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1.
Sci Total Environ ; 803: 150078, 2022 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-34525758

RESUMO

Influenza A viruses (IAVs) deposited by wild birds into the environment may lead to sporadic mortality events and economically costly outbreaks among domestic birds. There is a paucity of information, however, regarding the persistence of infectious IAVs within the environment following deposition. In this investigation, we assessed the persistence of 12 IAVs that were present in cloacal and/or oropharyngeal swabs of naturally infected ducks. Infectivity of these IAVs was monitored over approximately one year with each virus tested in five water types: (1) distilled water held in the lab at 4 °C and (2-5) filtered surface water from each of four Alaska sites and maintained in the field at ambient temperature. By evaluating infectivity of IAVs in ovo following sample retrieval at four successive time points, we observed declines in IAV infectivity through time. Many viruses persisted for extended periods, as evidenced by ≥25% of IAVs remaining infectious in replicate samples for each treatment type through three sampling time points (144-155 days post-sample collection) and two viruses remaining viable in a single replicate sample each when tested upon collection at a fourth time point (361-377 days post-sample collection). The estimated probability of persistence of infectious IAVs in all five water types was estimated to be between 0.25 and 0.75 during days 50-200 post-sample collection as inferred through Kaplan-Meier survival analysis. Our results provide evidence that IAVs may remain infectious for extended periods, up to or even exceeding one year, when maintained in surface waters under ambient temperatures. Therefore, wetlands may represent an important medium in which infectious IAVs may reside outside of a biotic reservoir.


Assuntos
Vírus da Influenza A , Influenza Aviária , Alaska/epidemiologia , Animais , Patos , Influenza Aviária/epidemiologia , Áreas Alagadas
2.
Am J Occup Ther ; 75(3)2021 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-34781340

RESUMO

Lung cancer claims more lives than any other cancer in the world and remains difficult to diagnose in the early stages. This article examines the current state of lung cancer detection and screening via low-dose computed tomography (LDCT) in Alaska and considers potential opportunities for occupational therapy practitioners in primary care settings. Medicare requires at least one documented shared decision-making encounter between provider and patient before LDCT lung cancer screening occurs. As a result of time constraints, documentation requirements, and the plethora of preventive health services they provide, primary care physicians often lack the time and training to conduct this essential service. This provides an opportunity for occupational therapy practitioners to perform these services as part of their practice and to play a role in this area as patient educators and prevention specialists in primary care settings. What This Article Adds: This article explores the national health crisis of lung cancer and describes how occupational therapists can participate in providing care in primary care settings.


Assuntos
Neoplasias Pulmonares , Terapia Ocupacional , Idoso , Alaska , Detecção Precoce de Câncer , Humanos , Neoplasias Pulmonares/diagnóstico , Medicare , Políticas , Estados Unidos
3.
PLoS One ; 16(9): e0258128, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34591944

RESUMO

Many animals migrate to take advantage of temporal and spatial variability in resources. These benefits are offset with costs like increased energetic expenditure and travel through unfamiliar areas. Differences in the cost-benefit ratio for individuals may lead to partial migration with one portion of a population migrating while another does not. We investigated migration dynamics and winter site fidelity for a long-distance partial migrant, barren ground caribou (Rangifer tarandus granti) of the Teshekpuk Caribou Herd in northern Alaska. We used GPS telemetry for 76 female caribou over 164 annual movement trajectories to identify timing and location of migration and winter use, proportion of migrants, and fidelity to different herd wintering areas. We found within-individual variation in movement behavior and wintering area use by the Teshekpuk Caribou Herd, adding caribou to the growing list of ungulates that can exhibit migratory plasticity. Using a first passage time-net squared displacement approach, we classified 78.7% of annual movement paths as migration, 11.6% as residency, and 9.8% as another strategy. Timing and distance of migration varied by season and wintering area. Duration of migration was longer for fall migration than for spring, which may relate to the latter featuring more directed movement. Caribou utilized four wintering areas, with multiple areas used each year. This variation occurred not just among different individuals, but state sequence analyses indicated low fidelity of individuals to wintering areas among years. Variability in movement behavior can have fitness consequences. As caribou face the pressures of a rapidly warming Arctic and ongoing human development and activities, further research is needed to investigate what factors influence this diversity of behaviors in Alaska and across the circumpolar Arctic.


Assuntos
Migração Animal/fisiologia , Rena , Estações do Ano , Alaska , Animais , Ecossistema , Feminino , Movimento , Telemetria
4.
J Invertebr Pathol ; 185: 107668, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34555364

RESUMO

Weathervane scallop, Patinopecten caurinus, the largest scallop species in the world, is distributed from northern California, U.S.A., to the Bering Sea, and is only commercially harvested in Alaska. The fishery is considered well managed by the State of Alaska (U.S.A) Department of Fish and Game (ADF&G) and federal government, with many precautionary measures in place to avoid overharvest. There have been episodic declines in some management areas due to unknown causes. Fishermen also encounter scallops with abnormal adductor muscles, a condition colloquially termed "weak meat", characterized by the retention of muscle when shucked, an obvious darkened discoloration, and/or an abnormal texture making the product unacceptable for marketing. A similar syndrome in Atlantic sea scallops, Placopecten magellanicus, described as "gray meat", occurs in the eastern U.S. and Canada, and proposed causes include senescence, loss of bioenergetics due to chronic infestations, or a synergism of these factors. Recently a severe apicomplexan infection was found to cause a gray meat condition in Iceland scallops, Chlamys islandica, and the collapse of that stock. This parasite was subsequently detected in Atlantic sea scallops with the gray meat condition off the U.S. East Coast. Studies that followed identified the parasite as Merocystis kathae, previously described from the common whelk, Buccinum undatum, more than 100 years ago. In 2015 Bering Sea fishermen reported weak meat in their catch, so samples were submitted to ADF&G for diagnosis. Adductor muscles from all affected scallops had many large foci of an apicomplexan associated with necrosis, fibrosis, and muscular atrophy. Given the reduced quality, marketability, and possibly fitness of affected scallops, we performed a survey to estimate prevalence, intensity, and geographic distribution of this apicomplexan in Alaskan weathervane scallops. We sampled 180 scallops, from individual beds within each of the three major geographically broad scallop areas in Alaska. Overall prevalence was about 82%, ranging from 69 to 100% by district. Overall mean infection intensity, based on the number of parasite foci/section, was about 9 (range of 5-29, by location), with scallops from the Bering Sea and Southwest Kodiak being most severely infected. Molecular analyses confirmed that the Alaskan parasite is M. kathae, i.e., the same apicomplexan that caused the collapse of Icelandic scallops and a suspected cause for gray meat and mass mortality of Atlantic sea scallops in northeast North America.


Assuntos
Coccídios/fisiologia , Parasitologia de Alimentos , Pectinidae/parasitologia , Alimentos Marinhos/parasitologia , Alaska , Animais
5.
Mar Pollut Bull ; 171: 112906, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34492562

RESUMO

Sampling was conducted in Port Valdez, the site of the Valdez marine oil terminal where crude oil is loaded onto tankers for ocean shipment, to characterize sediment polycyclic aromatic hydrocarbons (PAH) concentrations arising from discharge of treated ballast-water from 1989 to 2019. Sediment PAH concentrations have declined since 1991 due to technological improvements in ballast water treatment processes and reductions in the volume of water treated. Spatial variations are associated with water depth reflecting geological and oceanographic characteristics. Comparisons between uncorrected hydrocarbon (compatible with data from 1989 to 2002) and surrogate-corrected concentrations for 2003-2019 suggest minor influence by corrections on inferences. It appears that if reliable measurements are made, the number of analytes and surrogate corrections have minimal influence for characterizing the directions and strengths of spatial and temporal change like that observed in Port Valdez. At present, PAH concentrations in the study area represent low risk for ecological effects.


Assuntos
Hidrocarbonetos Policíclicos Aromáticos , Poluentes Químicos da Água , Alaska , Monitoramento Ambiental , Sedimentos Geológicos , Análise Multivariada , Hidrocarbonetos Policíclicos Aromáticos/análise , Poluentes Químicos da Água/análise
7.
Artigo em Inglês | MEDLINE | ID: mdl-34501677

RESUMO

In the United States, American Indian and Alaska Native (AI/AN) people are frequently under- or misrepresented in research and health statistics. A principal reason for this disparity is the lack of collaborative partnerships between researchers and tribes. There are hesitations from both academic Western scientists and tribal communities to establish new partnerships due to differences in cultural and scientific understanding, from data ownership and privacy to dissemination and project expansion. An infamous example is the mishandling of samples collected from the Havasupai Tribe by Arizona State University (ASU) scientists, leading to a legal battle between the tribe and ASU and ending in a moratorium of research with the Havasupai people. This paper will explore three successful and positive collaborations with a large and small tribe, including how the partnerships were established and the outcomes of the collaboration. In addition, the paper will provide perspective of what needs to be addressed by Western scientists if productive collaborations with tribal groups are to be established.


Assuntos
Nativos do Alasca , Pesquisa Participativa Baseada na Comunidade , Índios Norte-Americanos , Alaska , Humanos , Estados Unidos , Universidades
8.
PLoS One ; 16(8): e0255368, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34343192

RESUMO

Most of our knowledge on reproductive biology of gray whales dates back to scientific research conducted during commercial whaling in the late 1950s and 1960s. The goal of the present study was to provide updated insights on reproductive physiology of gray whales, using progesterone and testosterone as biomarkers. We measured hormone concentrations using enzyme immunoassay (EIA) techniques in blubber biopsies collected from 106 individual whales from March to November over a span of 12 years (2004-2016) between California and Alaska. We found testosterone concentrations in males to increase significantly with age (P = 0.03). Adult males showed significantly elevated testosterone concentrations when sampled in the fall compared to the summer (P = 0.01), likely indicating physiological preparation for mating. We measured testosterone concentrations in females of different age classes, but no statistical differences were found. We found significantly higher progesterone concentrations in pregnant females compared to non-pregnant females and adult males (P< 0.001), indicating progesterone is a valid biomarker for pregnancy in gray whales. Both female and male calves had elevated progesterone concentrations, suggesting maternal transfer via lactation. We fit a mixture of two normal distributions to progesterone data from all non-calf females to identify clusters of high and low progesterone and estimated the probability of being pregnant for whales of unknown reproductive status. With this approach we identified likely pregnant and non-pregnant animals. This study represents an important milestone on reproductive profiles in this population, that can be used to estimate more accurate and precise reproductive parameters to be used for better understanding population dynamics of gray whales.


Assuntos
Biomarcadores/metabolismo , Progesterona/metabolismo , Comportamento Sexual Animal/fisiologia , Testosterona/metabolismo , Baleias/fisiologia , Fatores Etários , Alaska , Animais , California , Feminino , Lactação/metabolismo , Masculino , Gravidez
9.
Int J Infect Dis ; 111: 130-137, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34419583

RESUMO

OBJECTIVES: This study describes the changes in lower respiratory tract infection (LRTI) rates from 1998 to 2014 among hospitalized American Indian/Alaska Native (AI/AN) adults residing in Alaska and other Indian Health Service (IHS) regions. METHODS: Age-adjusted hospital discharge rates and rate ratios were calculated from the IHS Direct and Contract Health Services Inpatient Dataset, IHS National Patient Information Reporting System for AI/AN adults ≥18 years, hospitalized at an IHS-operated, tribally operated, or contract hospital with an LRTI-associated diagnosis during 1998-2014. RESULTS: Overall, there were 13 733 LRTI-associated hospitalizations in Alaska (1998-2014), with an age-adjusted rate of 13.7/1000 adults. Among non-Alaska (non-AK) AI/AN, there were a total of 79 170 hospitalizations, with a rate of 8.6/1000 adults. In the pre-PCV7 and pre-PCV13 periods, LRTI rates were higher in Alaska (AK) AI/AN (12.4 and 14.1, respectively) when compared to non-AK AI/AN (10.1 and 9.1, respectively) (P < 0.0001). In the post-PCV7 and post-PCV13 periods, LRTI rates were also higher in AK (13.5 and 15.0, respectively) compared to non-AK (9.2 and 7.3, respectively) (P < 0.0001). CONCLUSIONS: Over the study period, a 26% increase in rates of LRTI among adult AI/AN residing in AK compared with a 38% decrease in rates among AI/AN residing in non-AK were observed. This disparity is likely due to a variety of factors such as tobacco use, crowding, etc. Strategies to reduce LRTI in AI/AN adults are needed.


Assuntos
Nativos do Alasca , Índios Norte-Americanos , Infecções Respiratórias , Adolescente , Adulto , Alaska/epidemiologia , Nativos Estadunidenses , Hospitalização , Humanos , Infecções Respiratórias/epidemiologia , Estados Unidos/epidemiologia , United States Indian Health Service
10.
MMWR Morb Mortal Wkly Rep ; 70(33): 1120-1123, 2021 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-34411078

RESUMO

Controlling the spread of SARS-CoV-2, the virus that causes COVID-19, in Alaska is challenging. Alaska includes many remote and isolated villages with small populations (ranging from 15 to >1,000 persons) that are accessible only by air from larger communities. Until rapid point-of-care testing became widely available, a primary challenge in the diagnosis of COVID-19 in rural Alaska was slow turnaround times for SARS-CoV-2 test results, attributable to the need to transport specimens to testing facilities. To provide more timely test results and isolation of cases, the Yukon Kuskokwim Health Corporation (YKHC) introduced Abbott BinaxNOW COVID-19 Ag rapid antigen test (BinaxNOW) on November 9, 2020, in the rural Yukon-Kuskokwim Delta region in southwestern Alaska. To evaluate the impact of implementing antigen testing, YKHC reviewed the results of 54,981 antigen and molecular tests for SARS-CoV-2 performed in the Yukon-Kuskokwim Delta during September 15, 2020-March 1, 2021. Introduction of rapid, point-of-care testing was followed by a more than threefold reduction in daily SARS-CoV-2 case rates during approximately 1 month before the introduction of COVID-19 vaccination. The median turnaround time for SARS-CoV-2 test results decreased by >30%, from 6.4 days during September 15-November 8, 2020, to 4.4 days during November 9, 2020-March 1, 2021 (p<0.001). Daily incidence decreased 65% after the introduction of BinaxNOW, from 342 cases per 100,000 population during the week of November 9 to 119 during the week of December 13 (p<0.001). These findings indicate that point-of-care rapid antigen testing can be a valuable tool in reducing turnaround times in rural communities where local access to laboratory-based nucleic acid amplification testing (NAAT) is not readily available and could thereby reduce transmission by facilitating rapid isolation of infected persons, contact tracing, and implementation of local mitigation strategies.


Assuntos
Teste Sorológico para COVID-19/estatística & dados numéricos , COVID-19/diagnóstico , População Rural , SARS-CoV-2/isolamento & purificação , Alaska/epidemiologia , Antígenos Virais , COVID-19/epidemiologia , Teste Sorológico para COVID-19/métodos , Humanos , SARS-CoV-2/imunologia , Fatores de Tempo
11.
J Acoust Soc Am ; 150(1): 145, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-34340468

RESUMO

Killer whales occur in the Arctic but few data exist regarding the ecotypes present. The calling behavior differs among ecotypes, which can be distinguished based on pulsed call type, call rate, and bandwidth. In this study, a passive acoustic recorder was deployed 75 km off Point Hope, Alaska, in the southeastern Chukchi Sea to identify which ecotypes were present. A total of 1323 killer whale pulsed calls were detected on 38 of 276 days during the summers (June-August) of 2013-2015. The majority of calls (n = 804, 61%) were recorded in 2013 with the most calls recorded in July (76% of total calls). The calls were manually grouped into six categories: multipart, downsweep, upsweep, modulated, single modulation, and flat. Most detections were flat (n = 485, 37%) or multipart calls (n = 479, 36%), which contained both high and low frequency components. Call comparisons with those reported in the published literature showed similarities with other transient populations in fundamental frequency contour point distribution and median frequency. This study provides the first comprehensive catalog of transient killer whale calls in this region as well as reports on previously undescribed calls.


Assuntos
Orca , Alaska , Animais , Regiões Árticas , Ecótipo , Vocalização Animal
12.
Nat Commun ; 12(1): 4780, 2021 08 06.
Artigo em Inglês | MEDLINE | ID: mdl-34362899

RESUMO

Globally, bird migration is occurring earlier in the year, consistent with climate-related changes in breeding resources. Although often attributed to phenotypic plasticity, there is no clear demonstration of long-term population advancement in avian migration through individual plasticity. Using direct observations of bar-tailed godwits (Limosa lapponica) departing New Zealand on a 16,000-km journey to Alaska, we show that migration advanced by six days during 2008-2020, and that within-individual advancement was sufficient to explain this population-level change. However, in individuals tracked for the entire migration (50 total tracks of 36 individuals), earlier departure did not lead to earlier arrival or breeding in Alaska, due to prolonged stopovers in Asia. Moreover, changes in breeding-site phenology varied across Alaska, but were not reflected in within-population differences in advancement of migratory departure. We demonstrate that plastic responses can drive population-level changes in timing of long-distance migration, but also that behavioral and environmental constraints en route may yet limit adaptive responses to global change.


Assuntos
Adaptação Fisiológica , Migração Animal/fisiologia , Aves/fisiologia , Charadriiformes/fisiologia , Alaska , Animais , Ásia , Cruzamento , Mudança Climática , Feminino , Masculino , Nova Zelândia , Estações do Ano
13.
Environ Int ; 156: 106767, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34425643

RESUMO

Particulate matter 2.5 (PM2.5) exposure induces oxidative stress associated with many negative health outcomes such as respiratory disorders, cardiovascular disease and neurodegenerative disease. Research shows that diet and exercise can improve antioxidant defense against oxidative stress. This study is the first to use an Arctic animal model to investigate the cumulative effects of two lifestyle interventions on the antioxidant response before, during, and after ambient PM 2.5 exposure from wildfire: antioxidant supplementation (Arthrospira platensis) and exercise. In a two-factorial, longitudinal design, this study divided sled dogs (n = 48) into four groups (exercise and supplemented, exercise, supplemented, and control) to (1) test the effects of a 30-day exercise and antioxidant supplementation protocol on antioxidant response; and (2) measure the antioxidant response of all groups during and after a natural wildfire event. Commercial assays for total antioxidant power (TAP) and the enzymatic antioxidant superoxide dismutase (SOD) were used as markers for antioxidant status and response. During the forest fire, SOD was increased 5- to 10-fold over pre/post-exposure levels in all groups suggesting an endogenous upregulation of defense systems in response to the acute environmental stress. TAP was lower in all groups at peak PM2.5 exposure compared to 48 h after peak exposure in all groups except the exercise alone group which may indicate that exercise offers improved endogenous defense.


Assuntos
Doenças Neurodegenerativas , Incêndios Florestais , Alaska , Animais , Cães , Material Particulado/análise , Material Particulado/toxicidade , Spirulina
14.
BMJ Open ; 11(8): e047162, 2021 08 27.
Artigo em Inglês | MEDLINE | ID: mdl-34452959

RESUMO

INTRODUCTION: Diet, shown to impact colorectal cancer (CRC) risk, is a modifiable environmental factor. Fibre foods fermented by gut microbiota produce metabolites that not only provide food for the colonic epithelium but also exert regulatory effects on colonic mucosal inflammation and proliferation. We describe methods used in a double-blinded, randomised, controlled trial with Alaska Native (AN) people to determine if dietary fibre supplementation can substantially reduce CRC risk among people with the highest reported CRC incidence worldwide. METHODS AND ANALYSES: Eligible patients undergoing routine screening colonoscopy consent to baseline assessments and specimen/data collection (blood, urine, stool, saliva, breath and colon mucosal biopsies) at the time of colonoscopy. Following an 8-week stabilisation period to re-establish normal gut microbiota post colonoscopy, study personnel randomise participants to either a high fibre supplement (resistant starch, n=30) or placebo (digestible starch, n=30) condition, repeating stool sample collection. During the 28-day supplement trial, each participant consumes their usual diet plus their supplement under direct observation. On day 29, participants undergo a flexible sigmoidoscopy to obtain mucosal biopsy samples to measure the effect of the supplement on inflammatory and proliferative biomarkers of cancer risk, with follow-up assessments and data/specimen collection similar to baseline. Secondary outcome measures include the impact of a high fibre supplement on the oral and colonic microbiome and biofluid metabolome. ETHICS AND DISSEMINATION: Approvals were obtained from the Alaska Area and University of Pittsburgh Institutional Review Boards and Alaska Native Tribal Health Consortium and Southcentral Foundation research review bodies. A data safety monitoring board, material transfer agreements and weekly study team meetings provide regular oversight throughout the study. Study findings will first be shared with AN tribal leaders, health administrators, providers and community members. Peer-reviewed journal articles and conference presentations will be forthcoming once approved by tribal review bodies. TRIAL REGISTRATION NUMBER: NCT03028831.


Assuntos
Nativos do Alasca , Neoplasias do Colo , Alaska , Neoplasias do Colo/prevenção & controle , Fibras na Dieta , Humanos , Ensaios Clínicos Controlados Aleatórios como Assunto
15.
Int J Circumpolar Health ; 80(1): 1961393, 2021 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-34350814

RESUMO

Low intake of fruits and vegetables and high intake of sugar-sweetened beverages persists as a public health concern in rural remote Alaska Native (AN) communities. Conducting key informant interviews with 22 storekeepers in 12 communities in the Yukon-Kuskokwim region of Alaska, we explored potential factors impeding or facilitating dietary change towards healthier food choices. We selected these sites as part of a multi-level intervention aimed at introducing more traditional AN subsistence foods, increasing fruit and vegetable intake, and decreasing SSB consumption among young children enrolled in Head Start (preschool) programmes (Clinicaltrials.gov #NCT03601299). Storekeepers in these communities agreed that seasonality and flight schedules were primary factors determining commercial foods' availability. Several storekeepers noted that federal food assistance programmes that specify which food items may be purchased with funds received from the programme and community policies that set limits on less healthy items promote customer purchases of healthier products. The fact that storekeepers are comfortable enforcing government assistance programme guidelines, company policies, and tribal resolutions suggests an important role storekeepers play in improving nutritional intake in their communities.


Assuntos
Frutas , Verduras , Alaska , Bebidas , Criança , Pré-Escolar , Dieta , Ingestão de Alimentos , Humanos , População Rural
16.
Proc Biol Sci ; 288(1957): 20211195, 2021 08 25.
Artigo em Inglês | MEDLINE | ID: mdl-34428964

RESUMO

The prevalence of disease-driven mass mortality events is increasing, but our understanding of spatial variation in their magnitude, timing and triggers are often poorly resolved. Here, we use a novel range-wide dataset comprised 48 810 surveys to quantify how sea star wasting disease affected Pycnopodia helianthoides, the sunflower sea star, across its range from Baja California, Mexico to the Aleutian Islands, USA. We found that the outbreak occurred more rapidly, killed a greater percentage of the population and left fewer survivors in the southern half of the species's range. Pycnopodia now appears to be functionally extinct (greater than 99.2% declines) from Baja California, Mexico to Cape Flattery, Washington, USA and exhibited severe declines (greater than 87.8%) from the Salish Sea to the Gulf of Alaska. The importance of temperature in predicting Pycnopodia distribution rose more than fourfold after the outbreak, suggesting latitudinal variation in outbreak severity may stem from an interaction between disease severity and warmer waters. We found no evidence of population recovery in the years since the outbreak. Natural recovery in the southern half of the range is unlikely over the short term. Thus, assisted recovery will probably be required to restore the functional role of this predator on ecologically relevant time scales.


Assuntos
Estrelas-do-Mar , Síndrome de Emaciação , Alaska , Animais , México/epidemiologia , Temperatura
17.
Appl Environ Microbiol ; 87(20): e0133921, 2021 09 28.
Artigo em Inglês | MEDLINE | ID: mdl-34347514

RESUMO

Permafrost soils store approximately twice the amount of carbon currently present in Earth's atmosphere and are acutely impacted by climate change due to the polar amplification of increasing global temperature. Many organic-rich permafrost sediments are located on large river floodplains, where river channel migration periodically erodes and redeposits the upper tens of meters of sediment. Channel migration exerts a first-order control on the geographic distribution of permafrost and floodplain stratigraphy and thus may affect microbial habitats. To examine how river channel migration in discontinuous permafrost environments affects microbial community composition, we used amplicon sequencing of the 16S rRNA gene on sediment samples from floodplain cores and exposed riverbanks along the Koyukuk River, a large tributary of the Yukon River in west-central Alaska. Microbial communities are sensitive to permafrost thaw: communities found in deep samples thawed by the river closely resembled near-surface active-layer communities in nonmetric multidimensional scaling analyses but did not resemble floodplain permafrost communities at the same depth. Microbial communities also displayed lower diversity and evenness in permafrost than in both the active layer and permafrost-free point bars recently deposited by river channel migration. Taxonomic assignments based on 16S and quantitative PCR for the methyl coenzyme M reductase functional gene demonstrated that methanogens and methanotrophs are abundant in older permafrost-bearing deposits but not in younger, nonpermafrost point bar deposits. The results suggested that river migration, which regulates the distribution of permafrost, also modulates the distribution of microbes potentially capable of producing and consuming methane on the Koyukuk River floodplain. IMPORTANCE Arctic lowlands contain large quantities of soil organic carbon that is currently sequestered in permafrost. With rising temperatures, permafrost thaw may allow this carbon to be consumed by microbial communities and released to the atmosphere as carbon dioxide or methane. We used gene sequencing to determine the microbial communities present in the floodplain of a river running through discontinuous permafrost. We found that the river's lateral movement across its floodplain influences the occurrence of certain microbial communities-in particular, methane-cycling microbes were present on the older, permafrost-bearing eroding riverbank but absent on the newly deposited river bars. Riverbank sediment had microbial communities more similar to those of the floodplain active-layer samples than permafrost samples from the same depth. Therefore, spatial patterns of river migration influence the distribution of microbial taxa relevant to the warming Arctic climate.


Assuntos
Microbiota , Pergelissolo/microbiologia , Rios/microbiologia , Alaska , Ciclo do Carbono , Movimentos da Água
18.
J Cancer Policy ; 292021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34395191

RESUMO

Background: Alaska Native (AN) people have the highest rates of colorectal cancer (CRC) globally. Increasing CRC screening has been effective in reducing CRC-related morbidity and mortality in other populations. Objective: To examine recent descriptive epidemiology and longer-term CRC trends among AN people. To determine any changes in the descriptive epidemiology of CRC among AN people concurrent with increases in screening prevalence. Methods: We estimated age-specific CRC incidence and mortality rates 2000-2017. To examine longer-term trends in incidence and mortality 1990-2017, we conducted Joinpoint regression analyses of three-year rolling average incidence and mortality rates. We calculated descriptive statistics for two time-periods: 2000-2008, and 2009-2017. Finally, we examined five-year survival probability. Results: CRC incidence increased over time (1990-2017) among AN people aged less than 50 years, while there were modest declines in AN people older than 50 years old since 2000. Overall, AN CRC mortality rates declined between 1990 and 2004, but have been increasing steadily since that time. Comparing 2000-2008 with 2009-2017 we observed no difference in CRC incidence and mortality, age at diagnosis, tumor size, tumor location, or stage distribution. Survival analyses indicated no change in hazard of death between 2004-2008 and 2009-2017 (HR 1.02, 95% CI: 0.74, 1.38, P = 0.93). Conclusions: Colorectal cancer prevention and control efforts across the Alaska Tribal Health System have not yet resulted in reduced mortality rates, or induced earlier stage migration. Policy Summary Statement: Intensified efforts will be necessary to reduce the burden of CRC among this high-risk population. Continued and increased focus on primary and secondary prevention efforts is warranted.


Assuntos
Nativos do Alasca/estatística & dados numéricos , Neoplasias Colorretais/epidemiologia , Detecção Precoce de Câncer , Mortalidade/tendências , Adulto , Idoso , Alaska/epidemiologia , Neoplasias Colorretais/diagnóstico , Feminino , Humanos , Incidência , Pessoa de Meia-Idade , Sistema de Registros/estatística & dados numéricos , Programa de SEER
19.
PLoS One ; 16(7): e0254097, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34214119

RESUMO

The relentless role of invasive species in the extinction of native biota requires predictions of ecosystem vulnerability to inform proactive management strategies. The worldwide invasion and range expansion of predatory northern pike (Esox lucius) has been linked to the decline of native fishes and tools are needed to predict the vulnerability of habitats to invasion over broad geographic scales. To address this need, we coupled an intrinsic potential habitat modelling approach with a Bayesian network to evaluate the vulnerability of five culturally and economically vital species of Pacific salmon (Oncorhynchus spp.) to invasion by northern pike. This study was conducted along 22,875 stream km in the Southcentral region of Alaska, USA. Pink salmon (O. gorbuscha) were the most vulnerable species, with 15.2% (2,458 km) of their calculated extent identified as "highly" vulnerable, followed closely by chum salmon (O. keta, 14.8%; 2,557 km) and coho salmon (O. kisutch, 14.7%; 2,536 km). Moreover, all five Pacific salmon species were highly vulnerable in 1,001 stream km of shared habitat. This simple to implement, adaptable, and cost-effective framework will allow prioritizing habitats for early detection and monitoring of invading northern pike.


Assuntos
Esocidae/fisiologia , Espécies Introduzidas , Oncorhynchus/fisiologia , Alaska , Animais , Teorema de Bayes , Ecossistema , Geografia , Atividades Humanas , Modelos Teóricos , Rios , Especificidade da Espécie
20.
PLoS One ; 16(7): e0254314, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34237085

RESUMO

The annual migration and spawning event of Pacific salmon (Oncorhynchus spp.) can lead to cross-boundary delivery of marine-derived nutrients from their carcasses into adjacent terrestrial ecosystems. The densities of some passerine species, including Pacific wrens (Troglodytes pacificus), have been shown to be positively correlated with salmon abundance along streams in Alaska and British Columbia, but mechanisms maintaining these densities remain poorly understood. Riparian areas near salmon streams could provide higher quality habitat for birds through greater food availability and more suitable vegetation structure for foraging and breeding, resulting in wrens maintaining smaller territories. We examined relationships between salmon biomass and Pacific wren territory size, competition, and habitat selection along 11 streams on the coast of British Columbia, Canada. We show that male wren densities increase and territory sizes decrease as salmon-spawning biomass increases. Higher densities result in higher rates of competition as male wrens countersing more frequently to defend their territories along streams with more salmon. Wrens were also more selective of the habitats they defended along streams with higher salmon biomass; they were 68% less likely to select low-quality habitat on streams with salmon compared with 46% less likely at streams without salmon. This suggests a potential trade-off between available high-quality habitat and the cost of competition that structures habitat selection. Thus, the marine-nutrient subsidies provided by salmon carcasses to forests lead to higher densities of wrens while shifting the economics of territorial defence toward smaller territories being defended more vigorously in higher quality habitats.


Assuntos
Aves/fisiologia , Salmão/fisiologia , Alaska , Animais , Biomassa , Colúmbia Britânica , Ecossistema , Florestas , Masculino , Oncorhynchus/fisiologia , Rios
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