Many animals in their natural habitat exhibit collective motion and form complex patterns to tackle environmental difficulties. Several physical and biological factors, such as animal motility, population densities, and chemical cues, play significant roles in this process. However, very little is known about how sensory information interplays with all these factors and controls the dynamics of collective response and pattern formation. Here, we use a model organism, Caenorhabditis elegans, to study the direct relation between oxygen sensing, pattern formation, and the emergence of swarming in active worm aggregates. We find that when thousands of animals gather on food, bacteria-mediated decrease in oxygen levels slowed down the animals and triggers motilityinduced phase separation. Three coupled factors-bacterial accumulation, aerotaxis, and population density-act together and control the dynamics of pattern formation. Through several intermediate stages, aggregates converge to a large scale swarming phase and collectively move across the bacterial lawn. Additionally, our theoretical model captures behavioral differences resulting from the genetic variations and oxygen sensitivity. Altogether, our study provides many physical insights and a new platform for investigating the complex relationship between neural sensitivity, collective dynamics, and pattern formation.

Many electrochemical devices are based on the fundamental process of ion migration and accumulation on surfaces. Complex interplay of molecular properties of ions and device dimensions control the entire process...

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Determination of the yield reductions and economic threshold caused by common cocklebur (Xanthium strumarium L.) in sunflower production fields in AnkaraHigh nutritive content, using in various industrial sectors and adaptation of various regions of sunflower (Helianthus annuus L.) have allowed of cultivation and consumption at high scale. One of the important problems of sunflower prevalently cultivated in Marmara and Central Anatolia Regions is weeds. Among the weeds, common cocklebur (Xanthium strumarium L.) is very important because it has a competitive character, and there is only one herbicide registered to control this weed. The field study was carried out to determine the economic threshold of common cocklebur in sunflower from 2013 to 2015 in Ankara. According to the three-year study values, the highest sunflower plant length (138.33 cm), head diameter (14.4 cm) and 1000-seed weight (85.03 g) were obtained from the control parcels while the lowest plant length (104.17 cm), head diameter (10.41 cm) and 1000-seed weight (62.81 g) were taken from the parcels consisted of 16 common cocklebur plants.The economic thresholds were calculated using the current sunflower price and the herbicide, imazamox (