RESUMEN
Archaeological studies of pre-historic Arctic cultures are often limited to artefacts and architecture; such records may be incomplete and often do not provide a continuous record of past occupation. Here, we used lake sediment archives to supplement archaeological evidence to explore the history of Thule and Dorset populations on Somerset Island, Nunavut (Canada). We examined biomarkers in dated sediment cores from two ponds adjacent to abandoned Thule settlements (PaJs-3 and PaJs-13) and compared these to sediment cores from two ponds without past human occupation. Coprostanol and epicoprostanol, δ15N measurements, sedimentary chlorophyll a and the ratio of diatom valves to chrysophyte cysts were elevated in the dated sediment profiles at both sites during Thule and Dorset occupations. Periods of pronounced human impact during the Thule occupation of the site were corroborated by 14C-dated caribou bones found at both sites that identified intense caribou hunting between ca 1185 and 1510 CE. Notably, these sediment core data show evidence of the Dorset occupation from ca 200 to 500 CE at sites where archaeological evidence was heretofore lacking. We highlight the utility of lake sediments in assisting archaeological studies to better establish the timings, peak occupations and even lifestyle practices of the Dorset and Thule Arctic peoples.
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Arqueología , Biomarcadores , Huesos , Sedimentos Geológicos , Sedimentos Geológicos/química , Sedimentos Geológicos/análisis , Regiones Árticas , Huesos/química , Animales , Humanos , Biomarcadores/análisis , Nunavut , Reno , Lagos/químicaRESUMEN
Chronic wasting disease (CWD), a prion disease affecting cervids, has been known in North America (NA) since the 1960s and emerged in Norway in 2016. Surveillance and studies have revealed that there are different forms of CWD in Fennoscandia: contagious CWD in Norwegian reindeer and sporadic CWD in moose and red deer. Experimental studies have demonstrated that NA CWD prions can infect various species, but thus far, there have been no reports of natural transmission to non-cervid species. In vitro and laboratory animal studies of the Norwegian CWD strains suggest that these strains are different from the NA strains. In this work, we describe the intracerebral transmission of reindeer CWD to six scrapie-susceptible sheep. Detection methods included immunohistochemistry (IHC), western blot (WB), enzyme-linked immunosorbent assay (ELISA), real-time quaking-induced conversion (RT-QuIC) and protein misfolding cyclic amplification (PMCA). In the brain, grey matter vacuolation was limited, while all sheep exhibited vacuolation of the white matter. IHC and WB conventional detection techniques failed to detect prions; however, positive seeding activity with the RT-QuIC and PMCA amplification techniques was observed in the central nervous system of all but one sheep. Prions were robustly amplified in the lymph nodes of all animals, mainly by RT-QuIC. Additionally, two lymph nodes were positive by WB, and one was positive by ELISA. These findings suggest that sheep can propagate reindeer CWD prions after intracerebral inoculation, resulting in an unusual disease phenotype and prion distribution with a low amount of detectable prions.
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Priones , Reno , Enfermedad Debilitante Crónica , Animales , Enfermedad Debilitante Crónica/transmisión , Ovinos , Priones/metabolismo , Noruega , Encéfalo/metabolismo , Fenotipo , Enfermedades de las Ovejas/transmisiónRESUMEN
Encounters between animals occur when animals are close in space and time. Encounters are important in many ecological processes including sociality, predation and disease transmission. Despite this, there is little theory regarding the spatial distribution of encounters and no formal framework to relate environmental characteristics to encounters. The probability of encounter could be estimated with resource selection functions (RSFs) by comparing locations where encounters occurred to available locations where they may have occurred, but this estimate is complicated by the hierarchical nature of habitat selection. We developed a method to relate resources to the relative probability of encounter based on a scale-integrated habitat selection framework. This framework integrates habitat selection at multiple scales to obtain an appropriate estimate of availability for encounters. Using this approach, we related encounter probabilities to landscape resources. The RSFs describe habitat associations at four scales, home ranges within the study area, areas of overlap within home ranges, locations within areas of overlap, and encounters compared to other locations, which can be combined into a single scale-integrated RSF. We apply this method to intraspecific encounter data from two species: white-tailed deer (Odocoileus virginianus) and elk (Cervus elaphus) and interspecific encounter data from a two-species system of caribou (Rangifer tarandus) and coyote (Canis latrans). Our method produced scale-integrated RSFs that represented the relative probability of encounter. The predicted spatial distribution of encounters obtained based on this scale-integrated approach produced distributions that more accurately predicted novel encounters than a naïve approach or any individual scale alone. Our results highlight the importance of accounting for the conditional nature of habitat selection in estimating the habitat associations of animal encounters as opposed to 'naïve' comparisons of encounter locations with general availability. This method has direct relevance for testing hypotheses about the relationship between habitat and social or predator-prey behaviour and generating spatial predictions of encounters. Such spatial predictions may be vital for understanding the distribution of encounters driving disease transmission, predation rates and other population and community-level processes.
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Ciervos , Ecosistema , Animales , Ciervos/fisiología , Modelos Biológicos , Coyotes/fisiología , Reno/fisiología , Conducta AnimalRESUMEN
Methods for determining the radiation dose received by exposed biota require major improvements to reduce uncertainties and increase precision. We share our experiences in attempting to quantify external dose rates to free-ranging wildlife using GPS-coupled dosimetry methods. The manuscript is a primer on fundamental concepts in wildlife dosimetry in which the complexities of quantifying dose rates are highlighted, and lessons learned are presented based on research with wild boar and snakes at Fukushima, wolves at Chornobyl, and reindeer in Norway. GPS-coupled dosimeters produced empirical data to which numerical simulations of external dose using computer software were compared. Our data did not support a standing paradigm in risk analyses: Using averaged soil contaminant levels to model external dose rates conservatively overestimate the dose to individuals within a population. Following this paradigm will likely lead to misguided recommendations for risk management. The GPS-dosimetry data also demonstrated the critical importance of how modeled external dose rates are impacted by the scale at which contaminants are mapped. When contaminant mapping scales are coarse even detailed knowledge about each animal's home range was inadequate to accurately predict external dose rates. Importantly, modeled external dose rates based on a single measurement at a trap site did not correlate to actual dose rates measured on free ranging animals. These findings provide empirical data to support published concerns about inadequate dosimetry in much of the published Chernobyl and Fukushima dose-effects research. Our data indicate that a huge portion of that literature should be challenged, and that improper dosimetry remains a significant source of controversy in radiation dose-effect research.
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Monitoreo de Radiación , Animales , Monitoreo de Radiación/métodos , Accidente Nuclear de Fukushima , Dosis de Radiación , Noruega , Accidente Nuclear de Chernóbil , Reno , Sus scrofa , Animales Salvajes , Radiometría/métodos , Lobos , Contaminantes Radiactivos del Suelo/análisisRESUMEN
We investigated Alongshan virus infection in reindeer in northeastern China. We found that 4.8% of the animals were viral RNA-positive, 33.3% tested positive for IgG, and 19.1% displayed neutralizing antibodies. These findings suggest reindeer could serve as sentinel animal species for the epidemiologic surveillance of Alongshan virus infection.
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Anticuerpos Antivirales , Reno , Animales , Reno/virología , China/epidemiología , Anticuerpos Antivirales/sangre , Anticuerpos Neutralizantes/sangre , Infecciones por Bunyaviridae/veterinaria , Infecciones por Bunyaviridae/epidemiología , Infecciones por Bunyaviridae/virología , ARN Viral , Inmunoglobulina G/sangreRESUMEN
Establishing freedom from disease is a key component of surveillance and may have direct consequences for trade and economy. Transboundary populations pose challenges in terms of variable legislation, efforts, and data availability between countries, often limiting surveillance efficiency. Chronic wasting disease (CWD) is a contagious prion disease of cervids. The long incubation period and slow initial epidemic growth make it notoriously difficult to detect CWD in the early phase of an epidemic. The recent emergence of CWD in wild reindeer in Norway poses a threat to approximately 250,000 semi-domesticated reindeer in Norway and 250,000 in Sweden, including transboundary populations. Here, we provide a first analysis of surveillance data (2016-2022) from all reindeer districts in Norway and Sweden to determine the probability of freedom from CWD infection. During the six years, 6017 semi-domesticated reindeer were tested in Sweden and 51,974 in Norway. Most samples came from healthy slaughtered animals (low risk). Reindeer use large and remote areas and (high risk) samples from fallen stock and animals with clinical signs were difficult to obtain. A scenario tree model was run for seven different set of values for the input parameters (design prevalence within and between districts, probability of introduction, and relative risks) to determine the effect on surveillance sensitivity. At the national level, the mean probability of disease freedom was 59.0â¯% in Sweden and 87.0â¯% in Norway by 2021. The most marked effect on sensitivity was varying the design prevalence both within and between districts. Uncertainty about relative risk ratios affected sensitivity for Sweden more than for Norway, due to the higher proportion of animals in the high-risk group in the former (13.8â¯% vs. 2.1â¯%, respectively). A probability of disease freedom of 90â¯% or higher was reached in 8.2â¯% of the 49 districts in Sweden and 43.5â¯% of the 46 districts in Norway for a design prevalence of 0.5â¯%. The probability of freedom remained below 60â¯% in 29 districts (59.2â¯%) in Sweden and 10 districts (21.7â¯%) in Norway. At the national level, only Norway had a sufficiently large number of samples to reach a probability of more than 95â¯% of disease freedom within a period of 10 years. Our cross-border assessment forms an important knowledge base for designing future surveillance efforts depending on the spatial pattern of prevalence of CWD and risk of spread.
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Reno , Enfermedad Debilitante Crónica , Animales , Noruega/epidemiología , Suecia/epidemiología , Enfermedad Debilitante Crónica/epidemiología , PrevalenciaRESUMEN
Competition for resources and space can drive forage selection of large herbivores from the bite through the landscape scale. Animal behaviour and foraging patterns are also influenced by abiotic and biotic factors. Fine-scale mechanisms of density-dependent foraging at the bite scale are likely consistent with density-dependent behavioural patterns observed at broader scales, but few studies have directly tested this assertion. Here, we tested if space use intensity, a proxy of spatiotemporal density, affects foraging mechanisms at fine spatial scales similarly to density-dependent effects observed at broader scales in caribou. We specifically assessed how behavioural choices are affected by space use intensity and environmental processes using behavioural state and forage selection data from caribou (Rangifer tarandus granti) observed from GPS video-camera collars using a multivariate discrete-choice modelling framework. We found that the probability of eating shrubs increased with increasing caribou space use intensity and cover of Salix spp. shrubs, whereas the probability of eating lichen decreased. Insects also affected fine-scale foraging behaviour by reducing the overall probability of eating. Strong eastward winds mitigated negative effects of insects and resulted in higher probabilities of eating lichen. At last, caribou exhibited foraging functional responses wherein their probability of selecting each food type increased as the availability (% cover) of that food increased. Space use intensity signals of fine-scale foraging were consistent with density-dependent responses observed at larger scales and with recent evidence suggesting declining reproductive rates in the same caribou population. Our results highlight potential risks of overgrazing on sensitive forage species such as lichen. Remote investigation of the functional responses of foraging behaviours provides exciting future applications where spatial models can identify high-quality habitats for conservation.
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Herbivoria , Densidad de Población , Reno , Animales , Reno/fisiología , Conducta Alimentaria , Modelos Biológicos , Conducta de Elección , EcosistemaRESUMEN
AbstractUngulates can respond to changes in food supply by altering foraging behavior, digestive function, and metabolism. A multifaceted response to an environmental change is considered robust. Short seasons of plant growth make herbivores sensitive to changes in food supply because maintenance and production must be accomplished in less time with fewer options in a more fragile response. Caribou live at high latitudes where short summers constrain their response to changes in food supply. We measured the ability of female caribou to resist and tolerate changes in the quality and quantity of their food supply during winter and summer. Caribou resisted changes in food abundance and quality by changing food intake and physical activity with changes in daily temperature within each season. Peak food intake rose by 134% from winter pregnancy to summer lactation (98 vs. 229 g kg-0.75 d-1), as digestible requirements to maintain the body increased by 85% for energy (1,164 vs. 2,155 kJ kg-0.75 d-1) and by 266% for N (0.79 vs. 2.89 g N kg-0.75 d-1). Caribou required a diet with a digestible content of 12 kJ g-1 and 0.8% N in pregnancy, 18 kJ g-1 and 1.9% N in early lactation, and 11 kJ g-1 and 1.2% N in late lactation, which corresponds with the phenology of the wild diet. Female caribou tolerated restriction of ad lib. food intake to 58% of their energy requirement (680 vs. 1,164 kJ kg-0.75 d-1) during winter pregnancy and to 84% of their energy requirement (1,814 vs. 2,155 kJ kg-0.75 d-1) during summer lactation without a change in stress level, as indicated by fecal corticosterone concentration. Conversely, caribou can respond to increased availability of food with a spare capacity to process digestible energy and N at 123% (2,642 vs. 2,155 kJ kg-0.75 d-1) and 145% (4.20 vs. 2.89 g N kg-0.75 d-1) of those respective requirements during lactation. Robust responses to changes in food supply allow caribou to sustain reproduction, which would buffer demographic response. However, herds may decline when thresholds of behavioral resistance and physiological tolerance are frequently exceeded. Therefore, the challenge for managing declining populations of caribou and other robust species is to identify declines in robustness before their response becomes fragile.
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Reno , Estaciones del Año , Femenino , Animales , Reno/fisiología , Embarazo , Lactancia/fisiología , Abastecimiento de Alimentos , Dieta , Ingestión de Alimentos/fisiología , TemperaturaRESUMEN
Density dependence is a fundamental ecological process. In particular, animal habitat selection and social behavior often affect fitness in a density-dependent manner. The Ideal Free Distribution (IFD) and niche variation hypothesis (NVH) present distinct predictions associated with Optimal Foraging Theory about how the effect of habitat selection on fitness varies with population density. Using caribou (Rangifer tarandus) in Canada as a model system, we test competing hypotheses about how habitat specialization, social behavior, and annual reproductive success (co)vary across a population density gradient. Within a behavioral reaction norm framework, we estimate repeatability, behavioral plasticity, and covariance among social behavior and habitat selection to investigate the adaptive value of sociality and habitat selection. In support of NVH, but not the IFD, we find that at high density habitat specialists had higher annual reproductive success than generalists, but were also less social than generalists, suggesting the possibility that specialists were less social to avoid competition. Our study supports niche variation as a mechanism for density-dependent habitat specialization.
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Ecosistema , Densidad de Población , Conducta Social , Animales , Reno/fisiología , Canadá , Reproducción/fisiología , Conducta Animal/fisiología , Femenino , MasculinoRESUMEN
Age estimation is crucial for investigating animal populations in the past and present. Visual examination of tooth wear and eruption is one of the most common ageing methods in zooarchaeology, wildlife management, palaeontology, and veterinary research. Such approaches are particularly advantageous because they are non-destructive, can be completed using photographs, and do not require specialized training. Several tooth wear and eruption methods have been developed for Rangifer tarandus, a widely distributed and long-utilized species in the North. This paper evaluates the practicality and effectiveness of three existing visual tooth wear and eruption methods for this species using a large known-age sample from several caribou populations in northern Canada (Bluenose East, Bluenose West, Dolphin-Union, Qamanirjuaq, and Beverly herds). These methods are evaluated based on: (1) the amount of error and bias between estimated and actual ages, (2) suitable and interpretable results, (3) user-friendly and unambiguous procedures, and (4) which teeth and visual features of those teeth are used to record wear and eruption status. This study finds that the three evaluated methods all have variable errors and biases, and two show extensive biases when applied to older individuals. Demographic data is simpler to generate and more flexible to report when methods allow age to be estimated as a continuous or discrete variable, rather than as age ranges. The dentition samples used by two of the previously developed methods impact their applicability to other populations of Rangifer. In one existing method, individuals were unavailable from some age ranges leaving gaps when assigning ages. For another Rangifer-ageing method, the population utilized was too distinct in morphology or diet to be used with the Canadian caribou analyzed here. Additional refinement of tooth wear and eruption ageing methods will benefit zooarchaeological research on reindeer and caribou remains.
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Ciervos , Reno , Animales , Canadá , Animales Salvajes , DietaRESUMEN
Recent studies show that Traditional Ecological Knowledge (TEK) of Indigenous Peoples' food systems and the transfer of that knowledge to their children are critical to physical and mental health, promote the transfer of language and culture, and further resilience. The aim of this exploratory, medical ecological study was to document TEK about foraging and plant use among the Dukha, a small, semi-nomadic reindeer herding community in Northern Mongolia. Field research was conducted at multiple remote camps in 2019 and 2023. Methods included semi-structured, open-ended interviews (N = 16), photo identification, and participant observation (N = 34 families). Study Informants identified 27 foraged plants. Results placed Dukha foraging practices within a framework illustrating the interconnectedness of their worldview and cultural norms, including the physical and spiritual aspects of the landscape, with health, illness, and curing. Dukha curative knowledge of the flora aligns with both Traditional Mongolian Medicine (TMM) and scientific studies on healing and preventative care. Through foraging and plant use, the Dukha balance relationships with the land and spirits, benefit from better nutrition and physical activity, utilise healing qualities of indigenous flora, and foster the intergenerational transfer of language and traditional knowledge.
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Reno , Lobos , Niño , Humanos , Perros , Animales , Mongolia , Plantas , HígadoRESUMEN
Bone extracellular matrix (ECM) proteins play a key role in bone formation and regeneration, including structural and regulatory functions. The Phylobone database consists of 255 ECM protein groups from 39 species and can be used to support bone research. Here, we gathered bone ECM proteins from reindeer (Rangifer tarandus), a member of the Cervidae family. The importance of reindeer lies in their ability to regenerate their antlers, in both male and female individuals. Protein sequences were extracted from the National Center for Biotechnology Information's repository and selected by homology searches. We identified 215 proteins and their corresponding functional domains, which are putatively present in the bone ECM of reindeer. Protein sequence alignments have shown a high degree of conservation between R. tarandus and other members of the Cervidae family. This update expands the Phylobone database and shows that it is a useful resource for the preliminary annotation of bone ECM proteins in novel proteomes.
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Reno , Humanos , Animales , Femenino , Masculino , Reno/genética , Biotecnología , Bases de Datos Factuales , Proteínas de la Matriz ExtracelularRESUMEN
Habitat loss is affecting many species, including the southern mountain caribou (Rangifer tarandus caribou) population in western North America. Over the last half century, this threatened caribou population's range and abundance have dramatically contracted. An integrated population model was used to analyze 51 years (1973-2023) of demographic data from 40 southern mountain caribou subpopulations to assess the effectiveness of population-based recovery actions at increasing population growth. Reducing potential limiting factors on threatened caribou populations offered a rare opportunity to identify the causes of decline and assess methods of recovery. Southern mountain caribou abundance declined by 51% between 1991 and 2023, and 37% of subpopulations were functionally extirpated. Wolf reduction was the only recovery action that consistently increased population growth when applied in isolation, and combinations of wolf reductions with maternal penning or supplemental feeding provided rapid growth but were applied to only four subpopulations. As of 2023, recovery actions have increased the abundance of southern mountain caribou by 52%, compared to a simulation with no interventions. When predation pressure was reduced, rapid population growth was observed, even under contemporary climate change and high levels of habitat loss. Unless predation is reduced, caribou subpopulations will continue to be extirpated well before habitat conservation and restoration can become effective.
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Conservación de los Recursos Naturales , Especies en Peligro de Extinción , Reno , Animales , Reno/fisiología , Conservación de los Recursos Naturales/métodos , Modelos Biológicos , Dinámica Poblacional , Lobos/fisiología , EcosistemaRESUMEN
Some worry the findings will stall efforts to halt logging-the root cause of caribou population declines.
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Conservación de los Recursos Naturales , Extinción Biológica , Reno , Lobos , Animales , Agricultura Forestal , Dinámica Poblacional , CanadáRESUMEN
Arctic regions are warming significantly faster than other parts of the globe, leading to changes in snow, ice and weather conditions, ecosystems and local cultures. These changes have brought worry and concern and triggered feelings of loss among Arctic Indigenous Peoples and local communities. Recently, research has started to address emotional and social dimensions of climate change, framed through the concept of ecological grief. In this study, we examine sociocultural impacts of climate change and expressions of ecological grief among members of reindeer herding communities in the Sámi Homeland in Finland. Results indicate that ecological grief is felt in connection to major environmental concerns in the area: changes in winter weather and extreme weather events, Atlantic salmon decline and land use changes, which all have cultural and social consequences. Our results indicate that ecological grief is strongly associated with ecological losses, but also with political decisions regarding natural resource governance.
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Cambio Climático , Pesar , Regiones Árticas , Humanos , Animales , Finlandia , Reno , Ecosistema , Pueblos Indígenas/psicología , Femenino , Masculino , Conservación de los Recursos NaturalesRESUMEN
Sedation, recovery response, and physiologic outcomes were evaluated in five captive reindeer (Rangifer tarandus) in Minnesota using a completely reversible immobilization protocol. Reindeer were immobilized with butorphanol (0.23-0.32 mg/kg), midazolam (0.23-0.32 mg/kg), and medetomidine (0.15 mg/kg) (BMM) via IM dart. Induction time (IT), recumbency time (DT), and recovery time (RT) were recorded. Temperature (T), respiratory rate (RR), pulse rate (PR), pulse oximetry (SpO2), arterial blood gas values including oxygen (PaO2), and carbon dioxide (PaCO2) tensions and lactate (Lac) were recorded preoxygen supplementation and 15 min postoxygen supplementation. Reversal was done using naltrexone (2.3-3.0 mg/kg), flumazenil (0.008-0.01 mg/kg) and atipamezole (0.62-0.78 mg/kg) (NFA) IM, limiting recumbency to 1 h. Median IT, DT, and RT were 5 min, 46 min, and 7 min, respectively. SpO2 (92 to 99%, P = 0.125), PaO2 (45.5 to 97 mmHg, P = 0.25), and PaCO2 (46.5 to 54.6 mmHg, P = 0.25) all increased, whereas Lac (3.02 to 1.93 mmol/L, P = 0.25) decreased between baseline and 15 min postoxygen supplementation, without statistical significance. BMM immobilization, and reversal with NFA provided rapid and effective immobilization and recovery, respectively. Oxygen supplementation mitigated hypoxemia in all reindeer.
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Ketamina , Reno , Animales , Medetomidina/farmacología , Midazolam/farmacología , Butorfanol/farmacología , Hipnóticos y Sedantes/farmacología , Ketamina/farmacología , Oxígeno , Inmovilización/veterinaria , Inmovilización/métodos , Frecuencia CardíacaRESUMEN
INTRODUCTION: Our group developed an Integrated Care Pathway to facilitate the delivery of evidence-based care for adolescents experiencing depression called CARIBOU-2 (Care for Adolescents who Receive Information 'Bout OUtcomes, 2nd iteration). The core pathway components are assessment, psychoeducation, psychotherapy options, medication options, caregiver support, measurement-based care team reviews and graduation. We aim to test the clinical and implementation effectiveness of the CARIBOU-2 pathway relative to treatment-as-usual (TAU) in community mental health settings. METHODS AND ANALYSIS: We will use a Type 1 Hybrid Effectiveness-Implementation, Non-randomized Cluster Controlled Trial Design. Primary participants will be adolescents (planned n = 300, aged 13-18 years) with depressive symptoms, presenting to one of six community mental health agencies. All sites will begin in the TAU condition and transition to the CARIBOU-2 intervention after enrolling 25 adolescents. The primary clinical outcome is the rate of change of depressive symptoms from baseline to the 24-week endpoint using the Childhood Depression Rating Scale-Revised (CDRS-R). Generalized mixed effects modelling will be conducted to compare this outcome between intervention types. Our primary hypothesis is that there will be a greater rate of reduction in depressive symptoms in the group receiving the CARIBOU-2 intervention relative to TAU over 24 weeks as per the CDRS-R. Implementation outcomes will also be examined, including clinician fidelity to the pathway and its components, and cost-effectiveness. ETHICS AND DISSEMINATION: Research ethics board approvals have been obtained. Should our results support our hypotheses, systematic implementation of the CARIBOU-2 intervention in other community mental health agencies would be indicated.
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Prestación Integrada de Atención de Salud , Reno , Adolescente , Animales , Niño , Humanos , Vías Clínicas , Depresión/psicología , Psicoterapia/métodos , Resultado del Tratamiento , Ensayos Clínicos Controlados no Aleatorios como Asunto , Investigación sobre la Eficacia ComparativaRESUMEN
Treponema spp. are associated with infectious lameness in livestock and wild ruminants. While extensive research has been conducted on cattle, investigations in wild ruminants are scarce. Hoof disease is common in caribou populations (Rangifer tarandus), but investigations are limited due to the remoteness of the Arctic. Our study aimed to assess the presence of Treponema spp. associated with bovine digital dermatitis in caribou. DNA was extracted from coronary band tissues from forty-eight caribou without visible hoof lesions and analyzed using two PCR methods (qPCR and nPCR). Treponema spp. were detected in low copy numbers/mg of tissue (3.6 to 6.6 × 101). T. phagedenis was the most prevalent and abundant species in 58% of samples by qPCR, followed by T. medium (44%), and T. pedis (10%). The qPCR and nPCR agreement ranged between 65% and 75% (Cohen's kappa 0.22-0.51). Sanger sequencing of thirteen nPCR products confirmed that treponemes in caribou are remarkably similar to those found in domestic ruminants and wild elk. Our study highlights the colonization of treponemes in healthy hooves of a wild ruminant in the Arctic, where there is no presence of livestock, and expands knowledge on the host range and distribution of treponemes. These findings also emphasize the need for further research into the multifactorial nature of treponema-associated hoof diseases and the putative role of treponemes in infectious lameness affecting caribou.
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Enfermedades de los Bovinos , Dermatitis Digital , Reno , Infecciones por Treponema , Bovinos , Animales , Treponema/genética , Cojera Animal , Animales Salvajes , Infecciones por Treponema/veterinariaRESUMEN
Habitat disturbance is a major driver of the decline of woodland caribou (Rangifer tarandus caribou) in Canada. Different disturbance agents and regimes negatively impact caribou populations to different degrees. It is therefore critical that land managers and scientists studying caribou have a detailed understanding of the disturbance regimes affecting caribou habitat. In this work we use recent advances in satellite-based disturbance detection to quantify polygonal forest disturbance regimes affecting caribou ecotypes and herds in British Columbia (BC) from 1985 to 2019. Additionally, we utilize this data to investigate harvesting rates since the implementation of the Species at Risk Act (SARA) and publication of recovery strategies for caribou in BC. Southern Mountain caribou herds are the most threatened yet experienced the highest rates of disturbance, with 22.75% of forested habitat within their ranges disturbed during the study period. Over the study period, we found that in total, 16.4% of forested area was disturbed across all caribou herd ranges. Our findings indicate that caribou in BC face high, and in many cases increasing, levels of habitat disturbance. Our results provide a detailed understanding of the polygonal disturbance regimes affecting caribou in BC at the herd scale, and highlight the need for effective implementation of policies aimed at preserving caribou habitat.
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Reno , Animales , Colombia Británica , Bosques , EcosistemaRESUMEN
Reindeer in the Arctic seasonally suppress daily circadian patterns of behavior present in most animals.1 In humans and mice, even when all daily behavioral and environmental influences are artificially suppressed, robust endogenous rhythms of metabolism governed by the circadian clock persist and are essential to health.2,3 Disrupted rhythms foster metabolic disorders and weight gain.4 To understand circadian metabolic organization in reindeer, we performed behavioral measurements and untargeted metabolomics from blood plasma samples taken from Eurasian tundra reindeer (Rangifer tarandus tarandus) across 24 h at 2-h intervals in four seasons. Our study confirmed the absence of circadian rhythms of behavior under constant darkness in the Arctic winter and constant daylight in the Arctic summer, as reported by others.1 We detected and measured the intensity of 893 metabolic features in all plasma samples using untargeted ultra-high-performance liquid chromatography-mass spectrometry (UPLC-MS). A core group of metabolites (66/893 metabolic features) consistently displayed 24-h rhythmicity. Most metabolites displayed a robust 24-h rhythm in winter and spring but were arrhythmic in summer and fall. Half of all measured metabolites displayed ultradian sleep-wake dependence in summer. Irrespective of the arrhythmic behavior, metabolism is rhythmic (24 h) in seasons of low food availability, potentially favoring energy efficiency. In seasons of food abundance, 24-h rhythmicity in metabolism is drastically reduced, again irrespective of behavioral rhythms, potentially fostering weight gain.