995 resultados para Creative Commons Copyright


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Breast and ovarian cancers are among the leading causes of cancer related deaths in women worldwide. In a subset of these cancers, dysregulation of the human epidermal growth factor receptor 2 (HER2) leads to overexpression of the receptor on the cell surface. Previous studies have found that these HER2+ cancers show high rates of progression to metastatic disease. Metastasis is driven by cytoskeletal rearrangements that produce filamentous actin (F-actin) based structures that penetrate and degrade extracellular matrix to facilitate tumour invasion. Advancements in targeted therapy have made F-actin an attractive target for the development of new cancer therapies. In this thesis, we tested the actin-depolymerizing macrolide toxin, Mycalolide B (MycB), as a potential warhead for a novel antibody drug conjugate (ADC) to target highly metastatic HER2+ breast and ovarian cancers. We found that MycB treatment of HER2+ breast (SKBR3, MDA-MB-453) and ovarian (SKOV3) cancer cells led to loss of viability (IC50 values ≤ 64 nM). Sub-lethal doses of MycB treatment caused potent suppression of leading edge protrusions, migration and invasion potential of HER2+ cancer cells (IC50 ≤ 32 nM). In contrast, other F-actin based processes such as receptor endocytosis were less sensitive to MycB treatment. MycB treatment skewed the size of endocytic vesicles, which may reflect defects in F-actin based vesicle motility or maturation. Given that HER2+ cancers have been effectively targeted by Trastuzumab and Trastuzumab-based ADCs, we tested the effects of a combination of Trastuzumab and MycB on cell migration and invasion. We found that MycB/ Trastuzumab combination treatments inhibited motility of SKOV3 cells to a greater degree than either treatment alone. Altogether, our results provide proof-of-principle that actin toxins such as MycB can be used as a novel class of warheads for ADCs to target and combat highly metastatic cancers.

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New immigrants to Canada are generally in similar or better physical and mental health than people born in Canada, however, many studies suggest that their health tends to decline quickly after immigration. Lower physical activity levels among new immigrants might be contributing to this phenomenon. There is a paucity of information regarding the physical activity behaviour of the Canadian immigrant population in general and of West Asian women, such as Iranians (Persians), in particular. Given that this group is characterised by an increasing population growth and lower rates of physical activity, it is critical to understand how best to address physical activity promotion in this population. Purpose: To understand the physical activity experiences of Persian women recently immigrated to Toronto, Canada in order to develop recommendations for the design and implementation of tailored physical activity programs. Methods: A qualitative interpretive description approach was chosen to collect and describe ideas, experiences, and perceptions of physical activity within 10 new immigrant women. Using an inductive approach, two fundamental techniques of immersion and crystallization were used throughout the analysis. Thematic analysis was conducted by performing a sequential process of open and axial coding. Emerged themes were further conceptualized through a socio-ecological lens. Results: The facilitators and barriers to physical activity among the women were situated within five overarching categories, 1) Perceptions about physical activity, 2) New physical environment and social structure, 3) Cultural heritage values, 4) Settlement and immigration factors, and 5) Physical activity program features. Discussion: Findings revealed that Persian new immigrant women’s engagement in physical activity after immigration is influenced by factors across the individual, sociocultural, environmental, institutional, and policy levels. Newcomer women’s physical activity was influenced by their transition from their society of origin to the host society and the challenges and successes experienced throughout the settlement and acculturation process. The most noticeable barrier to physical activity in Canada for the women emerged as the lack of communication of physical activity information to newcomers. A set of recommendations is provided for developing efficient physical activity programs for Persian immigrant women, which may also be relevant for other immigrant groups in Canada.

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This thesis examines the rise and decline of the New Left in Toronto from 1958 to 1985. It argues that New Leftism — whose three leading ideals were self-management, national liberation, and community — arose as much from the Old Left as it did from the peace movement. In contrast to earlier readings that interpret the New Left narrowly — essentially, as the combined forces of the white student and peace movements evident mainly on university campuses — this thesis documents the extent to which New Leftism, interpreted as a political formation, provided a framework for a diversity of radical social movements, especially feminism, Black Power, gay liberation, resistance to the capitalist redevelopment of the city, and transnational solidarity. It also questions a declensionist narrative that adopts a “decadal” approach to the radicalism of the sixties, according to which 1970 spelled the end of “60s” radicalism. Quite the contrary, this thesis argues: in Toronto, it would be truer to say that 1970s were “the sixties,” in that only in this later decade did many New Left movements attain their full maturity. New Leftists successfully challenged a host of institutions, sometimes with permanent effects. The educational system was transformed. Cultural institutions and practices were revolutionized. Questions of race and gender, once peripheral to the left, were made central to it. Democratic community institutions became far more powerful. A token of the strength and durability of the New Left in Toronto was the extent to which it remained the bête noir of a series of other radical groups upholding the model of the vanguard communist party — which challenged the New Leftists’ prominence but many members of which often wound up agreeing with their positions. It was only in the early 1980s, with the ascent of a new right, that Toronto’s New Left unmistakably entered a period of decline. Yet, even then, many of its key themes were picked up by fast-growing anarchist and socialist feminist currents. Far from constituting a minor phenomenon, Toronto’s New Left, one of the largest movements for social justice in Canadian history, bequeathed to its progressive successors an imposing legacy of struggle and cultural achievements. It is the purpose of this thesis to evaluate, both critically and sympathetically, the extent to which the New Left attained its radical ambition.

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This dissertation examines the origins of filial responsibility laws in Canada and the United States, laws which prescribe that adult children have an obligation of support which is owed to their parents. Filial responsibility laws enable an indigent parent, or an institution providing medical treatment and care to an indigent parent, to seek financial support from that parent’s adult children through the use of litigation. While those who favour these rarely-used laws claim that they bring many benefits to both the family and the state, there is little evidence to suggest that such benefits are actualized. The development and use of the laws in Canada and the United States make it clear that the limitation of the expenditure of government funds was the primary motive for these laws and the support of families a distant secondary motive.

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Although persuasion often occurs via oral communication, it remains a comparatively understudied area. This research tested the hypothesis that changes in three properties of voice influence perceptions of speaker confidence, which in turn differentially affects attitudes according to different underlying psychological processes that the Elaboration Likelihood Model (ELM, Petty & Cacioppo, 1984), suggests should emerge under different levels of thought. Experiment 1 was a 2 (Elaboration: high vs. low) x 2 (Vocal speed: increased speed vs. decreased speed) x 2 (Vocal intonation: falling intonation vs. rising intonation) between participants factorial design. Vocal speed and vocal intonation influenced perceptions of speaker confidence as predicted. In line with the ELM, under high elaboration, confidence biased thought favorability, which in turn influenced attitudes. Under low elaboration, confidence did not bias thoughts but rather directly influenced attitudes as a peripheral cue. Experiment 2 used a similar design as Experiment 1 but focused on vocal pitch. Results confirmed pitch influenced perceptions of confidence as predicted. Importantly, we also replicated the bias and cue processes found in Experiment 1. Experiment 3 investigated the process by which a broader spectrum of speech rate influenced persuasion under moderate elaboration. In a 2 (Argument quality: strong vs. weak) x 4 (Vocal speed: extremely slow vs. moderately slow vs. moderately fast vs. extremely fast) between participants factorial design, results confirmed the hypothesized non-linear relationship between speech rate and perceptions of confidence. In line with the ELM, speech rate influenced persuasion based on the amount of processing. Experiment 4 investigated the effects of a broader spectrum of vocal intonation on persuasion under moderate elaboration and used a similar design as Experiment 3. Results indicated a partial success of our vocal intonation manipulation. No evidence was found to support the hypothesized mechanism. These studies show that changes in several different properties of voice can influence the extent to which others perceive them as confident. Importantly, evidence suggests different vocal properties influence persuasion by the same bias and cue processes under high and low thought. Evidence also suggests that under moderate thought, speech rate influences persuasion based on the amount of processing.

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I distinguish two ways that philosophers have approached and explained the reality and status of human social institutions. I call these approaches “naturalist” and “post-naturalist”. Common to both approaches is an understanding that the status of mind and its relation to the world or “nature” has implications on a conception of the status of institutional reality. Naturalists hold that mind is explicable within a scientific frame that conceives of mind as a fundamentally material process. By proxy, social reality is also materially explicable. Post-naturalists critique this view, holding instead that naturalism is parasitic on contemporary science—it therefore is non-compulsory and distorts how we ought to understand mind and social reality. A comparison of naturalism and post-naturalism will comprise the content of the first chapter. The second chapter turns to tracing out the dimensions of a post-naturalist narrative of mind and social reality. Post-naturalists conceive of mind and its activity of thought as sui generis, and it transpires from this that social institutions are better understood as a rational mind’s mode of the expression in the world. Post-naturalism conceives of social reality as a necessary dimension of thought. Thought requires a second person and thereby a tradition or context of norms that come to both structure its expression and become the products of expression. This is in contrast to the idea that social reality is a production of minds, and thereby derivative. Social reality, self-conscious thought, and thought of the second person are therefore three dimensions of a greater unity.

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This thesis describes the preparation of polymersomes from poly(ethylene glycol)-block-polycarbonate (PEG-PC) copolymers functionalized with pendant coumarin groups. Coumarin groups undergo photo-reversible dimerization when irradiated with specific ultraviolet wavelengths, so they can be used to prepare polymers with photo-responsive properties. In this case, the pendant coumarin groups enable stabilization of the polymersome membrane through photo-crosslinking of the hydrophobic block. Initially, several novel cinnamoyl and coumarin functionalized cyclic carbonate monomers were synthesized using ester, ether, or amide linkages. While the homopolymerization of these functionalized monomers proved challenging due to their high melting points, both cinnamoyl and coumarin functionalized monomers were successfully copolymerized with trimethylene carbonate (TMC) at 100 ℃ using a catalyst-free melt polymerization process where the TMC doubled as a solvent for the higher melting point monomer. Using this system, polycarbonate copolymers with up to 33% incorporation of the functionalized monomers were prepared. In addition, an investigation of some anomalous polymerization results identified previously unreported triethylamine-based catalysts for the melt polymerization of carbonate monomers. These studies also demonstrated that the catalyst-free polymerization of TMC occurs faster and at lower temperatures than previously reported. Subsequently, the photo-crosslinking of cinnamoyl and coumarin functionalized polycarbonates was compared and coumarin was identified as the more effective crosslinking agent when using 300-400 nm UV. An investigation of the photo-reversibility of the coumarin dimerization revealed no discernible change in the properties of crosslinked networks, but rapid photo-reversion in dilute solutions. The photo-crosslinking and photo-reversion kinetics of the coumarin functionalized polycarbonates were determined to be second-order in both cases. Finally, the self-assembly of PEG-PC diblock copolymers functionalized with coumarin was examined and both reverse solvent evaporation and solvent displacement were found to induce self-assembly, with hydrophilic mass fractions (f-factors) of 12-28% resulting in the formation of solid microparticles and nanoparticles and f-factors of 33-43% resulting in the formation of polymersomes. The stabilization of these polymersome membranes through photo-initiator-free photo-crosslinking was demonstrated with the crosslinking allowing polymersomes to withstand centrifugation at 12,000 x g. In addition, the encapsulation of calcein, as a model small molecule drug, in the stabilized polymersomes was successfully demonstrated using confocal microscopy.

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An investigation into karst hazard in southern Ontario has been undertaken with the intention of leading to the development of predictive karst models for this region. The reason these are not currently feasible is a lack of sufficient karst data, though this is not entirely due to the lack of karst features. Geophysical data was collected at Lake on the Mountain, Ontario as part of this karst investigation. This data was collected in order to validate the long-standing hypothesis that Lake on the Mountain was formed from a sinkhole collapse. Sub-bottom acoustic profiling data was collected in order to image the lake bottom sediments and bedrock. Vertical bedrock features interpreted as solutionally enlarged fractures were taken as evidence for karst processes on the lake bottom. Additionally, the bedrock topography shows a narrower and more elongated basin than was previously identified, and this also lies parallel to a mapped fault system in the area. This suggests that Lake on the Mountain was formed over a fault zone which also supports the sinkhole hypothesis as it would provide groundwater pathways for karst dissolution to occur. Previous sediment cores suggest that Lake on the Mountain would have formed at some point during the Wisconsinan glaciation with glacial meltwater and glacial loading as potential contributing factors to sinkhole development. A probabilistic karst model for the state of Kentucky, USA, has been generated using the Weights of Evidence method. This model is presented as an example of the predictive capabilities of these kind of data-driven modelling techniques and to show how such models could be applied to karst in Ontario. The model was able to classify 70% of the validation dataset correctly while minimizing false positive identifications. This is moderately successful and could stand to be improved. Finally, suggestions to improving the current karst model of southern Ontario are suggested with the goal of increasing investigation into karst in Ontario and streamlining the reporting system for sinkholes, caves, and other karst features so as to improve the current Ontario karst database.

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Larger lineups could protect innocent suspects from being misidentified; however, they can also decrease correct identifications. Bertrand (2006) investigated whether the decrease in correct identifications could be prevented by adding more cues, in the form of additional views of lineup members’ faces, to the lineup. Adding these cues was successful to an extent. The current series of studies attempted to replicate Bertrand’s (2006) findings while addressing some methodological issues—namely, the inconsistency in image size as lineup size increased. First, I investigated whether image size could affect face recognition (Chapter 2) and found it could, but that it also affected previously-seen (“old”) versus previously-unseen (“new”) faces differently. Specifically, smaller image sizes at exposure lowered accuracy for old faces, while these same image sizes at recognition lowered accuracy for new faces. Although these results indicate that target recognition would be unaffected by image size at recognition (i.e., during a lineup), lineups are also comprised of previously-unseen faces, in the form of fillers and innocent suspects. Because image size could affect lineup decisions, as it could become more difficult to realize fillers are previously-unseen, I decided to replicate Bertrand (2006) while keeping image size constant in Chapters 3 (simultaneous lineups) and 4 (simultaneous-presentation, sequential decisions). In both Chapters, the integral findings were the same: correct identification rates decreased as lineup size increased from 6- to 24-person lineups, but adding cues had no effect. The inability to replicate Bertrand (2006) could mean that the original finding was due to chance, but alternate explanations also exist, such as the overall size of the array, the degree to which additional cues overlap, and the length of the target exposure. These alternate explanations, along with directions for future research, are discussed in the following Chapters.

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Two novel studies examining the capacity and characteristics of working memory for object weights, experienced through lifting, were completed. Both studies employed visually identical objects of varying weight and focused on memories linking object locations and weights. Whereas numerous studies have examined the capacity of visual working memory, the capacity of sensorimotor memory involved in motor control and object manipulation has not yet been explored. In addition to assessing working memory for object weights using an explicit perceptual test, we also assessed memory for weight using an implicit measure based on motor performance. The vertical lifting or LF and the horizontal GF applied during lifts, measured from force sensors embedded in the object handles, were used to assess participants’ ability to predict object weights. In Experiment 1, participants were presented with sets of 3, 4, 5, 7 or 9 objects. They lifted each object in the set and then repeated this procedure 10 times with the objects lifted either in a fixed or random order. Sensorimotor memory was examined by assessing, as a function of object set size, how lifting forces changed across successive lifts of a given object. The results indicated that force scaling for weight improved across the repetitions of lifts, and was better for smaller set sizes when compared to the larger set sizes, with the latter effect being clearest when objects were lifting in a random order. However, in general the observed force scaling was poorly scaled. In Experiment 2, working memory was examined in two ways: by determining participants’ ability to detect a change in the weight of one of 3 to 6 objects lifted twice, and by simultaneously measuring the fingertip forces applied when lifting the objects. The results showed that, even when presented with 6 objects, participants were extremely accurate in explicitly detecting which object changed weight. In addition, force scaling for object weight, which was generally quite weak, was similar across set sizes. Thus, a capacity limit less than 6 was not found for either the explicit or implicit measures collected.

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The thesis focuses on a central theme of the epidemiology and health economics of ankle sprains to inform health policy and the provision of health services. It describes the burden, prognosis, resource utilization, and costs attributed to these injuries. The first manuscript systematically reviewed 34 studies on the direct and indirect costs of treating ankle and foot injuries. The overall costs per patient ranged from $2,075- $3,799 (2014 USD) for ankle sprains; $290-$20,132 for ankle fractures; and $6,345-$45,731 for foot fractures, reflecting differences in injury severity, treatment methods, and study characteristics. The second manuscript provided an epidemiological and economic profile of non-fracture ankle and foot injuries in Ontario using linked databases from the Institute for Clinical Evaluative Sciences. The incidence rate of ankle sprains was 16.9/1,000 person-years. Annually, ankle and foot injuries cost $21,685,876 (2015 CAD). The mean expenses per case were $99.98 (95% CI, $99.70-100.26) for any injury. Costs ranged from $133.78-$210.75 for ankle sprains and $1,497.12-$1,755.69 for dislocations. The third manuscript explored the impact of body mass index on recovery from medically attended grade 1 and 2 ankle sprains using the Foot and Ankle Outcome Score. Data came from a randomized controlled trial of a physiotherapy intervention in Kingston, Ontario. At six months, the odds ratio of recovery for participants with obesity was 0.60 (0.37-0.97) before adjustment and 0.74 (0.43-1.29) after adjustment compared to non-overweight participants. The fourth manuscript used trial data to examine the health-related quality of life among ankle sprain patients using the Health Utilities Index version 3 (HUI-3). The greatest improvements in scores were seen at one month post-injury (HUI-3: 0.88, 95% CI: 0.86-0.90). Individuals with grade 2 sprains had significantly lower ambulation scores than those with grade 1 sprains (0.70 vs. 0.84; p<0.05). The final manuscript used trial data to describe the financial burden (direct and indirect costs) of ankle sprains. The overall mean costs were $1,508 (SD: $1,452) at one month and increased to $2,206 (SD: $3,419) at six months. Individuals with more severe injuries at baseline had significantly higher (p<0.001) costs compared to individuals with less severe injuries, after controlling for confounders.

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Understanding the reasons for long-term population change in a species requires an evaluation of ecological variables that may account for the observed dynamics. In this study, long-term changes in indices of Smallmouth Bass condition and population levels were examined for eastern Lake Ontario and the Bay of Quinte. Smallmouth Bass are an extremely important recreational fish species native to Lake Ontario. They have experienced numerous changes in their environment through direct human impacts, climate change, predation, and habitat sharing with non-native species. Smallmouth Bass have experienced an increase in body length and weight likely due to a diet shift from crayfish to predominantly Round Gobies which has allowed them to increase their growth rate. According to existing assessment data however, this increase in body size has not been associated with an increase in abundance. Long-term data from gill net sampling shows that Smallmouth Bass populations have been declining since the late 1980s with no indication of recovery. This could be due to a variety of factors, but it is most likely due to a change in the selectivity of gill nets because of the change in body size as well as a habitat shift away from gill net sampling sites. Adjusting for gill net selectivity has revealed that sub-adult bass abundance is currently greater than it was historically, and that very large bass are likely not being retained within the gill nets that are currently used. The use of a long-term data set in this study has led to a much better understanding of Smallmouth Bass abundance and ecology.

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In geotechnical engineering, the stability of rock excavations and walls is estimated by using tools that include a map of the orientations of exposed rock faces. However, measuring these orientations by using conventional methods can be time consuming, sometimes dangerous, and is limited to regions of the exposed rock that are reachable by a human. This thesis introduces a 2D, simulated, quadcopter-based rock wall mapping algorithm for GPS denied environments such as underground mines or near high walls on surface. The proposed algorithm employs techniques from the field of robotics known as simultaneous localization and mapping (SLAM) and is a step towards 3D rock wall mapping. Not only are quadcopters agile, but they can hover. This is very useful for confined spaces such as underground or near rock walls. The quadcopter requires sensors to enable self localization and mapping in dark, confined and GPS denied environments. However, these sensors are limited by the quadcopter payload and power restrictions. Because of these restrictions, a light weight 2D laser scanner is proposed. As a first step towards a 3D mapping algorithm, this thesis proposes a simplified scenario in which a simulated 1D laser range finder and 2D IMU are mounted on a quadcopter that is moving on a plane. Because the 1D laser does not provide enough information to map the 2D world from a single measurement, many measurements are combined over the trajectory of the quadcopter. Least Squares Optimization (LSO) is used to optimize the estimated trajectory and rock face for all data collected over the length of a light. Simulation results show that the mapping algorithm developed is a good first step. It shows that by combining measurements over a trajectory, the scanned rock face can be estimated using a lower-dimensional range sensor. A swathing manoeuvre is introduced as a way to promote loop closures within a short time period, thus reducing accumulated error. Some suggestions on how to improve the algorithm are also provided.

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This dissertation examines a process of indigenous accumulation among Tonga farmers in Zambia’s Southern Province. In the 1970s multiple authors concluded that capitalist farmers had emerged among Tonga agro-pastoralists, predominantly within private titled holdings. Relying on archival research, newspapers, secondary sources and extensive oral testimony this thesis fills a 35-year gap on the topic, providing insights into the social and environmental impacts of neoliberal policy among African peasants and capitalist farmers. In contrast to dominant narratives of the post-independence period, this study argues that Zambia did experience a developmental process post-independence, which saw significant achievements made in the agricultural sector, including the doubling of national cattle stocks. The data reveals a painful process of disarticulation beginning in the late 1980s. Following neoliberal adjustment, we observe significant heterogeneity in production systems, some regional specialization, and processes of migration. Most importantly, the thesis uncovers processes of overwhelming ecosystemic change that contributed to livestock epidemics of severe scale and scope. Amazingly, this went largely undocumented because of the simultaneous crisis of the state, which left the national statistics office and other state bodies incapable of functioning from the late 1980s into the 2000s. In response, the Zambian state has introduced a number of neodevelopmental initiatives in the sector, yet the lack of animal traction remained up to 2008 and agricultural production declined, while more capitalized farmers (largely white, and/or with foreign direct investment) have become more significant players in the country. This thesis provides compelling evidence to challenge dominant economic thinking of the Washington institutions as well as many of the common Marxian formulations.

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Sexual scripts—the definitions and expectations that individuals hold for sexual interactions—are thought to play an important role in the maintenance of sexual well-being. Sexual scripts can be rigid or flexible, and they can be concordant or discordant between members of a couple. Sex therapists support sexual script flexibility for maintaining sexual and relationship satisfaction when couples are navigating sexual issues. However, empirical research examining the role of sexual script flexibility and the degree of script concordance/discordance in couples’ sexual well-being has been limited, due in part to the limited measures available. Furthermore, within the existing research, there has been an unfortunate tendency to exclude individuals in same-gender relationships – perpetuating the long-standing knowledge gap in the literature on positive sexuality in diverse relationships. To address these gaps in the literature, we conducted a series of online studies that recruited individuals in diverse relationships. A measure of individual sexual script flexibility in response to sexual issues was developed (Chapter 2); in addition, the structure of an existing measure assessing couple sexual scripts in response to a sexual issue was evaluated (Chapter 3). Chapter 4 examined how individuals in diverse relationships compared on measures of individual sexual script flexibility and on couple sexual scripts. Findings suggest that there are more similarities than differences across diverse couples. Chapter 5 explored how flexibility in an individual’s approach to sexual issues relates to sexual well-being, specifically by assessing sexual communication and partner responses as mediators. Results suggest that individual sexual script flexibility relates to sexual well-being through reciprocal partner processes. Collectively, this research program suggests that more similarities than differences exist between individuals in same- and mixed-gender relationships, and that partners are important to consider in the relationship between individual sexual script flexibility and sexual well-being. These findings have implications for sex and couple therapy; these results emphasize the importance of interventions that target both members of the couple, and further our understanding of sexuality in same- and mixed-gender relationships.