Publications
NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.
2023
Authors
Melanie Furrer Sara A. Meier Maxime Jan Paul Franken Monica Alterskjær Sundset Steven A. Brown Gabriela Wagner Reto HuberAbstract
Timing and quantity of sleep depend on a circadian (ca 24-h) rhythm and a specific sleep requirement. Sleep curtailment results in a homeostatic rebound of more and deeper sleep, the latter reflected in increased electroencephalographic (EEG) slow-wave activity (SWA) during non-rapid eye movement (NREM) sleep. Circadian rhythms are synchronized by the light-dark cycle but persist under constant conditions. Strikingly, arctic reindeer behavior is arrhythmic during the solstices. Moreover, the Arctic’s extreme seasonal environmental changes cause large variations in overall activity and food intake. We hypothesized that the maintenance of optimal functioning under these extremely fluctuating conditions would require adaptations not only in daily activity patterns but also in the homeostatic regulation of sleep. We studied sleep using non-invasive EEG in four Eurasian tundra reindeer (Rangifer tarandus tarandus) in Tromsø, Norway (69degreesN) during the fall equinox and both solstices. As expected, sleep-wake rhythms paralleled daily activity distribution, and sleep deprivation resulted in a homeostatic rebound in all seasons. Yet, these sleep rebounds were smaller in sum- mer and fall than in winter. Surprisingly, SWA decreased not only during NREM sleep but also during rumination. Quantitative modeling revealed that sleep pressure decayed at similar rates during the two behavioral states. Finally, reindeer spent less time in NREM sleep the more they ruminated. These results suggest that they can sleep during rumination. The ability to reduce sleep need during rumination—undisturbed phases for both sleep recovery and digestion—might allow for near-constant feeding in the arctic summer.
Authors
Gabriela WagnerAbstract
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Authors
Gabriela WagnerAbstract
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Authors
Benjamin Guillaume Hanane Aroui Boukbida Gerben Bakker Andrzej Bieganowski Yves Brostaux Wim Cornelis Wolfgang Durner Christian Hartmann Bo V. Iversen Mathieu Javaux Joachim Ingwersen Krzysztof Lamorski Axel Lamparter András Makó Ana María Mingot Soriano Ingmar Messing Attila Nemes Alexandre Pomes-Bordedebat Martine van der Ploeg Tobias Karl David Weber Lutz Weihermüller Joost Wellens Aurore DegréAbstract
The soil water retention curve (SWRC) is a key soil property required for predicting basic hydrological processes. The SWRC is often obtained in the laboratory with non-harmonized methods. Moreover, procedures associated with each method are not standardized. This can induce a lack of reproducibility between laboratories using different methods and procedures or using the same methods with different procedures. The goal of this study was to estimate the inter- and intralaboratory variability of the measurement of the wet part (from 10 to 300 hPa) of the SWRC. An interlaboratory comparison was carried out between 14 laboratories, using artificially constructed, porous reference samples that were transferred between laboratories according to a statistical design. The retention measurements were modelled by a series of linear mixed models using a Bayesian approach. This allowed the detection of sample-to-sample variability, interlaboratory variability, intralaboratory variability and the effects of sample changes between measurements. The greatest portion of the differences in the measurement of SWRCs was due to interlaboratory variability. The intralaboratory variability was highly variable depending on the laboratory. Some laboratories successfully reproduced the same SWRC on the same sample, while others did not. The mean intralaboratory variability over all laboratories was smaller than the mean interlaboratory variability. A possible explanation for these results is that all laboratories used slightly different methods and procedures. We believe that this result may be of great importance regarding the quality of SWRC databases built by pooling SWRCs obtained in different laboratories. The quality of pedotransfer functions or maps that might be derived is probably hampered by this inter- and intralaboratory variability. The way forward is that measurement procedures of the SWRC need to be harmonized and standardized.
Authors
Jorunn BørveAbstract
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Authors
Tony Waterhouse Ann McLaren Aimee Walker John P. Holland Claire Morgan-Davies Shelemia Nyamuryekung'e Andrew Cox Santiago A. UtsumiAbstract
Comprehensive livestock tracking and behavioral characterization in extensive systems is technically challenging and expensive. Some technologies and data strategies based around proximity information may be more affordable. This paper brings together experiences from two major PLF projects involving cattle in extensive U.S. rangelands and sheep in extensive UK mountains and considers proximity technology for two resources, water in dry rangelands, and supplementary feed in pregnancy, respectively. Opportunities to characterize useful livestock variables include presence/absence, diurnal patterns, use of resources and changing use patterns. Results covering supplementary feed, used fixed Bluetooth Low Energy (BLE) readers arrayed around feeding points, 48 Blackface and 50 Lleyn ewes on 33ha of grazing that wore small (c14 g) BLE beacons. Beacons on ewes communicated identity and RSSI (Received Signal Strength Indicator) via receiving readers, pushing data in near-real time via LPWAN to an ArCGIS Online database. Differences in proximity at feeding areas were found for breed and age and patterns of activity over 24-hour periods, supporting the view that BLE technology covering only proportions of grazing areas could be useful for management purposes. For water access in arid rangelands, 11 cows in a 480ha paddock wore NoFence virtual fencing collars with GNSS real-time tracking using cellphone communications. Daily patterns of proximity to the only water source derived from GNSS data support the view that useful information could be provided by BLE proximity systems at lower cost than GNSS collars. Proximity approaches alone provides less information than GNSS systems.
Abstract
No abstract has been registered