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1.
J Med Internet Res ; 24(1): e29559, 2022 01 13.
Artigo em Inglês | MEDLINE | ID: mdl-35023846

RESUMO

BACKGROUND: eHealth tools have the potential to meet the mental health needs of individuals who experience barriers to accessing in-person treatment. However, most users have less than optimal engagement with eHealth tools. Coaching from peer specialists may increase their engagement with eHealth. OBJECTIVE: This pilot study aims to test the feasibility and acceptability of a novel, completely automated web-based system to recruit, screen, enroll, assess, randomize, and then deliver an intervention to a national sample of military veterans with unmet mental health needs; investigate whether phone-based peer support increases the use of web-based problem-solving training compared with self-directed use; and generate hypotheses about potential mechanisms of action for problem-solving and peer support for future full-scale research. METHODS: Veterans (N=81) with unmet mental health needs were recruited via social media advertising and enrolled and randomized to the self-directed use of a web-based problem-solving training called Moving Forward (28/81, 35%), peer-supported Moving Forward (27/81, 33%), or waitlist control (26/81, 32%). The objective use of Moving Forward was measured with the number of log-ins. Participants completed pre- and poststudy measures of mental health symptoms and problem-solving confidence. Satisfaction was also assessed post treatment. RESULTS: Automated recruitment, enrollment, and initial assessment methods were feasible and resulted in a diverse sample of veterans with unmet mental health needs from 38 states. Automated follow-up methods resulted in 46% (37/81) of participants completing follow-up assessments. Peer support was delivered with high fidelity and was associated with favorable participant satisfaction. Participants randomized to receive peer support had significantly more Moving Forward log-ins than those of self-directed Moving Forward participants, and those who received peer support had a greater decrease in depression. Problem-solving confidence was associated with greater Moving Forward use and improvements in mental health symptoms among participants both with and without peer support. CONCLUSIONS: Enrolling and assessing individuals in eHealth studies without human contact is feasible; however, different methods or designs are necessary to achieve acceptable participant engagement and follow-up rates. Peer support shows potential for increasing engagement in web-based interventions and reducing symptoms. Future research should investigate when and for whom peer support for eHealth is helpful. Problem-solving confidence should be further investigated as a mechanism of action for web-based problem-solving training. TRIAL REGISTRATION: ClinicalTrials.gov NCT03555435; http://clinicaltrials.gov/ct2/show/NCT03555435.


Assuntos
Intervenção Baseada em Internet , Veteranos , Estudos de Viabilidade , Humanos , Saúde Mental , Projetos Piloto
2.
Sensors (Basel) ; 21(20)2021 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-34695914

RESUMO

BACKGROUND: This study aimed to determine the effects of a standard therapeutic cooling protocol using crushed ice on the elbow to explore if changes in the motor unit (MU) firing rates in the first dorsal interosseous (FDI) muscle are comparable to known changes in sensory and motor nerve conduction velocity (NCV) due to a regional temperature drop around a peripheral nerve. METHODS: Twelve healthy individuals were assessed before cooling, immediately after cooling, and 15 min of rewarming. Assessments included two standard non-invasive nerve conduction velocity tests and a non-invasive investigation of the MU firing rates using surface electromyography decomposition (dEMG). RESULTS: Repeated ANOVAs showed significant differences in the MU firing rates and NCV between time points (p = 0.01 and p < 0.001). All measures showed significant differences between pre and post cooling and between pre-cooling and 15 min of passive re-warming, however, no changes were seen between post cooling and rewarming except in the sensory NCV, which increased but did not return to the pre-cooled state. CONCLUSIONS: This current study showed a significant, temporary, and reversible reduction in ulnar NCV across the elbow in healthy subjects, which was associated with a significant decrease in mean MU firing rates in the FDI muscle.


Assuntos
Articulação do Cotovelo , Cotovelo , Temperatura Baixa , Eletromiografia , Humanos , Condução Nervosa
3.
Ecol Lett ; 20(1): 50-59, 2017 01.
Artigo em Inglês | MEDLINE | ID: mdl-27891770

RESUMO

Predicting species responses to climate change is a central challenge in ecology. These predictions are often based on lab-derived phenomenological relationships between temperature and fitness metrics. We tested one of these relationships using the embryonic stage of a Chinook salmon population. We parameterised the model with laboratory data, applied it to predict survival in the field, and found that it significantly underestimated field-derived estimates of thermal mortality. We used a biophysical model based on mass transfer theory to show that the discrepancy was due to the differences in water flow velocities between the lab and the field. This mechanistic approach provides testable predictions for how the thermal tolerance of embryos depends on egg size and flow velocity of the surrounding water. We found support for these predictions across more than 180 fish species, suggesting that flow and temperature mediated oxygen limitation is a general mechanism underlying the thermal tolerance of embryos.


Assuntos
Longevidade , Rios/química , Salmão/fisiologia , Termotolerância , Animais , California , Desenvolvimento Embrionário , Espécies em Perigo de Extinção , Modelos Biológicos , Óvulo/crescimento & desenvolvimento , Salmão/crescimento & desenvolvimento , Estações do Ano , Temperatura
4.
Muscle Nerve ; 55(1): 28-34, 2017 01.
Artigo em Inglês | MEDLINE | ID: mdl-27170098

RESUMO

INTRODUCTION: The aims of this study were to determine the motor unit behavior of the erector spinae muscles and to assess whether differences exist between the dominant/nondominant sides of the back muscles. METHODS: Nine healthy women, aged 21.7 years (SD = 0.7), performed a back extension test. Surface electromyographic decomposition data were collected from both sides of the erector spinae and decomposed into individual motor unit action potential trains. The mean firing rate for each motor unit was calculated, and a regression analysis was performed against the corresponding recruitment thresholds. RESULTS: The mean firing rate ranged from 15.9 to 23.9 pps and 15.8 to 20.6 pps on the dominant and nondominant sides, respectively. However, the early motor unit potentials of the nondominant lumbar erector spinae muscles were recruited at a lower firing rate. CONCLUSIONS: This technique may further our understanding of individuals with back pain and other underlying neuromuscular diseases. Muscle Nerve 55: 28-34, 2017.


Assuntos
Potencial Evocado Motor/fisiologia , Contração Muscular/fisiologia , Músculos Paraespinais/fisiologia , Fenômenos Biomecânicos , Eletromiografia , Feminino , Voluntários Saudáveis , Humanos , Região Lombossacral , Adulto Jovem
6.
Adm Policy Ment Health ; 43(6): 834-849, 2016 11.
Artigo em Inglês | MEDLINE | ID: mdl-27480546

RESUMO

Implementation planning typically incorporates stakeholder input. Quality improvement efforts provide data-based feedback regarding progress. Participatory system dynamics modeling (PSD) triangulates stakeholder expertise, data and simulation of implementation plans prior to attempting change. Frontline staff in one VA outpatient mental health system used PSD to examine policy and procedural "mechanisms" they believe underlie local capacity to implement evidence-based psychotherapies (EBPs) for PTSD and depression. We piloted the PSD process, simulating implementation plans to improve EBP reach. Findings indicate PSD is a feasible, useful strategy for building stakeholder consensus, and may save time and effort as compared to trial-and-error EBP implementation planning.


Assuntos
Assistência Ambulatorial/organização & administração , Transtorno Depressivo/terapia , Prática Clínica Baseada em Evidências/organização & administração , Serviços de Saúde Mental/organização & administração , Psicoterapia , Transtornos de Estresse Pós-Traumáticos/terapia , Humanos , Política Organizacional , Projetos Piloto , Análise de Sistemas , Estados Unidos , United States Department of Veterans Affairs
7.
J Nerv Ment Dis ; 202(2): 91-6, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24469519

RESUMO

Apparent psychotic symptoms are often associated with posttraumatic stress disorder (PTSD), but these symptoms are poorly understood. In a sample of 30 male Vietnam combat veterans with severe and chronic PTSD, we conducted detailed assessments of psychotic symptom endorsement, insight, symptom severity, neurocognitive function, and feigning. Two thirds of the subjects endorsed a psychotic item but did not believe that the experiences were real. Those endorsing psychotic items were higher in PTSD severity, general psychopathology, and dissociation but not depression, functional health, cognitive function, or feigned effort. Severity of psychotic symptoms correlated with dissociation, combat exposure, and attention but not PTSD, depression, or functional health. Those endorsing psychotic items scored higher on a screen but not on a detailed structured interview for malingering. Endorsement of psychotic experiences by combat veterans with PTSD do not seem to reflect psychotic symptoms or outright malingering.


Assuntos
Transtornos Psicóticos/diagnóstico , Transtornos de Estresse Pós-Traumáticos/diagnóstico , Veteranos/psicologia , Doença Crônica , Distúrbios de Guerra/diagnóstico , Distúrbios de Guerra/epidemiologia , Distúrbios de Guerra/etiologia , Comorbidade , Humanos , Masculino , Pessoa de Meia-Idade , Transtornos Psicóticos/epidemiologia , Transtornos Psicóticos/etiologia , Índice de Gravidade de Doença , Transtornos de Estresse Pós-Traumáticos/epidemiologia , Transtornos de Estresse Pós-Traumáticos/etiologia , Estados Unidos , Guerra do Vietnã
8.
Conserv Biol ; 27(6): 1222-33, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24299088

RESUMO

Aquatic species are threatened by climate change but have received comparatively less attention than terrestrial species. We gleaned key strategies for scientists and managers seeking to address climate change in aquatic conservation planning from the literature and existing knowledge. We address 3 categories of conservation effort that rely on scientific analysis and have particular application under the U.S. Endangered Species Act (ESA): assessment of overall risk to a species; long-term recovery planning; and evaluation of effects of specific actions or perturbations. Fewer data are available for aquatic species to support these analyses, and climate effects on aquatic systems are poorly characterized. Thus, we recommend scientists conducting analyses supporting ESA decisions develop a conceptual model that links climate, habitat, ecosystem, and species response to changing conditions and use this model to organize analyses and future research. We recommend that current climate conditions are not appropriate for projections used in ESA analyses and that long-term projections of climate-change effects provide temporal context as a species-wide assessment provides spatial context. In these projections, climate change should not be discounted solely because the magnitude of projected change at a particular time is uncertain when directionality of climate change is clear. Identifying likely future habitat at the species scale will indicate key refuges and potential range shifts. However, the risks and benefits associated with errors in modeling future habitat are not equivalent. The ESA offers mechanisms for increasing the overall resilience and resistance of species to climate changes, including establishing recovery goals requiring increased genetic and phenotypic diversity, specifying critical habitat in areas not currently occupied but likely to become important, and using adaptive management. Incorporación de las Ciencias Climáticas en las Aplicaciones del Acta Estadunidense de Especies en Peligro para Especies Acuáticas.


Assuntos
Organismos Aquáticos/fisiologia , Mudança Climática , Conservação dos Recursos Naturais/legislação & jurisprudência , Animais , Biodiversidade , Espécies em Perigo de Extinção , Modelos Teóricos , Medição de Risco , Estados Unidos
9.
PLoS One ; 18(2): e0272599, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36753482

RESUMO

BACKGROUND: VA primary care patients are routinely screened for current symptoms of PTSD, depression, and alcohol disorders, but many who screen positive do not engage in care. In addition to stigma about mental disorders and a high value on autonomy, some veterans may not seek care because of uncertainty about whether they need treatment to recover. A screen for mental health risk could provide an alternative motivation for patients to engage in care. METHOD: Data from samples of veterans and traumatic injury survivors were analyzed to identify mental health risk factors that are characteristics of individuals or stressors or of post-trauma, post-deployment, or post-military service resources, experiences, or responses. Twelve risk factors were strongly related to PTSD (r > .50): current PTSD, depression, dissociation, negative thinking, and emotional lability symptoms, life stress, relationship stress, social constraints, and deployment experiences of a difficult environment, concerns about life and family, perceived threat, and moral injury. Items assessing each of these risk factors were selected and their validity to prospectively predict PTSD and/or depression 6 months later was assessed in a new sample of 232 VA primary care patients. RESULTS: Twelve items assessing dissociation, emotional lability, life stress, and moral injury correctly classified 86% of those who later had elevated PTSD and/or depression symptoms (sensitivity) and 75% of those whose later symptoms were not elevated (specificity). Performance was also very good for 110 veterans who identified as members of ethnic/racial minorities. CONCLUSIONS: Mental health status was prospectively predicted in VA primary care patients with high accuracy using a screen that is brief, easy to administer, score, and interpret, and fits well into VA's integrated primary care. When care is readily accessible, appealing to veterans, and not perceived as stigmatizing, information about mental health risk may result in higher rates of engagement than information about current mental disorder status.


Assuntos
Transtornos de Estresse Pós-Traumáticos , Veteranos , Humanos , Veteranos/psicologia , Saúde Mental , Saúde dos Veteranos , Transtornos de Estresse Pós-Traumáticos/diagnóstico , Transtornos de Estresse Pós-Traumáticos/epidemiologia , Transtornos de Estresse Pós-Traumáticos/psicologia , Fatores de Risco
10.
Sports Biomech ; : 1-12, 2023 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-37339268

RESUMO

Despite squatting being important in strength training and rehabilitation, few studies have investigated motor unit (MU) behaviour. This study explored the MU behaviour of vastus medialis (VM) and vastus lateralis (VL) during the concentric and eccentric phases of a squat exercise performed at two speeds. Twenty-two participants had surface dEMG sensors attached over VM and VL, and IMUs recorded thigh and shank angular velocities. Participants performed squats at 15 and 25 repetitions per minute in a randomised order, and EMG signals were decomposed into their MU action potential trains. A four factor (muscle × speed × contraction phase × sexes) mixed methods ANOVA revealed significant main effects for MU firing rates between speeds, between muscles and between sexes, but not contraction phases. Post hoc analysis showed significantly greater MU firing rates and amplitudes in VM. A significant interaction was seen between speed and the contraction phases. Further analysis revealed significantly greater firing rates during the concentric compared to the eccentric phases, and between speeds during the eccentric phase only. VM and VL respond differently during squatting depending on speed and contraction phase. These new insights in VM and VL MU behvaviour may be useful when designing training and rehabilitation protocols.

11.
Conserv Biol ; 25(5): 932-44, 2011 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-21797926

RESUMO

To remain viable, populations must be resilient to both natural and human-caused environmental changes. We evaluated anthropogenic effects on spatial connections among populations of Chinook salmon (Oncorhynchus tshawytscha) and steelhead (O. mykiss) (designated as threatened under the U.S. Endangered Species Act) in the lower Columbia and Willamette rivers. For several anthropogenic-effects scenarios, we used graph theory to characterize the spatial relation among populations. We plotted variance in population size against connectivity among populations. In our scenarios, reduced habitat quality decreased the size of populations and hydropower dams on rivers led to the extirpation of several populations, both of which decreased connectivity. Operation of fish hatcheries increased connectivity among populations and led to patchy or panmictic populations. On the basis of our results, we believe recolonization of the upper Cowlitz River by fall and spring Chinook and winter steelhead would best restore metapopulation structure to near-historical conditions. Extant populations that would best conserve connectivity would be those inhabiting the Molalla (spring Chinook), lower Cowlitz, or Clackamas (fall Chinook) rivers and the south Santiam (winter steelhead) and north fork Lewis rivers (summer steelhead). Populations in these rivers were putative sources; however, they were not always the most abundant or centrally located populations. This result would not have been obvious if we had not considered relations among populations in a metapopulation context. Our results suggest that dispersal rate strongly controls interactions among the populations that comprise salmon metapopulations. Thus, monitoring efforts could lead to understanding of the true rates at which wild and hatchery fish disperse. Our application of graph theory allowed us to visualize how metapopulation structure might respond to human activity. The method could be easily extended to evaluations of anthropogenic effects on other stream-dwelling populations and communities and could help prioritize among competing conservation measures.


Assuntos
Conservação dos Recursos Naturais/métodos , Demografia , Ecossistema , Atividades Humanas , Oncorhynchus mykiss/crescimento & desenvolvimento , Salmão/crescimento & desenvolvimento , Animais , Humanos , Oregon , Densidade Demográfica , Rios
12.
Biol Psychiatry ; 89(9): 857-867, 2021 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-33516458

RESUMO

BACKGROUND: Exposure-based psychotherapy is a first-line treatment for posttraumatic stress disorder (PTSD), but its mechanisms are poorly understood. Functional brain connectivity is a promising metric for identifying treatment mechanisms and biosignatures of therapeutic response. To this end, we assessed amygdala and insula treatment-related connectivity changes and their relationship to PTSD symptom improvements. METHODS: Individuals with a primary PTSD diagnosis (N = 66) participated in a randomized clinical trial of prolonged exposure therapy (n = 36) versus treatment waiting list (n = 30). Task-free functional magnetic resonance imaging was completed prior to randomization and 1 month following cessation of treatment/waiting list. Whole-brain blood oxygenation level-dependent responses were acquired. Intrinsic connectivity was assessed by subregion in the amygdala and insula, limbic structures key to the disorder pathophysiology. Dynamic causal modeling assessed evidence for effective connectivity changes in select nodes informed by intrinsic connectivity findings. RESULTS: The amygdala and insula displayed widespread patterns of primarily subregion-uniform intrinsic connectivity change, including increased connectivity between the amygdala and insula; increased connectivity of both regions with the ventral prefrontal cortex and frontopolar and sensory cortices; and decreased connectivity of both regions with the left frontoparietal nodes of the executive control network. Larger decreases in amygdala-frontal connectivity and insula-parietal connectivity were associated with larger PTSD symptom reductions. Dynamic causal modeling evidence suggested that treatment decreased left frontal inhibition of the left amygdala, and larger decreases were associated with larger symptom reductions. CONCLUSIONS: PTSD psychotherapy adaptively attenuates functional interactions between frontoparietal and limbic brain circuitry at rest, which may reflect a potential mechanism or biosignature of recovery.


Assuntos
Terapia Implosiva , Transtornos de Estresse Pós-Traumáticos , Tonsila do Cerebelo , Encéfalo , Humanos , Imageamento por Ressonância Magnética , Transtornos de Estresse Pós-Traumáticos/diagnóstico por imagem , Transtornos de Estresse Pós-Traumáticos/terapia
14.
J Rural Health ; 36(2): 266-273, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-30875145

RESUMO

PURPOSE: Access to mental health care and programs that address violence prevention can be a challenge for veterans residing in rural and underserved areas. A growing number of trauma-affected veterans are now returning to rural areas upon completion of military service. The Palo Alto VA Health Care System has piloted a program known as the Peer Support Program (PSP) where certified peer support specialists hold group sessions for their fellow veterans in remote, community-based outpatient clinics. METHODS: A total of 29 peer-support group participants and 1 certified peer specialist were interviewed. Semistructured interviews began with open-ended questions regarding participant firsthand experiences with the support group setting. These were followed by direct questions that addressed the role of the PSP, expectations for the PSP, as well as benefits and limitations of the program. We performed a domain analysis using the Spradley ethnographic method on 325 pages of compiled narrative data focusing on violence-related themes. FINDINGS: Four key themes emerged, including: 1) Violence in Military Training Not Acceptable in Civilian Life, 2) Peer Support Creates the Trust to Speak Freely, 3) Skills Are Taught to Defuse Violence, and 4) The Veteran Peer Support Specialist Relationship Is Multi-Dimensional. CONCLUSIONS: These emergent themes illustrate how trauma-focused assistance rendered by peer support specialists as part of an interdisciplinary mental health team can be implemented to benefit trauma-affected individuals and their communities in the prevention of future violence.


Assuntos
Veteranos , Humanos , Grupo Associado , População Rural , Grupos de Autoajuda , Violência/prevenção & controle
15.
Fed Pract ; 37(6): 276-281, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32669780

RESUMO

BACKGROUND: Repetitive transcranial magnetic stimulation (rTMS) uses a device to create magnetic fields that cause electrical current to flow into targeted neurons in the brain. The most common clinical use of rTMS is for the treatment of major depressive disorder (MDD). The annual suicide rate of veterans has been higher than the national average; treating depression with rTMS would likely decrease suicide risk. MDD in many patients can be chronic and reoccurring with medication and psychotherapy providing inadequate relief. METHODS: A pilot program was created to supply rTMS devices to 35 different sites in the VA nationwide in order to treat treatment-resistant depression. CONCLUSIONS: At time of analysis more than 950 veterans have started the program and 412 have finished. Nationwide, we have seen the depression scores decline, indicating an improvement in well-being. In addition, there is high patient satisfaction. Collecting data on a national level is a powerful way to examine rTMS efficacy and predictors of response which might be lost on a smaller subset of cases.

17.
Foot (Edinb) ; 41: 24-29, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31675597

RESUMO

BACKGROUND: The use of surface EMG (sEMG) to record muscle activity is common place yet due to restrictions in technology studies on the intrinsic foot muscles have been limited or only fine wire instruments have been used. AIM: This paper looks at the potential reliability of a sEMG protocol for assessing the intrinsic foot muscles. METHODS: Six intrinsic muscles were defined using ultrasound and muscle function testing. A protocol for sensor placement was created with repeatability and reliability testing of the protocol conducted by three separate testers on three subjects over two different time frames. Inter tester and Inter session repeatability and reliability was measured with ICC and percentage standard error of measurement. RESULTS: Although there was good correlation between Extensor Digitorum Brevis, Dorsal Interossei, Abductor Digiti Minimi and Flexor Digitorum Brevis there was increased variability and poor correlation for Flexor hallucis Brevis and Abductor Hallucis. The percentage standard error of measurement did not support the high ICC values indicating a lower precision of measurement. SIGNIFICANCE: Variability between testers and sessions shows an inconsistent reliability of sEMG and further work is required with protocols focussing on grouping muscles to improve the understanding of the intrinsic foot muscles.


Assuntos
Eletromiografia , Pé/fisiologia , Músculo Esquelético/fisiologia , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Músculo Esquelético/diagnóstico por imagem , Reprodutibilidade dos Testes , Ultrassonografia
18.
Psychol Serv ; 16(3): 415-424, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-30407050

RESUMO

Veterans returning from recent conflicts present with increased rates of posttraumatic stress disorder (PTSD), and veterans from prior service eras continue to seek trauma-based services. Peer support for veterans with PTSD has the potential to resolve ongoing challenges in access and engagement in mental health care. Assessing the value of peer support services requires a thorough understanding of the expected role and the empirical mechanisms of peer support participation in PTSD recovery. To better understand these mechanisms, this study interviewed 29 veteran participants from an established peer support program (PSP), located in the Central Valley of the Veterans Affairs (VA) Palo Alto Health Care System (VAPAHCS) in Northern California. A domain analysis of narrative transcripts generated 34 codes through a grounded theory method. Codes were organized into the following thematic categories: the perceived role of the PSP, supportive experiences of the PSP, global gains from the PSP, and limitations to PSP and further mental health engagement. These results were synthesized into a theoretical model that identifies improved functioning and reduced distress as the expected outcomes of PSP-mediated recovery and illustrates the continuum from in-group experiences to these outcomes. Our results suggest that PSP-mediated recovery is defined as acceptance of PTSD into daily life and identity, rather than resolution of symptoms. This conceptualization has implications for peer support provider training, PSP integration into health care settings, and future outcome analyses on the effectiveness of PSPs. (PsycINFO Database Record (c) 2019 APA, all rights reserved).


Assuntos
Aconselhamento , Grupo Associado , Apoio Social , Transtornos de Estresse Pós-Traumáticos/terapia , Veteranos/psicologia , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Modelos Teóricos , Pacientes Ambulatoriais , Aceitação pelo Paciente de Cuidados de Saúde , Transtornos de Estresse Pós-Traumáticos/psicologia , Estados Unidos , United States Department of Veterans Affairs
19.
PLoS One ; 14(7): e0217711, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31339895

RESUMO

Major ecological realignments are already occurring in response to climate change. To be successful, conservation strategies now need to account for geographical patterns in traits sensitive to climate change, as well as climate threats to species-level diversity. As part of an effort to provide such information, we conducted a climate vulnerability assessment that included all anadromous Pacific salmon and steelhead (Oncorhynchus spp.) population units listed under the U.S. Endangered Species Act. Using an expert-based scoring system, we ranked 20 attributes for the 28 listed units and 5 additional units. Attributes captured biological sensitivity, or the strength of linkages between each listing unit and the present climate; climate exposure, or the magnitude of projected change in local environmental conditions; and adaptive capacity, or the ability to modify phenotypes to cope with new climatic conditions. Each listing unit was then assigned one of four vulnerability categories. Units ranked most vulnerable overall were Chinook (O. tshawytscha) in the California Central Valley, coho (O. kisutch) in California and southern Oregon, sockeye (O. nerka) in the Snake River Basin, and spring-run Chinook in the interior Columbia and Willamette River Basins. We identified units with similar vulnerability profiles using a hierarchical cluster analysis. Life history characteristics, especially freshwater and estuary residence times, interplayed with gradations in exposure from south to north and from coastal to interior regions to generate landscape-level patterns within each species. Nearly all listing units faced high exposures to projected increases in stream temperature, sea surface temperature, and ocean acidification, but other aspects of exposure peaked in particular regions. Anthropogenic factors, especially migration barriers, habitat degradation, and hatchery influence, have reduced the adaptive capacity of most steelhead and salmon populations. Enhancing adaptive capacity is essential to mitigate for the increasing threat of climate change. Collectively, these results provide a framework to support recovery planning that considers climate impacts on the majority of West Coast anadromous salmonids.


Assuntos
Conservação dos Recursos Naturais , Ecossistema , Oncorhynchus mykiss/fisiologia , Salmão/fisiologia , Animais , California , Mudança Climática , Humanos , Oregon , Oceano Pacífico , Estações do Ano , Água do Mar , Temperatura
20.
Nat Ecol Evol ; 3(12): 1731-1742, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31768021

RESUMO

Males and females often differ in their fitness optima for shared traits that have a shared genetic basis, leading to sexual conflict. Morphologically differentiated sex chromosomes can resolve this conflict and protect sexually antagonistic variation, but they accumulate deleterious mutations. However, how sexual conflict is resolved in species that lack differentiated sex chromosomes is largely unknown. Here we present a chromosome-anchored genome assembly for rainbow trout (Oncorhynchus mykiss) and characterize a 55-Mb double-inversion supergene that mediates sex-specific migratory tendency through sex-dependent dominance reversal, an alternative mechanism for resolving sexual conflict. The double inversion contains key photosensory, circadian rhythm, adiposity and sex-related genes and displays a latitudinal frequency cline, indicating environmentally dependent selection. Our results show sex-dependent dominance reversal across a large autosomal supergene, a mechanism for sexual conflict resolution capable of protecting sexually antagonistic variation while avoiding the homozygous lethality and deleterious mutations associated with typical heteromorphic sex chromosomes.


Assuntos
Oncorhynchus mykiss , Animais , Feminino , Masculino , Fenótipo , Cromossomos Sexuais
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