL). Utilizing a murine skin infection model, we confirmed that the lead compound and three analogues exhibited potent antimicrobial activity in vivo, with similar capability as the antibiotic mupirocin, as they reduced the burden of MRSA present in skin wounds by more than 90%. Taken altogether, the present study provides important evidence that these thiazole compounds warrant further investigation for development as novel topical antimicrobials to treat MRSA skin infections. © 2015 Mohammad et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited

Improved inference for the generalized Pareto distribution under linear, power and exponential normalization

summary:We discuss three estimation methods: the method of moments, probability weighted moments, and L-moments for the scale parameter and the extreme value index in the generalized Pareto distribution under linear normalization. Moreover, we adapt these methods to use for the generalized Pareto distribution under power and exponential normalizations. A simulation study is conducted to compare the three methods on the three models and determine which is the best, which turned out to be the probability weighted moments. A new computational technique for improving fitting quality is proposed and tested on two real-world data sets using the probability weighted moments. We looked back at various maximal data sets that had previously been addressed in the literature and for which the generalized extreme value distribution under linear normalization had failed to adequately explain them. We use the suggested procedure to find good fits

Case finding for chronic obstructive pulmonary disease (COPD) in primary care: finding the optimal approach

Chronic obstructive pulmonary disease (COPD) is an important cause of morbidity and mortality but widely underdiagnosed. This thesis explores methods to improve case finding for COPD in primary care. It includes two systematic reviews- the first evaluated the diagnostic accuracy of screening tests and showed that handheld flow meters are more accurate than the COPD Diagnostic Questionnaire. The second evaluated the comparative effectiveness of different case finding strategies and found that inviting symptomatic ever smokers for a screening assessment may be more efficient than inviting all ever smokers directly for diagnostic spirometry. The thesis then reports the development and external validation of two risk prediction models for COPD using data from electronic health records and a cluster randomised controlled trial. These models can be used to assess the risk of undiagnosed COPD to help target patients for case finding and can potentially be integrated with clinical information systems. Finally, primary care providers were interviewed to explore their views on case finding for COPD, including potential benefits and harms, as well as barriers and facilitators. This suggests that more training and support for community respiratory services may be needed in order to improve the timely diagnosis of COP

Design and development of dialysate temperature control module prototype for hemodialysis

In the last few decades, complications caused during hemodialysis (HD) treatment remain a significant cause of morbidity and mortality in patients. During standard HD, there is a significant tendency for the body temperature to rise slightly, which is sufficient to cause complications. Recent studies show that the controlling of body temperature by altering the dialysate temperature, can reduce the complication episodes. Although the importance of active regulation of dialysate temperature control and its benefits have mentioned in literature, an enhanced design of controller and its comparison with dated commercial controller -Blood Temperature Monitor (BTM) have not been reported yet. Hence, it is the intention of this work to introduce the development of an effective dialysate temperature control module (DTCM) prototype and its comprehensive analysis in providing stable body temperature during the HD treatment. This study is incorporated with various prototype development stages such as prototype design, implementation, controller optimization, parameter estimation through simulation and in-vitro evaluation. Primarily, an innovative dialysate proportioning method is proposed for the development of the DTCM prototype. The study also involves a simulation of the heat transfer in a dialyzer and optimization of fuzzy logic controller design in real environment for the benefit of the DTCM evaluation. Finally, the DTCM prototype was evaluated and validated through in-vitro experiments. For the simulation study, a Polyflux 210H dialyzer model was developed using COMSOL Multiphysics software. Results showed the decrease in blood temperature along the membrane could be one of the consequences of venous line cooling as reported in literature and thus necessitates an effective system to control the dialysate temperature. Prior to the DTCM controller implementation, the performance of fuzzy logic-based temperature control was optimized from numerous designs. Optimum performance was found in the fuzzy logic design with a symmetrical rule base and the highest number of overlapping triangular membership functions. However, the optimized design shows a significant improvement in accuracy (±0.125°C) compared to the accuracy (±0.5°C) of published experimental study. For the in-vitro evaluation of DTCM prototype, an extracorporeal thermal energy model incorporating the heat transfer in dialyzer was proposed to estimate the arterial and venous temperatures. The results showed that the estimated arterial and venous temperature under standard dialysate are in accordance to that of published literature. Then, the working of DTCM prototype was evaluated under real-time environment for pre-defined trend of body temperatures and other various parameters. The results showed a remarkable response in maintaining body temperature with a tolerance of ±0.09°C under shorter duration. In fact, the DTCM prototype was then validated and noted to have as lightly better error tolerance in comparison with BTM experimental data (±0.16°C). The results obtained provides a gateway towards the development of dialysate temperature control system for HD machines. The potential of DTCM prototype to control the body temperature during the treatment has been proven through this work. The prototype design used in the current study can be implemented in HD machines, making it more affordable and accessible, paving the way to reduce HD related mortality

Impact of Coupled Resonator Geometry on Silicon-on Insulator Wavelength Filter Characteristics

We have analyzed and discussed the issues arising in the design of Silicon - on - Insulator (SOI) wavelength filters with different types of device geometry. Microring and microdisk geometries have been chosen as the device configurations and in order to demonstrate the device performance and potential, Free Spectral Range (FSR), and Q-factor values are computed. Studies of the transmittance characteristics are carried out using Finite- Difference Time-Domain (FDTD) methods by RSOFT Software. Results show that the microring-based wavelength filter has a FSR of 1.4 THz and a Q-factor value of 486. On the other hand,the microdisk based filter has a broader FSR with slightly smaller Q-factor