Measuring temporal variability in pore-fluid chemistry to assess gas hydrate stability: development of a continuous pore-fluid array.

A specialized pore-fluid array (PFA) sampler was designed to collect and store pore fluids to monitor temporal changes of ions and gases in gas hydrate bearing sediments. We tested the hypothesis that pore-fluid chemistry records hydrate formation or decomposition events and reflects local seismic activity. The PFA is a seafloor probe that consists of an interchangeable instrument package that houses OsmoSamplers, long-term pore-fluid samplers, a specialized low-dead volume fluid coupler, and eight sample ports along a 10 m sediment probe shaft. The PFA was deployed at Mississippi Canyon 118, a Gulf of Mexico hydrate site. A 170 day record was acquired from the overlying water and 1.3 m below seafloor (mbsf). Fluids were measured for dissolved chloride, sulfate, and methane concentrations and dissolved inorganic carbon and methane stable carbon and deuterium isotope ratios. Chloride and sulfate did not change significantly over time, suggesting the absence of gas hydrate formation or decomposition events. Over the temporal record, methane concentrations averaged 4 mM at 1.3 mbsf, and methane was thermogenic in origin (delta13C-CH4 = -32.4 +/- 3.4 per thousand). The timing of an anomalous 14 mM methane spike coincided with a nearby earthquake (Mw = 5.8), consistent with the hypothesis that pore-fluid chemistry reflects seismic events.

Oxygen consumption in unfertilized salmonid eggs: an indicator of egg quality?

A negative correlation between oxygen consumption and fertility was observed in both steelhead and chinook salmon eggs. However, this relationship was attributed to bacterial growth. Elimination of samples with bacterial growth resulted in no significant relationship between the rate of oxygen consumption (VO2) and fertility. VO2 of unfertilized eggs of both steelhead and chinook salmon was measured over a storage period of up to 24 days (d). Despite declines in fertility during storage, VO2 did not significantly change throughout storage. The average respiration rate for steelhead eggs was 3.4 nmol O2 per egg per h, and was 4.3 nmol O2 per egg per h for chinook salmon eggs. Treatment of chinook salmon eggs with uncouplers of mitochondrial respiration, 2,4-dinitrophenol (2,4-DNP) and carbonyl cyanide 4-trifluoro-methoxyphenylhydrazone (FCCP), resulted in an increase in VO2 to 12.9 and 11.5 nmol O2 per egg per h, respectively. Treatment with the putative uncoupler, clove oil, resulted in no change in VO2, while KCN, an inhibitor of oxidative phosphorylation, reduced oxygen consumption to zero. Copper caused an increase in oxygen consumption, even in the absence of eggs, suggesting a need for caution in interpreting changes in respiration rates as a result of metal exposure. Thus, unfertilized salmonid eggs demonstrated submaximal VO2, which was not correlated with fertility.

Morphine metabolism in the pregnant guinea pig and her pups.

The study of chronic in utero exposure to heroin and morphine in the human is limited by polysubstance abuse. The guinea pig was used as a model for the human to determine the in vivo and in vitro effect of chronic morphine exposure on morphine metabolism in the pregnant dam and her offspring. In vivo pharmacokinetics of morphine were examined in pregnant guinea pigs following pretreatment with either saline or morphine. In vitro hepatic enzyme kinetics were also examined in a similar group of pregnant dams and their fetuses. Additional pregnant dams were allowed to give birth and their pups' enzyme kinetics were studied at 1, 3, and 7 days. Apparent V(MAX) for the formation of both morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G) formation was significantly increased in the morphine-treated pregnant guinea pig. However, no effect of morphine treatment was detectable on the in vivo pharmacokinetics of morphine in the pregnant dam. The apparent morphine K(M) for the formation of M3G was significantly different than the apparent K(M) for the formation of M6G. Significant age effects on the enzyme kinetics were found. The apparent V(MAX) for the formation of both glucuronides increased through the neonatal period. Through literature comparisons, the guinea pig was shown to have in vivo pharmacokinetics similar to the pregnant human, and the guinea pig pups were found to have enzyme development consistent with in vivo pharmacokinetic development seen in human neonates, infants and children.

Optical and thermal characterization of natural (Sepia officinalis) melanin.

The optical properties and the thermal diffusivity of natural cuttlefish (Sepia officinalis) melanin have been measured. The optical absorption and scattering properties of melanin particles were determined at 580 nm and 633 nm, using photometric and photothermal techniques. For the photometric studies, the absorption and the transport scattering coefficients were determined from the measurements of diffuse reflectance and transmittance. The scattering anisotropy was obtained from an additional measurement of the total attenuation coefficient and independently obtained by goniometry. For photothermal studies, pulsed photothermal radiometry was used to deduce the absorption and transport scattering coefficients via a model based on optical diffusion theory. Pulsed photothermal radiometry was also used to provide the thermal diffusivity of solid melanin pressed pellets.

Applying a DRO schedule and compliance training to reduce aggressive and self-injurious behavior in an autistic man: a case report.

An autistic man who displayed aggressive, self-injurious, and destructive behavior in a psychiatric hospital ward despite administration of psychotropic medications and repeated application of physical restraints was treated with a differential reinforcement of other behavior (DRO) schedule and compliance training. These were employed in conjunction with ongoing medical interventions. After introduction of behavioral procedures, the frequency of applying restraints for violent behavior declined from an average of more than once per day to less than once per month. Data taken while the program was maintained over a 1-year period showed that violent behavior remained at a very low level.

Re-establishing conversational skills in overtly psychotic, chronic schizophrenic patients. Discrete trials training on the psychiatric ward.

A discrete trials procedure incorporating graduated prompts, social and consumable reinforcement, corrective feedback, delay of reinforcement, and a chaining procedure was used to teach four actively psychotic, chronic schizophrenic patients rudimentary conversational skills. In a multiple-baseline design, training was sequentially applied to the target conversational skills of giving a salutation, addressing the trainer by his or her name, making a personal inquiry, and asking a conversational question. Results showed systematic training effects in three of the four subjects. Training gains were reliable but slow, requiring over 70 trials to reach acquisition criterion on certain skills. The fourth subject exhibited only unstable gains on the first target response and minor improvements on the second target response, the latter of which disappeared when training procedures were withdrawn. All subjects displayed spontaneous recovery on the generalization measure of answering a personal inquiry.

Combating poster fatigue: how to use visual grammar and analysis to effect better visual communications.

Posters are increasingly being used as a medium for the communication of results and ideas. The organization and presentation of a poster plays an important role in the facilitation of effective communication. In this article John D. Woolsey describes how best to maximize the visual impact of a poster.

Behavioral treatment of violent psychiatric patients.

This article reviewed major accelerative and decelerative behavioral treatments for aggressive and destructive behavior in psychiatric patients. Accelerative procedures supplant antagonistic behavior by teaching adaptive skills, and by strengthening competing responses; they are realized in token economies, social skills training, differential reinforcement of other behavior, and activity programming. Current decelerative procedures reduce violent behavior by decreasing reinforcement accessible to the patient following violent acts; they are exemplified by social extinction, response cost, time out from reinforcement, overcorrection, and contingent restraint. All behavioral interventions are applied within a philosophic framework that emphasizes observable behavior, measurement of treatment effects, and restructure of the social and physical environment to improve patients' response patterns. This approach extends beyond a problem-oriented model and presents proven techniques for developing and maintaining patients' adaptive functioning.