Chemical stimuli, species

Still another factor in spacing conununication system stability is residual activity of a chemical stimulus, which may vary over time according to the insect species and the nature of the message conveyed. For example, the repellent pheromone deposited by Xylocopa bees following extraction of nectar from passion flowers persists for only about 10 minutes, which may coincide with the time required for replenishment of some of the nectar, whereas Oecophylla ants deposit territorial pheromone which persists for up to 12 days, designating areas of continuous exploitation (see Section 11.5). Residual activity... 

In almost all chemical measurements, an experimentally observable quantity, such as absorption, emission, or current, is used to calculate the concentration of the species of interest. Calibration consists of defining the relationship between the observed instrumental response to a chemical stimulus and the sought concentration. It must be done for all instrumental analysis techniques. The calibration funaion establishes the relationship between the measured response variable (an instrumental response such as spectral absorption, which is usually converted into a current or voltage) and the desired dependent variable (usually the concentration of the sought chemical species). Problems that arise to impose uncertainty or complexity on calibration include interferences, matrix effects, and interactions among chemical species. 

The best possible outcome of a bioassay is the elicitation of a specific behavior pattern by a defined chemical stimulus (Miiller-Schwarze 1977). This chapter presents methods to assess the role of chemical stimuli in the behavior of birds and mammals. An overview of the chemosensory capacities of birds and mammals to perceive stimuli is provided first, followed by a description of test paradigms that can be incorporated into bioassays. The preponderance of the chapter describes examples of these paradigms incorporated into bioassays to assess the role of chemical signals in inter- and intra-specific behaviors. The examples, like past studies in mammalian and avian chemical ecology, are disproportionately represented by rodents. Most of the described procedures, however, could be modified for other species, provided the apparatuses and the response variables can be altered to accommodate the different subject and stimuli. 

Except for the case of an ideal plug flow reactor, different fluid elements will take different lengths of time to flow through a chemical reactor. In order to be able to predict the behavior of a given piece of equipment as a chemical reactor, one must be able to determine how long different fluid elements remain in the reactor. One does this by measuring the response of the effluent stream to changes in the concentration of inert species in the feed stream—the so-called stimulus-response technique. In this section we will discuss the analytical form in which the distribution of residence times is cast, derive relationships of this type for various reactor models, and illustrate how experimental data are treated in order to determine the distribution function. 

If the operation of the devices considered above on their specific substrate (photon, electron, ion) is triggered by external optical, electrical or chemical stimuli, their features may be switched between two (or more) states presenting different characteristics. Such switching devices are therefore formed by two main components a trigger, the switching unit, activated by an external stimulus and a substrate, the switched species they should operate with efficiency, reversibility and resistance to fatigue. 

The hope that chemical reactions can be used to pump efficient and powerful lasers is a major stimulus to studies of the chemical production of excited species [429]. There have now been a very large number of papers [430] on lasers which oscillate on the vibration-rotation transitions of molecules produced in atom-transfer reactions, although laser oscillation following... 

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