Effect of background information on object identification.

Previous research using briefly presented displays has indicated that objects in a coherent scene are easier to identify than are objects in incoherent backgrounds. Of interest is whether the identification of the target object depends on the identification of the scene or the identification of other diagnostic objects in the scene. Experiment 1 indicated objects are more difficult to identify when located in an "episodically" inconsistent background even when the same diagnostic objects are present in both inconsistent and consistent backgrounds. Experiment 2 demonstrated that the degree to which noncued (cohort) objects are consistent with the target object has no effect on the object identification task. Experiment 3 showed consistent episodic background information facilitated object identification and inconsistent episodic background information did not interfere relative to "nonsense" backgrounds roughly equated on visual characteristics. Implications for models of scene perception are discussed.

Identification of objects in scenes: the role of scene background in object naming.

Research with brief presentations of scenes has indicated that scene context facilitates object identification. In the present experiments we used a paradigm in which an object in a scene is "wiggled"--drawing both attention and an eye fixation to itself--and then named. Thus the effect of scene context on object identification can be examined in a situation in which the target object is fixated and hence is fully visible. Experiment 1 indicated that a scene background that was episodically consistent with a target object facilitated the speed of naming. In Experiments 2 and 3, we investigated the time course of scene background information acquisition using display changes contingent on eye movements to the target object. The results from Experiment 2 were inconclusive; however, Experiment 3 demonstrated that scene background information present only on either the first or second fixation on a scene significantly affected naming time. Thus background information appears to be both extracted and able to affect object identification continuously during scene viewing.

Effect of body size and ration on specific dynamic action in the Antarctic plunderfish, Harpagifer antarcticus Nybelin 1947.

The feeding energetics of the Antarctic spiny plunderfish (Harpagifer antarcticus) were examined with respect to the effect of both ration size and animal size. Fish of different sizes were fed single meals at one of two ration levels (2.5% wet body mass and satiation) to determine the maximum aerobic scope that could be elicited by the specific dynamic action. The excretion rates of ammonia, urea, and fluorescamine-positive substances were also monitored. Neither fish size nor ration had any effect on the factorial aerobic scope of feeding, which suggests that cellular metabolic processes associated with feeding were satiated by relatively small meals. The factorial scope in ammonia excretion was affected by both ration and fish size, indicating that respiration and excretion respond to a meal independently. The duration of the specific dynamic action response (240-390 h) increased with fish size but not ration, whereas both the time to reach the peak oxygen consumption and the duration of the ammonia response increased with ration but not fish size. The percentage of the ingested energy that was expended following feeding (the specific dynamic action coefficient) was high at low rations (approximately 56%) but lower (roughly 10%) at satiation rations. This is because the absolute energetic cost of processing a meal was largely independent of meal size. The change in O:N ratios after feeding was very ration-dependent; at low rations, O:N ratios increased, whereas at satiation rations, the O:N ratios decreased.

Effect of lead acetate and carbon particles on the expression of glutathione S-transferase YfYf in rat liver.

Administration of intracardiac lead acetate produces a complex response in glutathione S-transferase (GST) YfYf expression in rat liver. The earliest response, an elevation of GST expression in Kupffer cells, can be mimicked by administering a suspension of carbon particles. The second effect of lead acetate administration is a marked elevation of GST YfYf in some but not all hepatocytes (the 'patchy' response). This effect is most marked 48-76 h after administration of a single dose of lead acetate and is easily detected by immunoblotting. Dexamethasone down-regulates the lead response in hepatocytes.

The development of glutathione S-transferase subunits in rat liver. Sensitive detection of the major subunit forms of rat glutathione S-transferase by using an e.l.i.s.a. method.

The development of the subunits of glutathione S-transferase in rat liver shows that there is a co-ordinated development of the Ya, Yb1, Yb2 and Yc subunits but that the Yf and Yk subunits show unique patterns of development. The Yk subunit is the only form that is expressed at relatively high levels during the foetal period as well as during the adult period. In contrast with all other forms, the Yf subunit in the rat declines rapidly during the last few days before parturition and is virtually undetectable in hepatocytes of adult animals. The expression of the Yf subunit in foetal liver presents a 'patchy' appearance that is similar to that induced by the administration of lead acetate and may reflect cell-cycle-associated regulation of expression.

Immunological studies on the rat peripheral-type benzodiazepine acceptor.

Photoaffinity labelling of rat adrenal mitochondrial preparations with [3H]PK 14105 resulted in a single 3H-labelled band on SDS/PAGE gels with an apparent-molecular-mass peak of 18 kDa. This represents a polypeptide associated with the peripheral-type benzodiazepine-binding site. Solubilization of photoaffinity-labelled membranes with 6 M-guanidine hydrochloride, followed by gel filtration and reversed-phase h.p.l.c. of the solubilized material, resulted in the purification to homogeneity of the [3H]PK 14105-labelled polypeptide. This purified polypeptide was used to raise a rabbit polyclonal antiserum which recognized the immunogen in pure form and exclusively recognized it in a crude preparation of rat adrenal mitochondria as judged by immunoblotting. By the same analysis the antiserum identified the corresponding polypeptide from rat kidney and salivary gland, demonstrating its cross-reactivity. Subsequent immunocytochemical studies localized the polypeptide to the cortex of the adrenal gland, the distal tubules of kidney, the interstitial cells of testis, the biliary epithelium of liver and the choroid plexus and ependyma cells within the brain. This selective localization within organs may provide an insight into the physiological role of the peripheral-type benzodiazepine acceptor.