Evaluating Graphical Perception of Visual Motion for Quantitative Data Encoding.

Information visualization uses various types of representations to encode data into graphical formats. Prior work on visualization techniques has evaluated the accuracy of perceived numerical data values from visual data encodings such as graphical position, length, orientation, size, and color. Our work aims to extend the research of graphical perception to the use of motion as data encodings for quantitative values. We present two experiments implementing multiple fundamental aspects of motion such as type, speed, and synchronicity that can be used for numerical value encoding as well as comparing motion to static visual encodings in terms of user perception and accuracy. We studied how well users can assess the differences between several types of motion and static visual encodings and present an updated ranking of accuracy for quantitative judgments. Our results indicate that non-synchronized motion can be interpreted more quickly and more accurately than synchronized motion. Moreover, our ranking of static and motion visual representations shows that motion, especially expansion and translational types, has great potential as a data encoding technique for quantitative value. Finally, we discuss the implications for the use of animation and motion for numerical representations in data visualization.

Hypericin activates L-type Ca2+ channels in cardiac myocytes.

The effects and the mode of action of hypericin (1) were studied, in the dark, on the action potential (AP) and the L-type Ca2+ channel of frog atrial heart muscle, using intracellular microelectrode and patch-clamp techniques, respectively. In the presence of Ca2+ in Ringer solution, hypericin (1 to 4 microM) did not markedly modify the AP. Total replacement of Ca2+ by Sr2+ in the solution (Ringer Sr2+) revealed that hypericin (4 microM) prolonged the AP duration (APD). Hypericin dose-dependently increased the magnitude of the Sr2+current, which develops through L-type Ca2+ channels in the Ringer solution containing tetrodotoxin (0.7 microM) and tetraethylammonium (10 mM), but did not modify the kinetics of activation and inactivation. This revealed that hypericin increased L-type Ca2+ channel conductance, which accounted for the APD lengthening. The hypericin-induced APD lengthening recorded in the Ringer Sr2+ was not prevented by (i) a blockade of alpha- and beta-adrenoceptors by yohimbine (1 microM), urapidil (1 microM), and propanolol (50 microM), respectively, and (ii) PKC blockade by staurosporine (1 microM). The hypericin-induced APD lengthening recorded in the Ringer Sr2+ was prevented by blocking soluble guanylate cyclase (sGC) activity by 1H-[1,2,4]-oxadiazolo[4,3-a]quinoxalin-1-one (13 microM), which mimicked the effects of hypericin. Hypericin decreased the cellular cGMP level by 69% in atrial myocytes. The compound also decreased the cellular cGMP level by inhibiting sGC, thus cancelling the nucleotide inhibitory effect on the cardiac L-type Ca2+ channel.

High ethanol preferring rats fail to show dependence following short- or long-term ethanol exposure.

AIMS: The high ethanol preferring (HEP) rat shows high total ethanol consumption, high spontaneous activity and high consumption of novel tastants. Because these animals consume large quantities of ethanol daily, we sought to determine whether they could become alcohol-dependent by repeated exposures of varying lengths and withdrawals of alcohol, both in short- and long-term ethanol exposure. METHODS: Male and female HEP rats were subjected to short (14 days) or long (20 weeks) exposure to 10% ethanol in a two choice (vs. water) test. During the short- and long-term ethanol exposures, the animals were repeatedly deprived of ethanol for 5 days followed by reinstatement of the two-choice test. Moreover, pharmacological interventions (morphine and naltrexone), adulteration of ethanol by quinine and addition of saccharine to water were applied to test the lability of a possible alcohol deprivation effect. RESULTS: In every case, deprivation produced a high initial intake of ethanol that lasted 0.5 h, but thereafter no significant increase in alcohol consumption, compared to predeprivation. Even after several months of continuous drinking of large amounts of ethanol, the animals were sensitive to adulteration of the alcohol solution by quinine, that reduced the intake, and still preferred a saccharine solution when presented as a free choice with the alcohol solution. Pretreatment with morphine increased ethanol consumption in the first 0.5 h following deprivation, whereas naltrexone reduced it. CONCLUSIONS: Taste reinforcement is probably a major component of alcohol drinking by the HEP rats, and that while these rats consume large quantities of ethanol both in the short- and long-term, they do not show a robust alcohol deprivation effect.

Effects of zolpidem and zaleplon on sleep, respiratory patterns and performance at a simulated altitude of 4,000 m.

The effects of zolpidem or zaleplon on sleep architecture, respiratory patterns and performance were assessed at a simulated altitude of 4,000 m. Twelve male healthy subjects spent 4 nights in a decompression chamber, 1 at sea level (baseline), 3 at 4,000 m to test zolpidem (10 mg), zaleplon (10 mg) and placebo, given 15 min before switching the lights off. Sleep and respiratory patterns were analysed using polysomnography. Cognitive and physical performance was examined the next morning at sea level conditions. The study demonstrates that both zolpidem and zaleplon improved slow wave sleep at altitude, with zolpidem showing more marked effects than zaleplon. Both agents did not adversely affect respiration at altitude during the night, or cognitive or physical performance the next morning at the dosages used in this study. Thus, climbers may safely use both hypnotic agents.

Genetics of behaviour: phenotypic and molecular study of rats derived from high- and low-alcohol consuming lines.

The aim of this study was to analyse the genetic basis of excessive ethanol consumption and its relationship with emotional reactivity. The high-ethanol preferring line of rats used is characterized by a: (i) high voluntary consumption of alcohol; (ii) high sensitivity to taste reinforcement (saccharine, quinine); (iii) high locomotor activity in a novel environment; and (iv) low emotional reactivity, these features being opposite in the Wistar-Kyoto (WKY) rat strain. The F2 population demonstrated a very large variability in these behavioural traits, and factor analysis revealed that these characteristics appear to be largely unrelated to each other. The molecular bases for these differences were investigated by quantitative trait loci (QTL) analysis. For this purpose, the 196 F2 rats were genotyped with regularly distributed markers on the whole genome, and genetic linkage maps were generated for all subsequent QTL analyses. A locus with a maximum LOD score of 7.6 and accounting for approximately 61% of the genetic variance of the trait in the F2 population was detected on chromosome 4 for alcohol drinking. In the same region, we found a QTL related to the reinforcement properties of saccharin, with a significant LOD score of 4.9 and explaining 46% of the variance of the trait. Other significant QTL were found for plus maze behaviour and open field activity on chromosome 1. Current research aims to identify the gene(s) involved.

Does lindane (gamma-hexachlorocyclohexane) increase the rapid delayed rectifier outward K+ current (IKr) in frog atrial myocytes?

BACKGROUND: The effects of lindane, a gamma-isomer of hexachlorocyclohexane, were studied on transmembrane potentials and currents of frog atrial heart muscle using intracellular microelectrodes and the whole cell voltage-clamp technique. RESULTS: Lindane (0.34 microM to 6.8 microM) dose-dependently shortened the action potential duration (APD). Under voltage-clamp conditions, lindane (1.7 microM) increased the amplitude of the outward current (Iout) which developed in Ringer solution containing TTX (0.6 microM), Cd2+ (1 mM) and TEA (10 mM). The lindane-increased Iout was not sensitive to Sr2+ (5 mM). It was blocked by subsequent addition of quinidine (0.5 mM) or E-4031 (1 microM). E-4031 lengthened the APD; it prevented or blocked the lindane-induced APD shortening. CONCLUSIONS: In conclusion, our data revealed that lindane increased the quinidine and E-4031-sensitive rapid delayed outward K+ current which contributed to the AP repolarization in frog atrial muscle.