Newts, abundant worldwide, have unclear pre-Pliocene evolution and phylogenetic relationships. North America has a sporadic pre-Pliocene newt record. Several undescribed fossils can address this lack of information. I built a character matrix of >70 morphological characters for extant newts and two fossil species, Taricha oligocenica and Taricha lindoei. Phylogenetic analyses were used to investigate the relationships of the fossil taxa within newts. The morphology of the fossil taxa was compared with extant North American newts to redescribe the fossil specimens. The past ecology and biogeography of North American fossil newts was compared with their current ecologies and distribution to better understand their evolution and dispersal and to predict possible changes for newts in the face of environmental change. Results indicate that T. oligocenica and T. lindoei are closely-related species nested within Taricha, but their relationships with extant species are unresolved; the genus itself is rooted at least 32 Ma. / 2015-09-29

A hallmark of retinal diseases is degeneration of neural cells, leading to subsequent vision loss. For such diseases, replenishment of functional neural cells may be an optimal therapy. Unlike humans, the adult red-spotted newt, Notophthalmus viridescens, possesses the remarkable ability to regenerate a complete retina following its removal or injury. The purpose of this study was to develop a reproducible model of retinal damage and regeneration in the newt to understand the process of retinal regeneration. Intense light, shown in other organisms to be a relevant model of visual cell loss, was tested in the newt and resulted in variable loss of retinal function, correlating with the appearance of apoptotic cells. Due to the variability of damage observed, surgical removal of the retina was used to complement the light-damage model. A novel and non-invasive protocol using full-field electroretinography was developed to assess retinal function in vivo following damage. Measures of retinal function with the electroretinogram protocol successfully showed that photoreceptor function is initially lost and subsequently restored during regeneration. These results enhance our understanding of retinal regeneration in the adult newt and serve as a starting point for further studies aimed at determining the molecular mechanisms involved in the regeneration process.

Amphibians are osmotically-challenged due to their highly permeable skin and egg membranes. As such, biologists have mostly ignored their occurrence in saline habitats. The goal of this dissertation was to investigate the ability of amphibians to adapt to inhabit these osmotically-stressful environments. As freshwater resources are increasingly salinized due to a combination of anthropogenic and natural stressors, including road-deicing salt application, coastal storm events, and sea-level rise, it is important to understand the abilities and constraints of sensitive organisms, like amphibians, to persist in these environments. I began by exploring what is known about amphibians inhabiting saline habitats around the world, and reviewed information dating from the 1800s to the present, documenting over 100 species inhabiting inland and coastal environments. I then proceeded to investigate the evolutionary potential for one species in particular, the rough-skinned newt (Taricha granulosa) to adapt to increased salinity in its habitat. I documented the negative effects of salinity (both NaCl and MgCl2 – the two most commonly-used road deicers) on embryonic and larval survival and development through a series of experiments, and explored the importance of both developmental and evolutionary history with a stressor on survival. I investigated the evolutionary potential of salt-naïve populations through examining intrapopulation and interfamily variation in critical early life-history traits, and determined that there is high interfamily variation in the salt tolerances of offspring of individual females within a population, providing the raw material for natural selection and local adaptation. Finally, I discovered a population of newts living in the tidal area of a coastal stream, with a natural source of salinity. Through conducting a series of laboratory salt challenges and assays on osmotic, stress, and immune physiology, I was able to determine that newts in the tidal area appear to be physiologically adapted to increased salinity compared to newts in a freshwater area upstream. All this information suggests that amphibians, while still osmotically-challenged, may also not be helpless in the face of salinization, and populations may be able to locally adapt to habitats impacted by natural and anthropogenic sources of salinity.

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This master thesis deals with the potential of GIS to provide a sophisticated model of newt occurence that would allow an evaluation of appropriateness of state driven subsidies granted to build new water tanks. The main purpose was especially to show what parameters that determine presence of newts should be further implemented into the founding documentation of environmental projects aimed to support amphibian populations.

Some populations of newts (Taricha granulosa) possess large quantities of the neurotoxin tetrodotoxin (TTX) in their skin and eggs. Many populations of garter snake (Thamnophis sirtalis) are resistant to this toxin and can consume large numbers of newts with no negative effects. Despite the wealth of information acquired on the interaction between newts and their predator, garter snakes, very little research has been conducted on possible interactions between newts and other predators. I conducted a suite of experiments examining for the presence of other predators on newts, specifically focusing on predators of their eggs and larvae. I found a single predator, caddisfly larvae were capable of consuming the toxic eggs. Larval caddisflies are extremely abundant at one study site (775,000 caddisfly larvae per pond), and appear to be resistant to the negative effects of ingesting tetrodotoxin. After hatching, larval newts retain substantial quantities of TTX and most are unpalatable to predatory dragonfly naiads. Ovipositing female newts respond to the presence of caddisflies by depositing their eggs at the top of the water column where they are out of the reach of most predatory caddisflies. When caddisflies do consume a newt egg, some of the toxin is retained in their body tissues. Finally, caddisflies consume more newt eggs when those eggs contain less toxin versus eggs that contain large amounts of TTX. This may cause newt eggs that contain low quantities of TTX to more likely to die of predation which could ultimately drive an increase in toxicity of the adult population over time. Collectively, these findings indicate an additional player, caddisfly larvae, is a major predator of newts and could be involved in the evolution of tetrodotoxin toxicity in newts.

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The rise of the new right in U.S. Politics from 1994-1996 is examined as a process of asymmetrical communication and informational deployments of signs constructed to appeal to a conservative political subculture. Lash and Urry’s analysis of the economy of signs and space is employed to trace the flow of these signs as they are “emptied-out” and recombined in ways that legitimate the conservative, pro-business agenda, or contract with America, unveiled during The 1994 congressional election. A re-reading of these signs seeks to replace the individual as a subject in the role of reflexive agent in a process of modernization which rejects the reassertion of the new right’s design for a social structure of moral values which maintain the distribution of risk. These risks, as managed by environmental policy, are one target of the new right’s deregulatory agenda and as such form, the central political issue examined in this paper using Lash and Urry’s theory of reflexive modernization. / Master of Urban Affairs

Le Congrès des Etats-Unis est une institution méconnue, mal comprise et souvent dénigrée, y compris par ses propres membres. On le dit en crise, inadapté aux exigences du monde moderne. L’objectif est donc d’évaluer les forces et les faiblesses objectives du Congrès contemporain pour le réinsérer dans la dynamique des freins et contre-pouvoirs au coeur du système politique américain. La période retenue s’étale de la victoire des Républicains menés par Newt Gingrich en 1994 jusqu’aux élections de mi-mandat de 2006 et au retour des Démocrates.  De la présidence Clinton à Bush, ces douze années offrent un contexte institutionnel varié. Elles forment une trajectoire historique fascinante de la rhétorique révolutionnaire qui accompagne les victoires de 1994 à la résignation d’une défaite marquée par une certaine corruption institutionnelle, partisane et idéologique. Le cœur de notre étude vise à étudier les conséquences institutionnelles du retour à un équilibre partisan dans les deux chambres du Congrès. La compétition entre les deux partis a été accompagnée par la polarisation du système politique. Notre étude retrace les débuts de l’entrée dans une nouvelle ère sur la colline du Capitole. On cherchera à combiner une approche politique et institutionnelle en analysant plus particulièrement trois domaines de l’action politique particulièrement révélateurs: les finances via la procédure budgétaire, la réforme de l’Etat providence, et les relations avec le judiciaire via les nominations des Juges d’Appel fédéraux, lieu privilégié de frictions entre la Maison-Blanche et le Sénat. À cette perspective institutionnelle, il s’agira d’ajouter une étude sociologique de cohorte des membres du Congrès, nécessaire pour comprendre les ressorts de l’action institutionnelle.  Au-delà des membres de la chambre, l’étude d’une période dominée par le parti de l’éléphant nous permettra de plonger au cœur du mouvement conservateur. Après avoir présenté les racines historiques de l'idéologie conservatrice qui domine au sein du Parti républicain, il s'agira de révéler comment un mouvement contestataire a transformé l’institution du Congrès mais aussi comment l’institution a transformé le mouvement conservateur et le Parti républicain.  Dans un contexte international de renforcement du pouvoir exécutif, l’étude du Congrès doit permettre de redécouvrir certaines leçons sur les modalités de fonctionnement d’un système démocratique. Il s’agit de montrer qu'au-delà des questions techniques, des jeux de procédures obscures, dans la tension qui anime le Congrès, se joue l’avenir du concept de démocratie représentative ; de rétablir un certain équilibre dans la perception du système américain : système plus complexe qu’il n’apparaît dans les médias et même parfois la littérature. On ne peut se contenter d’étudier la présidence impériale sans prêter attention au vortex qui siège, toujours, au coeur de la constitution. Ainsi, sans  faire un panégyrique du pouvoir législatif, il s’agira de remettre en cause la tentation d’un Césarisme plus ou moins démocratique qui chercherait à faire du Congrès une chambre d’enregistrement des volontés de l’exécutif. / The United States Congress is often disparaged including by its own members. The critics of the institution decry the gridlock on Capitol Hill and Congress's alleged inability to deal with the challenges of the modern world. The unpopularity of today's Congress calls into question its ability to represent the American people. In that context it is necessary to try to assess whether or not Congress is truly dysfunctional. To that end, this study proposes to study a period of twelve years from 1994 to 2006 during which the Republican party dominated the institution. In 1994, under the leadership of Newt Gingrich, the Republicans returned to the majority in the House of Representatives for the first time in forty years. In 2006, after another midterm election, the Republican majorities in the House and the Senate were soundly defeated. Drawing on the long and tortuous history of the relationship between the Republican party and conservatism, the new majorities proposed large-scale change that amounted to a conservative revolution. They had initially laid out a clearly conservative agenda that insisted on balancing the budget and reducing the size of government. A detailed study of their fiscal policy and their attempts at entitlement reform over the period actually leads us to conclude that they eventually governed over ever larger deficits and a growing federal government whose policies were adjusted to favor different portions of the population. It is therefore necessary to try to account for the discrepancy between the initial goals and the eventual results. This entails studying first the evolution of the Republican members of Congress themselves to see whether the policy changes can be explained by the members becoming more moderate. Another explanation centers on the relationship between the members of the Congress and their constituents. The Republican majorities could have been forced to moderate their positions by the voters themselves in the elections of 1996, 1998, 2000, 2002 and 2004. Here the complex interplay that implies the interpretation of election results comes into play. Over the past decades, the American political system has been polarizing clearly. The growing ideological gap between the two parties and their bases calls into question the institutional stability of an institution built on the necessity to compromise. Especially since both parties have polarized while the margins of the majorities have grown more narrow. It is thus essential to look at the constraints set up by the institutional system. The arcane nuances of the legislative process directly impinges on the content of legislation. Indeed, if the majority rules decisively over the House of Representatives, in the Senate, the minority can very easily block most initiatives. The growing recourse to procedural shortcuts offered by the budget process is a testament to that fact.Finally, the relationship with the president of the United States is very much a factor in the equation. The twelve years of Republican domination in Congress covers two very different periods. Until January 2001, they had to battle with President Clinton in a context of divided government. Following George W. Bush's election in 2000, they started working under the command of the White House. The stark contrast in the way Senate republicans dealt with the two presidents when it came to their judicial nominees for the Federal Courts of Appeal offers an excellent opportunity to evaluate the continuing yet variable strength of the system of checks and balances set up by the U.S. Constitution. A deeper understanding of the workings of the contemporary Congress might allow for a more nuanced vision of the institution as much more than a roadblock on the road of presidential leadership and, perhaps, lead to a better appreciation of the way its members are trying or failing to fulfill their constitutional duty.