Abstract
Pronounced changes in the Arctic environment add a new potential driver of anomalous weather patterns in midlatitudes that affect billions of people. Recent studies of these ...Arctic/midlatitude weather linkages, however, state inconsistent conclusions. A source of uncertainty arises from the chaotic nature of the atmosphere. Thermodynamic forcing by a rapidly warming Arctic contributes to weather events through changing surface heat fluxes and large-scale temperature and pressure gradients. But internal shifts in atmospheric dynamics—the variability of the location, strength, and character of the jet stream, blocking, and stratospheric polar vortex (SPV)—obscure the direct causes and effects. It is important to understand these associated processes to differentiate Arctic-forced variability from natural variability. For example in early winter, reduced Barents/Kara Seas sea-ice coverage may reinforce existing atmospheric teleconnections between the North Atlantic/Arctic and central Asia, and affect downstream weather in East Asia. Reduced sea ice in the Chukchi Sea can amplify atmospheric ridging of high pressure near Alaska, influencing downstream weather across North America. In late winter southward displacement of the SPV, coupled to the troposphere, leads to weather extremes in Eurasia and North America. Combined tropical and sea ice conditions can modulate the variability of the SPV. Observational evidence for Arctic/midlatitude weather linkages continues to accumulate, along with understanding of connections with pre-existing climate states. Relative to natural atmospheric variability, sea-ice loss alone has played a secondary role in Arctic/midlatitude weather linkages; the full influence of Arctic amplification remains uncertain.
Women with atypical hyperplasia (AH) or lobular carcinoma in situ (LCIS) have a significantly increased risk of breast cancer, which can be substantially reduced with antiestrogen therapy for ...chemoprevention. However, antiestrogen therapy for breast cancer risk reduction remains underutilized. Improving knowledge about breast cancer risk and chemoprevention among high-risk patients and their healthcare providers may enhance informed decision-making about this critical breast cancer risk reduction strategy.
We are conducting a cluster randomized controlled trial to evaluate the effectiveness and implementation of patient and provider decision support tools to improve informed choice about chemoprevention among women with AH or LCIS. We have cluster randomized 26 sites across the U.S. through the SWOG Cancer Research Network. A total of 415 patients and 200 healthcare providers are being recruited. They are assigned to standard educational materials alone or combined with the web-based decision support tools. Patient-reported and clinical outcomes are assessed at baseline, after a follow-up visit at 6 months, and yearly for 5 years. The primary outcome is chemoprevention informed choice after the follow-up visit. Secondary endpoints include other patient-reported outcomes, such as chemoprevention knowledge, decision conflict and regret, and self-reported chemoprevention usage. Barriers and facilitators to implementing decision support into clinic workflow are assessed through patient and provider interviews at baseline and mid-implementation.
With this hybrid effectiveness/implementation study, we seek to evaluate if a multi-level intervention effectively promotes informed decision-making about chemoprevention and provide valuable insights on how the intervention is implemented in U.S. clinical settings.
NCT04496739
Coastal saltmarshes provide globally important ecosystem services including ‘blue carbon’ sequestration, flood protection, pollutant remediation, habitat provision and cultural value. Large portions ...of marshes have been lost or fragmented as a result of land reclamation, embankment construction, and pollution. Sea level rise threatens marsh survival by blocking landward migration where coastlines have been developed. Research-informed saltmarsh conservation and restoration efforts are helping to prevent further loss, yet significant knowledge gaps remain. Using a mixed methods approach, this paper identifies ten research priorities through an online questionnaire and a residential workshop attended by an international, multi-disciplinary network of 35 saltmarsh experts spanning natural, physical and social sciences across research, policy, and practitioner sectors. Priorities have been grouped under four thematic areas of research: Saltmarsh Area Extent, Change and Restoration Potential (including past, present, global variation), Spatio-social contexts of Ecosystem Service delivery (e.g. influences of environmental context, climate change, and stakeholder groups on service provisioning), Patterns and Processes in saltmarsh functioning (global drivers of saltmarsh ecosystem structure/function) and Management and Policy Needs (how management varies contextually; challenges/opportunities for management). Although not intended to be exhaustive, the challenges, opportunities, and strategies for addressing each research priority examined here, providing a blueprint of the work that needs to be done to protect saltmarshes for future generations.
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•Saltmarshes are key ecosystems for coastal biodiversity and ecosystem services.•Science-based evidence is needed for successful conservation and management.•An international, interdisciplinary network of saltmarsh experts was assembled.•10 top research priorities were identified for future saltmarsh research.
Structural variants (SVs) are known to play important roles in a variety of cancers, but their origins and functional consequences are still poorly understood. Many SVs are thought to emerge from ...errors in the repair processes following DNA double strand breaks (DSBs).
We used experimentally quantified DSB frequencies in cell lines with matched chromatin and sequence features to derive the first quantitative genome-wide models of DSB susceptibility. These models are accurate and provide novel insights into the mutational mechanisms generating DSBs. Models trained in one cell type can be successfully applied to others, but a substantial proportion of DSBs appear to reflect cell type-specific processes. Using model predictions as a proxy for susceptibility to DSBs in tumors, many SV-enriched regions appear to be poorly explained by selectively neutral mutational bias alone. A substantial number of these regions show unexpectedly high SV breakpoint frequencies given their predicted susceptibility to mutation and are therefore credible targets of positive selection in tumors. These putatively positively selected SV hotspots are enriched for genes previously shown to be oncogenic. In contrast, several hundred regions across the genome show unexpectedly low levels of SVs, given their relatively high susceptibility to mutation. These novel coldspot regions appear to be subject to purifying selection in tumors and are enriched for active promoters and enhancers.
We conclude that models of DSB susceptibility offer a rigorous approach to the inference of SVs putatively subject to selection in tumors.
Bone marrow transplantation (BMT) is an important therapeutic option for a variety of malignant and nonmalignant disorders. Unfortunately, BMT recipients are at increased risk of infection, and in ...particular, pulmonary complications occur frequently. Although the risk of infection is greatest during the neutropenic period immediately following transplant, patients are still vulnerable to pulmonary infections even after neutrophil engraftment. We evaluated the risk of infection in this postengraftment period by using a well-established mouse BMT model. Seven days after syngeneic BMT, B6D2F(1) mice are no longer neutropenic, and by 3 wk, they demonstrate complete reconstitution of the peripheral blood. However, these mice remain more susceptible throughout 8 wk to infection after intratracheal administration of Pseudomonas aeruginosa; increased mortality in the P. aeruginosa-infected BMT mice correlates with increased bacterial burden in the lungs as well as increased systemic dissemination. This heightened susceptibility to infection was not secondary to a defect in inflammatory cell recruitment to the lung. The inability to clear P. aeruginosa in the lung correlated with reduced phagocytosis of the bacteria by alveolar macrophages (AMs), but not neutrophils, decreased production of TNF-alpha by AMs, and decreased levels of TNF-alpha and IFN-gamma in the bronchoalveolar lavage fluid following infection. Expression of the beta(2) integrins CD11a and CD11c was reduced on AMs from BMT mice compared with wild-type mice. Thus, despite restoration of peripheral blood count, phagocytic defects in the AMs of BMT mice persist and may contribute to the increased risk of infection seen in the postengraftment period.
Influenza is a common respiratory pathogen causing both seasonal and pandemic disease. Influenza infection predisposes the host to secondary bacterial infection of the respiratory tract, which is a ...major cause of both morbidity and mortality in flu-related disease. In this review, we will discuss innate and adaptive antiviral responses during influenza infection, and review how these responses modulate protective immunity against secondary bacterial pathogens of the lung. Specific emphasis will be placed on implications of bacterial superinfection and mechanisms involved.
One consequence of recent Arctic warming is an increased
occurrence and longer seasonality of above-freezing air temperature
episodes. There is significant disagreement in the literature concerning
...potential physical connectivity between high-latitude open water duration
proximate to the Greenland Ice Sheet (GrIS) and late-season (i.e.,
end-of-summer and autumn) GrIS melt events. Here, a new date of sea ice
advance (DOA) product is used to determine the occurrence of Baffin Bay sea
ice growth along Greenland's west coast for the 2011–2015 period. Over the
2-month period preceding the DOA, northwest Atlantic Ocean and atmospheric
conditions are analyzed and linked to late-season melt events observed at a
series of on-ice automatic weather stations (AWSs) along the K-transect in
southwestern Greenland. Surrounding ice sheet, tundra, and coastal winds
from the Modèle Atmosphérique Régional (MAR) and Regional
Atmospheric Climate Model (RACMO) provide high-resolution spatial context to
AWS observations and are analyzed along with ERA-Interim reanalysis fields
to understand the meso-to-synoptic-scale (thermo)dynamic drivers of the melt
events. Results suggest that late-season melt events, which primarily occur
in the ablation area, are strongly affected by ridging atmospheric
circulation patterns that transport warm, moist air from the subpolar North Atlantic toward west Greenland. Increasing concentrations of North Atlantic
water vapor are shown to be necessary to produce melt conditions as autumn
progresses. While thermal conduction and advection off south Baffin Bay open waters impact coastal air temperatures, local marine air incursions are
obstructed by barrier flows and persistent katabatic winds along the western
GrIS margin.
The Arctic Andersen, J. K.; Andreassen, Liss M.; Baker, Emily H. ...
Bulletin of the American Meteorological Society,
08/2020, Letnik:
101, Številka:
8
Journal Article
Recenzirano
Odprti dostop
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Summer and autumn sea ice conditions in the Western Arctic have rapidly changed in recent years, while increases in lower tropospheric air temperature and moisture have concurrently been observed ...across much of the high northern latitudes during the autumn (October to December) and winter (January to March) months. However, the spatiotemporal relationships between this region's ice cover and North American climate are not particularly well understood. This study employs a synoptic climatological weather typing scheme known as the Spatial Synoptic Classification (SSC) to holistically evaluate temperature and moisture characteristics throughout the terrestrial North American Arctic (NAA) associated with the Western Arctic sea ice freezeup dates from 1979 to 2013. Monthly climatologies and linear trends of autumn/winter-dominant SSC weather types in the region, Moist Polar (MP) and Dry Polar (DP), are assessed and statistically linked to the freeze dates. Results suggest that the MP weather types are increasing, at the expense of DP types, across much of the domain. The apparent NAA transition to MP conditions is positively correlated with the timing of the Western Arctic freeze-up, and far more MP days occur during late-freeze versus early-freeze years, especially at the most northerly weather stations. Positive near-surface temperature anomalies and northerly low-level winds across the Western Arctic Ocean during late minus early freeze years potentially connect delayed ice formation to a changing NAA climate.
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