Search

This manuscript presents the use of three novel technologies for the implementation of wireless green battery-less sensors that can be used in agriculture. The three technologies, namely, additive manufacturing, energy harvesting, and wireless power transfer from airborne transmitters carried from UAVs, are considered for smart agriculture applications, and their combined use is demonstrated in a case study experiment. Additive manufacturing is exploited for the implementation of both RFID-based sensors and passive sensors based on humidity-sensitive materials. A number of energy-harvesting systems at UHF and ISM frequencies are presented, which are in the position to power platforms of wireless sensors, including humidity and temperature IC sensors used as agriculture sensors. Finally, in order to provide wireless energy to the soil-based sensors with energy harvesting features, wireless power transfer (WPT) from UAV carried transmitters is utilized. The use of these technologies can facilitate the extensive use and exploitation of battery-less wireless sensors, which are environmentally friendly and, thus, "green". Additionally, it can potentially drive precision agriculture in the next era through the implementation of a vast network of wireless green sensors which can collect and communicate data to airborne readers so as to support, the Artificial Intelligence and Machine Learning-based decision-making with data. [ABSTRACT FROM AUTHOR]

Populations at the margins of a species' distribution range are often smaller and more spatially isolated compared to centrally located populations. Therefore, a decline in within-population genetic variation and increased differentiation among populations towards range edges is expected. The edge effect can be enhanced by historical range expansions following glaciations in populations located at high latitudes. We investigated the level and distribution of genetic variation between 17 populations (collected from six countries) of the terrestrial orchid Anacamptis pyramidalis, using AFLP markers. Our study revealed no decline in genetic diversity in disjunct populations in Estonia at the northern border of the distribution area of this species, nor in the populations located at the southern edge of the range, on the island of Cyprus. Similarly, edge populations were not more differentiated from each other than the central populations in Slovenia and in Spain. Our results suggest that the degree of genetic variation is determined by the size of populations rather than geographic location of this species and underlines the impact of long-distance gene flow on the maintenance of genetic diversity in connection with major range shifts in the past. [ABSTRACT FROM AUTHOR]