Thresholds birds

Hubner, C.B. Bird, M. Rassnick, S. and Kometsky, C. The threshold lowering effects of MDMA (ecstasy) on brain-stimulation reward. Psychopharmacology 95 49-51, 1988. 

Since we now know that birds rely on odors in a variety of contexts, we are interested in how sensitive they are to odorants and how their olfac-toiy performance compares with mammals. Birds sensitivity has been measured in different ways behavioral thresholds differ from electrophysiological... 

Table 5.4 Thresholds for odorants in birds, obtained by behavioral, cardiac, and electrophysiological techniques...

Han JS, Bird GC, Neugebauer V (2004) Enhanced group 111 mGluR-mediated inhibition of pain-related synaptic plasticity in the amygdala. Neuropharmacology 46 918-926 Hansel C, Artola A, Singer W (1996) Different threshold levels of postsynaptic [Ca2-h](i) have to be reached to induce LTP and LTD in neocortical pyramidal cells. J Physiol Paris... 

Still, of interest in view of Evarts results are the observations of Blough (1957). This author, using a rather intricate behavioral test arrangement, was able to measure the "absolute visual threshold" in pigeons. When the birds were given... 

ENEMIES. Birds, especially coal-tits, are important enemies of winter moth caterpillars. The feeding requirements of these birds at brood time are very high (300 caterpillars/day for the brood). Coal-tits are capable of keeping winter moth infestation below the damage threshold. 

It is not possible to consider all of the available DSMC chemistry models in detail. Due to its importance in air chemistry, dissociation has received the most attention, and interesting models have been proposed by Koura, Bird, and Lord. Wadsworth and Wysong compared the threshold line model to those of Refs. 38 and 53. It was concluded that the threshold line model and that of Koura gave results consistent with quasiclassical trajectory calculations for hydrogen dissociation. Some of these data will be shown later in the article. 

Aquatic organisms, especially those at the top of the food chain, such as fish-eating birds, are much more sensitive to toxic metals in their habitat than are terrestrial biota. There is some circumstantial evidence to suggest that the noeffect thresholds for some metals is fairly close to their current levels in natural waters (see Table 6.1). 

Researchers were also able to establish the link between declines of other predatory species such as the European sparrowhawk and the use of organo-chlorine pesticides other than DDT. For instance, the cyclodiene insecticides aldrin, dieldrin, and he-ptachlor used as seed treatments caused massive mortality of both seed-eating species and their predators. All of the insecticides had the following points in common they were highly soluble in fats and refractory to metabolism. The impacts on the predatory species typically take place in periods of food stress when fat soluble residues are released from fat stores and returned into general circulation. In a food-stressed individual, the brain remains as the most lipid rich tissue and this is where contaminants move to. Toxicity results when threshold values in brain tissue are exceeded. At sublethal levels, documented effects of cyclodiene insecticides in birds have included changes in their reproductive, social, and avoidance behaviors. 

Schmiedeberg L, Skene P, Deaton A, Bird A (2009) A temporal threshold for formaldehyde crosslinking and fixation. PLoS ONE 4(2) e4636. 

That is, if they lowered the threshold for Which blips they interpreted as signifying enemy planes, they falsely identified clouds and migrating birds, etc., as planes more often. 

Incident—Contact. An undesired event that could or does make contact with a source of energy above the threshold limit of body or structure (Bird and Loftus, 1976). The categories of contact incident events are often represented by the 11 accident types. The... 

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