Publications by authors named "Stephen Petersen"

Assessing genetic structure and diversity in wildlife is particularly important in the context of climate change. The Arctic is rapidly warming, and endemic species must adapt quickly or face significant threats to persistence. Bowhead whales (Balaena mysticetus) and narwhals (Monodon monoceros) are two long-lived Arctic species with similar habitat requirements and are often seen together in the Canadian Arctic.

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The Arctic is the fastest-warming region on the planet, and the lengthening ice-free season is opening Arctic waters to sub-Arctic species such as the killer whale (Orcinus orca). As apex predators, killer whales can cause significant ecosystem-scale changes. Setting conservation priorities for killer whales and their Arctic prey species requires knowledge of their evolutionary history and demographic trajectory.

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An intense public debate has fuelled governmental bans on marine mammals held in zoological institutions. The debate rests on the assumption that survival in zoological institutions has been and remains lower than in the wild, albeit the scientific evidence in support of this notion is equivocal. Here, we used statistical methods previously applied to assess historical improvements in human lifespan and data on 8864 individuals of four marine mammal species (harbour seal, ; California sea lion, ; polar bear, ; common bottlenose dolphin, ) held in zoos from 1829 to 2020.

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Introduction: The wave-over-wave effect of the COVID-19 pandemic on hospital visits for non-COVID-19-related diagnoses in Ontario, Canada remains unknown.

Methods: We compared the rates of acute care hospitalizations (Discharge Abstract Database), emergency department (ED) visits, and day surgery visits (National Ambulatory Care Reporting System) during the first five "waves" of Ontario's COVID-19 pandemic with prepandemic rates (since January 1, 2017) across a spectrum of diagnostic classifications.

Results: Patients admitted in the COVID-19 era were less likely to reside in long-term-care facilities (OR 0.

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Infrared thermography or thermal imagery is a noninvasive tool that can be used to measure the temperature of surfaces. Typically, thermal imagery is used for construction or military purposes but is increasingly used as a noninvasive tool in wildlife studies. We investigated the use of thermal imagery to measure surface temperature changes as a proxy for energetic expenditure.

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Cardiovascular magnetic resonance (CMR) has become one of the main imaging techniques for the diagnosis and prognostic stratification of the different cardiovascular diseases. Proof of this is the growing interest in training in this imaging technique which was evident in the past EuroCMR 2019 where 1379 specialists (26.5% more than in the previous edition) met in Lido (Venice) to discuss the latest scientific advances in the CMR field.

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When health systems aim to improve, two key considerations tend to be front and centre: cost and quality. On the cost side, health spending in Canada continues to rise. On the quality side, improvement is needed across the country.

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Objectives: In 2007, the Ontario Health Technology Advisory Committee (OHTAC) developed a decision framework to guide decision making around nondrug health technologies. In 2012, OHTAC commissioned a revision of this framework to enhance its usability and deepen its conceptual and theoretical foundations.

Methods: The committee overseeing this work used several methods: (a) a priori consensus on guiding principles, (b) a scoping review of decision attributes and processes used globally in health technology assessment (HTA), (c) presentations by methods experts and members of review committees, and (d) committee deliberations over a period of 3 years.

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Herein, we use genetic data from 277 sleeper sharks to perform coalescent-based modeling to test the hypothesis of early Quaternary emergence of the Greenland shark () from ancestral sleeper sharks in the Canadian Arctic-Subarctic region. Our results show that morphologically cryptic somniosids and can be genetically distinguished using combined mitochondrial and nuclear DNA markers. Our data confirm the presence of genetically admixed individuals in the Canadian Arctic and sub-Arctic, and temperate Eastern Atlantic regions, suggesting introgressive hybridization upon secondary contact following the initial species divergence.

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Although predators influence behavior of prey, analyses of electronic tracking data in marine environments rarely consider how predators affect the behavior of tracked animals. We collected an unprecedented dataset by synchronously tracking predator (killer whales, [Formula: see text] = 1; representing a family group) and prey (narwhal, [Formula: see text] = 7) via satellite telemetry in Admiralty Inlet, a large fjord in the Eastern Canadian Arctic. Analyzing the movement data with a switching-state space model and a series of mixed effects models, we show that the presence of killer whales strongly alters the behavior and distribution of narwhal.

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Objective: As health technology assessment (HTA) organizations in Canada and around the world seek to involve the public and patients in their activities, frameworks to guide decisions about whom to involve, through which mechanisms, and at what stages of the HTA process have been lacking. The aim of this study was to describe the development and outputs of a comprehensive framework for involving the public and patients in a government agency's HTA process.

Methods: The framework was informed by a synthesis of international practice and published literature, a dialogue with local, national and international stakeholders, and the deliberations of a government agency's public engagement subcommittee in Ontario, Canada.

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Global climate change during the Late Pleistocene periodically encroached and then released habitat during the glacial cycles, causing range expansions and contractions in some species. These dynamics have played a major role in geographic radiations, diversification and speciation. We investigate these dynamics in the most widely distributed of marine mammals, the killer whale (Orcinus orca), using a global data set of over 450 samples.

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Household indoor air pollution from open-fire cookstoves remains a public health and environmental hazard which impacts negatively on people's right to health. Technologically improved cookstoves designed to reduce air pollution have demonstrated their efficacy in laboratory studies. Despite the tremendous need for such stoves, in the field they have often failed to be effective, with low rates of long-term adoption by users, mainly due to poor maintenance of the stoves.

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Introduction: Autoimmune diseases such as systemic lupus erythematosus, rheumatoid arthritis, and multiple sclerosis affect millions of people worldwide. Interferon regulatory factor 5 (IRF5) contains polymorphisms associated with these autoimmune diseases. Two of these functional polymorphisms are found upstream of the IRF5 gene.

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This paper provides a reflection on the findings of Canada's first-ever chartbook on the quality of healthcare in Canada. Quality of Healthcare in Canada: A Chartbook was published in 2010 by the Canadian Health Services Research Foundation in partnership with the Canadian Institute for Health Information and the Canadian Patient Safety Institute, and with support from Statistics Canada. This paper, by the chartbook authors (Sutherland and Leatherman) and colleagues (Law, Verma and Petersen), presents selected key findings and lessons from the chartbook and aims to serve as a catalyst for ideas and discussion in the papers that follow.

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