20 research outputs found
Self-transcendence: An alternative explanation for voluntourism in developing countries
In recent years, travel associated with volunteering activities has attracted a cross section of people with varying demographic characteristics and aspiration to both developing and developed countries and has been on increase. This paper argues for self-transcendence as an alternative altruistic motivation for some individuals who choose to travel to developing nations destinations which are considered risky as VOLUNtourists. A descriptive research design was used to guide the research process. This study was based on a sample of 501 respondents who had completed their visit to Uganda for various reasons.
Results indicate that, there was no significant association between gender and purpose of the visit, while age group was significantly associated with the purpose of visiting. Most visitors were seeking that which they perceived to be beyond themselves associated with spirituality. Currently most facilities within tourist attractions in Uganda favour the adult age group and it is recommended that special consideration be given to the development of affordable facilities such as accommodation to cater for all age groups in order to continue realising the positive contribution to the potential of tourism in developing countries
Barcoding and border biosecurity: Identifying cyprinid fishes in the aquarium trade
10.1371/journal.pone.0028381PLoS ONE71
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Co-treatment of Municipal Wastewater and Landfill Leachate in an Activated Sludge Sequencing Batch Reactor
A year-long bench-scale treatability study was performed to assess the feasibility of using an activated sludge sequencing batch reactor (SBR) to treat a mixture of domestic wastewater and landfill leachate. A 50/50 (v/v) of domestic wastewater and landfill leachate was treated in a 1 L SBR operated on a 12 hour cycle with a hydraulic retention time (HRT) of 4 days, mean solids retention time (SRT) no less than 25 days, and an average mixed liquor volatile suspended solids (MLVSS) of 2500 ± 500 mg/L. The combined influent had high chemical oxygen demand (COD) and total ammonia nitrogen (TAN), with average concentrations exceeding 1500 mg/L and 450 mg N/L respectively. The combined influent had a carbonaceous biochemical oxygen demand (CBOD₅) to COD ratio of 40 ± 10%, a TAN to COD ratio of 26 ± 7%, and also showed seasonal variability in pollutant loadings due to changes in rainfall. The SBR was capable of meeting effluent targets for 5-day carbonaceous biochemical oxygen demand (CBOD₅) and TAN, which were 10 mg/L and 5 mg N/L respectively, at loadings of up to 100 mg CBOD₅/L-d and 140 mg N/L-d. However, during the first 8 months, CBOD₅ removal was less consistent, with effluent values often above 20 mg/L, after which time effluent CBOD₅ was consistently below 20 mg/L. Filtration reduced effluent CBOD₅ by 50%, suggesting that a significant fraction was
association with particulate matter. Nitrification performance was inconsistent during the first 7 months of operation, with accumulation of both TAN and NO₂-N, although good nitrification performance was eventually attained with complete nitrification of TAN to NO₃-N and almost 100% TAN removal. The decreased nitrification performance was most likely related to factors such as excess ammonia loading, aeration intensity, and free ammonia, rather than other inhibitory substances in the landfill leachate such as metals or organics. Aeration adjustments under different loading scenarios showed that the extent of nitrification was highly affected by aeration intensity, with improved nitrification observed with increased aeration. Increased aeration resulted in the complete nitrification of TAN to NO₃-N with effluent TAN and CBOD below target values for a combined influent of 67% landfill leachate and 33% wastewater. Denitrification was achieved only with the addition of methanol, which could provide another option for nitrogen removal in the SBR if reduction of NO₂-N or NO₃-N is needed. Average phosphorus removal in the SBR was approximately 10%. Based on mass wasting of reactor sludge, the reduction in phosphorus corresponded to normal microbial uptake and not to the presence of phosphorus accumulating organisms (PAOs). Metals analysis showed effluent manganese to be consistently below the preliminary target value of 5 mg/L and that reactor solids contained regulated heavy metals at concentrations well below the EPA ceiling limits for land application. Volatile organics and pesticides selected as additional preliminary target pollutants were either well below target limits or were not detected at all in the SBR effluent, although additional data may be needed to further verify whether these contaminants would be an issue in terms of effluent requirements
The intervention of plants in the conflicts between buildings and climate - A case study in Singapore
Ph.DDOCTOR OF PHILOSOPH
Essays in Experimental Economics and Applied Econometrics
This dissertation presents one essay that utilizes an experiment and two essays that use observational data to causally examine important economic questions. In the first essay, I describe a laboratory experiment with human participants designed to test key theoretical predictions related to the effects of using public and secret reserve prices in independent private value, first-price sealed bid auctions. The results support theoretical predictions related to bidding in public reserve auctions and predicted revenue differences between public and secret reserve auctions. Predictions regarding buyer bidding in secret reserve auctions, and that public and secret reserves generate higher revenue than no reserve auctions, is not supported by the data.
The second essay investigates the relationship between air quality and human endurance and strength. I utilize a database of physical fitness scores from members of the United States Air Force and merge this with particulate matter measures from the Environmental Protection Agency. I exploit daily variation in particulate matter and the random assignment of members to work locations to identify a causal effect of particulate matter on member run times, push-ups, and crunches. I find that particulate matter exposure results in significant decreases in push-up and crunch repetitions and increases run times. Furthermore, I find that the physical fitness test failure rate increases with exposure to high particulate matter concentrations.
The third essay, a joint project with Celeste K. Carruthers (University of Tennessee, Knoxville), Michael Koefed and Aaron Phipps (United States Military Academy), and Jenna Webb Kramer (RAND Corporation), estimates the causal effects of providing free community college on military enlistments and aptitude. To identify these relationships we employ a two-way fixed effects model and exploit the staggered rollout of the Tennessee Promise scholarship program, which is a last-dollar aid program that became available to graduating high school seniors in a subset of Tennessee counties in 2009 and by 2015 was implemented statewide. Our quantitative analysis complements the findings of Dr. Kramer’s qualitative analysis and shows that Tennessee promise led to a significant decrease in military enlistments. We also find that Tennessee Promise motivated more technically adapt persons to enlist
Removal of copper ion (CU2+) from industrial effluent by immobilized microbial cells.
by So Chi Ming.Thesis (M.Phil.)--Chinese University of Hong Kong, 1991.Includes bibliographical references.Acknowledgement --- p.iAbstract --- p.iiChapter 1. --- Objectives of the Study --- p.1Chapter 2. --- Literature Review --- p.2Chapter 2.1 --- Heavy Metals in the Environment --- p.2Chapter 2.2 --- Heavy Metal Pollution in Hong Kong --- p.3Chapter 2.3 --- Chemistry and Toxicity of Copper in the Environment --- p.6Chapter 2.4 --- Conventional and Alternative Methods for Heavy Metal Removal --- p.10Chapter 2.5 --- Heavy Metal Removal by Microorganisms --- p.14Chapter 2.6 --- Factors Affecting Biosorption of Heavy Metals --- p.27Chapter 2.7 --- Applicability of Biosorbent in Heavy Metal Removal --- p.31Chapter 3. --- Materials and Methods --- p.36Chapter 3.1 --- Screening of Bacteria for Copper Removal Capacity --- p.36Chapter 3.1.1 --- Isolation of Bacteria from Activated Sludge --- p.36Chapter 3.1.2 --- Selection of Copper Resistant Bacteria from Water Samples --- p.37Chapter 3.1.3 --- Pre-screening of Bacteria for Copper Uptake --- p.37Chapter 3.1.4 --- Determination of Copper Removal Capacity of Selected Bacteria --- p.37Chapter 3.2 --- Effect of Culture Conditions on Copper Removal Capacity of Pseudomonas putida 5-X --- p.39Chapter 3.2.1 --- Effect of Nutrient Limitation --- p.39Chapter 3.2.2 --- Effect of Incubation Temperature and Culture Age --- p.41Chapter 3.3 --- Determination of Copper Uptake Mechanism of Pseudomonas putida 5-X --- p.41Chapter 3.3.1 --- Effect of Glucose and Sodium Azide on Copper Removal Capacity --- p.41Chapter 3.3.2 --- Transmission Electron Micrograph of Pseudomonas putida 5-X after Copper Uptake --- p.43Chapter 3.4 --- Effect of Pretreatment of Cells on Copper Removal Capacity of Pseudomonas putida 5-X --- p.43Chapter 3.5 --- Physico-chemical Characterization of Pseudomonas putida 5-X as Biosorbent for Copper Removal --- p.43Chapter 3.5.1 --- Determination of Copper Uptake Kinetics --- p.43Chapter 3.5.2 --- Determination of Freundlich Isotherm for Copper Uptake --- p.44Chapter 3.5.3 --- Effect of pH on Copper Removal Capacity --- p.44Chapter 3.5.4 --- Effect of Metal Ions on Copper Removal Capacity --- p.44Chapter 3.5.5 --- Effect of Anions on Copper Removal Capacity --- p.45Chapter 3.6 --- Copper Removal by Immobilized Cells of Pseudomonas putida 5-X --- p.45Chapter 3.6.1 --- Effect of Retention Time on Copper Removal Capacity of Immobilized Cells --- p.47Chapter 3.6.2 --- Efficiency of Copper Recovery from Immobilized Cells by Various Eluants --- p.47Chapter 3.6.3 --- Performance of Immobilized Cells on Multiple Copper Loading-elution Cycles --- p.48Chapter 3.6.4 --- Treatments of Effluent from an Electroplating Factory by Immobilized Cells --- p.48Chapter 4. --- Results --- p.49Chapter 4.1 --- Screening of Bacteria for Copper Removal Capacity --- p.49Chapter 4.2 --- Effect of Culture Conditions on Copper Removal Capacity of Pseudomonas putida 5-X --- p.49Chapter 4.2.1 --- Effect of Nutrient Limitation --- p.49Chapter 4.2.2 --- Effect of Incubation Temperature and Culture Age --- p.52Chapter 4.3 --- Determination of Copper Uptake Mechanism of Pseudomonas putida 5-X --- p.52Chapter 4.3.1 --- Effect of Glucose and Sodium Azide on Copper Removal Capacity --- p.52Chapter 4.3.2 --- Transmission Electron Micrograph of Pseudomonas putida 5-X after Copper Uptake --- p.52Chapter 4.4 --- Effect of Pretreatment of Cells on Copper Removal Capacity of Pseudomonas putida 5-X --- p.56Chapter 4.5 --- Physico-chemical Characterization of Pseudomonas putida 5-X as Biosorbent for Copper Removal --- p.56Chapter 4.5.1. --- Determination of Copper Uptake Kinetics --- p.56Chapter 4.5.2 --- Determination of Freundlich Isotherm for Copper Uptake --- p.56Chapter 4.5.3 --- Effect of pH on Copper Removal Capacity --- p.60Chapter 4.5.4 --- Effect of Metal Ions on Copper Removal Capacity --- p.60Chapter 4.5.5 --- Effect of Anions on Copper Removal Capacity --- p.60Chapter 4.6 --- Copper Removal by Immobilized Cells of Pseudomonas putida 5-X --- p.60Chapter 4.6.1 --- Copper Removal Capacity of Immobilized Cells and Breakthrough Curve for Copper Removal --- p.60Chapter 4.6.2 --- Effect of Retention Time on Copper Removal Capacity of Immobilized Cells --- p.65Chapter 4.6.3 --- Efficiency of Copper Recovery from Immobilized Cells by Various Eluants --- p.65Chapter 4.6.4 --- Performance of Immobilized Cells on Multiple Copper Loading-elution Cycles --- p.65Chapter 4.6.5 --- Treatment of Effluent from an Electroplating Factory by Immobilized Cells --- p.65Chapter 5. --- Discussion --- p.72Chapter 5.1 --- Screening of Bacteria for Copper Removal Capacity --- p.72Chapter 5.2 --- Effect of Culture Conditions on Copper Removal Capacity of Pseudomonas putida 5-X --- p.73Chapter 5.2.1 --- Effect of Nutrient Limitation --- p.73Chapter 5.2.2 --- Effect of Incubation Temperature and Culture Age --- p.74Chapter 5.3 --- Determination of Copper Uptake Mechanism of Pseudomonas putida 5-X --- p.75Chapter 5.3.1 --- Effect of Glucose and Sodium Azide on Copper Removal Capacity --- p.75Chapter 5.3.2 --- Transmission Electron Micrograph of Pseudomonas putida 5-X after Copper Uptake --- p.75Chapter 5.4 --- Effect of Pretreatment of Cells on Copper Removal Capacity of Pseudomonas putida 5-X --- p.76Chapter 5.5 --- Physico-chemical Characterization of Pseudomonas putida 5-X as Biosorbent for Copper Removal --- p.77Chapter 5.5.1 --- Copper Uptake Kinetics --- p.77Chapter 5.5.2 --- Freundlich Isotherm for Copper Uptake --- p.78Chapter 5.5.3 --- Effect of pH on Copper Removal Capacity --- p.78Chapter 5.5.4 --- Effect of Metal Ions on Copper Removal Capacity --- p.79Chapter 5.5.5 --- Effect of Anions on Copper Removal Capacity --- p.80Chapter 5.6 --- Copper Removal by Immobilized Cells of Pseudomonas putida 5-X --- p.80Chapter 5.6.1 --- Copper Removal Capacity of Immobilized Cells and Breakthrough Curve for Copper Removal --- p.80Chapter 5.6.2 --- Effect of Retention Time on Copper Removal Capacity of Immobilized Cells --- p.82Chapter 5.6.3 --- Efficiency of Copper Recovery from Immobilized Cells by Various Eluants --- p.82Chapter 5.6.4 --- Performance of Immobilized Cells on Multiple Copper Loading-elution Cycles 的 --- p.83Chapter 5.6.5 --- Treatment of Effluent from an Electroplating Factory by Immobilized Cells --- p.84Chapter 6. --- Conclusion --- p.85Chapter 7. --- Summary --- p.87Chapter 8. --- References --- p.8
Effect of heavy metals on salt march biota
Environmental restoration of disturbed, degraded and potentially contaminated wetland sites aims for the persistent and sustainable re-establishment of biological communities and important wetland functions. An ecologically informed restoration strategy presupposes some understanding of these system processes, but also of potential impacts on contaminants in the environment for risk assessment, long-term management, and potential cost-effective mitigative measures. In this study, potential effects of moderate heavy metal contamination in sediments of the urban salt marsh Harrier Meadow, NJ, were evaluated on growth performance of the common salt marsh plant S. patens and associated arbuscular mycorrhizal fungi (AMF) colonizing its roots. Growth performance as well as uptake of heavy metals into roots and translocation from below- into above-ground parts was studied as a function of basic environmental conditions such as pH and redox potential, absence or presence of AMF, as well as additional contamination with nickel (Ni) at selected times during the first growing season, and after the third growing season.
The experimental setup in the greenhouse with soil cores containing S. patens from Harrier Meadow resulted in consistent environmental conditions in cores within and between treatments, with values for most physicochemical parameters being not significantly different at comparable depths. Concentrations and spectra of total hydrolysable amino acids (THAA) in the organic material analyzed after the third growing season as measure for organic matter quality and thus metabolic processes were similar in cores of all treatments and thus indicated no significant biotic environmental differences that might have developed in time as a function of treatments. Measures for AMF were similar on plants from all treatments even though small, statistically significant differences were obtained for percent root length colonized, and arbuscular or vesicular colonization. Since none of the treatments eliminated AMF, these differences could not be related to treatment effects, but were suggested to be the result of potential shifts in AMF community structure, that, however, were not analyzed within the scope of the thesis.
Plant growth performance assessment based on leaf nitrogen (N) content, stable isotope ratios (δC), carboxylation efficiency (CE), CO2 saturated photosynthetic capacity (Amax), estimations of optimal transfer efficiency of open photosynthesis II (PSII) reaction centers (Fv/Fm), sprout numbers, and shoot and root biomass generally showed seasonal variation in these characteristics only. However, additional variation was displayed for parameters such as Amax, Fv/Fm, and shoot and root biomass where significant effects of Ni amendment were found during reproduction . These effects were no longer significant at the end of the growing season, and were not obtained when Ni amendment was combined with AMF suppression.
Sediment of Harrier Meadow was found to be moderately contaminated with heavy metals (Cd, Cr, Cu, Ni, Zn). Calculations using MineQL+, a data driven, chemical equilibrium modeling program suggested that, under suboxic and anoxic conditions found in all cores, only Cd, and under anoxic conditions, Ni would not form precipitates, while Cd, Cr, Cu, Pb and Zn would mainly form precipitates. 70-95% of the total concentration of the dissolved forms of all heavy metals could also be adsorbed to organic compounds. None of the heavy metals nor the additional Ni application resulted in uptake or translocation values typical for hyperaccumulating plants, but rather values in the typical range found for many agricultural plants. Since all values in plant tissues were above the critical deficiency contents and below the critical toxicity contents, effects on plant growth performance should not be expected. Ni amendment did not increase uptake and translocation in most cases although effects of Ni amendment were displayed for root uptake of certain heavy metals (i.e., Cu, Pb, Zn and Fe) at the depth of 7.5 cm.
These results demonstrate that moderate heavy metal contamination found in sediments of Harrier Meadow did not affect growth performance of the common salt marsh plant S. patens and associated arbuscular mycorrhizal fungi (AMF) colonizing its roots during key points of the growing season. Although considerable uptake of all heavy metals into or adsorption to roots was encountered, translocation from below- into aboveground parts of S. patens was not significant, and always below regulatory action limits (maximum limit levels for vegetative leaves of Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn are 0.2, 2.30, 73.3, 425.50, 500, 67.90, 0.3 and 99.40 mg.kg-1). Thus, the risks associated with the restoration of moderately contaminated salt marshes with S. patens, i.e., the potential of S. patens to act as a conduit for the movement of toxic metals into the food web, are minimal and thus of low public health concern
Proceedings of the BEST EN Think Tank XVII: innovation and progress in sustainable tourism
BEST EN is an international consortium of educators committed to the development and dissemination of knowledge in the field of sustainable tourism. The organization's annual Think Tank brings together academics and industry representatives from around the world to discuss a particular theme related to sustainable tourism in order to move research and education in this specific field forward.
We are pleased to present the proceedings of the BEST Education Network (BESTEN) Think Tank XVII entitled Innovation and Progress in Sustainable Tourism. The event was held in Mauritius, June 14-17, 2017, in conjunction with the International Center for Sustainable Tourism and Hospitality, University of Mauritius.
The term 'sustainable tourism' emerged in the early 1980s building on earlier concerns about the negative impacts of tourism and linking tourism to the wider sustainability movement. Despite 30 years of discussion of tourism and sustainability in academic and government documents, recent reviews suggest that there is considerable room for improvement in the practice of sustainable tourism.
The proceedings present work by academics and practitioners worldwide, conducted on various aspects of innovation and progress in sustainable tourism. They include abstracts and papers accepted by the scientific committee following a double blind peer review process.
Twenty-eight research papers were presented at the conference. Presentations were held within the following themed sessions:
• Assessing Progress, Contributions & Teaching and Learning
• Innovation – Sustainable, Experiential, Product and Marketing
• Tourism Impacts, Sustainable Tourism Education, Interpretation
• Theoretical and Methodological Approaches for Researching Sustainable Tourism
The contributions were thematically selected for each group and are arranged in order of presentation in the proceedings. The full proceedings as well as the PowerPoint presentations are available on the BEST EN website www.besteducationnetwork.org/
The Editor and the BEST EN Executive Committee anticipate that readers of this volume will find the papers informative, thought provoking and of value to their research
How to procure flexibility services within the electricity distribution system: lessons from an international review of innovation projects
The aim of this paper is to analyse and evaluate the deployment of smart platforms (operated by distribution system operators—DSOs—or by independent parties) in key jurisdictions that facilitate the trading of flexibility services—primarily by DSOs. We look at key innovation projects/initiatives from seven jurisdictions, including Australia, France, Germany, Great Britain, Japan, The Netherlands and Norway. We have deliberately selected 13 use cases that operate under different regulatory frameworks and market rules, and have been recently implemented (from 2017 onwards). With the selection of key use cases this study seeks to discuss the different smart architecture solutions and main capabilities across different demonstrators and their relationship to business as usual. It also analyses flexibility market designs, identifies main characteristics, and compares different price formation schemes and procurement methods. The value of flexibility for DSOs is also discussed