239 research outputs found

    Quantitative Validation of a Habitat Suitability Index for Oyster Restoration

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    Habitat suitability index (HSI) models provide spatially explicit information on the capacity of a given habitat to support a species of interest, and their prevalence has increased dramatically in recent years. Despite caution that the reliability of HSIs must be validated using independent, quantitative data, most HSIs intended to inform terrestrial and marine species management remain unvalidated. Furthermore, of the eight HSI models developed for eastern oyster (Crassostrea virginica) restoration and fishery production, none has been validated. Consequently, we developed, calibrated, and validated an HSI for the eastern oyster to identify optimal habitat for restoration in a tributary of Chesapeake Bay, the Great Wicomico River (GWR). The GWR harbors a high density, restored oyster population, and therefore serves as an excellent model system for assessing the validity of the HSI. The HSI was derived from GIS layers of bottom type, salinity, and water depth (surrogate for dissolved oxygen), and was tested using live adult oyster density data from a survey of high vertical relief reefs (HRR) and low vertical relief reefs (LRR) in the sanctuary network. Live adult oyster density was a statistically-significant sigmoid function of the HSI, which validates the HSI as a robust predictor of suitable oyster reef habitat for rehabilitation or restoration. In addition, HRR had on average 103–116 more adults m−2 than LRR at a given level of the HSI. For HRR, HSI ≥ 0.3 exceeded the accepted restoration target of 50 live adult oysters m−2. For LRR, the HSI was generally able to predict live adult oyster densities that meet or exceed the target at HSI ≥ 0.3. The HSI indicated that there remain large areas of suitable habitat for restoration in the GWR. This study provides a robust framework for HSI model development and validation, which can be refined and applied to other systems and previously developed HSIs to improve the efficacy of native oyster restoration

    Continuous-Flow Asymmetric Hydrogenation of the β-Keto Ester Methyl Propionylacetate in Ionic Liquid–Supercritical Carbon Dioxide Biphasic Systems

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    A continuous-flow process for the asymmetric hydrogenation of methyl propionylacetate as a prototypical β-keto ester in a biphasic system of ionic liquid and supercritical carbon dioxide (scCO2) is presented. An established ruthenium/2,2′-bis(diphenylphosphino)-1,1′-binaphthyl (BINAP) catalyst was immobilised in an imidazolium-based ionic liquid while scCO2 was used as mobile phase transporting reactants in and products out of the reactor. The use of acidic additives led to significantly higher reaction rates and enhanced catalyst stability albeit at slightly reduced enantioselectivity. High single pass conversions (>90%) and good enantioselectivity (80–82% ee) were achieved in the first 80 h. The initial catalyst activity was retained to 91% after 100 h and to 69% after 150 h time-on-stream, whereas the enantioselectivity remained practically constant during the entire process. A total turnover number of ∼21,000 and an averaged space-time yield (STYav) of 149 g L−1 h−1 were reached in a long-term experiment. No ruthenium and phosphorus contaminants could be detected via inductively coupled plasma optical emission spectrometry (ICP-OES) in the product stream and almost quantitative retention by the analysis of the stationary phase was confirmed. A comparison between batch-wise and continuous-flow operation on the basis of these data is provided

    Settlement, Growth, And Survival Of Eastern Oysters On Alternative Reef Substrates

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    Restoration of the native eastern oyster (Crassostrea virginica) has been severely hindered by the dwindling supply and rising costs of fossil and new oyster shell (OS) for use in reef restoration. Consequently, emphasis has shifted to the use of alternative oyster reef materials, which need to be tested for their effectiveness as settlement substrate. Furthermore, low recruitment of wild larvae has also impeded restoration, indicating a need to assess the potential of field setting of cultured larvae. We experimentally examined oyster settlement, growth and survival on unconsolidated OS, vertically embedded oyster shell (ES) in concrete, and concrete Oyster Castles (OC) in field and mesocosm experiments. In addition, we examined settlement success of cultured larvae in the mesocosm experiment. In the field experiment, juvenile recruitment was 3 higher on castles and unconsolidated shell than on embedded shell. Castles retained 4Xthe number of oysters and hosted 5Xthe biomass than embedded shell, and retained 1.5Xthe oysters and hosted 3Xthe biomass than unconsolidated shell. The proportion of live oyster recruits on castles was 1.5Xthat on both embedded and unconsolidated shell. In the mesocosm experiment (90-d postlarval deployment), the castles recruited, retained, and hosted an oyster biomass 4Xhigher than that of unconsolidated and embedded shell. This study confirms that artificial reef materials, such as OC, are suitable alternative substrates for oyster restoration, and remote setting of larvae can be effective under controlled environmental conditions. Future restoration efforts should consider use of alternative reef substrates and field setting of larvae, where recruitment is limited, to maximize oyster recruitment, while simultaneously minimizing the cost of reef restoration

    Preoperative Cognitive Impairment and Postoperative Delirium Predict Decline in Activities of Daily Living after Cardiac Surgery-A Prospective, Observational Cohort Study.

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    Cardiac surgery and subsequent treatment in the intensive care unit (ICU) has been shown to be associated with functional decline, especially in elderly patients. Due to the different assessment tools and assessment periods, it remains yet unclear what parameters determine unfavorable outcomes. This study sought to identify risk factors during the entire perioperative period and focused on the decline in activity of daily living (ADL) half a year after cardiac surgery. Follow-ups of 125 patients were available. It was found that in the majority of patients (60%), the mean ADL declined by 4.9 points (95% CI, -6.4 to -3.5; p < 0.000). In the "No decline" -group, the ADL rose by 3.3 points (2.0 to 4.6; p < 0.001). A multiple regression analysis revealed that preoperative cognitive impairment (MMSE ≤ 26; Exp(B) 2.862 (95%CI, 1.192-6.872); p = 0.019) and duration of postoperative delirium ≥ 2 days (Exp(B) 3.534 (1.094-11.411); p = 0.035) was independently associated with ADL decline half a year after the operation and ICU. Of note, preoperative ADL per se was neither associated with baseline cognitive function nor a risk factor for functional decline. We conclude that the preoperative assessment of cognitive function, rather than functional assessments, should be part of risk stratification when planning complex cardiosurgical procedures

    Psychometric Evaluation of the German Version of the Demoralization Scale-II and the Association Between Demoralization, Sociodemographic, Disease- and Treatment-Related Factors in Patients With Cancer

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    Objective: To test the psychometric properties, internal consistency, dimensional structure, and convergent validity of the German version of the Demoralization Scale- II (DS-II), and to examine the association between demoralization, sociodemographic, disease- and treatment-related variables in patients with cancer. Methods: We recruited adult patients with cancer at a Psychosocial Counseling Center and at oncological wards. Participants completed the 16-item DS-II, Patient Health Questionnaire-9 (PHQ-9), Generalized Anxiety Disorder Screener-2 (GAD-2), Distress Thermometer (DT), and Body Image Scale (BIS). We analyzed internal consistency of the DS-II using Cronbach‘s Alpha (a). We tested the dimensional structure of the DS-II with Confirmatory Factor Analyses (CFA). Convergent validity was expressed through correlation coefficients with established measures of psychological distress. The associations between demoralization, sociodemographic, disease- and treatmentrelated variables were examined with ANOVAs. Results: Out of 942 eligible patients, 620 participated. The average DS-II total score was M = 5.78, SD = 6.34, the Meaning and Purpose subscale M = 2.20, SD = 3.20, and the Distress and Coping Ability subscale M = 3.58, SD = 3.45. Internal consistency ranged from high to excellent with a = 0.93 for the DS-II total scale, a = 0.90 for the Meaning and Purpose subscale, and a = 0.87 for the Distress and Coping Ability subscale. The one-factor and the two-factor model yielded similar model fits, with CFI and TLI ranging between 0.910 and 0.933, SRMR < 0.05. The DS-II correlated significantly with depression (PHQ-9: r = 0.69), anxiety (GAD-2: r = 0.72), mental distress (DT: r = 0.36), and body image disturbance (BIS: r = 0.58). High levels of demoralization were reported by patients aged between 18 and 49 years (M = 7.77, SD = 6.26), patients who were divorced/separated (M = 7.64, SD = 7.29), lung cancer patients (M = 9.29, SD = 8.20), and those receiving no radiotherapy (M = 7.46, SD = 6.60). Conclusion: The DS-II has very good psychometric properties and can be recommended as a reliable tool for assessing demoralization in patients with cancer. The results support the implementation of a screening for demoralization in specific risk groups due to significantly increased demoralization scores

    Using existing infrastructure as ground control points to support citizen science coastal UAS monitoring programs

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    Recent publications have described the ability of citizen scientists to conduct unoccupied aerial system (UAS) flights to collect data for coastal management. Ground control points (GCPs) can be collected to georeference these data, however collecting ground control points require expensive surveying equipment not accessible to citizen scientists. Instead, existing infrastructure can be used as naturally occurring ground control points (NGCPs), although availably of naturally occurring ground control point placement on such infrastructure differs from published best practices of ground control point placement. This study therefore evaluates the achievable accuracy of sites georeferenced with naturally occurring ground control points through an analysis of 20 diverse coastal sites. At most sites naturally occurring ground control points produced horizontal and vertical root mean square errors (RMSE) less than 0.060 m which are similar to those obtained using traditional ground control points. To support future unoccupied aerial system citizen science coastal monitoring programs, an assessment to determine the optimal naturally occurring ground control point quantity and distribution was conducted for six coastal sites. Results revealed that generally at least seven naturally occurring ground control points collected in the broadest distribution across the site will result in a horizontal and vertical root mean square errors less than 0.030 m and 0.075 m respectively. However, the relationship between these placement characteristics and root mean square errors was poor, indicating that georeferencing accuracy using naturally occurring ground control points cannot be optimized solely through ideal quantity and distribution. The results of these studies highlight the value of naturally occurring ground control points to support unoccupied aerial system citizen science coastal monitoring programs, however they also indicate a need for an initial accuracy assessment of sites surveyed with naturally occurring ground control points at the onset of such programs

    Non-chaotic dynamics in general-relativistic and scalar-tensor cosmology

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    In the context of scalar-tensor models of dark energy and inflation, the dynamics of vacuum scalar-tensor cosmology are analysed without specifying the coupling function or the scalar field potential. A conformal transformation to the Einstein frame is used and the dynamics of general relativity with a minimally coupled scalar field are derived for a generic potential. It is shown that the dynamics are non-chaotic, thus settling an existing debate.Comment: 20 pages, LaTeX, to appear in Class. Quantum Gra

    Restoring shellfish reefs: Global guidelines for practitioners and scientists

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    Widespread global declines in shellfish reefs (ecosystem-forming bivalves such as oysters and mussels) have led to growing interest in their restoration and protection. With restoration projects now occurring on four continents and in at least seven countries, global restoration guidelines for these ecosystems have been developed based on experience over the past two decades. The following key elements of the guidelines are outlined: (a) the case for shellfish reef resto- ration and securing financial resources; (b) planning, feasibility, and goal set- ting; (c) biosecurity and permitting; (d) restoration in practice; (e) scaling up from pilot to larger scale restoration, (f) monitoring, (g) restoration beyond oyster reefs (specifically mussels), and (h) successful communication for shell- fish reef restoration projects
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