Combined effects of bioavailable organic contaminants in the aquatic environment.

In contrast to conventional spot or bottle water sampling techniques, passive sampling has been shown to be a reliable and efficient method for monitoring the toxicologically-relevant, freely-dissolved (e.g. bioavaialable) concentrations of a wide range of organic contaminants in water. At the same time, techniques for partitioning controlled delivery (passive dosing; PD) promise to overcome many of the challenges associated with toxicity testing of hydrophobic substances, which can bias the interpretation of toxicity data. The present study investigated the feasibility of coupling silicone rubber passive sampling devices (SR-PSDs) with bioassay techniques for both chemical and ecotoxicological assessment of complex mixtures of organic contaminants in the aquatic environment. SR-PSDs were deployed for seven to nine weeks in water at various locations within the Ythan catchment (north-east of Scotland), and within the Forth estuary and the Firth of Forth (east coast of central Scotland). Following retrieval, extracts from the SR-PSDs were analysed for dissolved concentrations of a variety of organic contaminants, including PAHs (using GC-MS) and PCBs (using GC-ECD). They were then screened for a wide range of pesticides using GC-MS/MS and LC-MS/MS. The extracts were further evaluated for acute cytotoxicity (i.e. neutral red uptake assay) and EROD induction potential using rainbow trout liver cell line (Oncorhynchus mykiss; RTL-W1). They were also evaluated for phytotoxicity and developmental toxicity potential, using an algal growth inhibition test with a marine phytoplankton (Diacronema lutheri) and a fish embryo toxicity test with embryos from zebrafish (Danio rerio) respectively. Overall, the individual and total dissolved concentrations of PAHs (Sigma-PAH40; parent and branched) and PCBs (Sigma-PCB32; ortho and mono-ortho) measured in water from the Ythan, Forth estuary and Firth of Forth were relatively low compared with other studies using PSDs. A number and level of pesticides, including insecticides, herbicides and fungicides of varying hydrophobicity (log KOWs ~2.25 to ~5.31) were detected in the silicone rubber (SR) extracts from all three areas, suggesting input mainly from agricultural run-off and possibly from direct discharges. No statistically significant (p < 0.05) acute cytotoxicity was observed following forty-eight hours of exposure of RTL-W1 cells to SR extracts from the Ythan catchment. However, on a sublethal level for every site, statistically significant EROD activity was observed to some degree following seventy-two hours of exposure. In addition, developmental and algal toxicities on embryos of D. rerio and D. lutheri were measured in all the deployed samples compared with the procedural controls (undeployed samples). Interestingly, extracts of SR-PSDs from the Forth estuary and the Firth of Forth exhibited growth inhibitions on D. lutheri that were similar to those of extracts from the Ythan, even though fewer pesticides were detected in the Forth estuary and Firth of Forth than the Ythan. This suggests that pesticides were not solely responsible for the observed effects in the Ythan catchment. To further improve data from toxicity testing of hydrophobic substances, the study identified the use of SR O-rings as a suitable passive dosing format in toxicity tests in vitro, and was partially validated through their use in dosing RTL-W1 cells with two individual PAHs, which subsequently determined both cytotoxicity and EROD-activity

Establishing agent staffing levels in queueing systems with cross-trained and specialized agents

The determination of the right number of servers in a multi-server queueing system is one of the most important problems in applied queueing theory. The problem becomes more complex in a system that consists of both cross-trained and specialized servers. Such queueing systems are readily found in the call centres (also called contact centres) of financial institutions, telemarketing companies and other organizations that provide services to customers in multiple languages. They are also found in computer network systems where some servers are dedicated and others are flexible enough to handle various clients' requests. Over-staffing of these systems causes increased labour costs for the underutilized pool of agents on duty, while under-staffing results in reduced revenue from lost customers and an increase in queue times. The efficient design and analysis of these systems helps management in making better staffing decisions. This thesis aims to develop models for establishing agent staffing levels in organizations with cross-trained and specialized staff with a view to minimizing cost and maintaining a desirable customer satisfaction. The work investigates the effect of various traffic loads on the number of agents required and the cost. It also considers how using specialized agents, flexible agents and a combination of both categories of agents affects the system. It uses a contact centre that has agents with monolingual, bilingual and trilingual (English, French and Spanish) capabilities to do the study

Digital Strategies to Manage and Transform Maritime Business Operation in Lagos, Nigeria

Studies have shown that the maritime sector creates socioeconomic opportunities and contributes significantly to the gross domestic product of Lagos state and Nigeria, but it misses digital opportunities for transformation. A literature gap existed on digital strategies to manage and transform maritime business operations in Lagos. The purpose of this qualitative exploratory multiple case study was to explore digital strategies that business leaders and managers may use to transform maritime business operations in Lagos. The digital business transformation (DBT) concept by Wade and an integrated DBT process concept framed this study. Data from purposefully sampled business leaders and managers in semi-structured interviews, with document review and reflective field notes, were analyzed through content analysis to answer the research question. The findings included the themes of (a) purpose and values of digital strategy inclusion, (b) why integrating digital objectives in the business process, (c) digital strategy as a business management tool, (d) as a transformational tool, (e) digital strategy implementation success factors, (f) DBT barriers, (g) supportive intervention measures, (h) the use of an integrated DBT process, (i) the horizon of digital strategy compliance, and (j) government and stakeholders’ involvement in Lagos’ maritime DBT. Digital strategies in Lagos’ maritime business operations as recommended in this study may influence change in process and management practice for business sustainability in Lagos and better living standards for positive social change

Exploring Occupational Stress among Nurse Leaders: Factors Influencing Nurse Leader Retention and Organizational Commitment

Background: Nurse leader sustainability is essential to organizational climate and patient care outcomes. The state of science of nurse leader sustainability is fragmented and warrants critical examination. Current research exists examining the impact of occupational stress among frontline nurses. However, research is scarce exploring occupational stress among nurse leaders. Purpose: To narrow knowledge gaps by exploring perceptions of occupational stress among nurse leaders and their responses to stress. Methods: A generic qualitative descriptive approach was used to explore perceptions of occupational stress among nurse leaders. The final sample consisted of 17 participants via purposive sampling. Thematic content analysis was used to categorize themes derived from the data. Data organization employed coding schemes to identify, label, and categorize concepts or themes. External validation via peer debriefing was used to ensure accurate interpretations. Findings: Ten theme clusters subsumed under six emergent themes, “Always under pressure”; “Lack of work/life balance”; “My senior leadership does not support me”; “Fear”; My senior leadership does support me”; “Organizational commitment”. Conclusion: Establishing and sustaining healthy work environments for the nurse leader generates a cascading effect on the organization. A heightened awareness of the elements that trigger occupational stress is a task that the organization must become astute to. It is imperative nurse leaders understand their response(s) to occupational stress directly impacts the organization, staff, and patient outcomes

The Ọkụmkpọ Masquerades of the Afikpo Society of Southeastern Nigeria: An Art Form and an Instrument of Social Control.

Masquerade performances are prevalent in West Africa, but they hold particular importance among the Igbo of Southeastern Nigeria. This thesis explores the cultural significance and artistic expressions of Okunkpo masquerade at Afikpo, a sub-Igbo group in Nigeria. It demonstrates how Okunkpo has served as a mechanism of social control using humorous skits, storytelling and dance up to the 21st century. Okunkpo is an elaborate and the most attended masquerade performance at Afikpo. It appears only once in a year and is exclusively reserved for male initiates. Its popularity draws audience from far and near. As a community theatre, Okunkpo provides entertainment and showcases the cultural values and socio-religious systems of the community. The songs and stories in Okunkpo play reveal some aspects of the community’s history and norms that may not be told in an ordinary social gathering. Okunkpo does not only check deviant behaviors but also acts as a unifying force that strengthens social stability and harmony while providing a platform for self-reflection and group therapy. The research captures sorcery as an important aspect of African worldview. It points out how Okunkpo employs amulets as a power device to ward off any form of sorcery attack during or after performances. A critical examination of the Okunkpo masks, their symbols, functions and significance reveals the use of art to represent social reality. The study highlights Okunkpo as a living symbol of art and traditional wisdom. By focusing on the aesthetic aspect and cultural roles of Okunkpo masquerade, this research contributes to the study of African art history. Thus, it fills a gap in the existing scholarship on African art history and portrays Okunkpo as an important African masquerade performance that deserves more scholarly attention

Optimal supply chain configuration for the additive manufacturing of biomedical implants

In this dissertation, we study two important problems related to additive manufacturing (AM). In the first part, we investigate the economic feasibility of using AM to fabricate biomedical implants at the sites of hospitals AM versus traditional manufacturing (TM). We propose a cost model to quantify the supply-chain level costs associated with the production of biomedical implants using AM technology, and formulate the problem as a two-stage stochastic programming model, which determines the number of AM facilities to be established and volume of product flow between manufacturing facilities and hospitals at a minimum cost. We use the sample average approximation (SAA) approach to obtain solutions to the problem for a real-world case study of hospitals in the state of Mississippi. We find that the ratio between the unit production costs of AM and TM (ATR), demand and product lead time are key cost parameters that determine the economic feasibility of AM. In the second part, we investigate the AM facility deployment approaches which affect both the supply chain network cost and the extent of benefits derived from AM. We formulate the supply chain network cost as a continuous approximation model and use optimization algorithms to determine how centralized or distributed the AM facilities should be and how much raw materials these facilities should order so that the total network cost is minimized. We apply the cost model to a real-world case study of hospitals in 12 states of southeastern USA. We find that the demand for biomedical implants in the region, fixed investment cost of AM machines, personnel cost of operating the machines and transportation cost are the major factors that determine the optimal AM facility deployment configuration. In the last part, we propose an enhanced sample average approximation (eSAA) technique that improves the basic SAA method. The eSAA technique uses clustering and statistical techniques to overcome the sample size issue inherent in basic SAA. Our results from extensive numerical experiments indicate that the eSAA can perform up to 699% faster than the basic SAA, thereby making it a competitive solution approach of choice in large scale stochastic optimization problems

EXERGY-BASED INVESTIGATION OF A COAL-FIRED ALLAM CYCLE

Allam cycle is a novel cycle that capitalizes on the unique thermodynamic properties of supercritical CO2 and the advantages of oxy-combustion for power generation. It is a high-pressure supercritical carbon dioxide cycle designed to combust fossil fuels such as natural gas or syngas (from coal gasification systems) with complete CO2 separation at a high-efficiency and zero atmospheric emissions. This semi-closed cycle produces sequestration-ready/pipeline quality CO2 by-product, and thus eliminates the need for additional CO2-capture system. The Coal-fueled Allam cycle is targeted to deliver between 51-52% net efficiency (lower heating value) for coal gasification. In this study, the expected energetic efficiency is verified by simulating the system in Ebsilon professional software and the result showed that the net efficiency of the simulated coal-fired plant is 30.7%, which is significantly lower than the targeted value. The lower efficiency maybe as a result of the missing heat integration in the system, the high power demand of the oxidant compressor and CO2 compressors. And an exergy analysis based on published cycle data is employed, to investigate the cycle performance, identify the sources of the cycle’s thermodynamic inefficiencies at the component level; a sensitivity analysis is also performed to study the effects of selected thermodynamic parameters on the overall performance of the coal-fired Allam cycle

Building a Wireless Broadband Infrastructure to Support Maritime Applications (semester?), IPRO 305: Wireless Broadband Infrastructure IPRO 305 Abstract Sp07

The objective of IPRO 305 is to build a wireless broadband network infrastructure along a local river to help Air2Access, an IIT University Technology Park Company, expand its maritime solutions offerings. We will do this by becoming familiar with cutting edge wireless broadband network technologies and the different vendors that offer and use this technology. We will also examine the pilot site and work with the appropriate Agencies to determine any natural, man-made or legal restrictions that we must abide by. To effectively complete our task in a timely manner, our team has divided into two sub-teams. The application team will focus on business applications and how to build them from off-the-shelf and custom built software. The infrastructure team will focus on technologies to support the necessary applications and will focus on the site itself, along with the required hardware deployment.Sponsorship: Air2Access, LLCDeliverables for IPRO 305: Building a Wireless Broadband Infrastructure to Support Maritime Applications for the spring 2007 semeste