617 research outputs found

    Mule Deer Impede Pando’s Recovery: Implications for Aspen Resilience from a Single-Genotype Forest

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    Aspen ecosystems (upland Populus-dominated forests) support diverse species assemblages in many parts of the northern hemisphere, yet are imperiled by common stressors. Extended drought, fire suppression, human development, and chronic herbivory serve to limit the sustainability of this keystone species. Here we assess conditions at a renowned quaking aspen (Populus tremuloides) grove—purportedly the largest living organism on earth—with ramifications for aspen biogeography globally. The “Pando” clone is 43 ha and estimated to contain 47,000 genetically identical aspen ramets. This iconic forest is threatened in particular by herbivory, and current management activities aim to reverse the potential for type conversion, likely to a non-forest state. We set out to gauge agents affecting recent deterioration through a network of monitoring plots and by examining a chronosequence of historic aerial photos to better understand the timing of putative departure from a sustainable course. Sixty-five permanent forest monitoring plots were located in three management regimes existing within Pando: no fencing, fencing with active and passive treatments, fencing with passive-only treatment. At each sample plot we measured live and dead mature trees, stem recruitment and regeneration, forest and shrub cover, browse level, and feces counts as a surrogate for ungulate presence. Ordination results indicate that aspen regeneration was the strongest indicator of overall forest conditions at Pando, and that mule deer (Odocoileus hemionus) presence strongly impacts successful regeneration. Additionally, fencing with active/passive treatments yielded the most robust regeneration levels; however, a fence penetrable by ungulates in the passive-only treatment most likely played a role in this outcome. The aerial photo sequence depicts various human intrusions over the past seven decades, but perhaps most telling, a decline in self-replacement beginning 30–40 years ago. Aspen communities in many locations in North American and Europe are impacted by unchecked herbivory. The Pando clone presents a unique opportunity for understanding browse mechanisms in a forest where tree genotype, closely aligned with growth and chemical defense, is uniform

    Human thrombin for the treatment of gastric and ectopic varices

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    AIM: To evaluate the efficacy of human thrombin in the treatment of bleeding gastric and ectopic varices. METHODS: Retrospective observational study in a Tertiary Referral Centre. Between January 1999-October 2005, we identified 37 patients who were endoscopically treated with human thrombin injection therapy for bleeding gastric and ectopic varices. Patient details including age, gender and aetiology of liver disease/segmental portal hypertension were documented. The thrombin was obtained from the Scottish National Blood Transfusion Service and prepared to give a solution of 250 IU/mL which was injected via a standard injection needle. All patient case notes were reviewed and the total dose of thrombin given along with the number of endoscopy sessions was recorded. Initial haemostasis rates, rebleeding rates and mortality were catalogued along with the incidence of any immediate complications which could be attributable to the thrombin therapy. The duration of follow up was also listed. The study was conducted according to the United Kingdom research ethics guidelines. RESULTS: Thirty-seven patients were included. 33 patients (89%) had thrombin (250 U/mL) for gastric varices, 2 (5.4%) for duodenal varices, 1 for rectal varices and 1 for gastric and rectal varices. (1) Gastric varices, an average of 15.2 mL of thrombin was used per patient. Re-bleeding occurred in 4 patients (10.8%), managed in 2 by a transjugular intrahepatic portosystemic shunt (TIPSS) (one unsuccessfully who died) and in other 2 by a distal splenorenal shunt; (2) Duodenal varices (or type 2 isolated gastric varices), an average of 12.5 mL was used per patient over 2-3 endoscopy sessions. Re-bleeding occurred in one patient, which was treated by TIPSS; and (3) Rectal varices, an average of 18.3 mL was used per patient over 3 endoscopy sessions. No re-bleeding occurred in this group. CONCLUSION: Human thrombin is a safe, easy to use and effective therapeutic option to control haemorrhage from gastric and ectopic varices

    Pando\u27s Lessons: Restoration of a Giant Aspen Clone

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    A 106 acre (43 ha) aspen clone lives in the Fishlake National Forest in south-central Utah. Clones are comprised of multiple aspen stems, called ramets, which are genetically identical. This particular colony of ramets was named “Pando” (Latin for “I spread”) by researchers believing it to be the largest living organism by mass on earth. Recently, forest managers have noted a rapid dying of mature stems without recruitment of younger trees. This unsustainable situation has galvanized restoration efforts at Pando. Human interventions caused this imbalance; restoration will rely on protection, monitoring, and innovation. As a laboratory, this forest icon may provide insights for much broader human-nature interactions

    New Hampshire Continental Shelf Geophysical Database: 2016-2017 Field Campaign – Seafloor Photographs

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    The New Hampshire Continental Shelf Geophysical Database: 2016-2017 Field Campaign – Seafloor Photographs” was developed by the University of New Hampshire (UNH) Center for Coastal and Ocean Mapping/Joint Hydrographic Center (CCOM/JHC). The field campaign was conducted to provide ground truth for surficial geology maps for the continental shelf off New Hampshire (NH) and focused on the inner shelf between the coast and the Isles of Shoals. Station locations were chosen where high-resolution bathymetry was available, including multibeam echosounder (MBES) surveys conducted by the UNH CCOM/JHC Hydrographic Field Course (Ocean Engineering 972), MBES surveys by the NOAA National Ocean Service (NOS), and a topo-bathy lidar (Shoals) survey by the United States Geological Survey (USGS) (see Ward et al., 2021c for details). In total, seafloor videography was collected at 151 stations and 855 photographs were extracted from the video. In addition, 150 sediment samples were collected from 85 of the stations and analyzed for grain size. The bottom sediment grain size data is available at the University of New Hampshire Scholars Repository (see Ward et al., 2021 https://dx.doi.org/10.34051/d/2021.2

    New Hampshire Continental Shelf Geophysical Database: 2016-2017 Field Campaign – Seafloor and Sample Photographs and Sediment Data

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    The New Hampshire Continental Shelf Geophysical Database: 2016-2017 Field Campaign - Seafloor and Sample Photographs and Sediment Data contains photographs of the seafloor from sampling locations, photographs of the sediment samples, and grain size data from a major field campaign conducted in 2016- 2017 and from the UNH Ocean Engineering 972 Hydrographic Field Course classes in 2012, 2014, and 2018. In total, sixteen one-day cruises provided 150 samples for grain size analysis. The database provides complete descriptions for each sample including identification, station and sample characteristics, sediment classifications, grain size statistics, and grain size distribution. Presented here are tables with the station locations and types of data available followed by single sample summaries for each sample collected and analyzed. Included in each summary are location information, seafloor photographs, photographs of the sample (in field and laboratory) where available, collection information, sediment classifications, grain size statistics, and grain size distribution. Samples were analyzed with standard sieve and pipette analyses after Folk (1980). The sediment grain size classifications include: CMECS (Coastal and Marine Ecological Classification Standard; FGDC, 2012); Gradistat (Blot and Pye, 2001); and Wentworth (Wentworth, 1922; described in Folk, 1954, 1980). Statistics are based on the phi scale and include the graphic mean, sorting, skewness, and kurtosis (Folk, 1980)

    Evolutionary instability of selfish learning in repeated games

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    Across many domains of interaction, both natural and artificial, individuals use past experience to shape future behaviors. The results of such learning processes depend on what individuals wish to maximize. A natural objective is one’s own success. However, when two such “selfish” learners interact with each other, the outcome can be detrimental to both, especially when there are conflicts of interest. Here, we explore how a learner can align incentives with a selfish opponent. Moreover, we consider the dynamics that arise when learning rules themselves are subject to evolutionary pressure. By combining extensive simulations and analytical techniques, we demonstrate that selfish learning is unstable in most classical two-player repeated games. If evolution operates on the level of long-run payoffs, selection instead favors learning rules that incorporate social (other-regarding) preferences. To further corroborate these results, we analyze data from a repeated prisoner’s dilemma experiment. We find that selfish learning is insufficient to explain human behavior when there is a trade-off between payoff maximization and fairness

    Trust and Risk Relationship Analysis on a Workflow Basis: A Use Case

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    Trust and risk are often seen in proportion to each other; as such, high trust may induce low risk and vice versa. However, recent research argues that trust and risk relationship is implicit rather than proportional. Considering that trust and risk are implicit, this paper proposes for the first time a novel approach to view trust and risk on a basis of a W3C PROV provenance data model applied in a healthcare domain. We argue that high trust in healthcare domain can be placed in data despite of its high risk, and low trust data can have low risk depending on data quality attributes and its provenance. This is demonstrated by our trust and risk models applied to the BII case study data. The proposed theoretical approach first calculates risk values at each workflow step considering PROV concepts and second, aggregates the final risk score for the whole provenance chain. Different from risk model, trust of a workflow is derived by applying DS/AHP method. The results prove our assumption that trust and risk relationship is implicit

    A rapid synthesis of evidence on whole systems approaches to obesity prevention to inform policy

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    © 2023 The Author(s) . Published by Oxford University Press on behalf of the European Public Health Association. This is an open-access meeting abstract distributed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International License (CC BY-NC), https://creativecommons.org/licenses/by-nc/4.0/Peer reviewe

    Fate and Transport of Per- and Polyfluoroalkyl Substances (PFAS) at Aqueous Film Forming Foam (AFFF) Discharge Sites: A Review

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    Per- and polyfluorinated alkyl substances (PFAS) are an environmentally persistent group of chemicals that can pose an imminent threat to human health through groundwater and surface water contamination. In this review, we evaluate the subsurface behavior of a variety of PFAS chemicals with a focus on aqueous film forming foam (AFFF) discharge sites. AFFF is the primary PFAS contamination risk at sites such as airports and military bases due to use as a fire extinguisher. Understanding the fate and transport of PFAS in the subsurface environment is a multifaceted issue. This review focuses on the role of adsorbent, adsorbate, and aqueous solution in the fate and transport of PFAS chemicals. Additionally, other hydrogeological, geochemical, ecological factors such as accumulation at air–water interfaces, subsurface heterogeneity, polyfluorinated PFAS degradation pathways, and plant interactions are discussed. This review also examines several case studies at AFFF discharge sites in order to examine if the findings are consistent with the broader PFAS literature. We present the most crucial future research directions and trends regarding PFAS and provide valuable insights into understanding PFAS fate and transport at AFFF discharge sites. We suggest a more comprehensive approach to PFAS research endeavors that accounts for the wide variety of environmental variables that have been shown to impact PFAS fate and transport

    Workplace harassment - a health issue: Anti-discrimination cases and work compensation claims

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    This article describes the adverse health-related effects of racial and sexual harassment elicited from files held by the Western Australian Equal Opportunity Commission where the complainant has nominated sexual or racial harassment as a ground of discrimination. Those results are compared with publicly available data on work-related stress claims obtained from the Compendium of Workers' Compensation Statistics Australia 2004-06, arising from allegations of harassment. Information gleaned from a survey of unreported court decisions (from publicly available legal data bases, such as www.austlii.edu.au and www.ohs.alert.com) is also reviewed. The purpose of examining this data is to consider the links between various forms of unlawful harassment, workplace stress and the evidence of adverse effect upon worker health. The results of this triangulation of data are consistent with that body of research which shows that workplace harassment can give rise to a range of adverse health outcomes. This paper explores how the inter-relationship of anti-discrimination and workers compensation laws may affect claimant behaviours
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