Página 13 dos resultados de 6294 itens digitais encontrados em 0.003 segundos

‣ Parens patriae : a comparative legal study of sovereign authority and public education policy in the province of Ontario and the state of New York

Blokhuis, Jason C. (1972 - ); Curren, Randall R.
Fonte: University of Rochester. Publicador: University of Rochester.
Tipo: Tese de Doutorado Formato: Number of Pages:xxiii, 500 leaves
Português
Relevância na Pesquisa
357.80285%
Thesis (Ph. D.)--University of Rochester, Margaret Warner Graduate School of Education and Human Development, 2009.; This is a comparative legal study of how courts in the Province of Ontario and the State of New York have interpreted and applied the common law doctrine of parens patriae, the mechanism by which the state exercises plenary custodial authority in the welfare and developmental interests of children. Chapter One traces the history of the doctrine from a Crown prerogative in feudal England to the common law basis for compulsory schooling legislation in the United States and Canada during the Progressive Era. Chapter Two provides a comparative jurisprudential history of the constitutional contexts in which provincial and state courts have exercised parens patriae authority. Supreme Court opinions from the Progressive Era to the present containing the key terms ‘parens patriae’ and ‘education’ are presented chronologically. Chapter Three examines how courts in New York and Ontario have interpreted and applied the doctrine of parens patriae when the custodial interests of children have been threatened by unreasonableness on the part of their custodians in the post-Yoder era. Chapter Four enumerates principles underlying the exercise of parens patriae authority supported by evidence gleaned from the judicial opinions surveyed in the preceding chapters. Chapter Five presents some theory and policy implications of a parens patriae perspective and examines the post-Yoder phenomenon of ‘homeschooling’ in Ontario and New York. The chapter concludes with comments on the limits of sovereign authority in each jurisdiction.

‣ Determining criteria for spawning areas of Muskellunge (Esox masquinongy) on Lake Ontario and the St. Lawrence River

Edwards, Jordan
Fonte: Quens University Publicador: Quens University
Tipo: Tese de Doutorado
Português
Relevância na Pesquisa
357.80285%
The muskellunge is an economically and ecologically important species in Ontario, Canada. Muskellunge spawning habitat plays a crucial role in the species recruitment and sustainability. Over the past few decades, muskellunge populations have experienced several stressors as a result of environmental disturbance. This study analyzed data provided by the Ontario Ministry of Natural Resources and Muskies Canada, to determine the location and characteristics of successful spawning habitats on the Canadian shoreline of Lake Ontario and the St. Lawrence River. Young of the year (YOY) muskellunge abundance was positively associated with the abundance of rock bass and alewives. Additionally, the results indicate that submergent vegetation and sand covered bottoms were the most common features in areas where YOY muskellunge were found. Finally, the results indicate that between the years of 1989-1995 and 2005-2012 there was a shift in species composition, and a significant decline in YOY muskellunge catch per unit effort.

‣ Urban Sprawl in the Greater Golden Horsehoe and the 2015 Ontario Coordinated Land Use Planning Review: Analysis and Recomendations

Goldney, Emily
Fonte: Quens University Publicador: Quens University
Tipo: Tese de Doutorado
Português
Relevância na Pesquisa
357.80285%
Historically, growth in the Greater Golden Horseshoe (GGH) region of Ontario, Canada, has been characterized by urban sprawl. The area is projected to undergo rapid population growth in the near future, which, if trends continue, will result in further sprawl. This is highly undesirable, as it will result in the conversion of agricultural and natural lands for low density development, a process which has significant social, environmental, and economic consequences. To address this issue, in 2005 the Ontario Government passed the Greenbelt Plan, a land use plan that aims to protect affected lands against development. However, the plan only covers a small portion of the GGH area, which leaves the majority of the region vulnerable to sprawl. However, there is currently an opportunity for this to change, as in 2015 4 provincial land use plans are being reviewed in tandem: The Niagara Escarpment Plan (NEP), the Greenbelt Plan, the Oak Ridges Moraine Conservation Plan (ORMCP), and the Growth Plan for the GGH. This study seeks to explore the idea of ‘completing’ the planning for the GGH, or extending policies protecting against sprawl across the GGH region as a whole. The purpose of this study was to support to support policy development work being done by an environmental not-for-profit organisation...

‣ Biogeochemistry of Paleozoic brachiopods from New York State and Ontario

Bates, Nicholas R.
Fonte: Brock University Publicador: Brock University
Tipo: Electronic Thesis or Dissertation
Português
Relevância na Pesquisa
357.80285%
A comprehensive elemental, isotopic and microstructural analyses was undertaken of brachiopod calcites from the Hamilton Group (Middle Devonian), Clinton Group (Middle Silurian) and Middle to Upper Ordovician strata of Ontario and New York State. The majority of specimens were microstructurally and chemically preserved in a pristine state, although a number of specimens show some degree of post-depositional alteration. Brachiopod calcites from the Hamilton and Clinton Groups were altered by marine derived waters whereas Trenton Group (Middle Ordovician) brachiopods altered in meteorically derived fluids. Analysis of the elemental and isotopic compositions of pristine Hamilton Group brachiopods indicates there are several chemical relationships inherent to brachiopod calcite. Taxonomic differentiation of Mg, Sr and Na contents was evident in three co-occuring species from the Hamilton Group. Mean Mg contents of pristine brachiopods were respectively Athyris spiriferoides (1309ppm), Mucrospirifer mucronatus (1035ppm) and Mediospirifer audacula (789ppm). Similarly, taxonomic differentiation of shell calcite compositions was observed in co-occuring brachiopods from the Clinton Group (Middle Silurian) and the Trenton Group (Middle Ordovician). The taxonomic control of elemental regulation into shell calcite is probably related to the slightly different physiological systems and secretory mechanisms. A relationship was observed in Hamilton Group species between the depth of respective brachiopod communities and their Mg...

‣ Sedimentology of the Sixteen Mile Creek Lagoon, Niagara Peninsula, Ontario, Canada

Otto, Judith E.
Fonte: Brock University Publicador: Brock University
Tipo: Electronic Thesis or Dissertation
Português
Relevância na Pesquisa
357.80285%
The effec s of relative water level changes in Lake Ontario were detected in the ysical, chemical and biological characteristics of the sediments of the Fifteen, Sixteen and Twenty Mile Creek lagoonal complexes. Regional environmental changes have occurred resulting in the following sequence of sediments in the three lagoons and marsh. From the base up they are; (I) Till,(2) Pink Clay, (3) Bottom Sand, (4) Gyttja, (5) Orange Sandy Silt, (6) Brown Clay and (7) Gray Clay. The till was only encountered in the marsh and channel; however, it is presumed to occur throughout the entire area. The presence of diatoms and sponge spicules, the vertical and ongitudinal uniformity of the sediment and the stratigr ic position of the Pink Clay indicate that it has a glacial or post-glacial lacustrine origin. Overl ng the Pink Clay or Till is a clayey, silty sand to gravel. The downstream fining and unsorted nature of this material indicate that it has a fluvial/deltaic origin. Water levels began rising in the lagoon 3,250 years ago resulting in the deposition of the Gyttja, a brown, organic-rich silty clay probably deposited in a shallow, stagnant environment as shown by the presence of pyrite in the organic material and relatively high proportions of benthic diatoms and grass pollen. Increase in the rate of deposition of the Gyttja on Twenty Mile Creek and a decrease in the same unit on Sixteen Mile Creek is possibly the result of a capture of the Sixteen Mile Creek by the Twenty Mile Creek. The rise in lake level responsible for the onset and transgression of this III unit may have been produced by isostatic rebound; however...

‣ The sedimentology of the Bloomington fan complex: an element of the Oak Ridges Moraine, Southern Ontario

Paterson, Jens Tore.
Fonte: Brock University Publicador: Brock University
Tipo: Electronic Thesis or Dissertation
Português
Relevância na Pesquisa
357.80285%
The Oak Ridges Moraine is a major physiographic feature of south-central Ontario, extending from Rice Lake westward to the Niagara Escarpment. While much previous work has largely postulated a relatively simple the origin of the moraine, recent investigations have concentrated on delineating the discernible glacigenic deposits (or landform architectural elements) which comprise the complex mosaic of the Oak Ridges Moraine. This study investigates the sedimentology of the Bloomington fan complex, one of the oldest elements of the Oak Ridges Moraine. The main sediment body of the Bloomington fan complex was deposited during early stages of the formation of the Oak Ridges Moraine, when the ice subdivided, and formed a confined, interlobate lake basin between the northern and southern lobes. Deposition from several conduits produced a fan complex characterized by multiple, laterally overlapping, fan bodies. It appears that the fans were active sequentially in an eastward direction, until the formation of the Bloomington fan complex was dominated by the largest fan fed by a conduit near the northeastern margin of the deposit. Following deposition of the fan complex, the northern and southern ice margins continued to retreat...

‣ Gas chromatographic electron capture negative ionization mass spectrometric (GC/ECNI/MS) determination of unique fluorinated compounds in the sediments of Lake Ontario and the effect of high-boiling alcohols (as injection solvents) on chromatographic behaviour of polycyclic aromatic hydrocarbons in gas chromatography

Zielinski-Lawrence, Rosalie Krystyna.
Fonte: Brock University Publicador: Brock University
Tipo: Electronic Thesis or Dissertation
Português
Relevância na Pesquisa
357.80285%
Part I - Fluorinated Compounds A method has been developed for the extraction, concentration, and determination of two unique fluorinated compounds from the sediments of Lake Ontario. These compounds originated from a common industrial landfill, and have been carried to Lake Ontario by the Niagara River. Sediment samples from the Mississauga basin of Lake Ontario have been evaluated for these compounds and a depositional trend was established. The sediments were extracted by accelerated solvent extraction (ASE) and then underwent clean-up, fractionation, solvent exchange, and were concentrated by reduction under nitrogen gas. The concentrated extracts were analyzed by gas chromatography - electron capture negative ionization - mass spectrometry. The depositional profile determined here is reflective of the operation of the landfill and shows that these compounds are still found at concentrations well above background levels. These increased levels have been attributed to physical disturbances of previously deposited contaminated sediments, and probable continued leaching from the dumpsite. Part II - Polycyclic Aromatic Hydrocarbons Gas chromatography/mass spectrometry is the most common method for the determination of polycyclic aromatic hydrocarbons (PAHs) from various matrices. Mass discrimination of high-boiling compounds in gas chromatographic methods is well known. The use of high-boiling injection solvents shows substantial increase in the response of late-eluting peaks. These solvents have an increased efficiently in the transfer of solutes from the injector to the analytical column. The effect of I-butanol...

‣ Bioindication of ozone using milkweed plants in Southern Ontario

Fonte: Brock University Publicador: Brock University
Tipo: Electronic Thesis or Dissertation
Português
Relevância na Pesquisa
357.80285%
Ambient (03) ozone concentrations were compared to ozone damage on milkweed plants to determine if there was a correlation. Eight survey sites of at least 100 plants each were located within 5 kilometers of Air Quality Index (AQI) stations in southern Ontario. Sites were visited nine times from June-September (2007) and milkweed leaves from 75 plants were assessed using methods pioneered in the United States. Ambient 0 3 results were calculated into SUM65, seasonal cumulative 0 3, and total 03. The 0 3 exposure indices SUM65 and cumulative 0 3 were tested statistically to determine which index is biologically relevant to milkweed as an 0 3 damage indicator species. The milkweed damage indices were incidence of leaves damaged per plant, incidence of plants damaged per site, and total 0 3• The incidence of plants injured per site was the best damage parameter with an F(1,28)=17.37, p=0.0003 for SUM65 and F(1,28)=7.5, p=O.0106 for cumulative 03 .. Milkweed plants showed quantifiable ozone damage with minimal spatial differences in damage and thus have potential use as a biomonitor species in southern Ontario.

‣ Predictors of primary health care utilization by former residents of institutions in Ontario

Cox, Alison
Fonte: Brock University Publicador: Brock University
Tipo: Electronic Thesis or Dissertation
Português
Relevância na Pesquisa
357.80285%
For years institutionalization has been the primary method of service delivery for persons with developmental disabilities (DD). However, in Ontario the last institution was closed on March 31, 2009 with former residents now residing in small, communitybased homes. This study investigated potential predictors of primary health care utilization by former residents. Several indirect measures were employed to gather information from 60 participants on their age, health status, adaptive functioning level, problem behaviour, mental health status and, total psychotropic medication use. A direct measure was used to gather primary health care utilization information, which served as the dependent variable. A stepwise linear regression failed to reveal significant predictors of health care utilization. The data were subsequently dichotomized and the outcomes of a logistic regression analysis indicated that mental health status, psychotropic medication use and, an interaction between mental health status and health status significantly predicted higher primary health care usage.

‣ Electrical Development Company of Ontario certificate of stock ownership, ca. 1910.

Cameron, Chantal
Fonte: Brock University Publicador: Brock University
Tipo: Outros
Português
Relevância na Pesquisa
357.80285%
The Electrical Development Company of Ontario was created in 1903. It was one of three private power companies that had water power leases with the Niagara Parks Commission, but was the only one that was financed with Canadian capital. The company built the Toronto Power Generating Station at Niagara Falls beginning in 1906, and the power house was completed in 1913. During the construction, there was much debate about whether the utility should remain privately operated or become a public utility. In 1920, the company became part of the public utility.; A blank certificate of stock ownerhsip in the Electrical Development Company of Ontario, ca. 1910.

‣ History and Theorizing: The Case of Winemaking in the Ontario Wine Industry

Hills, Shilo
Fonte: Brock University Publicador: Brock University
Tipo: Electronic Thesis or Dissertation
Português
Relevância na Pesquisa
357.80285%
Despite the fact that theorization has been established as an important social mechanism in a variety of contexts, little research has explicated how this process works. I argue that theorization entails strategic constructions of history, or rhetorical history, in order to persuade audiences of legitimacy. I examine the role that history plays in actors’ theorizations of the Ontario wine industry as world class. By conducting a rhetorical analysis of the newsletters and websites of Ontario wineries, I find that various themes of history are routinely employed to re-theorize the industry as one that produces world class wines. In general, the findings suggest that the narratives of Ontario wineries tap into global repertoires of fine wine to portray the continuity of current practices with those of Old World winemaking. In addition, wineries sometimes tap into local histories to convey a sense of uniqueness, but they also obscure the history of poor winemaking in the region.

‣ Equitable and Inclusive Education for All? Public Funding for Denominational Schools in Ontario

Medway, James
Fonte: Brock University Publicador: Brock University
Português
Relevância na Pesquisa
357.80285%
Roman Catholic separate schools’ denominational right to receive public funding is a contentious issue in Ontario’s educational system. Ontario’s publicly funded denominational schools historically served a purpose at Confederation; however, in light of Ontario’s evolving demographics, publicly funding denominational schools today may no longer serve the needs of Ontario. The research problem in this study is expressed through growing problems reconciling Roman Catholic schools with diversity and current public views. Additionally, recent tensions, public views, and political consensus suggest it is time to revisit the existing policy. In order to understand both the history of denominational schools and the present context, this study conducted II policy analyses as its research design by completing 2 policy cycles. The first policy cycle determined that based upon Upper and Lower Canada’s pre-Confederation diversity, extending public funding to denominational schools at Confederation was an effective way of protecting minority rights; however, the analysis in the second policy cycle; which examined how equitable and inclusive denominational schools are today, concluded that the denominational school system no longer serves the diversity and equity needs of contemporary Ontario. Building on these findings...

‣ Helping Youth Venture Into Volunteerism: A Resource for Ontario Secondary School Educators

Benko, Katherine
Fonte: Brock University Publicador: Brock University
Português
Relevância na Pesquisa
357.80285%
This study sought to create a curriculum resource for Ontario secondary school educators that addresses the inadequate preparation of students prior to their involvement in community service. Specifically, Helping Youth Venture Into Volunteerism: A Resource for Ontario Secondary School Educators was designed to help grade 10 Civics and Citizenship teachers prepare students for the 40 hours of community service that are a prerequisite for the Ontario Secondary School Diploma. The resource discusses problems with the current unstructured program, outlines researchers’ recommendations to address such problems, and provides comprehensive unit and lesson plans to help educators meet curriculum expectations for grade 10 Civics and Citizenship. In addition, the study examined the rationale and development of the community service program and reviewed related literature corresponding both to Ontario’s community service program as well as service-learning programs in schools. Study results and the accompanying resource will help improve the community service program’s effectiveness by integrating it into school practices and curriculum and making it more relevant, structured, and meaningful to students. By improving the community service program...

‣ The Ontario Municipal Freedom of Information and Protection of Individual Privacy Act: an analysis of its application to school boards

Verworn, Brenda Stokes.
Fonte: Brock University Publicador: Brock University
Tipo: Electronic Thesis or Dissertation
Português
Relevância na Pesquisa
357.80285%
In Canada freedom of information must be viewed in the context of governing -- how do you deal with an abundance of information while balancing a diversity of competing interests? How can you ensure people are informed enough to participate in crucial decision-making, yet willing enough to let some administrative matters be dealt with in camera without their involvement in every detail. In an age when taxpayers' coalition groups are on the rise, and the government is encouraging the establishment of Parent Council groups for schools, the issues and challenges presented by access to information and protection of privacy legislation are real ones. The province of Ontario's decision to extend freedom of information legislation to local governments does not ensure, or equate to, full public disclosure of all facts or necessarily guarantee complete public comprehension of an issue. The mere fact that local governments, like school boards, decide to collect, assemble or record some information and not to collect other information implies that a prior decision was made by "someone" on what was important to record or keep. That in itself means that not all the facts are going to be disclosed, regardless of the presence of legislation. The resulting lack of information can lead to public mistrust and lack of confidence in those who govern. This is completely contrary to the spirit of the legislation which was to provide interested members of the community with facts so that values like political accountability and trust could be ensured and meaningful criticism and input obtained on matters affecting the whole community. This thesis first reviews the historical reasons for adopting freedom of information legislation...

‣ Hydrodynamic Modelling of Lake Ontario

Hall, ERIN
Fonte: Quens University Publicador: Quens University
Tipo: Tese de Doutorado Formato: 15002012 bytes; application/pdf
Português
Relevância na Pesquisa
359.7296%
The 2006 Clean Water Act requires each municipality to come up with science-based plans to protect the quality and quantity of their drinking water. A literature review concerning applicable processes in Lake Ontario along with previous modelling of the lake is presented. The three dimensional Estuary, Lake and Coastal Oceans Model (ELCOM) is used to model Lake Ontario on a 2×2km grid scale. The model is forced using meteorological data from the 2006 summer season, inflows and outflows. The lake-wide model is evaluated using field data from thermistor chains and ADCPs as well as historical water level data. Simulated and observed temperature profiles compared well. However, modelled temperature profiles were slightly cooler than observed. Current results were more variable than temperature profile results but compared better to observed data in the offshore regions. Simulating Lake Ontario water levels proved to be problematic because an accurate water balance is difficult to force with a large drainage basin. A 300×300m nearshore model of the eastern portion of Lake Ontario and the upper St. Lawrence River is also presented. The open boundary is forced using temperature data which is (A) varied with depth, (B) constant with depth and (C) spatially varied over the length of the open boundary and varied with depth. Both spatially varied and non-varied water level data forcing the open boundary is also compared. Spatially varied temperature and water level data is computed from the coarse grid lake-wide model. Lake-wide coarse grid model error appears to propagate through the open boundary negatively affecting nearshore modelled current when coupling the models. It was concluded that lake-wide model results should not be used to force the open boundary for the nearshore model. Nearshore model results using constant temperature with depth forcing files and non-spatially varied water level data agree well with observed temperature profiles...

‣ Age and Growth of Black Bass in Eastern Lake Ontario and the Bay of Quinte as Sampled Through Competitive Angling Events

ZHU, CHANGHAI
Fonte: Quens University Publicador: Quens University
Tipo: Tese de Doutorado
Português
Relevância na Pesquisa
359.7296%
This three year study (2012-2014) investigated the age and growth parameters of two economically important recreational fish species, Smallmouth Bass (Micropterus dolomieu) and Largemouth Bass (Micropterus salmoides). Age and length data were obtained for both species through sampling at competitive fishing events held on Lake Ontario and the Bay of Quinte. Scales, dorsal spines, and otoliths were used to determine age in both species. The results of this study found that scales and dorsal spines were effective aging structures for fish up to an age of 9 in Smallmouth Bass, and 7 in Largemouth Bass. As previously demonstrated, otoliths were found to be an effective aging structure at all ages. A comparison of the aging structures for tournament bass indicated that scales would be an effective aging structure for most tournament caught Smallmouth Bass, while otoliths would be required to effectively age tournament caught Largemouth Bass. Growth was determined through back calculation of length-at-age. Growth in Lake Ontario Smallmouth Bass was found to be greater than growth in Largemouth Bass, which is in contrast to findings of growth studies on other North American bass populations. Growth in present day Smallmouth Bass also exceeds growth of historical Smallmouth Bass from Lake Ontario. The results of this growth study indicate that there has been a recent change in the ecology of Lake Ontario Smallmouth Bass populations that makes it unique relative to other North American populations. The potential of competitive fishing tournaments as an assessment tool for recreationally important fish populations in large water bodies is demonstrated through this study. Although tournaments are biased towards the older fish in a population...

‣ A Population-Based Study of Factors Affecting Access to Radiotherapy for Endometrial Cancer in Ontario

HANNA, TIMOTHY
Fonte: Quens University Publicador: Quens University
Tipo: Tese de Doutorado Formato: 2105551 bytes; application/pdf
Português
Relevância na Pesquisa
359.7296%
Aims: To describe use of post-operative radiation for endometrial cancer in Ontario. To identify system-related and patient-related factors affecting access to this treatment. Materials and Methods: We performed a retrospective population-based cohort study of patients with surgically resected endometrial cancer in the Canadian province of Ontario between 1992-2003. Patients with evidence of incurable cancer at diagnosis or previous cancer diagnosis were excluded. We used multiple logistic regression to assess patient and system factors affecting radiation use. We controlled for disease-related and treatment-related factors: histology, surgical staging, type of hysterectomy and peritoneal biopsy. We applied a mixed model to account for clustering of data by operating hospital. Results: 9,411 women comprised the study cohort. The median age was 63 years. 26.2% received adjuvant radiation. The proportion of patients receiving radiation varied between cancer centre catchment areas from 18.0% to 34.3% (median 26.3%). In multivariate analysis, older patients were more likely to receive radiation up to the age of 80 (p<.0001). Patients who lived further from regional cancer centres were less likely to receive radiation (p=.0210). Patients who had their surgery during longer prevailing wait times at regional cancer centres were less likely to receive radiation (p=.0441). There was a 2.7-fold variation in the odds of radiation use between cancer centre catchments (p<.0001). Management at a comprehensive gynecologic oncology centre was associated with use of radiation for patients who had surgical staging of lymph nodes. Year of diagnosis and neighborhood income quintile did not significantly affect the use of radiation. Conclusions: There is wide variation in use of radiation for endometrial cancer in Ontario. There is evidence that system factors unrelated to patient’s needs affect use of adjuvant radiation for endometrial cancer in Ontario. Age is a key patient-related factor affecting radiation use.; Thesis (Master...

‣ Benchmarking and development of webGIS in Ontario: implications for public use in planning

Chan, Calvin
Fonte: Quens University Publicador: Quens University
Tipo: Tese de Doutorado Formato: 5934085 bytes; application/pdf
Português
Relevância na Pesquisa
359.7296%
Governments use the Internet as another means to offer services to the public. One such service is to deliver GIS over the Internet, also known as webGIS. While some Ontario municipalities provide webGIS services, its level of deployment across Ontario is unknown. Further, the mechanisms behind implementation and its effects on public engagement in planning issues are uncertain. This thesis attempts to answer some of these questions. All known Ontario municipal websites were surveyed to determine the level of webGIS provision. These webGIS were then benchmarked using a set of criteria from four categories (Accessibility, Data Availability, Functionality, Presentation/Utilities). A secondary set of criteria was also used to analyze related areas about webGIS provision. Interviews were conducted with nine municipal officials about the development and implementation of their municipality’s webGIS. Issues discussed include rationales, funding, implementation, webGIS technology, data issues, positive effects, obstacles to development, and user effects. Of the 445 Ontario municipalities, 41 offered webGIS services to their community. The municipal webGIS showed a wide range of services from basic visualization to more advanced editing tools. The scores within each category and from the secondary criteria were discussed. The interviews revealed a variety of reasons for developing and implementing webGIS. The major positive effect from webGIS was an increase in efficiency for municipal officials and greater access to municipal data for everyday users. Municipal webGIS has benefited both municipal employees and public users as an information tool. However...

‣ The Development of resistance to antibiotics from bacteria exposed to Triclosan and Triclocarban in Lake Ontario

Boone, Daniel
Fonte: Rochester Instituto de Tecnologia Publicador: Rochester Instituto de Tecnologia
Tipo: Tese de Doutorado
Português
Relevância na Pesquisa
359.7296%
Triclocarban (3,4,4'-trichlorocarbanilide) (TCC) and Triclosan ( 2,4,4'-trichloro-2'-hydroxydiphenyl ether) (TCS) are antimicrobials used extensively in soaps and detergents. They're known to bypass wastewater treatment plants and bioaccumulate in aquatic sediments. Their accumulation leads to an increase in bacterial exposure, which may lead to both antiseptic and antibiotic resistance, known as cross-resistance. This study investigates the occurrence of cross-resistance with bacteria exposed to TCS and TCC in Lake Ontario sediments. Sediment samples were chosen at various sites with a high probability of TCS and TCC exposure. The bacteria were enriched with 5mg/L TCS (equivalent to environmental concentrations) and the top biodegraders were tested for antibiotic resistance. Relationships were seen with top TCS and TCC degraders in Lake Ontario and antibiotic resistance. A site along Durand Eastman Beach in Lake Ontario had TCS and TCC degraders that were resistant to almost 95% of common antibiotics. Few TCS and TCC degraders had little antibiotic resistance. Future applications with non-antibiotic resistant TCS and TCC degraders, however, could be used in wastewater treatment to decrease concentrations of antiseptics and therefore decrease bacterial exposure in our environment.

‣ Mathematical Modeling of Phytoplankton in Lake Ontario,Part 2 Simulations Using Lake 1 Model

Thomann, Robert V.; Winfield, Richard P.; Di Toro, Dominic M.; O'Connor, Donald J.
Fonte: Enviromental Protection Agency (EPA) Publicador: Enviromental Protection Agency (EPA)
Tipo: Relatório Formato: 4819543 bytes; application/pdf
Português
Relevância na Pesquisa
359.7296%
The results of a series of simulations of the response of the open lake region of Lake Ontario to various levels of nutrient input are described in this report. The simulations use a simplified dynamic model of phytoplankton nutrient interactions in a vertically segmented structure. The lake is assumed to be well-mixed in the horizontal direction. The problem of long term simulations (10-20 years) that draw on short term observation and verification periods (5 years) is discussed and it is indicated that the overall loss rates of nutrient are of particular importance. Under a hypothesized, but reasonable, set of model parameters, the simulations indicate that the present observed open lake phytoplankton biomass of Lake Ontario does not appear to be in equilibrium with the present input nutrient load. Therefore, if the present load is continued, it is estimated that spring peak phytoplankton chlorophyll in the epilimnion will continue to increase to a new level about 45% higher than present levels. The interaction of nitrogen and phosphorus is also described by the simulations and the results indicate a tendency for nitrogen limitation to be an increasing dominant factor in controlling the spring bloom. A pastoral" simulation using load estimates...