Stimuli for

Generalizations. Several generalizations can be made regarding taste (16,26). A substance must be in water solution, eg, the Hquid bathing the tongue (sahva), to have taste. Water solubiUty is the first requirement of the taste stimulus (12). The typical stimuli are concentrated aqueous solution in contrast with the Hpid-soluble substances which act as stimuli for olfaction (22). Many taste substances are hydrophilic, nonvolatile molecules (15). Taste detection thresholds for lipophilic molecules tend to be lower than those of their hydrophilic counterparts (16). 

Gustation. A taste sense, the receptors of which He in the mucous membrane covering the tongue, and the stimuli for which consist of certain soluble chemicals, eg, salts, acid, and sugar. 

Emesis. Figure 1 Afferent pathways involved in vomiting. Some stimuli for initiation of vomiting from the various locations are shown in the boxes. The presence of receptors at a particular location does not imply that they are necessarily involved in normal transmission of the vomiting reflex. 

Sensory nerves are peripheral nerves involved in the detection of exogenous and endogenous stimuli for transmission into the CNS. They can be subdivided into RARs and C-fibres according to their channel characteristics. 

Ton-molecule reactions are of great interest and importance in all areas of kinetics where ions are involved in the chemistry of the system. Astrophysics, aeronomy, plasmas, and radiation chemistry are examples of such systems in which ion chemistry plays a dominant role. Mass spectrometry provides the technique of choice for studying ion-neutral reactions, and the phenomena of ion-molecule reactions are of great intrinsic interest to mass spectrometry. However, equal emphasis is deservedly placed on measuring reaction rates for application to other systems. Furthermore, the energy dependence of ion-molecule reaction rates is of fundamental importance in assessing the validity of current theories of ion-molecule reaction rates. Both the practical problem of deducing rate parameters valid for other systems and the desire to provide input to theoretical studies of ion-molecule reactions have served as stimuli for the present work. 

Molecular approaches will be surely crucial to clarify at least some of these problems. An improved knowledge will provide new stimuli for the better dissection of the role and functioning of mycorrhizal fungi in the rhizosphere. 

Vasopressin is a peptide hormone produced by the hypothalamus and secreted by the posterior pituitary in response to stimulation. Normal stimuli for vasopressin release are hyperosmolarity and hypovolemia, with thresholds for secretion of greater than 280 mOsm/kg and greater than 20% plasma volume depletion. A number of other stimuli, such as pain, nausea, epinephrine, and numerous drugs, induce release of vasopressin. Vasopressin release is inhibited by volume expansion, ethanol, and norepinephrine. The physiological effect of vasopressin is to promote free water clearence by altering the permeability of the renal collecting duct to water. In addition, it has a direct vasoconstrictor effect. Consequently, vasopressin results in water retention and volume restoration. In patients with septic shock, vasopressin is appropriately secreted in response to hypovolemia and to elevated serum osmolarity (R14). 

In vitro platelet activation is dependent on the anticoagulant that is used for blood collection. In one study it was demonstrated that PF4 levels in platelet-poor plasma isolated after incubation without any stimuli for 1 hour at 37°C were as follows conventional heparin, 1180 ng/ml hirudin, 469 ng/ml citrate, 440 ng/ml and EDTA, 217 ng/ml (110). EDTA appears to suppress platelet degranulation. PF4 levels obtained with a low-molecular-weight heparin preparation called Frag-min were, however, comparable to those obtained with hirudin (110). 

Several biochemical events occur posttranscriptionally that define the response of cells to stimuli. For instance, alternative splicing, posttrans-lational modifications, regulation of enzyme activities, distribution of metabolites between cellular compartments, necessitate analysis at the level of the proteome and the metabolome. 

The posterior multimodal association area is located at the junction of the parietal, temporal, and occipital lobes. It pools and integrates somatic, auditory, and visual stimuli for complex perceptual processing. As such, this area is involved primarily with visuospatial localization, language, and attention. Lesions here interfere with awareness of one s body position and of the space in which it moves as well as the ability to integrate and make sense of elements of a visual scene. In other words, these patients have normal visual acuity but cannot focus on an object of interest. 

Fig. 1.1. Economic and social challenges and stimuli for the development of some important branches of analytical chemistry...

The authors suggest that it was the structural diversity of the environment which made biogenesis possible in other words, there was an enormous selection of regions with different properties and states on the young Earth which acted as stimuli for the increasing complexity of the evolving systems. As complexity increased, those regions of the primeval Earth which were not available for earlier, more primitive systems could be colonized . 

As seen in Fig. 32.1 and Fig. 32.2, the frequency of sucking movements differed across the 4 odour stimuli for the tests conducted at 36 weeks PCA, but not at 34 weeks PCA. At the later test age, each of the 3 milk odours elicited greater sucking... 

In countries like the United States, Canada, Australia, many European countries and certain others food regulations have existed for many decades. Many countries have yet to formulate national food policies, responding appropriately to their health situation and economy, or, where these policies have been formulated, they often do not reflect appropriately the tme nature and extent of current or emerging food safety problems. The advances in science and technology are important stimuli for modification of the laws.1... 

This affect guides learning. It leads us to investigate appropriate stimuli for example, stimuli that are moderately novel and complex for the subject are the most interesting. In this way, we are drawn to stimuli that are not so simple and familiar that they can teach... 

Chemical cues often have to be accompanied, preceded, or succeeded by visual, auditory, or tactile stimuli for appropriate behavior to occur. Bats, for example, use both olfactory and acoustic information for individual recognition (Kunz, 1982). 

Fry of the Atlantic salmon, Salmo salar, probably rely on olfactory and gustatory stimuli for their first meal. Injured prey such as small crustaceans will leak free amino acids, which can serve as a feeding signal to the fish fry. Such handicapped prey will be easier to catch for the fry. If the prey is dead, and/or its free amino acids are depleted, the fry show no interest in them. In this way, the salmon can optimize its capturing efforts as well as its prey digestion. In laboratory experiments, frozen daphnids leaked as much as 35% of its methionine upon thawing. On their first 3 days of feeding, salmon fry typically chose undepleted daphnids first and virtually all spit-out prey were depleted daphnids (Holm and Walther, 1988). Table 12.2 lists some chemical predator-prey relationships in freshwater fish. 

Sheffield, L. P., Law, J. M., and Burghardt, G. M. (1968). On the nature of chemical food sign stimuli for newborn garter snakes. Communications in Behavioral Biology 7-12. 

Sola, C. and Tosi L. (1993). Bile salts and taurine as chemical stimuli for glass eels Anguilla anguilla zbehaviotai study. Errviwnmental Biology of Fishes 37,197-204. 

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