Self-Assemblage and Quorum in the Earthworm Eisenia fetida (Oligochaete, Lumbricidae)

Despite their ubiquity and ecological significance in temperate ecosystems, the behavioural ecology of earthworms is not well described. This study examines the mechanisms that govern aggregation behaviour specially the tendency of individuals to leave or join groups in the compost earthworm Eisenia fetida, a species with considerable economic importance, especially in waste management applications. Through behavioural assays combined with mathematical modelling, we provide the first evidence of self-assembled social structures in earthworms and describe key mechanisms involved in cluster formation. We found that the probability of an individual joining a group increased with group size, while the probability of leaving decreased. Moreover, attraction to groups located at a distance was observed, suggesting a role for volatile cues in cluster formation. The size of earthworm clusters appears to be a key factor determining the stability of the group. These findings enhance our understanding of intra-specific interactions in earthworms and have potential implications for extraction and collection of earthworms in vermicomposting processes

Flexible Bow-Tie Antennas with Reduced Metallization

This paper presents design, simulation, fabrication and measurement of a modified bow-tie antenna with reduced metallization. The antenna is mounted on a flexible substrate which is fabricated at the Flexible Display Center (FDC) of Arizona State University (ASU). The substrate is heat stabilized polyethylene naphthalate (PEN) which allows the antenna to be flexible. The antenna is fed by the aid of a microstrip-to-coplanar feed network balun. The reduction of the metallization is based on the observation that the majority of the current density is confined towards the edges of the regular bow-tie antenna. Hence, the centers of the triangular parts of the bow-tie antenna are removed. The radiation performance of the modified bow-tie is verified to be very close to the conventional bow-tie by simulations and measurements

Flexible Bow-tie Antennas

The Flexible Display Center (FDC) at Arizona State University (ASU) was founded in 2004 as a partnership between academia, industry, and government to collaborate on the development of a new generation of innovative displays and electronic circuits that are flexible, lightweight, low power, and rugged [1]. Due to the increasing need for flexible and lightweight electronic systems, FDC aims to develop materials and structural platforms that allow flexible backplane electronics to be integrated with display components that are economical for mass-production [2]. Currently, FDC is focusing on the incorporation of antenna structures, which can function cooperatively with the other flexible circuit elements. Design of flexible antennas, as a part of flexible electronic circuits, may have a very wide spectrum of applications in military and civilian wireless communication, which can allow people to wear antenna structures instead of carry them. Hence, flexible and fluidic antennas have a great potential [3]. In this paper, the design, fabrication, simulation and measurements of a bow-tie antenna with a flexible substrate is discussed. The antenna is modeled and simulated with Ansoft HFSS, and the simulations are compared with measurements performed in the Electromagnetic Anechoic Chamber (EMAC) at ASU