66 research outputs found

    Effects of Elevated Temperature and Carbon Dioxide on the Growth and Survival of Larvae and Juveniles of Three Species of Northwest Atlantic Bivalves

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    Rising CO2 concentrations and water temperatures this century are likely to have transformative effects on many coastal marine organisms. Here, we compared the responses of two life history stages (larval, juvenile) of three species of calcifying bivalves (Mercenaria mercenaria, Crassostrea virginica, and Argopecten irradians) to temperatures (24 and 28°C) and CO2 concentrations (∼250, 390, and 750 ppm) representative of past, present, and future summer conditions in temperate estuaries. Results demonstrated that increases in temperature and CO2 each significantly depressed survival, development, growth, and lipid synthesis of M. mercenaria and A. irradians larvae and that the effects were additive. Juvenile M. mercenaria and A. irradians were negatively impacted by higher temperatures while C. virginica juveniles were not. C. virginica and A. irradians juveniles were negatively affected by higher CO2 concentrations, while M. mercenaria was not. Larvae were substantially more vulnerable to elevated CO2 than juvenile stages. These findings suggest that current and future increases in temperature and CO2 are likely to have negative consequences for coastal bivalve populations

    Secondary Metabolites of Marine Microbes: From Natural Products Chemistry to Chemical Ecology

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    Marine natural products (MNPs) exhibit a wide range of pharmaceutically relevant bioactivities, including antibiotic, antiviral, anticancer, or anti-inflammatory properties. Besides marine macroorganisms such as sponges, algae, or corals, specifically marine bacteria and fungi have shown to produce novel secondary metabolites (SMs) with unique and diverse chemical structures that may hold the key for the development of novel drugs or drug leads. Apart from highlighting their potential benefit to humankind, this review is focusing on the manifold functions of SMs in the marine ecosystem. For example, potent MNPs have the ability to exile predators and competing organisms, act as attractants for mating purposes, or serve as dye for the expulsion or attraction of other organisms. A large compilation of literature on the role of MNPs in marine ecology is available, and several reviews evaluated the function of MNPs for the aforementioned topics. Therefore, we focused the second part of this review on the importance of bioactive compounds from crustose coralline algae (CCA) and their role during coral settlement, a topic that has received less attention. It has been shown that certain SMs derived from CCA and their associated bacteria are able to induce attachment and/or metamorphosis of many benthic invertebrate larvae, including globally threatened reef-building scleractinian corals. This review provides an overview on bioactivities of MNPs from marine microbes and their potential use in medicine as well as on the latest findings of the chemical ecology and settlement process of scleractinian corals and other invertebrate larvae

    Curve-Crossing Problems. I

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    Patients and nurses determine variation in adherence to guidelines at Dutch hospitals more than internists or settings.

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    Contains fulltext : 59148.pdf (publisher's version ) (Closed access)AIMS: To measure adherence to recently developed diabetes guidelines at Dutch hospital outpatient clinics and distinguish determinants for variations in care on hospital, internist and patient levels. METHODS: Thirteen general hospitals with 58 internists recruited 1950 diabetic patients. Data were extracted from medical files (n = 1915) and from patient questionnaires (n = 1465). Multilevel logistic regression analysis was performed to explain differences in adherence rates to the guidelines. RESULTS: Adherence to process measures was high, except for the examination of feet, calculation of the body mass index and patient education activities (the mean of 12 process measures was 64%). Adherence to intermediate outcome indicators was moderate. The mean percentage of patients with HbA(1c) < 7.0% was 23%. Adherence variation on a hospital level was very small (0.6-7.9%), on an internist level moderate (0.4-18.8%) and on a patient level high (74.4-98.8%). Adherence to all process measures and most of the intermediate outcome indicators was highest in the patients seen by a diabetes specialist nurse. DISCUSSION: More focus on patient involvement in diabetic care and the contribution of diabetes specialist nurses may be important factors in improving the quality of diabetes care

    Correcting misinformation about climate change: the impact of partisanship in an experimental setting

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    Misperceptions of the scientific consensus on climate change are an important problem in environmental policy. These misperceptions stem from a combination of ideological polarization and statements from prominent politicians who endorse information contradicting or misrepresenting the scientific consensus on climate change. Our study tests a source credibility theory of correction using different partisan sources of information in a survey experiment. We find that corrections from Republicans speaking against their partisan interest are most likely to persuade respondents to acknowledge and agree with the scientific consensus on anthropogenic climate change. The extent of these effects vary by the partisanship of the recipient. Our results suggest that the partisan gap on climate change can be reduced by highlighting the views of elite Republicans who acknowledge the scientific consensus on anthropogenic climate change
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