Plankton Imagery Data Inform Satellite-Based Estimates of Diatom Carbon

Estimating the biomass of phytoplankton communities via remote sensing is a key requirement for understanding global ocean ecosystems. Of particular interest is the carbon associated with diatoms given their unequivocal ecological and biogeochemical roles. Satellite-based algorithms often rely on accessory pigment proxies to define diatom biomass, despite a lack of validation against independent diatom biomass measurements. We used imaging-in-flow cytometry to quantify diatom carbon in the western North Atlantic, and compared results to those obtained from accessory pigment-based approximations. Based on this analysis, we offer a new empirical formula to estimate diatom carbon concentrations from chlorophyll a. Additionally, we developed a neural network model in which we integrated chlorophyll a and environmental information to estimate diatom carbon distributions in the western North Atlantic. The potential for improving satellite-based diatom carbon estimates by integrating environmental information into a model, compared to models that are based solely on chlorophyll a, is discussed.

What do our patients understand about their trial participation? Assessing patients' understanding of their informed consent consultation about randomised clinical trials

BACKGROUND

Ethically, informed consent regarding randomised controlled trials (RCTs) should be understandable to patients. The patients can then give free consent or decline to participate in a RCT. Little is known about what patients really understand in consultations about RCTs.

METHODS

Cancer patients who were asked to participate in a randomised trial were surveyed using a semi-standardised interview developed by the authors. The interview addresses understanding, satisfaction and needs of the patients. The sample included eight patients who participated in a trial and two who declined. The data were analysed on the basis of Mayring's qualitative analysis.

RESULTS

Patients' understanding of informed consent was less developed than anticipated, especially concerning key elements such as randomisation, content and procedure of RCTs. Analysing the result about satisfaction of the patients, most of the patients described their consultations as hectic and without advance notice. Health limitations due to cancer played a decisive role. However, most of the patients perceived their physician to be sympathetic. Analysing the needs of patients, they ask for a clear informed consent consultation with enough time and adequate advance notice.

CONCLUSION

This study fills an important empirical research gap of what is ethically demanded in an RCT consultation and what is really understood by patients. The qualitative approach enabled us to obtain new results about cancer patients' understanding of informed consent, to clarify patients' needs and to develop new ideas to optimise the informed consent.