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This chapter explores the character of the local rural–urban labour market, testing theories of labour market mobility and segmentation using a substantial survey from 1999 to 2000 along with field case material both in Arni and in nearby ‘suburban’ villages. It focusses on the commonest form of work in India accounting for 60 % of Arni’s workforce—self-employment—distinguishing it from wage labour (with which it is often conflated in labour economics and law). The social origins of petty-producing and trading firms are analysed along with the patriarchal domination of their respective households. Occupational reproduction is found to be substantially determined by caste; and social discrimination significantly restricts occupational and sectoral mobility. Self-employment expands by multiplication rather than accumulation. Arni’s ‘markets’ show clear evidence of persistent rural–urban, occupational–sectoral social and economic segmentation.

There is increased interest in new classes of mini- and micro-UAVs with sizes ranging from one metre to ten centimetres. Many envisioned applications of such UAVs require them to be able to fly close to the ground in complex environments. The difficulties associated with flying in such environments coupled with the reduced payload capacity of such airframes means that new methods of sensing and control need to be considered. Good models for such methods are found in the world of flying insects. One particular visual cue used by insects is optic flow, which is the apparent visual motion seen by the insect as a result of its motion through the environment. This paper discusses several research efforts aimed at developing new sensing and control algorithms inspired by insect vision and flight behaviors. These efforts are part of DARPA’s controlled biological and biomimetic systems (CBBS) programme.

Recent research has uncovered a number of different visual cues which bees use for controlling and stabilising flight. Bees flying through a tunnel maintain equidistance to the flanking walls by balancing the speeds of the images of the two walls. This strategy enables them to negotiate narrow passages or to fly between obstacles. The speed of flight in the tunnel is controlled by holding constant the average image velocity as seen by the two eyes. This mechanism prevents potential collisions by ensuring that the bee slows down when it flies through a narrow passage. Bees landing on a horizontal surface hold constant the image velocity of the surface as they approach it, thus automatically ensuring that flight speed is close to zero at touchdown. The movement-sensitive mechanisms underlying these various behaviours differ qualitatively as well as quantitatively, from those that mediate the well-investigated optomotor response. Flight thus appears to be co-ordinated by a number of visuomotor systems acting in concert.

Many flying insects display remarkable visual agility in capturing prey or pursuing a potential mate. They are capable of detecting, recognising, tracking and capturing a rapidly moving object on the wing. These manoeuvres are usually completed in a couple of seconds. The interval of time between the absorption of light quanta by the photoreceptors and the generation of an appropriate behavioural response is very short, encompassing only a few tens of milliseconds. In this time the visual nervous system has abstracted the essential features of the object, and recognized it (where appropriate), or measured its movement and computed an interception course. As an elementary unit of computation, we know that a neuron in the nervous system is considerably slower than, say, a flip-flop in the CPU of a modern computer. However, it is evident from the visual performance of an insect that the nervous system as a whole processes optical information much faster than a modern computer does. Rapid processing of visual information by animals therefore has to be attributed to the structure and the modus operandi of the nervous system.

Batches hematite particles were reduced to magnetite by hydrogen in small scale fluidized bed, from which samples of partially reduced ore could be extracted for metallographic studies or surface area measurements. A stabilized zirconia cell was used to monitor the gas phase composition at eight locations in the bed. With this device a complete picture of the consumption of hydrogen was established that could detect small changes in the efficiency of the reduction reaction. Approximate rates of reduction could also be calculated. Hematite reduction took place in three stages; an initial period in which the efficiency of the reaction increased with time, followed by a period of relatively constant reduction efficiency, and finally after about 85 to 90 pct transformation a period of falling efficiency. Wustite did not form while hematite was present. The efficiency of the reaction increased when the hematite particles were coated with platinum and decreased when the particles were coated either with silica or with a naturally occurring dirt film. A kinetic and morphological analysis indicated that the reaction was rate controlled by a surface reaction at the bottom of pores in the magnetite. These pores do not appear to penetrate to the receding hematite interface. The initial increase in the efficiency of the reaction was attributed to the developing pore structure of the magnetite which increased the area for reaction.