48 research outputs found

    An Ecogeomorphic Model to Assess the Response of Padilla Bay\u27s Eelgrass Habitat to Sea Level Rise

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    Estuaries worldwide are facing the possibility of conversion to open water if accretion cannot keep pace with increasing rates of sea level rise. Recent research into sediment elevation dynamics in Padilla Bay, a National Estuarine Research Reserve in Puget Sound, has revealed a mean bay-wide elevation deficit of -0.37 cm yr-1 since 2002. However, a more mechanistic prediction of the estuary’s response to future sea level rise should also incorporate non-linear feedback mechanisms between water depth, plant growth, and sediment deposition. Therefore, I used measurements of sediment accretion rates, suspended sediment concentrations, eelgrass stem density, and above- and belowground eelgrass biomass to build and calibrate a marsh equilibrium model (MEM), developed elsewhere but applied here for the first time to this eelgrass-dominated intertidal habitat. I then coupled the MEM with a relative elevation model (REM), which has previously been applied here, to create a hybrid that combines each model’s strengths in mechanistically simulating above- and belowground processes, respectively. The model predicts elevation change under various scenarios of sea level rise and suspended sediment concentrations. I used a 12-year elevation change dataset obtained from an extensive surface elevation table (SET) network in Padilla Bay for model validation. Field measurements indicated sediment accretion rates to be primarily determined by eelgrass stem density instead of biomass or relative elevation. I modified the hybrid model to reflect this relationship, which differentiates it from its predecessors. The model validation exercise revealed the need for an erosion parameter, without which projected relative elevation gain was substantially overestimated. Model projections without erosion showed an increase in relative elevation over much of the bay’s elevation gradient over a 100-year timeframe, reaching an equilibrium at an elevation where Zostera japonica stem density is maximized. These scenarios would involve an increase in Z. japonica cover in Padilla Bay, and a decrease in Z. marina cover. In contrast, model projections with erosion revealed a loss in relative elevation along the entire elevation gradient for all but the most conservative sea level rise scenario. The magnitude of loss was predicted to be greater at higher elevations. The suspended sediment concentrations required for the bay to maintain a stable relative elevation were higher than the current concentration of 3.93 mg L-1 for all sea level rise scenarios, with up to 15 mg L-1 being required for the most extreme scenario

    Coastal Blue Carbon Opportunity Assessment for Snohomish Estuary: The Climate Benefits of Estuary Restoration

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    This report presents the findings of a groundbreaking study that confirms the climate mitigation benefits of restoring tidal wetland habitat in the Snohomish Estuary, located within the nation's second largest estuary: Puget Sound. The study, the first of its kind, finds major climate mitigation benefits from wetland restoration and provides a much needed approach for assessing carbon fluxes for historic drained and future restored wetlands which can now be transferred and applied to other geographie

    Carbon Sequestration in a Pacific Northwest Eelgrass (Zostera marina) Meadow

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    Coastal wetlands are known to be efficient carbon sinks due to high rates of primary productivity, carbon burial by mineral sediments, and low rates of sediment organic matter decomposition. Of the three coastal wetland types: tidal marshes, tidal forests, and seagrass meadows, carbon burial by seagrasses is relatively under-studied, and reported rates range widely from 45 to 190 g C m-2 yr-1. Additionally, most of these seagrass rates are biased toward tropical and subtropical species, particularly Posidonia oceanica, with few focused on Zostera marina, the most widespread species in the northern hemisphere. We measured sediment organic content, carbon content, and long-term accretion rates to estimate organic carbon stocks and sequestration rates for a Z. marina meadow in Padilla Bay, a National Estuarine Research Reserve in Washington. We found rates of carbon sequestration to be quite low relative to commonly reported values, averaging 9 to 11 g C m-2 yr-1. We attribute this to both low sediment organic content and low rates of accretion. We postulate here that Padilla Bay\u27s low carbon sequestration capacity may be representative of healthy Z. marinameadows rather than an anomaly, and that Z. marina meadows have an inherently low carbon sequestration capacity because of the species\u27 low tolerance for suspended sediment (which limits light availability) and sediment organic content (which leads to toxic sulfide levels). Further research should focus on measuring carbon sequestration rates from other Z. marina meadows, particularly from sites that exhibit, a priori, the potential for higher rates of carbon sequestration

    Teilhabe am Arbeitsleben durch Andere Leistungsanbieter

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    Für Menschen mit Behinderungen stellt der Zugang zum allgemeinen Arbeitsmarkt eine hohe, vielfach nicht zu überwindende Hürde dar. Um dies zu kompensieren, besteht ein Rechtsanspruch auf Leistungen zur Teilhabe am Arbeitsleben nach SGB IX. Das Bundesteilhabegesetz (BTHG) ergänzt diesen Anspruch mit der Maßnahme „Andere Leistungsanbieter“ (aLA) (§ 60 SGB IX). Dadurch ist eine neue Möglichkeit entstanden, die für Menschen mit dauerhafter Erwerbsminderung den Zugang zum Arbeitsleben erweitern und flexibilisieren soll. Einschätzungen zu dieser Maßnahme beschreibt dieser Beitrag, in dem empirische Ergebnisse der Autorenschaft einfließen. (DIPF/Orig.

    Introduction

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    Introduction to the assessing, planning and adapting to climate change Impacts in Skagit River watershed session of the Salish Sea Conference

    Measurement and data transmission validity of a multi-biosensor system for real-time remote exercise monitoring among cardiac patients

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    Background: Remote telemonitoring holds great potential to augment management of patients with coronary heart disease (CHD) and atrial fibrillation (AF) by enabling regular physiological monitoring during physical activity. Remote physiological monitoring may improve home and community exercise-based cardiac rehabilitation (exCR) programs and could improve assessment of the impact and management of pharmacological interventions for heart rate control in individuals with AF.Objective: Our aim was to evaluate the measurement validity and data transmission reliability of a remote telemonitoring system comprising a wireless multi-parameter physiological sensor, custom mobile app, and middleware platform, among individuals in sinus rhythm and AF.Methods: Participants in sinus rhythm and with AF undertook simulated daily activities, low, moderate, and/or high intensity exercise. Remote monitoring system heart rate and respiratory rate were compared to reference measures (12-lead ECG and indirect calorimeter). Wireless data transmission loss was calculated between the sensor, mobile app, and remote Internet server.Results: Median heart rate (-0.30 to 1.10 b∙min-1) and respiratory rate (-1.25 to 0.39 br∙min-1) measurement biases were small, yet statistically significant (all P≤.003) due to the large number of observations. Measurement reliability was generally excellent (rho=.87-.97, all P<.001; intraclass correlation coefficient [ICC]=.94-.98, all P<.001; coefficient of variation [CV]=2.24-7.94%), although respiratory rate measurement reliability was poor among AF participants (rho=.43, P<.001; ICC=.55, P<.001; CV=16.61%). Data loss was minimal (<5%) when all system components were active; however, instability of the network hosting the remote data capture server resulted in data loss at the remote Internet server during some trials.Conclusions: System validity was sufficient for remote monitoring of heart and respiratory rates across a range of exercise intensities. Remote exercise monitoring has potential to augment current exCR and heart rate control management approaches by enabling the provision of individually tailored care to individuals outside traditional clinical environments

    Variable marsh resilience to stress offers clues to climate change adaptive management

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    In Puget Sound’s Stillaguamish estuary, tidal marshes exhibit evidence of multiple stressors that affect their vulnerability and provide insight into adaptive management opportunities to enhance their resilience. Despite high accretion rates, some marsh areas have receded by 10m/yr since 1964. Sources of stress include overgrazing by snow geese, high soil salinities, insect attacks, and changes in flow and inundation patterns. These interact with winter vegetation structure, sediment composition, and wave exposure to result in spatially variable marsh resilience. Some marshes are receding quickly, some slowly, and others are minimally affected. In the context of climate change, with potentially substantial near-term salinity changes due to summer low flow projections, and likely changes in sediment dynamics, it is critical to identify how marshes will respond, and develop adaptive management actions to increase resilience. Geese consume the rhizomes of four dominant bulrushes, and loosen the soil during winter storm season. Each bulrush species has different winter structural characteristics that affect grazing vulnerability, and the ability to trap sediment and attenuate erosive wave energy. Coarser sediments affect grazing intensity, being more difficult for geese bills to probe. Sediment and soil salinity affect plant density and height. During summer 2015, a harbinger for coming decades, twice-normal soil salinities resulted in stunted marsh that failed to flower. Finally, small differences in winter wave exposure affect marsh susceptibility to erosion after heavy grazing. With spatially variable marsh resilience to stress, potential adaptive management responses should similarly vary. Responses could include, among others, restoration to improve freshwater connectivity, sediment addition in restored areas to shift them above erosion thresholds or to target grazing-resistant bulrush species, snow goose population management or behavior modification, manipulation of soil particle size with sediment addition, and strategic use of logjams and sediment addition to reduce wave energy

    Screening for left ventricular hypertrophy in patients with type 2 diabetes mellitus in the community

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    <p>Abstract</p> <p>Background</p> <p>Left ventricular hypertrophy (LVH) is a strong predictor of cardiovascular disease and is common among patients with type 2 diabetes. However, no systematic screening for LVH is currently recommended for patients with type 2 diabetes. The purpose of this study was to determine whether NT-proBNP was superior to 12-lead electrocardiography (ECG) for detection of LVH in patients with type 2 diabetes.</p> <p>Methods</p> <p>Prospective cross-sectional study comparing diagnostic accuracy of ECG and NT-proBNP for the detection of LVH among patients with type 2 diabetes. Inclusion criteria included having been diagnosed for > 5 years and/or on treatment for type 2 diabetes; patients with Stage 3/4 chronic kidney disease and known cardiovascular disease were excluded. ECG LVH was defined as either the Sokolow-Lyon or Cornell voltage criteria. NT-proBNP level was measured using the Roche Diagnostics Elecsys assay. Left ventricular mass was assessed from echocardiography. Receiver operating characteristic curve analysis was carried out and area under the curve (AUC) was calculated.</p> <p>Results</p> <p>294 patients with type 2 diabetes were recruited, mean age 58 (SD 11) years, BP 134/81 ± 18/11 mmHg, HbA<sub>1c </sub>7.3 ± 1.5%. LVH was present in 164 patients (56%). In a logistic regression model age, gender, BMI and a history of hypertension were important determinants of LVH (p < 0.05). Only 5 patients with LVH were detected by either ECG voltage criteria. The AUC for NT-proBNP in detecting LVH was 0.68.</p> <p>Conclusions</p> <p>LVH was highly prevalent in asymptomatic patients with type 2 diabetes. ECG was an inadequate test to identify LVH and while NT-proBNP was superior to ECG it remained unsuitable for detecting LVH. Thus, there remains a need for a screening tool to detect LVH in primary care patients with type 2 diabetes to enhance risk stratification and management.</p

    Three birds with one stone: Tidal wetland restoration, carbon sequestration, and enhancing resilience to rising sea levels in the Snohomish River Estuary, Washington

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    Recent attention has focused on exploring the carbon storage and sequestration values of tidal wetlands to mitigate greenhouse gas emissions. Efforts are now underway to develop the tools and refine the science needed to bring carbon markets to bear on tidal wetland restoration activities. Effective restoration not only maximizes carbon storage in former tidal wetlands but also, through the accumulation of organic and mineral matter, enhances these systems’ resilience to rising sea levels. To this end, this project focuses on the Snohomish River estuary of the Puget Sound, Washington, which offers a continuum of diked and un-diked wetlands including seasonal floodplains, open mudflats, mature and tidal forests, and salt marsh habitats. In addition, there is strong restoration potential in a suite of ongoing and proposed projects. We report here on the carbon storage pools, long-term sediment accretion rates (100 years), and estimated rates of carbon storage, derived from sediment cores collected at representative sites within the Snohomish estuary during the spring and summer of 2013. We found that natural wetlands (open to tidal exchange and riverine inputs) were accreting at rates that equaled or exceeded current rates of eustatic sea level rise, while formerly, or currently diked wetlands (closed to such exchanges and inputs) revealed marked evidence of subsidence. Restored sites showed evidence of both high rates of sediment accretion (1.61 cm/year) and carbon storage (352 g C/m2/year)

    Convalescent troponin and cardiovascular death following acute coronary syndrome

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    Objectives: High-sensitivity cardiac troponin testing is used in the diagnosis of acute coronary syndromes but its role during convalescence is unknown. We investigated the long-term prognostic significance of serial convalescent high-sensitivity cardiac troponin concentrations following acute coronary syndrome. Methods: In a prospective multicentre observational cohort study of 2140 patients with acute coronary syndrome, cardiac troponin I concentrations were measured in 1776 patients at 4 and 12 months following the index event. Patients were stratified into three groups according to the troponin concentration at 4 months using the 99th centile (women&gt;16 ng/L, men&gt;34 ng/L) and median concentration of those within the reference range. The primary outcome was cardiovascular death. Results: Troponin concentrations at 4 months were measurable in 99.0% (1759/1776) of patients (67±12 years, 72% male), and were ≤5 ng/L (median) and &gt;99th centile in 44.8% (795) and 9.3% (166), respectively. There were 202 (11.4%) cardiovascular deaths after a median of 4.8 years. After adjusting for the Global Registry of Acute Coronary Events score, troponin remained an independent predictor of cardiovascular death (HR 1.4, 95% CI 1.3 to 1.5 per doubling) with the highest risk observed in those with increasing concentrations at 12 months. Patients with 4-month troponin concentrations &gt;99th centile were at increased risk of cardiovascular death compared with those ≤5 ng/L (29.5% (49/166) vs 4.3% (34/795); adjusted HR 4.9, 95% CI 3.8 to 23.7). Conclusions: Convalescent cardiac troponin concentrations predict long-term cardiovascular death following acute coronary syndrome. Recognising this risk by monitoring troponin may improve targeting of therapeutic interventions
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