Exposure to pesticides and hepatocellular carcinoma (HCC) risk in and around Monroe County, NY

The impact of long-term exposure and persistence of pesticides in the environment on human biology is not completely understood. With the proliferation of pesticide application technologies, there have been documented associations between exposure to every major functional group of pesticide and adverse health effects in humans such as cancer and neurological disease. Of observed pesticide-induced cancer health-risks, hepatocellular carcinoma (HCC) has shown some of the most significant associations. Epidemiological study is complex, especially when examining pesticide health risks. It is difficult to understand the significance behind interactions between the large list of pesticide compounds, external environmental factors, and biological variables. Therefore, complexity is a driving factor of uncertainty in pesticide epidemiology research. Using cancer data from New York State Department of Health (NYSDOH) aggregated to census block groups and NYS pesticide data from Cornell University aggregated to zip-codes, this study developed a Geographic Information System (GIS) based statistical model to investigate the possibility of an association between pesticide applications and higher indices of HCC sites in NYS. Model development progressed from simple linear regressions (such as Generalized Linear Regression (GLR)) to analysis using Local Bivariate Relationships (LBR), Geographically Weighted Regression (GWR), and a final model utilizing random forest-based classification and regression. Modeling was performed over all of NYS, including localized Areas of Interest (AOIs) around Rochester, Syracuse, and Buffalo. Additional models were performed on clusters generated using Multivariate Cluster Analysis (MCA). Models based on LBR indicated clusters of statistically significant relationships, including importance of pesticide exposure in explaining variance in HCC indices between zip-codes in random forest models. These results are evidence of possible association, though it must be noted that further study is needed to establish significant correlation or causality. The methods developed in this study serve as a framework and showcase of geospatial statistical analysis in environmental epidemiology

Joint Head Selection and Airtime Allocation for Data Dissemination in Mobile Social Networks

Mobile social networks (MSNs) enable people with similar interests to interact without Internet access. By forming a temporary group, users can disseminate their data to other interested users in proximity with short-range communication technologies. However, due to user mobility, airtime available for users in the same group to disseminate data is limited. In addition, for practical consideration, a star network topology among users in the group is expected. For the former, unfair airtime allocation among the users will undermine their willingness to participate in MSNs. For the latter, a group head is required to connect other users. These two problems have to be properly addressed to enable real implementation and adoption of MSNs. To this aim, we propose a Nash bargaining-based joint head selection and airtime allocation scheme for data dissemination within the group. Specifically, the bargaining game of joint head selection and airtime allocation is first formulated. Then, Nash bargaining solution (NBS) based optimization problems are proposed for a homogeneous case and a more general heterogeneous case. For both cases, the existence of solution to the optimization problem is proved, which guarantees Pareto optimality and proportional fairness. Next, an algorithm, allowing distributed implementation, for join head selection and airtime allocation is introduced. Finally, numerical results are presented to evaluate the performance, validate intuitions and derive insights of the proposed scheme

Assessment Practices and Challenges of Training and Development at the Ethiopian Textile Industry Development Institute(ETIDI)

Employees are considered as the key determinants of the success of an organization that shall have different training and development so as to cope up with the fast-changing business world. Training and development programs are essential for every organization for its long term planning that requires careful preparation if they are to be successful and help to achieve its objectives in time and enhance the knowledge, skills, and competencies of its workforce. The overall objective of this study is to assess the practices and challenges of training and development at the Ethiopian Textile Industry Development Institute(ETIDI).  The study adopted a mixed approach and used both primary and secondary data sources. The primary data collected from ETIDI through self-administered questionnaire for 116 selected operating employees and middle-level managers using a purposive sampling method to make sure that they have gone through the training program or understand the training and development program in the institute and semi-structured interview question employed for top managers(directors and deputy directors and training coordinator) through interview. The collected data were analyzed by using statistical tools (SPSS-Version 22). Both descriptive and inferential statistics were used for the data analysis. The descriptive statistics such as frequency and percent were used for describing the demographic characteristics of respondents and the dependent and independent variables. Qualitative data obtained through interviews were analyzed using content analysis. Inferential statistics like Pearson correlation coefficient(r) and multiple linear regression were used to determine if there is a relationship existed between independent and dependent variables. The study shows that 62.5% of the variation in the dependent variable was explained by independent variables. The findings also indicated that the relationship between the dependent variable was positively correlated and claimed to be a statistically significant relationship with the independent variables. The findings of the study indicated that there is no series of attention to allocate enough time, sufficient budget and resource for the training and development; in ETIDI there is no SMART manual and instrument of need assessment; training and development need assessment is not prepared by considering the need of prospective trainees; the organized training by the Institute is for the sake of refreshment or to collect allowance with less attention to the outcome of the training; training and development objectives are not set in advance; training and development program of the organization is not designed in line with the actual job to be performed and training and development program not followed by a reward.  Hence, the researcher recommended that the management of the institute, the board, and other stakeholders should define an appropriate training and development policy and programs that bring or capacitate the organization as well as the employee, Staff in the institute should be helped to grow into more responsibility by systematic training and development rather than consider it training as means to make themselves free from staff routine and receive allowance without considering the objective and benefits of training for themselves and for their institute so that they will be confident enough to carry out the responsibility of the job and the management of the institute, the board, and other concerned bodies should come up with training and development practices and policies for their ETIDI because they are the strategic link between the institute’s vision and its day-to-day operations. Keywords: SMART manual, training and development, reward DOI: 10.7176/JAAS/68-02 Publication date:September 30th 202

Investigation of Contributing Factors for Smart Parking Development Projects Delay:The Case of Addis Ababa, Ethiopia

Considering the increase of urban population and traffic congestion, smart parking is always a strategic issue to work on, not only in the research field but also from economic interests. The existing and ongoing works on smart parking are complicated and Trans disciplinary. The construction industry is one of the main sectors that provide important ingredients for the development of an economy. However it is becoming more complex because of the sophistication of the construction process itself and the large number of parties involved in the construction process. Delay in construction project completion is a global phenomenon that occurs in the construction industry and considered as one of the most common problems causing a multitude of negative effects on the project. The objective of this study is to identify the major determinants factor smart parking project delay. Both primary and secondary data were used in this study. A survey questionnaire was structured and distributed to contractor, consultant, client and subcontractor who were working in smart parking construction projects. The questionnaire included 30 predefined factors, which were grouped into six major factors, client, contractor, and consultant, and material, external and labor factors. The relative importance index (RII) was determined and the factors were ranked within their groups and overall. The results showed that the group of client factors ranked first among the six groups. The top ten factors causing delay of smart parking projects are: delay in sub-contractors, slow in decision making by client, delay in delivering the site to the contractor, Dollar insecure in government, delay in obtaining permits from municipality, less capacity to admin the project, lack in qualified labors/shortage of qualified engineers, shortage of construction materials, late procurement of materials and Ineffective planning and scheduling of projects.  Finally, recommendations have been developed for each of the contract parties’ client, contractor, consultant and subcontractor where present in this research in order to minimize and avoid the delay factor and get the project completed within the planned schedule. Keywords: Smart parking, project delay, determinant factor, Relative Importance Index (RII) DOI: 10.7176/JAAS/67-02 Publication date:August 31st 202

Simulation Model for Pipeline Network System with Non-pipe Elements for Natural Gas Transmission

The ever growing demand for natural gas enhances the development of complex transmission pipeline network system (TPNS) which requires simulation procedures for design and operation of the network. TPNS simulation is usually performed in order to determine the nodal pressures, temperatures and flow variables under various configurations. These variables are essential for analyzing the performance of the TPNS. The addition of non-pipe elements like compressor stations, valves, regulators and others make TPNS simulation analysis more difficult. A new simulation model was developed based on performance characteristic of compressors and the principles of conservation of energy and mass of the system to analyze TPNS with non-pipe elements for various configurations. The TPNS simulation model analyzes single phase gas flow and two-phase gas-liquid flow. The simulation model also takes into account temperature variation and age of the pipes. The model was designed for the evaluation of the unknown pressure, flow and temperature variables for the given pipeline network. The two solution schemes developed were iterative successive substitution scheme for simple network configurations and a generalized solution scheme which adopt Newton-Raphson algorithm for complex network configurations. The generalized Newton-Raphson based TPNS simulation model was tested based on the three most commonly found network configurations, namely: gunbarrel, branched and looped pipeline. In all the tests conducted, the solutions to the unknown variables were obtained with a wide range of initial estimations. A maximum of ten iterations were required to get solutions to nodal pressure, flow and temperature variables with relative percentage errors of less than 10- 11. The results of TPNS simulation model were compared with Newton loop-node method based on looped pipeline network configurations and an exhaustive optimization technique based on gunbarrel pipeline network configuration. For both cases, the results indicate that the model is able to provide solutions similar to the compared models. In addition, the TPNS simulation model provides detail information for the compressor stations. This information is essential for evaluation of the performance of the system. The application of the TPNS simulation model for real pipeline network system was also conducted based on existing pipeline network system. Three modules of TPNS simulation model which included input parameter analysis, function evaluation and network evaluation module were evaluated using the data taken from the real system. Analyses of the performance of compressor for existing pipeline network system which included discharge pressure, compression ratio and power consumption were also conducted using the developed TPNS simulation model. The performance characteristics maps generated by the developed TPNS simulation model show the variation of discharge pressure, compression ratio, and power consumption with flow rate similar to the one available in the literatures. Based on the results from the simulation tests and validation of the model, it is noted that the developed TPNS simulation model could be used for performance analysis to assist in the design and operations of transmission pipeline network systems. vii

Schistosoma mansoni extracellular vesicles: immunobiology and vaccine efficacy

Desalegn Kifle characterized the molecular composition of extracellular vesicles secreted by Schistosoma mansoni parasites. He demonstrated their role in host-parasite communication via host cell gene regulation, as well as their vaccine potential. His findings could have potential impact on our understanding of schistosome biology and the wider field of molecular parasitology

Estimating water balance of Tegona watershed in southeastern Ethiopia, using SWAT model

Water resource development is certainly the basic and crucial infrastructure for a nation’s sustainable development. To utilize water resources in a sustainable manner, it is necessary to understand the quantity and quality in space and time. This study was initiated with the objective of evaluating the performance and applicability of the Soil and Water Assessment Tool (SWAT) in analyzing the influence of hydrologic parameters on the stream flow variability and estimation of monthly water yield at the outlet of Tegona river watershed in Bale mountainous area.. The total 468 km2 area of the watershed was subdivided into 12 sub-basins and 60 hydrologic response units (HRUs). Sensitivity analysis, model calibration and validation were made to evaluate the model performance for simulation of stream flow on monthly time step. The calibrated SWAT model performed well for simulation of monthly stream flow. Statistical model performance measures, coefficient of determination (r2) of 0.71, the Nash-Sutcliffe simulation efficiency (ENS) of 0.77 and Percent difference (D) of 8.33, for monthly calibration and 0.86, 0.83 and -12.25 respectively for validation, indicated good to very good performance of the model simulation. Mean monthly and annual water yield simulated with the calibrated model were found to be 23.7 mm and 284.2 mm, respectively. The model slightly overestimated the flow on most of rainy months. The baseflow separation result indicated that subsurface flow was source of water in the study watershed. Overall, the model demonstrated good performance in capturing the patterns and trend of the observed flow series, which confirmed the appropriateness of the model for future scenario simulation. Therefore, it is recommended that SWAT model can be a potential tool for simulation of stream flow and water balance components of ungauged watershed in the highlands of Ethiopia with similar hydro-meteorological characteristics to Tegona watershed.

Infant feeding practice and associated factors of HIV positive mothers attending prevention of mother to child transmission and antiretroviral therapy clinics in Gondar Town health institutions, Northwest Ethiopia

<p>Abstract</p> <p>Background</p> <p>It has been estimated that 430,000 children under 15 years of age were newly infected with HIV in 2008, and more than 71% are living in sub-Saharan Africa. In the absence of intervention to prevent mother-to-child transmission, 30-45% of infants born to HIV-positive mothers in developing countries become infected during pregnancy, delivery and breastfeeding. The aim of this study was to assess infant feeding practice and associated factors of HIV positive mothers attending prevention of mother to child transmission and antiretroviral therapy clinics of Northwest Ethiopia.</p> <p>Methods</p> <p>Institution based cross sectional study was conducted from January to May 2011 among all HIV positive mothers with less than two years old child attending prevention of mother to child transmission and antiretroviral therapy clinics in Gondar Town health institutions. A structured pre-tested questionnaire using interview technique was used for data collection. The data was entered and analyzed using SPSS version 16 statistical package.</p> <p>Results</p> <p>A total of 209 HIV positive mothers were included in the study. Of these, 187 (89.5%) had followed the recommended way of infant feeding practice while significant percentage (10.5%) had practiced mixed breast feeding. In multivariate analysis, disclosure of HIV status with their spouse, insufficient breast milk and occupational status were found to be independently associated (p-value of < 0.05) with recommended infant feeding practice. Lack of resource, stigma of HIV/AIDS, and husband opposition were also obtained as factors that influenced choice of infant feeding options by respondents.</p> <p>Conclusions</p> <p>Higher proportion of respondents used the recommended way of infant feeding practice by WHO as well as by Ethiopian Ministry of Health. However, mixed feeding in the first 6 months of age, an undesirable practice in infant feeding, were reported in this study. Infant feeding education that is aligned to national policy should be strengthened in primary health care, particularly in situations where prevention of mother to child transmission of HIV is prioritized.</p

Multiple Reflections and Diffuse Scattering in Bragg Scattering at Optical Lattices

We study Bragg scattering at 1D atomic lattices. Cold atoms are confined by optical dipole forces at the antinodes of a standing wave generated inside a laser-driven cavity. The atoms arrange themselves into an array of lens-shaped layers located at the antinodes of the standing wave. Light incident on this array at a well-defined angle is partially Bragg-reflected. We measure reflectivities as high as 30%. In contrast to a previous experiment devoted to the thin grating limit [S. Slama, et al., Phys. Rev. Lett. 94, 193901 (2005)] we now investigate the thick grating limit characterized by multiple reflections of the light beam between the atomic layers. In principle multiple reflections give rise to a photonic stop band, which manifests itself in the Bragg diffraction spectra as asymmetries and minima due to destructive interference between different reflection paths. We show that close to resonance however disorder favors diffuse scattering, hinders coherent multiple scattering and impedes the characteristic suppression of spontaneous emission inside a photonic band gap

Evaluating Teaching Quality in Higher Education: A Focus on Students' Learning Experiences

Beishuizen, J.J. [Promotor]Os, W. van [Copromotor