Assessment of the effects of sex, age, and rearing condition on ultrasonic vocalizations elicited by pups during the maternal potentiation paradigm in C57BL/6J mice

Isolation-induced ultrasonic vocalizations (USVs) are important to elicit parental retrieval. This behavior is critical for the animal's survival and can be altered in models of developmental disorders. The potentiation of vocalizations in response to reunion with the dam, also called maternal potentiation, has been extensively studied in rats. However, the assessment of this paradigm in mice is scarce. In rats, the potentiation of vocalizations is dependent on rearing conditions. Since mice are the main species used for genetic models of diseases, we aimed to investigate how different factors such as age, sex, and rearing conditions can affect the potentiation of vocalizations in the maternal potentiation paradigm in mice. We carried out experiments using biparental (dam and sire) or uniparental rearing (dam). Pups were tested on postnatal days (PD) 9 or 12. Pups showed increased potentiation in both sexes at PD9 with uniparental rearing. Both rearing conditions and ages changed the repertoire from the first to the second isolation. Spectral parameters were affected by sex, rearing condition and reunion at PD9. At PD12, only duration was altered by reunion. We conclude that the performance of the pups in the maternal potentiation paradigm is dependent on age, sex, and rearing condition.

Sorption and degradation characteristics of phosmet in two contrasting Australian soils

The organophosphate insecticide phosmet [phosphorodithioic acid, s-((1,3-dihydro-1,3-dioxo-2H-isoindol-2yl)methyl), o,o-dimethyl ester] is used to control red-legged earth mites (Halotydeus destructor), lucerne flea (Sminthurus viridis), and Oriental fruit moth (Cydia molesta) in horticulture and vegetable growing. This study was undertaken with two soils of contrasting properties to determine the extent to which sorption and degradation of the insecticide might influence its potential to leach from soil into receiving waters. Two soils were used: a highly organic, oxidic clay soil (Ferrosol) and a sandy soil low in organic matter (Podosol), sampled to 0.3 m depth. The extent of sorption and decomposition rate of a phosmet commercial formulation were measured in laboratory experiments. Sorption followed a Freundlich isotherm at all depths. The Freundlich coefficient K was significantly correlated (p = 0.005) with organic C content in the Podosol, and significantly correlated (p = 0.005) with organic C and clay content in the Ferrosol. K was highest (48.8 L kg-1) in the 0- to 0.05-m depth of the Ferrosol, but lowest (1.0 L kg-1) at this depth in the Podosol. Degradation followed first-order kinetics, with the phosmet half-life ranging from 14 h (0-0.05 m depth) to 187 h (0.2-0.3 m depth) in the Ferrosol. The half-life was much longer in the sandy Podosol, ranging from 462 to 866 h, and did not change significantly with depth. Soil organic C and to a lesser degree clay content influenced phosmet sorption and degradation, but the interaction was complex and possibly affected by co-solvents present in the commercial formulation.

Cocaine and development: a retrospective perspective

Neurobehavioral alterations evident in offspring of Sprague-Dawley rat dams exposed to 40 mg/kg/day cocaine subcutaneously from gestational days 8-20 are reviewed. Consequences for offspring are often age dependent: for instance, reliable deficits in classical conditioning are evident during the early postnatal period, whereas cognitive effects are less pervasive in adulthood, although apparent in tasks such as reversal training. Gender of offspring is another variable of importance, particularly when testing animals in adulthood, with adult male offspring being more likely than their female counterparts to exhibit alterations following the prenatal exposure regimen. Characteristics of the test situation likewise influence detection of outcome effects, with effects particularly likely to emerge under stressful testing conditions or other challenges to the organism. Under these circumstances, alterations in responsiveness to stressors also sometimes emerged in offspring of pair-fed (PF) dams (whose food intake was restricted to match that of cocaine-exposed [COC] dams); these findings perhaps should not be surprising given that pair feeding is a stressor and prenatal stress is known to alter later stressor responsiveness. Although several approaches to equate food intake or avoid pair feeding have yielded disappointing findings, one promising approach is to initiate cocaine administration prior to mating followed by exposure throughout gestation. Premating exposure to cocaine was sufficient to eliminate anorexic effects of drug delivery during pregnancy, although it remains to be seen how similar the pattern of neurobehavioral alterations that emerge with this extended exposure regimen will be to effects seen following more restricted gestational exposure.

Adrenoleukodystrophy: a nursing challenge

Adrenoleukodystrophy has only recently been recognized as a disorder unique to children. Its debilitating sequelae have a profound impact on the physical, psychosocial, and cognitive development of children. Superimposed on coping with the crisis of illness is the stressor of hospitalization, a common experience for children with adrenoleukodystrophy. This article focuses on nursing's contribution to facilitating children's adaptation to the stressors of a progressive disorder, adrenoleukodystrophy, and hospitalization. Utilizing a developmental approach, the psychosocial needs of these children are addressed in a format based on the nursing process.

Effects of time of urea application on combine-sown Calrose rice in south-east Australia. II. Mineral nitrogen transformations in the soil-water system

A combine-sown crop of Calrose rice was grown on an alkaline self-mulching, grey clay soil. Prilled urea was broadcast onto the dry soil surface or into the floodwater at one of four different times: sowing, before permanent flood, after permanent flood or panicle initiation. Within 24 days of fertilisation at sowing, levels of extractable N in the control and fertilised treatments were not significantly different. The rapid disappearance of fertiliser N was associated with rapid loss of NO-3 from the top 20 cm, and this loss appeared to be due to denitrification rather than leaching. The notable difference between fertilisation before and after permanent flood was the distribution of the fertiliser N in the soil and water. Fertiliser applied to the dry soil before flooding was carried deeper into the soil, while fertiliser applied a few hours later into the floodwater was located in the water and top 2 cm of soil. Therefore the potential for loss by ammonia volatilisation and nitrification/denitrification was probably higher in the latter treatment. Fertiliser N topdressed at panicle initiation was also located in the floodwater and top 2 cm of soil. However, fertilisation at this later growth stage was not associated with a yield decline when compared with fertilisation before permanent flood (Part I). Presumably this reflected the greater ability of the plants to compete with the processes leading to fertiliser N loss at this later growth stage, together with a lower ammonia volatilisation potential due to the influence of greater canopy cover on various factors influencing ammonia volatilisation. The data suggested that the efficiency of fertilisation at sowing and before permanent flood might be improved further by deep placement of the fertiliser or by use of a nitrification inhibitor.

Effects of soil salinity and mineral nitrogen on the acetylene reduction activity of Trifolium subterraneum

Subterranean clover (Trifolium subrerraneum L.) was grown under controlled environmental conditions in pots containing a variety of soils. Non-destructive assays were used to measure rates of acetylene (C2H2) reduction by the plants. Soil mineral nitrogen (N) status and, to a lesser extent, soil salinity were found to be the most important soil properties relating to the development of C2H2reduction activity in subterranean clover. Application of KNO3 to pots resulted in an immediate decrease in the rate of C2H2reduction. A linear relationship was found between the loss in C,H, reduction activity and the amount of N applied up to 40 mg N kg-1 soil. Addition of salt (NaCl) to pots caused an immediate decrease in C2H2 reduction activity, followed by a gradual recovery. A linear relationship was found between the loss in C2H2 reduction activity and the level of soil salinity induced by salt addition. The loss in C2H2reduction \vas reflected in the lower total N content of the plants when soil salinity levels exceeded 4 mS cm-1.