Latitudinal variation in life-cycle characteristics of Potamogeton pectinatus L.: vegetative growth and asexual reproduction

Across latitudinal gradients, environmental conditions that influence plant growth and reproduction largely change. Here we study clonal variation in life-cycle characteristics of the cosmopolitan water plant Potamogeton pectinatus L. across a broad latitudinal range. Two consecutive experiments were performed under standardised laboratory conditions (photoperiod, irradiance and temperature). In the first experiment we investigated asexual reproduction among fifteen clones, obtained from latitudes ranging from 24 to 68° N. After 90 days of growth, high-latitude clones produced more but smaller tubers, while the aboveground biomass was lower as compared to the clones obtained from low latitudes. In a second experiment we studied inherent differences in early growth, morphology and photosynthesis for eleven clones (obtained from the same latitudinal range as in experiment 1). We found high among clonal variation for most measured variables, but the number of latitude-correlated traits was limited. The only trait that correlated with latitude was the number of leaves per plant, which increased in clones from higher latitudes. Our results agree with the hypothesis of a latitude-correlated switch in life-cycle strategy for this species. For northern clones this results in a short life-cycle, with an early and high investment in tuber biomass, while for low latitude clones the length of the life-cycle is prolonged, with a delayed reproduction and increased total plant biomass. [KEYWORDS: Asexual reproduction, Growth rate, Latitude, Morphology, Photosynthesis

Unknown Risks: Parental Hesitation about Vaccination.

OBJECTIVE: This qualitative study of a select sample of vaccine-hesitant parents (VHPs) explores perceived and constructed personal judgments about the risks and uncertainties associated with vaccines and vaccine-preventable diseases (VPDs) and how these subjective risk judgments influence parents\u27 decisions about childhood vaccination. METHODS: The study employed semistructured focus group interviews with 42 VHPs to elicit parents\u27 perceptions and thought processes regarding the risks associated with vaccination and nonvaccination, the sources of these perceptions, and their approach to decision making about vaccination for their children. RESULTS: VHPs engage in various reasoning processes and tend to perceive risks of vaccination as greater than the risks of VPDs. At the same time, VHPs engage in other reasoning processes that lead them to perceive ambiguity in information about the harms of vaccination-citing concerns about the missing, conflicting, changing, or otherwise unreliable nature of information. CONCLUSIONS: VHPs\u27 refusal of vaccination may reflect their aversion to both the risk and ambiguity they perceive to be associated with vaccination. Mitigating this vaccine hesitancy likely requires reconstructing the risks and ambiguities associated with vaccination-a challenging task that requires providing parents with meaningful evidence-based information on the known risks of vaccination versus VPDs and explicitly acknowledging the risks that remain truly unknown

Physicians\u27 perceptions of the value of prognostic models: the benefits and risks of prognostic confidence.

BACKGROUND: The communication of prognosis in end-of-life (EOL) care is a challenging task that is limited by prognostic uncertainty and physicians\u27 lack of confidence in their prognostic estimates. Clinical prediction models (CPMs) are increasingly common evidence-based tools that may mitigate these problems and facilitate the communication and use of prognostic information in EOL care; however, little is known about physicians\u27 perceptions of the value of these tools. OBJECTIVE: To explore physicians\u27 perceptions of the value of CPMs in EOL care. DESIGN: Qualitative study using semi-structured individual interviews which were analysed using a constant comparative method. SETTING AND PARTICIPANTS: Convenience sample of 17 attending physicians representing five different medical specialties at a single large tertiary care medical centre. RESULTS: Physicians perceived CPMs as having three main benefits in EOL care: (i) enhancing their prognostic confidence; (ii) increasing their prognostic authority; and (iii) enabling patient persuasion in circumstances of low prognostic and therapeutic uncertainty. However, physicians also perceived CPMs as having potential risks, which include producing emotional distress in patients and promoting prognostic overconfidence in EOL care. DISCUSSION AND CONCLUSIONS: Physicians perceive CPMs as a potentially valuable means of increasing their prognostic confidence, communication and explicit use of prognostic information in EOL care. However, physicians\u27 perceptions of CPMs also indicate a need to establish broad and consistent implementation processes to engage patients in shared decision making in EOL care, to effectively communicate uncertainty in prognostic information and to help both patients and physicians manage uncertainty in EOL care decisions

Het geintegreerde duurzaamheidsmodel IMAGE. Mondiale scenario's van IMAGE 2.1.

Alleen digitaal beschikbaar<br>The IMAGE User Support System contains scenarios from the IMAGE-2.1 or global environmental change model with extensive HTML documentation. The tool is used to interactively explore global change and analyse future developments of the Earth system. IMAGE 2.1 is designed to evaluate cross-linkages in the society-biosphere-climate system.DGM-NO