Invasive non-indigenous species are among the principle drivers of global change, altering nutrient cycles, changing disturbance regimes, and generally threatening biodiversity. Climate change is widely expected to exacerbate invasions by relaxing abiotic barriers, such as low temperature, but the mechanistic evidence supporting this is limited. Here, I evaluate the hypothesis that low temperatures determine the northern range limit of kudzu (Pueraria montana var. lobata), an invasive Asiatic vine in North America, by assessing freezing and chilling tolerance of kudzu plants in winter, spring, summer, and fall. Kudzu was widely planted throughout the southeastern U.S. in the early 20th Century to prevent erosion. It is winter-deciduous and reproduces primarily from buds on stem nodes. In the last 40 years, kudzu has migrated northward in concert with a northward shift in the -20oC minimum winter temperature isocline, indicating that less severe winter cold is permitting northward migration. Freezing mortality during winter does not explain this correlation. Electrolyte leakage assays demonstrate that above- and belowground kudzu stems can survive to -27oC and -17oC. Insulation provided by soil and snow protects belowground stems from lethal temperatures to well north of kudzu's current range limit. Severe spring chill stops growth and photosynthesis and causes some shoot mortality, but both growth and photosynthesis recover quickly following the chill. Summer growth rates are rapid (up to 22 cm/d), responding within hours to temperature changes, and are unimpaired by nighttime lows. Photosynthesis is reduced at cool temperatures, but on cool days, kudzu leaves tend to be warmer than air temperature, so photosynthesis rates generally remain close to optimal values. In autumn, growth stops below 15oC, but leaves are retained and maintain modest photosynthetic competence until killed by frost in November. In colder climates that occur far north of kudzu's current range, reductions in the length and quality of the growing season could accumulate over time to reduce kudzu's success. There is, however, no strong evidence that low temperatures in any season will prevent kudzu from migrating throughout southern Ontario, making kudzu a good candidate for invasive species regulations.

This thesis focuses on exacerbating chemicals risk in workplaces under the background of rapid industrialization in developing countries. The overall aim is to investigate the development of regulatory tools which aim at minimizing the health risks from chemical substances in the workplace. The contents of the thesis are divided into three sections: the profile of occupational diseases in China (paper I), occupational exposure limits (paper II and III), and comparison between chemicals regulat ions in Europe and China (paper IV). Paper I presents an analysis of the development of occupational diseases in China between 2000 and 2010. The number of recorded cases of occupational diseases increased rapidly in China during this period and the majority of cases were attributable to dust and other chemicals exposures. Difficulties in diagnosis and inefficient surveillance are major impediments to the proper identification and mitigation of occupational diseases. Migrant workers are extremely vulnerable to occupational hazards. Paper II investigates the state of harmonization of OELs between twenty-five OEL systems in Europe and Asia. The majority of the investigated organizations declare themselves to have been influenced by the American Conference of Governmental Industrial Hygienists (ACGIH), and in many cases this can be empirically confirmed. However, large international differences still exist in substance selection and in the level of OELs among organizations. Paper III explores the setting of risk-based OELs on non-threshold carcinogens. Relatively few agencies set risk-based OELs. Differences exist in policy, both regarding the magnitude of risk considered as tolerable or acceptable and whether a general risk level or case-by-case substance-specific risk levels are determined. In regards to the level of the OELs both differences in science and policy contribute, and it was not possible to determine which has the larger influence. Paper III explores the setting of risk-based OELs on non-threshold carcinogens. Relatively few agencies set risk-based OELs. Differences exist in policy, both regarding the magnitude of risk considered as tolerable or acceptable and whether a general risk level or case-by-case substance-specific risk levels are determined. In regards to the level of the OELs both differences in science and policy contribute, and it was not possible to determine which has the larger influence. Paper IV systematically compares the regulation systems for chemicals in the EU and China in terms of substances covered, requirement on information, risk assessment and risk management. It shows that the European and Chinese chemicals legislations are remarkably similar.The differences are larger in terms of substance coverage and data requirements than in terms of risk assessment and management. Substitution of hazardous substances is driven more by updates of the EU regulatory system than of the Chinese system. / <p>QC 20130830</p>

Una de las principales teorías jurídicas ha sido la de soberano absoluto, la cual supone que es inherente a cualquier sistema jurídico la existencia de un soberano absoluto e ilimitado. En la primera parte de la tesis examino a los principales autores que han sostenido tal concepción (Jean Bodin, Thomas Hobbes, John Austin), así como los principales argumentos.En la segunda parte de la tesis mi propósito es criticar tal concepción y plantear una visión pluralista de la idea de autoridad suprema en un orden jurídico y, en este sentido, distingo cuatro modelos de autoridad suprema:1) autoridad preinstitucional suprema primaria;2) autoridad preinstitucional suprema secundaria;3) autoridad jurídica suprema continua;4) autoridad jurídica suprema autocomprensiva.De tales modelos trato de ofrecer un correlato empírico, así como una explicación de los justificaciones político-jurídicas en las que pueden descansar. / Una de les principals teories jurídiques ha estat la de sobirà absolut, la qual suposa que és inherent a qualsevol sistema jurídic l'existència d'un sobirà absolut i il·limitat. A la primera part de la tesi examino els principals autors que han sostingut tal concepció (Jean Bodin, Thomas Hobbes, John Austin), així com els principals arguments.A la segona part de la tesi el meu propòsit és criticar tal concepció i plantejar una visió pluralista de la idea d'autoritat suprema en un ordre jurídic i, en aquest sentit, distinguo quatre models d'autoritat suprema:1) autoritat preinstitucional suprema primària;2) autoritat preinstitucional suprema secundària;3) autoritat jurídica suprema contínua;4) autoritat jurídica suprema autocomprensiva.De tals models tracte d'oferir un correlat empíric, així com una explicació dels justificacions polític-jurídiques en les que poden descansar. / One of the main juridical theories has been that of absolute sovereign, which supposes that the existence of an absolute and unlimited sovereign is inherent to any juridical system. In the first part of the thesis I examine the main authors of such conception (Jean Bodin, Thomas Hobbes, John Austin), as well as the main arguments they have sustained.In the second part of the thesis my purpose is to criticise such conception and to bring up a pluralistic vision of the idea about supreme authority in a juridical order and, in this sense, I distinguish four models of supreme authority:1) primary supreme pre-institutional authority;2) secondary supreme pre-institutional authority;3) continuous supreme juridical authority;4) selfcomprehensive supreme juridical authority.On the other hand I tried to offer a correlated empirical of these models, as well as an explanation of their justifications political-juridical.

We consider a class of queueing systems that consist of server pools in parallel and multiple customer classes. Customer service times are assumed to be exponentially distributed. We study the asymptotic behavior of these queueing systems in a heavy traffic regime that is known as the Halfin and Whitt many-server asymptotic regime. Our main contribution is a general framework for establishing state space collapse results in the Halfin and Whitt many-server asymptotic regime for parallel server systems having multiple customer classes. In our work, state space collapse refers to a decrease in the dimension of the processes tracking the number of customers in each class waiting for service and the number of customers in each class being served by various server pools. We define and introduce a state space collapse function, which governs the exact details of the state space collapse. Our methodology is similar in spirit to that in Bramson (1998); however, Bramson studies an asymptotic regime in which the number of servers is fixed and Bramson does not require a state space collapse function. We illustrate the applications of our results in three different parallel server systems. The first system is a distributed parallel server system under the minimum-expected-delay faster-server-first (MED-FSF) or minimumexpected- delay load-balancing (MED-LB) policies. We prove that the MED-FSF policy minimizes the stationary distribution of total number of customers in the system. However, under the MED-FSF policy all the servers in our distributed system except those with the lowest service rate experience 100% utilization but under the MED-LB policy, on the other hand, the utilizations of all the server pools are equal. The second system we consider is known as the N-model. We show that when the service times only depend on the server pool providing service a static priority rule is asymptotically optimal. Finally, we study two results conjectured in the literature for V-systems. We show for all of these systems that the conditions on the hydrodynamic limits can easily be checked using the standard tools that have been developed in the literature to analyze fluid models.

Cross median crashes have become a serious problem in recent years. Most of the median cross sections used for divided highways have terrains with steep slopes. Traffic barriers, frequently used on slopes, are generally designed based on the findings obtained from crash tests performed on flat terrain. For barriers placed on roadside and median slopes, vehicle impact height varies depending on the trajectory of the vehicle along the ditch section and lateral offset of the barrier. Thus depending on the placement location on a relatively steep slope, a barrier can be impacted by an errant vehicle at height and orientation more critical compared to those considered during its design. Hence, detailed study of performance of barriers on roadside and median slopes is needed to achieve acceptable safety performance. In this study, performances of modified G4(1S) W-beam, Midwest Guardrail System (MGS), modified Thrie-beam, modified weak post W-beam, and box-beam guardrail systems on sloped terrains are investigated using numerical simulations. A procedure is developed that provide guidance for their placement on roadside and median slopes. The research approach consists of nonlinear finite element analyses and multi-rigid-body dynamic analyses approach. Detailed finite element representation for each of the barriers is developed using LS-DYNA. Model fidelity is assessed through comparison of simulated and measured responses reported in full scale crash test studies conducted on flat terrain. LS-DYNA simulations of vehicle impacts on barriers placed on flat terrain at different impact heights are performed to identify performance limits of the barriers in terms of acceptable vehicle impact heights. The performances of the barriers are evaluated following the guidelines provided in NCHRP Report 350. Multi-rigid-body dynamic analysis code, CARSIM, is used to identify trajectories of the vehicles traversing various roadside and median cross-slopes. After analyzing vehicle trajectories and barrier performance limits, a guideline has been prepared with recommendations for the placement of barriers along roadside and median slopes. This guideline is then verified and refined using the responses obtained from full-scale LS-DYNA simulations. These simulations capture the full encroachment event from departure of the vehicle off the traveled way through impact with the barrier.

Trots att avloppsreningsverkens primära syfte är att minska människans påverkan på miljön genom att bland annat reducera halten näringsämnen i vattnet bidrar de samtidigt till den ökande växthuseffekten. FN:s klimatpanel pekar ut avloppsreningsverk som en signifikant källa till direkt emission av lustgas och metan och det sker även indirekta emissioner uppströms och nedströms reningsverket. Samtidigt som diskussionen om klimatpåverkan från avloppsreningsverk växer är många recipienter hårt belastade och nu väntas en skärpning av utsläppsvillkoren för att minska tillförseln av näringsämnen till de naturliga vattensystemen. Studier har visat att skärpta utsläppsvillkor ökar klimatpåverkan från avloppsreningsverk. Två miljöproblem, övergödning och klimatförändringar, står mot varandra och måste värderas för att framtidens avloppsrening ska kunna planeras. Syftet var att undersöka hur klimatpåverkan från avloppsreningsverk påverkas av teknikval och utsläppsvillkor. Simuleringsverktyget BioWin användes för att beräkna koldioxidavtryck från Enköpings framtida avloppsreningsverk. Tre olika processtekniker (aktivslamprocessen, membranbioreaktor och aktivslamprocessen med biologisk fosforreduktion) och sju olika utsläppsvillkor studerades. I beräkningarna togs hänsyn till både direkta och indirekta emissioner genom bland annat lustgasproduktion, kemikalieförbrukning och användning av el. Den konventionella aktivslamprocessen orsakade minst koldioxidavtryck medan avtrycket från den moderna membranbioreaktorn var överlägset störst. En skärpning av utsläppsvillkoren för kväve och fosfor gav en ökning av koldioxidavtrycket med upp till 55 % och det var speciellt kvävekravet som styrde ökningen. Då utsläppsvillkoren skärptes ökade avtrycket mest från membranbioreaktorn vilket indikerar att den ur klimatsynpunkt lämpar sig sämre vid skärpta utsläppsvillkor. Lustgasemission stod för den största delen av koldioxidavtrycket. Lustgasemissionen ökade vid skärpta utsläppsvillkor samt då kvävereningen stördes, exempelvis vid låga vattentemperaturer. Fler komponenter bör tas i åtanke vid utvärdering av miljöpåverkan från ett avloppsreningsverk, exempelvis övergödning. Detta skulle göra det möjligt att bedöma den totala miljövinsten, eller förlusten, med att skärpa villkoren. / Although the primary aim for wastewater treatment plants (WWTP) is to minimize the environmental impact by reducing the content of nutrients in the wastewater, they also contribute to the increasing greenhouse effect. The International Panel on Climate Change refer to WWTP:s as a significant source of direct emission of nitrous oxide and methane and indirect emission also occurs upstream and downstream the WWTP. As the discussion about climate impact from WWTP is growing, many recipients are congested and a tightening of the discharge limits is expected in order to reduce the load of nutrients on the natural water systems. Studies have shown that more stringent discharge limits increases the climate impact from WWTP. Two environmental problems, eutrophication and climate change, are facing each other and they must be valued in order for future WWTP to be planned. The aim was to investigate how the climate impact of wastewater treatment plants is affected by choice of technology and discharge limits. The simulation tool BioWin was used to calculate the carbon footprint (CF) from the future WWTP in the town of Enköping. Three different process technologies (activated sludge process, membrane bioreactor and activated sludge process with biological phosphorus removal) and seven different discharge limits were examined. The calculations took into account both direct and indirect emissions from e.g. production of nitrous oxide and use of electricity. The conventional activated sludge process caused the smallest CF, while the modern membrane bioreactor by far caused the largest CF. Tightening of the discharge limits gave an increase of the CF with up to 55 %, and especially the demands on nitrogen governed the increase. More stringent limits increased the CF from the membrane bioreactor the most, which indicates that from an environmental point of view, this technique is less suitable when limits are tightened. Emission of nitrous oxide accounted for the largest part of the CF and this emission increased as the discharge limits were tightened and when the nitrogen treatment was disturbed by, for instance, low water temperatures. More components should be accounted for when environmental impact from WWTP is investigated, e.g. eutrophication. This would make it possible to assess the overall environmental gain, or loss, from tightening of the discharge limits.

The work presented here develops a gamma-ray spectral construction and analysis software tool that was used to analyze multi-detector data collected using a digital spectrometer with list mode capabilities. The tool was used to parse the output from three detectors and generate new spectra that the user chooses from post-processing suppression routines, such as simulated anticoincidence and coincidence spectra. Part of this research was also to characterize the improvements in the detection limits and the various detector efficiencies from this method as opposed to creating these spectra using traditional electronic gating systems. A focus is placed on the detection capability improvements for nuclear forensics purposes, particularly the identification and quantification of fission product samples, and structuring the code framework for handling these types of time-dependent samples while increasing the versatility of the detector system. Improvements to the minimum detectable activity for a series of fission products was accomplished through post-processing suppression methods and multi-dimensional spectral data structures are now achievable. / text

A model of the accurate harmonic allocation methods is developed to improve the current emission limits of IEEE Std.519. IEC 61000-3-6 and IEEE Std. 519 have by now been accepted as two well known standards for interconnecting the MV and HV-EHV customers to utility systems and widely adopted as standards to many power utilities. It is worth noting that the harmonic current emission limits of both standards have not been compared and justified with analytical proofs because there is still no explanation that discusses the origin of the emission limits in IEEE Std. 519, or the complex feature of IEC 61000-3-6. Two new novel methods of allocating the harmonic current emission limits for MV customers and HV-EHV customers have been proposed. Both methods have been developed in accordance with the principles of IEC 61000-3-6. Task II has compared and investgated the emission limits of both IEC 61000-3-6 and IEEE Std. 519. The difference, inconsistency and inaccuracy have been proven with the perspective of practical evaluations based on their own principles. The investigations focus on the specific numerical proofs of the resulting voltage distortions and the current emission limits in the MV and HV-EHV systems rather than on the philosophies. The proposed methods strongly support IEC 61000-3-6 and IEEE Std. 519, and add to their value; these methods could also help utilities allocate fairly and accurately harmonic emission limits to their MV and HV-EHV customers.

Le présent mémoire soulève divers questionnements face au traitement singulier qu'a reçu l'âge en tant que motif prohibé de discrimination, sous la Charte des droits et libertés de la personne du Québec et la Charte canadienne des droits et libertés. Ainsi, nous verrons que même si la discrimination fondée sur l'âge n'est pas à strictement parler « autorisée », elle est néanmoins souvent jugée acceptable. Tout d'abord, nous procéderons à une revue générale et synthétique des notions de discrimination et de droit à l'égalité, telles qu'elles sont prévues par les articles 10 de la Charte québécoise et 15 de la Charte canadienne. Ensuite, nous évoquerons un certain nombre de limites législatives qui ont été apportées à ces droits et qui peuvent constituer des obstacles importants dans la lutte effective contre la discrimination fondée sur l'âge. Enfin, nous nous permettrons de faire quelques réflexions critiques, afin de souligner comment la perspective particulière qu'ont adoptée les juges dans l'étude des questions relatives à la discrimination fondée sur l'âge a pu introduire un certain nombre d'incohérences au sein de la logique plus générale qui se dégage de l'ensemble de la jurisprudence portant sur le droit à l'égalité. / The present Master's Thesis raises questions regarding the singular treatment to which "age" has been subjected as a prohibited ground of discrimination, under the Canadian Charter of Rights and Freedom and the Quebec Charter of Rights and Freedoms. We will see that even though age discrimination is not strictly "authorised", it is nonetheless often held to be acceptable. First, we will synoptically review the concepts of discrimination and equality which emanate from section 10 of the Quebec Charter and section 15 of the Canadian Charter. Then, we will identify a certain number of legislative limits which affect these rights, and may constitute significant obstacles in the effective fight against age discrimination. Finally, we will allow ourselves to advance sorne critical thoughts, highlighting how the peculiar perspective thatjudges have taken in age discrimination matters has introduced non sequiturs in the overall logic that can be drawn from the more general equality jurisprudence. / "Mémoire présenté à la Faculté des études supérieures en vue de l'obtention du grade de Maître en droit (LL.M.)"

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