The influence of an irrelevant stimulus on two discriminations.

In 3 experiments, the effect of adding an irrelevant stimulus to a discrimination was examined. In Exp 1, a group of pigeons received autoshaping with an A+Bo discrimination in which 1 stimulus signaled food, A+, and a simultaneous compound of A with another stimulus, B, signaled the absence of food, ABo. A 2nd group received similiar training, except that a 3rd stimulus, C, was present in both types of trials, AC+BCo. The A+Bo discrimination was acquired more readily than the AC+BCo discrimination. Exps 2 and 3 used a negative-patterning design, A+Bo+. In both experiments, this problem was mastered more readily than when an irrelevant stimulus was used to create an AC+BCoC+ discrimination. The results fail to confirm predictions derived from elemental theories of conditioning. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Volatiles from feces of wild male house mice

Volatile compounds from the fecal pellets deposited by a house mouse could be used for the purpose of communication with conspecifics. Analysis of volatiles from fresh and aged pellets by gas chromatography-mass spectrometry showed that many compounds were present and that ketones, alcohols, and carboxylic acids were the most common. Introducing volatiles from the fecal pellets of strange males into the territory of a singly housed male altered the site at which the resident mouse deposited most of its feces, and introducing the fecal pellets of a male mouse into the environment where it encountered a conspecific improved its success in an encounter with a stranger. The combined volatiles from feces of strange males had a greater effect on the heart rate of a male mouse than the combined volatiles from its own feces. Several individual volatiles from the fecal pellets of strange males affected the heart rates of test animals, but individual animals responded differently to constituents with similar retention times.     

Effect of early seed removal during fermentation on proanthocyanidin extraction in red wine: A commercial production example

Wines (Vitis vinifera L. cv. Merlot) were made by a commercial winery to examine the effects of seed removal at ∼10 °Brix on the extraction of proanthocyanidins during fermentation. Seeds were removed at the point when they fell to the bottom of the fermenter, and were thus easily removed during regular pump-over operations. Proanthocyanidin extraction was compared to wine made from traditional winemaking regime in which no seed removal occurred. Proanthocyanidin differences observed in the wines were minor. The control wine contained a slightly higher percentage molar proportion of seed proanthocyanidins ((−)-epicatechin-3-O-gallate extension and terminal subunits), demonstrating higher seed tannin extraction, and the seed removed wine contained a higher percentage molar proportion of skin proanthocyanidin indicators ((−)-epigallocatechin extension subunits). Seed removed Merlot wines had higher concentrations of total anthocyanins. Minor differences in colour measurement values between the two wines were also observed. The control wine was slightly more orange (larger hue angle, h°), lighter (larger L^∗ value), and more saturated (higher chroma value, C^∗) in colour. This appears to be the first paper to report the effects of early seed removal in Merlot winemaking, and demonstrates how winery tannin management techniques contribute to proanthocyanidin composition.     

Membrane technology at St. Saviours water treatment works, Guernsey, Channel Islands

This brief report describes how and why membrane technology was chosen for this water treatment works (WTWs), together with some of the experiences of operating Britain's first full-size municipal surface water membrane treatment works. This report also details the chemical and power requirements of such a plant.     

Summation in autoshaping is affected by the similarity of the visual stimuli to the stimulation they replace.

Pigeons received autoshaping with 2 stimuli, A and B, presented in adjacent regions on a television screen. Conditioning with each stimulus was therefore accompanied by stimulation that was displaced from the screen whenever the other stimulus was presented. Test trials with AB revealed stronger responding if this displaced stimulation was similar to, rather than different from, A and B. For a further experiment the training just described included trials with A and B accompanied by an additional, similar, stimulus. Responding during test trials with AB was stronger if the additional trials signaled the presence rather than the absence of food. The results are explained with a configural theory of conditioning. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Configural analysis of summation in autoshaping.

In 4 experiments, pigeons received autoshaping with various combinations of three stimuli, A, B, and C, before test trials in which responding during all three stimuli, ABC, was compared with that during a three-element control compound, DEF, which had been consistently paired with food. Pairing A, B, and C individually with food resulted in similar rates of responding during ABC and DEF (Experiments 1 and 2). Responding was faster, however, during ABC than during DEF after training in which food was signaled by the pairs of stimuli (AB, AC, and BC; Experiment 1). Responding was also faster during ABC than during DEF after training involving reinforced (+) and nonreinforced (°) trials of the form ABC+ A° BC°, followed by A+ BC+ (Experiment 2), or AB+ BC+ B° (Experiments 3 and 4). The results are consistent with those of a configural analysis of summation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Supernormal conditioning.

In Experiment 1, rats received an A+AX° discrimination in which food was presented after Stimulus A by itself but not after a simultaneous compound of A with Stimulus X. AX was then paired with food in a 2nd stage, followed by test trials with A alone. Responding on the test trials with A was more vigorous than during a control stimulus that had been consistently paired with food. The remaining experiments were of similar design to Experiment 1, except that the 2nd stage also contained conditioning trials with X. The results from the test trials were essentially the same as for Experiment 1. The high level of responding during the test trials with Stimulus A is regarded as evidence of supernormal conditioning. Overall, the results are more consistent with a configural than an elemental theory of conditioning. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Spontaneous spinal epidural haemorrhage complicating transjugular intrahepatic portosystemic stent shunting

A patient with chronic liver disease and portal hypertension who developed acute spinal cord compression following transjugular intrahepatic portosystemic stent shunting is described. Radiological and pathological examinations revealed an epidural haematoma.     

Volatile compounds from excreta of laboratory mice (Mus musculus)

Volatile components of all the excretory products deposited by house mice may contribute to their ability to identify their own territories. When mice were placed on a clean surface, they deposited feces, secretions discharged from the anus (anal secretion) and urine. Exposure to several clean surfaces in succession caused a decline in the number of fecal pellets and urine spots deposited and an increase in the number of anal smears. The volatile compounds emanating from feces and anal secretion appeared to be qualitatively and quantitatively different from those emanating from urine, but many compounds with short retention times appeared to be common to feces and anal secretion. Introducing volatiles from feces of strange males into the territory of a singly housed male altered the site at which the resident animal deposited its feces but had no effect on the site at which it urinated. Introducing the feces or the anal secretion of a male mouse into the environment where it encountered a strange conspecific appeared to improve its success in encounters with a conspecific. It was concluded that at least some of the volatile compounds that enable mice to distinguish their own territory from those of neighboring groups may be derived from feces and that many fecal volatiles may originate from the secretions of glands opening into the digestive tract.