Impact of Early-Life Exposure to Bisphenol A on Survival and Histopathology of Liver and Kidney of Zebrafish (Danio rerio)

Bisphenol A (BPA) is a highly used chemical and an ubiquitous environmental contaminant in urban aquatic ecosystems. BPA disrupts hormonal and metabolic pathways of living organisms through its endocrine disrupting activity. Early-life BPA exposure could perturb key developmental processes, thus affecting the survival of living organisms. BPA is known to accumulate in water bodies, therefore it is important to understand the impact of BPA on aquatic organisms and ecosystem health. The objective of this study was to investigate the impact of early-life BPA exposure on survival and histology of kidney and liver of zebrafish. Zebrafish model is widely used in environmental monitoring and BPA-related studies. During the study zebrafish were treated for 60 days with two environmentally prevalent concentrations of BPA (1 μg/L and10 μg/L) and with a treatment control. Twenty wild-type juvenile zebrafish of age 35 dpf (days post fertilisation) were assigned to triplicate tanks and were treated until maturity in 95 dpf. Water of the tanks were changed once per three days. Survival percentage of the fish were calculated weekly. The kidney and liver of a sample of five fish from control treatment and 10 μg/L of BPA were obtained at 95 dpf for histopathological study. Kidney and liver sections were stained using heamatoxylin/eosin and examined under light microscope for structural pathology. The highest mean survival of 90% was observed in the control group at the end of the treatment period while, 56.57% and 41.67 % of survival were observed at 1 μg/L and 10 μg/L of BPA treatments respectively. This observation led to the conclusion that BPA has a significant impact on fish survival where high BPA concentrations resulted in significantly low survival. Histopathological analysis of the kidneys of fish treated with 10 μg/L of BPA revealed damaged renal tubules, shrinkage of tubules or tubule lumen, degeneration of tubules and hematopoietic tissue when compared with the control group. The liver histopathology of BPA-treated fish revealed lipid accumulation in hepatocytes. The reduced survival and structural distortion of liver and kidney of zebrafish in BPA-treated tanks could be due to chronic early-life BPA exposure as the quality of water significantlyaffects the fish survival, growth and development. It can be concluded that early-life exposure to environmentally prevalent doses of BPA can result in increased mortality in zebrafish model. This study calls for more comprehensive studies to understand the physiological impact of early-life BPA exposure on aquatic organisms.Keywords: Bisphenol A, Zebrafish, Survival, Histology, Liver, Kidne

Aspects of the phonology of the Sinhalese verb: A prosodic analysis.

The purpose of the thesis is to study Sinhalese verb forms in relation to slow and rapid styles. The theory used in the analysis is that of Prosodic Phonology. The thesis is presented in seven chapters and an appendix. Discussed in Chapter 1 are styles, speech situations, the theory used in the analysis, the choice of the theory as the theoretical background, the nature of the analysis, research procedure, data, informants, and new information arising from the research. Chapter 2 is divided into two parts. Part 1 is an outline description of vowel and consonant sounds. The physical characteristics of these sounds and their distribution are given here. Part 2 includes a discussion of the syllable: syllable structure, syllable quantity, syllable prominence and syllable division. Chapter 3 contains an analysis of simple verb stems. Structures and patterns of verb stems, and contrasts and functions of elements within patterns are given here. In the analysis of disyllabic structures, the relationship between the first and second syllables is also discussed. Included in chapter 4 is a phonological analysis of phrasal verb stems. Here, three types of stems, non-free morphemes, loan stems and onomatopoeic stems are described. At the end of each analysis, differences of the phonological structure of stems of the given three types are considered. In the analysis of the onomatopoeic stems, the relationship between the initial and non-initial syllables is also examined. Chapter 5 includes a phonological analysis of affixes which can be suffixes, infixes or prefixes. How phonological structures of affixes differ from those of stems is also discussed. Discussed in chapter 6 are the conjug. marker, conjug. classes, the relationship between non-past vol. and invol. stems and non-past and past vol. stems, junction prosodies, reduplication and the length relationship. The analysis of rapid verb forms is given in chapter 7. Here, stems and affixes are described separately. In the analysis, phonological structures of parallel slow forms of stems and affixes are also given for comparison with structures of rapid forms. This chapter is followed by a summary and conclusion. The appendix includes a grammatical analysis of verb forms and a list of simple verbs which are analyzed in the thesis. In the grammatical analysis, volitive and involitive forms, tenses, aspects, overlapping forms and the grammatical function of suffixes are discussed

Immigration, Politics, and Mental Health: An Undergraduate Independent Study

The implications of a polarizing political climate on the plight of immigrants with disabilities in the United States are physiological and emotional. Rehabilitation and human services professionals are inclined to recognize the intersection of the process of immigration with related legislation and the presence of disability. Undergraduate students of relevant disciplines can benefit from the focused investigation that an independent study can provide – particularly because legislative directives evolve so rapidly, are directly associated with service provision and the availability of resources, and draw upon training and continuing education expectations from a variety of practitioner ethical codes

Valuing the Hikkaduwa Coral Reef: An Application of the Zonal Travel Cost Method

Hikkaduwa marine ecosystem is one of the major attractions among the recreationists for its fringing coral reef and the beach. However, a rapid degradation of the coral reef and the beach pollution are the main influences on the sustainable tourism. In this context, valuing the Hikkaduwa Marine National Park is important in order to draw the attention for the protection of the ecosystem. The objectives of this research were to estimate the economic values derived by the local visitors and to derive an optimal entrance fee. This research also aimed at investigating factors that influence visitation rates. Data collected from an onsite survey carried out among a sample of 231 visitors from 16 districts in Sri Lanka were analysed, using the Zonal Travel Cost Method to estimate the recreational value derived by the local visitors. The travel cost function showed that visitation rate is significantly and positively influenced by recreational experience and urban population fraction. The explanatory power of the estimated model was strong with an adjusted R2 value of 0.752. In the second stage, these significant explanatory variables were used to construct the demand curve. The estimated local recreational value of the park is around 380 times the income from the local visitors per year, which is worth about Rs. 1,300 per local visitor. As this site does not have a proper entrance fee, the calculated entrance fee which maximises the total revenue was around Rs.1,100. However, the current level of visitors will be reduced by more than 50%, if this entrance fee is imposed implying intragenerational equity issues. The outcomes of this research are useful in the management decision making for the protection of the Hikkaduwa coral reef and the surrounding environment.Keywords: Consumer surplus, Hikkaduwa coral reef, Tourism, Zonal Travel Cost Metho

User-preference based evolutionary algorithms for many-objective optimisation

Evolutionary Algorithms (EA) have enjoyed great success in finding solutions for multi-objective problems that have two or three-objectives in the past decade. The majority of these Evolutionary Multi-objective Optimisation (EMO) algorithms explored the decision-space using the selection pressure governed methods that are based on dominance relation. Although these algorithms are effective locating solutions for multi-objective problems, they have not been very successful for problem instances having more than three objectives, usually named as many-objective problems. The main reason behind this shortcoming is the fact that the dominance comparison becomes ineffective as the number of objectives increases. In this thesis, we incorporate some user-preference methods into EMO algorithms to enhance their ability to handle many-objective problems. To this end, we introduce a distance metric derived from user-preference schemes such as the reference point method and light beam search found in multi-criteria decision making. This distance metric is used to guide the EMO algorithm to locate solutions within certain areas of the objective-space known as preferred regions. In our distance metric approach, the decision maker is allowed to specify the amount of spread of solutions along the solution front as well. We name this distance metric based EMO algorithm as d-EMO, which is a generalised framework that can be constructed using any EA. This distance metric approach is computationally less expensive as it does not rely on dominance ranking methods, but very effective in solving many-objective problems. One key issue that remains to be resolved is that there are no suitable metrics for comparing the performance of these user-preference EMO algorithms. Therefore, we introduce a variation of the normalised Hyper-Volume (HV) metric suitable for comparing user-preference EMO algorithms. The key feature in our HV calculation process is to consider only the solutions within each preferred region. This methodology favours user-preference EMO algorithms that have converged closely to the Pareto front within a preferred region. We have identified two real-world engineering design problems in optimising aerofoil and lens designs, and formulated them as many-objective problems. The optimisation process of these many-objective problems is computationally expensive. Hence, we use a reference point PSO algorithm named MDEPSO to locate solutions effectively in fewer function evaluations. This PSO algorithm is less prone to getting stuck in local optimal fronts and still retains its fast convergence ability. In MDEPSO, this feature is achieved by generating leader particles using a differential evolution rule rather than picking particles directly from the population or an external archive. The main feature of the optimisation process of these aerofoil and lens design problems is the derivation of reference points based on existing designs. We illustrate how these existing designs can be used to either obtain better or new design solutions that correspond to various requirements. This process of deriving reference points based on existing design models, and integrating them into a user-preference EMO framework is a novel approach in the optimisation process of such computationally expensive engineering design problems

The effect of a hyaluronic acid nasal pack, and insulin-like growth factor 1, on mucosal healing after endoscopic

Thesis (M.S.)--University of Adelaide, Dept. of Surgery, 200

I. Stereoselective Construction of Polycyclic Architectures: Enantioselective Catalytic Transannular Ketone-Ene Reactions and an Enantioselective Total Synthesis of (+)-Reserpine II. Synthesis of Chiral Bisthioureas for Anion-Abstraction Catalysis

The research presented herein explores three aspects of asymmetric catalysis: (1) the development of new catalytic enantioselective reactions, (2) the application of stereoselective catalysis to natural product total synthesis, and (3) the design and synthesis of new chiral catalysts.Chemistry and Chemical Biolog

A quantitative exploration of the sociocultural context of teenage pregnancy in Sri Lanka

Background: In common with other countries, teenage pregnancy is attracting policy attention in Sri Lanka because of the risks it poses to maternal and infant health and social and economic well-being. This study aimed to increase understanding of the context of teenage pregnancy, by (1) describing the socio-economic and demographic characteristics of pregnant teenagers and their partners; (2) exploring whether teenage pregnancies are planned and how they are received; and (3) exploring factors associated with unplanned teenage pregnancy. Methods: A population health-register based sample survey was conducted in Badulla District, Sri Lanka. Interviewer-administered questionnaires were administered to two samples: 450 pregnant women aged less than 20years; and 150 male partners of pregnant women aged less than 20years. Bivariate statistics described the characteristics and context of teenage pregnancy. Multivariate logistic regression explored correlates of unplanned pregnancy. Results: Over 60% of pregnant teenagers and male partners indicated that the current pregnancy was planned; while 79% of pregnant teenagers and 85% of male partners welcomed the pregnancy. Most pregnant teenagers were living within stable and supportive family environments, with 94% reporting that they felt 'very well supported'. Nevertheless, a sub-group of pregnant teenagers appeared to be vulnerable, reporting unplanned and unhappy pregnancy; factors that were also associated with first intercourse being reported as not wanted. Levels of reproductive and contraceptive knowledge were poor among both pregnant teenagers and male partners. Just 46% of teenagers and 64% of male partners knew that pregnancy was possible at first intercourse. Mothers appear to be an important source of information and support for young women, with peers being reported far less often. Conclusions: Intervention to reduce teenage pregnancy must recognise the normative nature of early childbearing for the majority of girls who currently conceive and their families. Avoiding such pregnancies will require a fundamental shift in life chances such that delaying pregnancy offers significant socioeconomic advantages. Meanwhile, improved provision of contraceptive information and services is needed to support the delay of second pregnancies for young mothers. In addition, strategies to identify and protect those girls who are vulnerable to unwanted sexual activity are needed.</p