Food Safety in the US: Regulation, Liability, and Tracing

This dissertation addresses three issues related to food safety. First, it examines the economic efficiency of irrigation water quality guidelines of Food Safety Modernization Act. Second, it estimates the value of traceability in the U.S. lettuce supply chain. Third, it uses state-level data and panel regression models to examine the relationship between product liability laws and reported foodborne illnesses in the U.S. The second chapter develops a theoretical framework and a corresponding empirical analysis to analyze the Food and Drug Administration\u27s irrigation water quality regulatory standard pursuant to the Food Safety Modernization Act. We develop a stochastic, price endogenous partial equilibrium model with recourse to examine the standard\u27s efficacy under various scenarios of foodborne illness severity, standard implementation, demand response to foodborne outbreaks, and irrigation costs. The stringency of regulation is evaluated with endogenous producer response to regulatory requirements and corresponding implications for economic surplus. Lettuce industry in California and Arizona is used as a case study. The baseline results show that in the case of the lettuce market, the proposed microbial irrigation water quality regulation is not cost-effective relative to the existing Leafy-Greens Marketing Agreements (LGMA) and results in 2.57% and 1.84% increases in head and leaf-romaine lettuce prices, respectively. The third chapter estimates the value of traceability in the U.S. lettuce industry using a stochastic price endogenous partial equilibrium model. Using irrigation water as a potential pathogen source we show that if the average cost per foodborne illness is $8,500, then the annual benefits of traceability in the lettuce industry vary between$680,000 and $2 million, depending on the length of produce shelf life. Also, the number of avoided symptomatic cases of foodborne illness due to traceability is between 81 and 232 cases. We also observe that the benefits of traceability depend on microbial die-off rate, monetary value of foodborne illness damages, pathogen transmission from source water to crop, and pathogenicity of water per unit of Generic E. coli. The fourth chapter examines the relationship between product liability laws and reported foodborne illnesses in the U.S. using state-level data and panel regression models. We find a positive and statistically significant relationship between strict liability with punitive damages and the number of reported foodborne illnesses. Most evidence, however, shows no statistically significant relationship between strict liability with punitive damages and the number of foodborne illness-related hospitalizations and deaths. Thus, the results suggest that strict liability with punitive damages encourages reporting but does not necessarily prevent serious foodborne illnesses

Real-time Regularized Tracking of Shear-Wave in Ultrasound Elastography

Elastography is a convenient and affordable method for imaging mechanical properties of tissue, which are often correlated with pathologies. An emerging novel elastography technique applies an external acoustic radiation force (ARF) to generate shear-wave in the tissue which are then tracked using ultrasound imaging. Accurate tracking of the small tissue motion (referred to as tissue displacement) is a critical step in shear-wave elastography, but is challenging due to various sources of noise in the ultrasound data. I formulate tissue displacement estimation as an optimization problem and propose two computationally efficient approaches to estimate the displacement field. The first algorithm is referred to as dynamic programming analytic minimization (DPAM), which utilizes first order Taylor series expansion of the highly nonlinear cost function to allow for its efficient optimization. DPAM was previously proposed for quasi-static elastography and I extend the approach to shear-wave elastography. The second algorithm is a novel technique that exploits second-order Taylor expansion of the non-linear cost function. I call the new algorithm as second-order analytic minimization elastography (SESAME). I compare DMAP and SESAME to the standard normalized Cross Correlation (NCC) approach in the context of estimating displacement and elasticity of the medium for shear-wave elastography (SWE). The results of micrometer-order displacement estimation in a uniform simulation phantom illustrate that SESAME outperforms DPAM, which in turn outperforms NCC in terms of signal to noise ratio (SNR) and jitter. In addition, the relative difference between true and reconstructed shear modulus (averaged over several excitations focusing at different focal depths with different scatterers realizations at each depth) is approximately 3.41%, 1.12% and 1.01%, respectively, for NCC, DPAM and SESAME. The performance of the proposed methods is also assessed with real data acquired using a tissue-mimicking phantom, wherein, in comparison to NCC, DPAM and SESAME improve the SNR of displacement by 7.6 dB and 9.5 dB, respectively. Experimental results on a tissue-mimicking phantom also show that shear modulus reconstruction is more accurate with DPAM and SESAME in comparison with NCC

Studying the Relationship between the Leadership Styles and the Foundations of E- government

Considering the recent achievements in ICT and the effectiveness of such a technology on different aspects of the life and the appearance of digital era and its inevitable consequent changes in the human life, any incompatibility to these changes will lead to the inefficiency of the organizations. This research aims to find solutions by which the organizations can find the best strategies to cope with the mentioned changes. This research intends to study the leadership styles and the foundations of E-government. Methodology of this research is based on correlative descriptive method. The statistical population of the research includes the managers of different departments of the fifth municipal district of Tehran among which 200 managers were selected as the sample group in simple sampling method as the sample of the research. With regard to the variables of the research, first we conducted statistical analyses using regression and Pearson correlative method for studying the mutual relationship of the subscales in investigating the relationship between the foundations of e-government and the leadership styles. The results were as follow: consultative leadership has a relationship with the foundations of "government to government", "government to business" and "government to employees" at 0.99 confidence level; supportive leadership has a relationship with the foundations of "government to government" and "government to citizens" at 0.99 confidence level; participative leadership has a relationship with the foundations of "government to business", "government to employees" at 0.99 confidence level; and agreement-based leadership has a relationship with the foundations of "government to business", and "government to employees" at 0.99 confidence level. According to these findings we can conclude that our main hypothesis was confirmed, that is, there is a relationship between the leadership styles and the foundations of e-government

Estimating the Risk for Chromosomal Abnormalities and Heteromorphic Variants in Azoospermic and Severe Oligozoospermic Men

Objectives: A reasonable number of male infertility cases are related to genetic factors. Considering the high prevalence of chromosomal abnormalities related to male infertility, this study investigated the association of the chromosomal aberrations and chromosome variants with hormonal levels, a positive family history, parental consanguinity and a specific lifestyle. We also aimed to find a predictive factor to estimate the risk of the presence of an abnormal karyotype in the azoospermic and especially sever oligozoospermic men. Materials and Methods: A total of 230 infertile men and 50 healthy controls enrolled in the study for cytogenetic evaluation. Data on patients" characteristics were gathered, accurately. Results: Among aforementioned factors, only luteinizing hormone (LH) >12 IU/l raised the chance of detecting a chromosomal abnormality (P < 0.05). The results also showed a higher level of follicle stimulating hormone (FSH) and parental consanguinity and a positive family history of infertility in infertile men compared with the control group (P < 0.05). The incidence of chromosome abnormalities and chromosomal variants were 15.2% and 10.9%, respectively. The investigated variables revealed no association with the prevalence of chromosome heteromorphic variants. Conclusiond: This study suggests a positive family history of infertility, parental consanguineous marriages and high levels of FSH as strong determinants or risk factors for male infertility. Nonetheless, the presence of these patient characteristics did not prove to have a direct correlation with chromosomal abnormalities in male infertility. Among the various possible risk factors studied, an elevated gonadotropin level provides a better risk assessment for the incidence of chromosomal abnormality in infertile men

The Impacts of Climate Change on Surface and Ground Water Withdrawal: A New Global Data Base of Costs and Returns of Irrigation Part I: Background, Method, and Data

This study introduces an improved global economic framework for investigating the impacts of climate change while focusing on local water constraints and international trade of agricultural products. This study measures the likely impacts of a counterfactual change in “irrigation yield gap” on irrigation expansion, groundwater withdrawal, surface water withdrawal, and international trade of agricultural commodities. We construct proposed economic framework based on GTAP (Global Trade Analysis Project) model, a widely used global model, to investigate various economic impacts. We extend GTAP Water Data Base (Haqiqi et al., 2016) by adding new global database on irrigation efficiency; introducing irrigation services as sectors; new global database of costs and returns of irrigation; introducing energy, capital, and labor inputs for water extraction and on-farm water distribution; distinguishing surface water from groundwater; and considering different irrigation technologies. We also introduce demand and supply of irrigation services by river basin AEZs (agro-ecological zones). Then, we calculate the likely impact of a counterfactual scenario of climate change (change in relative yields of irrigated and non-irrigated crops)

The Impacts of Climate Change on Surface and Ground Water Withdrawal: A New Global Data Base of Costs and Returns of Irrigation Part I: Background, Method, and Data

This study introduces an improved global economic framework for investigating the impacts of climate change while focusing on local water constraints and international trade of agricultural products. This study measures the likely impacts of a counterfactual change in “irrigation yield gap” on irrigation expansion, groundwater withdrawal, surface water withdrawal, and international trade of agricultural commodities. We construct proposed economic framework based on GTAP (Global Trade Analysis Project) model, a widely used global model, to investigate various economic impacts. We extend GTAP Water Data Base (Haqiqi et al., 2016) by adding new global database on irrigation efficiency; introducing irrigation services as sectors; new global database of costs and returns of irrigation; introducing energy, capital, and labor inputs for water extraction and on-farm water distribution; distinguishing surface water from groundwater; and considering different irrigation technologies. We also introduce demand and supply of irrigation services by river basin AEZs (agro-ecological zones). Then, we calculate the likely impact of a counterfactual scenario of climate change (change in relative yields of irrigated and non-irrigated crops)