The individual feathers in the skin of a developing chicken embryo are arranged in a precise array within a series of so-called 'tracts'. The images above show nascent feather buds in the legs of embryos at 8–9 days of incubation. Buds are added sequentially across the forming feather tract, as shown by the range of developmental stages in the image at top left. (In all three upper images, buds...

statistical studies on palynology contents of late cretaceous to paleocene age gurpi formation in a surface section in zagros basin,sw iran indicate changes in abundance, species diversity, ratio of spiniferites to cyclonephelium (s/c), palynological marine index(pmi) values and organic facies. these palynological variations clearly reflect fluctuations in relative sea-level and depositionalenv...

This paper treats the problem of the merging of formations, where the underlying model of a formation is graphical. We first analyze the rigidity and persistence of metaformations, which are formations obtained by connecting several rigid or persistent formations. Persistence is a generalization to directed graphs of the undirected notion of rigidity. In the context of moving autonomous agent f...

Multi-agent formations have been recently the subject of many studies. An important operational challenge, largely unaddressed in the literature, is to ensure that functionality of the formation is retained should agents be lost through misadventure, mission reassignment, and so on. In the context of sensor networks, it is also important to allow for the loss of multiple sensors as the low qual...

Marine transgressions or microbial precipitation: What was the controlling factor of continental margin iron formation deposition? Introduction Iron formations, which can be found around the world today, have great importance as sources of iron and manganese ore, clues about the evolution of life on Earth, and even hints at possible life on Mars (Weber et al., 2006). Precambrian iron formations...

This paper is concerned with rigid formations of mobile autonomous agents using a leader-follower structure. A formation is a group of agents moving in real 2or 3dimensional space. A formation is called rigid if the distance between each pair of agents does not change over time under ideal conditions. Sensing/communication links between agents are used to maintain a rigid formation. Two agents ...

This paper presents a method for control of formations of Unmanned Aerial Vehicles (UAVs) in urban environments with several obstacles. Therefore the trajectories for each UAV are planned using mixed integer quadratic programming (MIQP) to describe a minimization problem. The result of this minimization problem then characterizes a collision free trajectory for each UAV using the commanded form...