<Session 6: Wildlife Tracking II>Methodological challenges for studying penguins eco-physiology in remote environments

19–22 May 2022 Kyoto, JapanHigher vertebrates situated at the top of food chains are often used as bio-indicators to provide information about the health of their ecosystem. Penguins are one of these species of interest, but the harsh environments they live in, as well as their pelagic lifestyle, make the development and deployment of adequate instrumentation challenging; moreover, these animals have a long lifespan that allows for long term eco-physiological and population dynamics studies but also causes additional technical difficulties. To address these limitations several techniques must be combined. First, since observed individuals live in dense colonies, Radio Frequency Identification by means of passive implantable tags provides a reliable and long lasting solution to monitor individuals while using automatic detection systems placed at strategic locations in the field. In parallel, physiology and behaviors (including long-distance swimming and deep diving activities) of penguins can be recorded for weeks or months using bio-logger attached to the feathers, and up to three years with surgically implanted devices. For most cases, recapture of the animals is necessary to retrieve the data. Yet, devices combining bio-logging and telemetric functions have been recently developed to allow periodical downloading of the data when animals come back to their colony

Motricité intestinale après résection jéjunale : étude électromyographique chez le rat

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Different displacement of bioimpedance vector due to Ag/AgCl electrode effect

Background/Objectives:Bioelectrical impedance vector analysis (BIVA) is increasingly used in clinical research to assess soft tissue hydration. It is known that physical characteristics of electrodes, such as low intrinsic impedance, low electrode/skin contact impedance and type of gel, affect the reliability of noninvasive bioimpedance assessments. The aim of this study was to determine the effect of intrinsic impedance of electrode on the bioimpedance vector displacement in RXc graph.Subjects/Methods:The intrinsic impedance is measured in nine pregelled disposable Ag/AgCl electrodes usually used for bioimpedance measures. The BIVA method is performed on 35 healthy volunteers using a 50 kHz phase-sensitive bioimpedance analyzer (BIA 101 Anniversary) with the lowest intrinsic impedance electrode and highest. The individual bioimpedance vector is plotted on the bivariate normal interval of reference population. The differences in the mean bioimpedance vectors obtained with each electrode are plotted, with their 95% confidence ellipses, on the dRXc graph. The paired one-sample Hotelling's T 2 -test is used to compare the differences of the mean bioimpedance vectors.Results:We found large variability in intrinsic resistance (11-665 Ω) and reactance (0.25-2.5 Ω) values of the electrodes analyzed and significant displacement (P<0.05) of bioimpedance vector positions in healthy adults according to the paired one-sample Hotelling's T 2 -test.Conclusions:A robust study of all physical characteristics of commercial Ag/AgCl electrodes is necessary to reach consensus on pregelled Ag/AgCl electrodes valid for bioimpedance measurement. This information will enable BIVA users to avoid systemic errors when performing BIVA assessments, specifically when these measurements are used for clinical interpretations