Environmental stress and disturbance can affect the structure and functioning of marine ecosystems by altering their physical, chemical and biological features. In estuaries, benthic invertebrate communities play important roles in structuring sediments, influencing primary production and biogeochemical flux, and occupying key food web positions. Stress and disturbance can reduce species diversity, richness and abundance, with ecological theory predicting that biodiversity will be at its lowest soon after a disturbance with assemblages dominated by opportunistic species. The Avon-Heathcote Estuary in Christchurch New Zealand has provided a novel opportunity to examine the effects of stress, in the form of eutrophication, and disturbance, in the form of cataclysmic earthquake events, on the structure and functioning of an estuarine ecosystem. For more than 50 years, large quantities (up to 500,000m3/day) of treated wastewater were released into this estuary but in March 2010 this was diverted to an ocean outfall, thereby reducing the nutrient loading by around 90% to the estuary. This study was therefore initially focussed on the reversal of eutrophication and consequent effects on food web structure in the estuary as it responded to lower nutrients. In 2011, however, Christchurch was struck with a series of large earthquakes that greatly changed the estuary. Massive amounts of liquefied sediments, covering up to 65% of the estuary floor, were forced up from deep below the estuary, the estuary was tilted by up to a 50cm rise on one side and a corresponding drop on the other, and large quantities of raw sewage from broken wastewater infrastructure entered the estuary for up to nine months. This study was therefore a test of the potentially synergistic effects of nutrient reduction and earthquake disturbance on invertebrate communities, associated habitats and food web dynamics. Because there was considerable site-to-site heterogeneity in the estuary, the sites in this study were selected to represent a eutrophication gradient from relatively “clean” (where the influence of tidal flows was high) to highly impacted (near the historical discharge site). The study was structured around these sites, with components before the wastewater diversion, after the diversion but before the earthquakes, and after the earthquakes. The eutrophication gradient was reflected in the composition and isotopic chemistry of primary producer and invertebrate communities and the characteristics of sediments across the sample sites. Sites closest to the former wastewater discharge pipe were the most eutrophic and had cohesive organic -rich, fine sediments and relatively depauperate communities dominated by the opportunistic taxa Capitellidae. The less-impacted sites had coarser, sandier sediments with fewer pollutants and far less organic matter than at the eutrophic sites, relatively high diversity and lower abundances of micro- and macro-algae. Sewage-derived nitrogen had became incorporated into the estuarine food web at the eutrophic sites, starting at the base of the food chain with benthic microalgae (BMA), which were found to use mostly sediment-derived nitrogen. Stable isotopic analysis showed that δ13C and δ15N values of most food sources and consumers varied spatially, temporally and in relation to the diversion of wastewater, whereas the earthquakes did not appear to affect the overall estuarine food web structure. This was seen particularly at the most eutrophic site, where isotopic signatures became more similar to the cleaner sites over two-and-a-half years after the diversion. New sediments (liquefaction) produced by the earthquakes were found to be coarser, have lower concentrations of heavy metals and less organic matter than old (existing) sediments. They also had fewer macroinvertebrate inhabitants initially after the earthquakes but most areas recovered to pre-earthquake abundance and diversity within two years. Field experiments showed that there were higher amounts of primary production and lower amounts of nutrient efflux from new sediments at the eutrophic sites after the earthquakes. Primary production was highest in new sediments due to the increased photosynthetic efficiency of BMA resulting from the increased permeability of new sediments allowing increased light penetration, enhanced vertical migration of BMA and the enhanced transport of oxygen and nutrients. The reduced efflux of NH4-N in new sediments indicated that the capping of a large portion of eutrophic old sediments with new sediments had reduced the release of legacy nutrients (originating from the historical discharge) from the sediments to the overlying water. Laboratory experiments using an array of species and old and new sediments showed that invertebrates altered levels of primary production and nutrient flux but effects varied among species. The mud snail Amphibola crenata and mud crab Austrohelice crassa were found to reduce primary production and BMA biomass through the consumption of BMA (both species) and its burial from bioturbation and the construction of burrows (Austrohelice). In contrast, the cockle Austrovenus stutchburyi did not significantly affect primary production and BMA biomass. These results show that changes in the structure of invertebrate communities resulting from disturbances can also have consequences for the functioning of the system. The major conclusions of this study were that the wastewater diversion had a major effect on food web dynamics and that the large quantities of clean and unpolluted new sediments introduced to the estuary during the earthquakes altered the recovery trajectory of the estuary, accelerating it at least throughout the duration of this study. This was largely through the ‘capping’ effect of the new liquefied, coarser-grained sediments as they dissipated across the estuary and covered much of the old organic-rich eutrophic sediments. For all aspects of this study, the largest changes occurred at the most eutrophic sites; however, the surrounding habitats were important as they provided the context for recovery of the estuary, particularly because of the very strong influence of sediments, their biogeochemistry, microalgal and macroalgal dynamics. There have been few studies documenting system level responses to eutrophication amelioration and to the best on my knowledge there are no other published studies examining the impacts of large earthquakes on benthic communities in an estuarine ecosystem. This research gives valuable insight and advancements in the scientific understanding of the effects that eutrophication recovery and large-scale disturbances can have on the ecology of a soft-sediment ecosystem.

Prescription opioid pain reliever utilization has been increasing since the 1990s, due in part to changes in recommendations for the treatment of chronic pain, but also to abuse and diversion. One innovative policy solution to the abuse and diversion of prescription opioids is state prescription drug monitoring programs (PDMPs), which provide prescribers and other selected parties with patient controlled substance dispensation history; thereby, correcting an information asymmetry problem between prescribers and patients. The widespread implementation of state PDMPs, which vary in program design and requirements, has resulted in a variety of intended and unintended consequences. Previous PDMP evaluations have suggested such outcomes as the reduction of consumer access to opioids, the influencing of healthcare provider prescribing behaviors for opioids, and the re-shaping of the United States market for prescription opioids. PDMPs may also be associated with unintended outcomes: namely, the restriction of pharmaceutical opioids could be associated with an increase in heroin use, as evidenced by increases in heroin substance abuse treatment facility discharges. The analyses in this project examine the influence of PDMPs on healthcare providers and the market for prescription drugs by comparing trends in opioid utilization in states with varying PDMP features using Medicaid prescription utilization data and commercial insurance claims. The effect of PDMPs on consumers is explored with an analysis comparing substance abuse treatment facility discharge data for heroin abuse with pharmaceutical opioid prescriptions before and after PDMP regulatory change. Finally, the impact of other related opioid policy interventions, opioid overdose medication access laws, are analyzed by comparing opioid overdose mortality across states with differing overdose medication access policies over time. Contributions to the understanding about the impacts of these state-level opioid abuse and diversion policies can be used to improve or amplify intended outcomes and ameliorate unintended consequences.

The lower Churchill River has been an important travel route for people living in its vicinity for a long period of time. Churchillians’ have used it for subsistence harvesting, as their potable water source and as a place of recreation and relaxation. Previous research has documented the importance of the Churchill River to the residents and has explored how the Churchill River Diversion affected the community of Churchill (Boothroyd, 1992; 2000; Four Directions Consulting Group, 1994; 1995). The purpose of this project was to identify how Churchill residents used the lower Churchill River (from 1970 to 2006), recognizing three distinct periods of time. Twenty interviews were conducted with former or current long-term residents of Churchill, as well as two interviews with experts on issues concerning the lower Churchill River. Many interviewees stated that additional negotiations and measures are required before they deem the mitigation compensation package from Manitoba Hydro to be adequate considering the impact of the diversion on the residents of Churchill.

Anthropogenic disruptions in the form of hydrological alterations, such as dam construction and the associated water diversions are a cause of much upheaval to local and regional ecosystems. Lake 626 within the Experimental Lakes Area of north-west Ontario, along with its downstream wetlands, 626A and 626B are one such system. Construction of a dam at the L626 inflow has completely restricted water flow, reducing and reshaping the watershed, increasing water retention time, and decreasing outflow into the wetlands. This study investigates the state of each wetland through physical and geochemical characterization during the first year following the diversion. Previous studies have found that hydrological diversions in wetlands can lower water table levels, altering soil chemistry and producing a shift in floral and faunal communities. Ultimate consequences involve significant loss of wetland area through conversion to upland habitat. This provides a model for climatic warming scenarios, wherein sustained drought conditions can produce the same result. Boreal wetlands are surprising fragile ecosystems that store massive quantities of carbon and are at risk of releasing it in such situations. One study showed that an extended summer drought in an otherwise average year with above average precipitation produced losses of 90 g C/m2 over the course of the year. Maintenance of reduced-flow in wetlands 626A and 626B is expected to convert the system into a carbon source and reduce overall wetland area. Radiocarbon dating has revealed that following deglaciation, both 626A and 626B basins were open water wetlands, depositing limnic peat for about 3200 and 1300 years respectively. Each site then transitioned into open sedge dominated fen – 626B to the present and 626A until about 2.5 ka BP when Sphagnum began to develop. Wetland 626B is decidedly an open shrub/sedge fen, supporting Myrica gale, Chamaedaphne calyculata and Carex rostrata / lasiocarpa communities. Wetland 626A is a bog/fen complex, sharing similar communities in the fen areas, but housing a large, centrally located bog of shrub species overlying Sphagnum hummocks. Tritium values in 626A were similar to cosmic background levels, indicating that recharge of basal pore water has not occurred in at least 60 years. Tritium in 626B was much higher, suggesting a substantial difference in hydrology or peat hydraulic conductivity between the basins. Measurement of DOC profiles showed high concentrations in near-surface water, reaching over 80 mg/L, and dropping to about 20 mg/L at maximum depths. An opposite trend was seen for DIC and CH4 profiles which increased concentration with depth (25 – 70 mg/L DIC; 75 – 700 μmol/L CH4). Isotopically however, 13C signatures from basal DIC were more positive while signatures from CH4 were typically more negative (-6 ‰ to +4 ‰ DIC; -57 ‰ to -73 ‰ CH4). Breakdown of DOC by LC-OCD showed high concentrations of humic substances and low molecular weight neutrals. The origin of humic substances in surface water became more pedogenic with increasing distance from the L626 outflow, indicating the influence of decaying wetland vegetation on the DOC of adjacent water. A comparison between contemporary and future characterization of boreal peatlands under drought-like conditions will provide a better understanding of the impacts suffered by wetlands during hydrological alterations. The high sensitivity of wetlands to changing hydrology should also provide a measure for gauging the effects of long term climate warming. This will assist in the development of environmental policies to better govern both the establishment of water diversions and the multitude of other practices leading to climate change.

A diversion weir is a headwork facility built across a river to raise the water level and to divert water for various purposes, such as irrigation, hydropower generation, etc. Diversion weirs with sidewise intakes are widely used in plain rivers. They are composed of many structural components which are designed for different purposes. In this thesis, a Windows-based, visual, user friendly program named WINDWEIR was developed in Visual Basic.NET programming language for the optimum design of a diversion weir with sidewise intake. It determines the overall dimensions of each of the components of the diversion weir and the total cost of the whole structure. It also performs stability analysis. It is such a flexible computer program that a design engineer can assess various dimensions of the structure from viewpoints of safety and economy by performing quick successive test runs to achieve an optimum solution among various alternatives.

National drug policy development is essential for effective drug policies, yet the process through which they emerge, the role of evidence and the theoretical basis for drug policy development are poorly understood. The present research adopted a cross-national analytical-descriptive approach to examine drug policy development between 1994 and 2006 in two nations: Portugal and Australia. Through contrasting atypical reforms - namely decriminalisation in Portugal and the Illicit Drug Diversion Initiative (IDDI) in Australia – with the preceding periods of typical reform, it provides a detailed examination of how atypical reforms are proposed, negotiated and adopted. Moreover, it critically analyses the application of three public policy theories – Multiple Streams, Advocacy Coalition and Punctuated Equilibrium – to identify common drivers and processes underpinning the developments. / Through a primarily qualitative approach involving interviews with 42 expert policy makers, supplemented with secondary sources and publicly available evaluations, this research demonstrates that the major drivers of atypical reform are policy advocates and their ability to convert opportunities into pragmatic responses. In Portugal policy entrepreneurs utilised the emergence of a problem opportunity, typified by a public health crisis in Casal Ventoso, to form an alliance between experts and politicians and adopt a paradigmatic change: decriminalisation. Policy entrepreneurs in Australia used the emergence of a highly politicised opportunity to convert what was initially a doctrinal solution of “zero tolerance” into a more humane response: drug diversion. / The research reveals that the process of policy formulation has critical impacts upon the mechanism, implementation and potential outcomes of reform, most notably whether there is evidence-based policy or policy-based evidence. It concludes by identifying practical and theoretical implications for more effective drug policy development, including the need for greater application of the theory of Punctuated Equilibrium. The current research asserts that policy makers must have realistic expectations over the role of evidence in policy making, but that the likelihood of pragmatic reform may be enhanced through expanding attention from “what works” to include alternative tools of persuasion. It further recommends that greater attention to the latter may increase the likelihood of effective reform. Due to the formation of an alliance between politicians and experts the Portuguese policy making process facilitated a more pragmatic reform. However, a paradigmatic change – and hence the potential for effective drug policy – would not have been possible without advocacy for a new vision of the drug user as a citizen.

Thesis (Ph. D.)--Virginia Polytechnic Institute and State University, 1995. / Vita. Abstract. Includes bibliographical references (leaves 137-140). Also available via the Internet.

Thesis (Ph. D.)--Virginia Polytechnic Institute and State University, 1996. / Vita. Abstract. Includes bibliographical references (leaves 161-166). Also available via the Internet.

Zugl.: München, Univ., Diss., 2009

Τα επίπεδα της γκρελίνης και του PYY μετά από χειρουργείο χολοπαγκρεατικής εκτροπής και Roux-en-Y γαστρικού bypass και μετά από χειρουργείο κολεκτομής: προοπτική συγκριτική μελέτη Οι ορμόνες του γαστρεντερικού γκρελίνη και PYY έχει αποδειχθεί ότι παίζουν κάποιο ρόλο στη ρύθμιση του μεταβολισμού και της όρεξης. Μελετάμε την επίδραση του χειρουργείου της χολοπαγκρεατικής εκτροπής και RYGBP (BPD-RYGBP) στα κυκλοφορούντα επίπεδα της γκρελίνης και του PYY άμεσα μετεγχειρητικά και τα συγκρίνουμε με την αντίστοιχη επίδραση μιας άλλης χειρουργικής επέμβασης της ίδιας βαρύτητας, την κολεκτομή. Μέθοδος. Μελετάμε τα επίπεδα νηστείας της γκρελίνης και του PYY σε 20 παχύσαρκους ασθενείς (super-obese) που υποβλήθηκαν σε BPDRYGBP και σε 13 ασθενείς που υποβλήθηκαν σε κολεκτομή για καρκίνο παχέος εντέρου. Οι μετρήσεις έγιναν προεγχειρητικά, και τις μετεγχειρητικές ημέρες 1,3,7,30 και 90 και στις δύο ομάδες, καθώς και στον 1 χρόνο στην ομάδα των παχυσάρκων. Αποτελέσματα. Προεγχειρητικά, τα επίπεδα και της γκρελίνης και του PYY ήταν χαμηλότερα στην ομάδα των παχυσάρκων. Μια προσωρινή μείωση των τιμών της γκρελίνης παρατηρήθηκε και στις δύο ομάδες άμεσα μετεγχειρητικά με σταδιακή επάνοδο στα προεγχειρητικά επίπεδα έως τον 3ο μήνα. Επιπλέον τα επίπεδα της γκρελίνης αυξήθηκαν 40%, σε σύγκριση με τα προεγχειρητικά, στην ομάδα των παχυσάρκων στον 1ο χρόνο παρακολούθησης. Τα επίπεδα του PYY στην ομάδα των κολεκτομών μειώθηκαν τις πρώτες 3 μετεγχειρητικές ημέρες και έπειτα επέστρεψαν στα προεγχειρητικά. Σε αντίθεση, τα επίπεδα του PYY στην ομάδα των παχυσάρκων δεν άλλαξαν άμεσα μετεγχειρητικά αλλά αυξήθηκαν σε επίπεδα 50% υψηλότερα στον 3ο μήνα και 170% υψηλότερα στον 1ο χρόνο, σε σύγκριση με τα προεγχειρητικά. Συμπεράσματα. Η μεγάλη μετεγχειρητική αύξηση των επιπέδων της ανορεξιογόνου ορμόνης PYY μετά από BPD-RYGBP μπορεί να παίζει ρόλο στην μειωμένη όρεξη που παρατηρείται μετά από αυτό τον τύπο βαριατρικής επέμβασης. Οι αλλαγές της γκρελίνης μετεγχειρητικά κάνουν τη συμμετοχή της ορμόνης αυτής στη μείωση της όρεξης λιγότερο πιθανή. / Ghrelin and Peptide YY levels anfter a variant of biliopancreatic diversion with Roux-en-Y gastric bypass versus after colectomy: A prospective comparative study Background. The gastrointestinal peptide hormones ghrelin and PYY, have been shown to play a role in the regulation of metabolism and apetite. We investigate the effect of the biliopancreatic diversion with Roux-en-Y gastric bypass (BPD-RYGBP) procedure on the circulating levels of ghrelin and PYY during the first 3 months postoperatively as compared to the effects of colectomy, an abdominal operation of similar severity. Methods. We determined the fasting plasma levels of ghrelin and PYY in 20 morbidly super obese patients that underwent BPD-RYGBP and in 13 subjects that underwent a colectomy because of large bowel cancer. Fasting plasma ghrelin and PYY levels were measured preoperatively and during the postoperative period on days 1,3,7,30 and 90 in all patients of both groups and at the 1 year for the patients who had attained 1-year follow up. Results. Preoperatively, both plasma ghrelin and PYY levels were lower in the BPD-RYGBP group of patients. A temporary decrease in plasma ghrelin levels was observed in both groups of patients during the immediate postoperative period with a gradual return to preoperative levels by the third month. In addition, ghrelin concentrations increased at one year to levels 40% higher than those in baseline, in ten of the BPD-RYGBP patients who had completed the one-year follow up (p=0.004). Plasma PYY levels in the colectomy group decreased the first three postoperative days and then returned to baseline. In contrast, PYY levels in the BPD-RYGBP group did not change during the early postopera¬tive period but increased to levels 50% higher at 3 months (p<0.001) and 170% higher at one year (p<0.001) than the baseline. Conclusions. The great postoperative increase of the levels of the anorexigenic peptide PYY following BPD-RYGBP may contribute to the reduced appetite observed after this type of bariatric surgery. The changes in ghrelin levels postoperatively make its contribution to the appetite suppression less likely.