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Under summer-like photoperiods (15∶9 L∶D) with abundant high-quality food, larval growth and development of the baetid mayflies (Ephemeroptera) Cloeon dipterum -IS1 and C. dipterum -CT1 were predictable and linear across a wide temperature range (14–30°C). However, some individuals exhibited larval quiescence with delayed adult emergence at a substantially larger size under certain combinations of photoperiod, temperature, and larval density. Results from a series of experiments indicate that photoperiod appears to be the primary factor underlying larval quiescence because at 20°C and short day length (10∶14 L∶D), cohorts split, with 1 group growing and developing quickly and the other entering a quiescence. The proportion of larvae exhibiting quiescence became progressively greater when temperatures declined, larval densities increased, and exposure to short day length occurred earlier in development. However, subsequent increases in day length terminated the quiescence, and larvae resumed normal (fast) growth and development. We show that larvae remain active and continue to feed, grow, and molt (albeit slowly) during quiescence. However, because development appears to be slowed proportionately more than growth at a given temperature, adult size and fecundity of larvae that enter quiescence is significantly greater. Cloeon dipterum -IS1 and C. dipterum -CT1 are multivoltine and, like many mayflies, overwinter as aquatic larvae. The species are ovoviviparous such that mated adult females must gestate their eggs for 2 wk or longer prior to oviposition, and we show that this process becomes less successful at progressively colder air temperatures. We propose that the adaptive significance of larval quiescence includes the avoidance of low reproductive success likely to be experienced by adults emerging in the fall. Thus, quiescence delays some adult emergence until the following spring when conditions for gestation may be more favorable. We also propose that larval quiescence induced by photoperiod may be widespread in mayflies and might contribute to the seasonal variability observed in adult size and fecundity for both univoltine and multivoltine species. [ABSTRACT FROM AUTHOR]

Presents a study which gave an account of an experimental series in which higher-density regions of ablatively accelerated planar targets were imaged by flash x radiography. Factors needed to study the uniformity and stability of the ablative acceleration process; Results of x-ray backlighting studies of planar foil targets of constants areal mass accelerated with the Pharos II laser system; Geometric factors that would present a thicker appearance to a highly absorbing planar object.

We employ molecular methods to profile the diet of the little brown bat, Myotis lucifugus, and describe spatial and temporal changes in diet over their maternity season. We identified 61 prey species of insects and 5 species of arachnid. The largest proportion of prey (∼32%) were identified as species of the mass-emerging Ephemeroptera (mayfly) genus Caenis. Bats roosting in agricultural settings had lower dietary richness than those occupying a roost located on a forest fragment in a conservation area. We detected temporal fluctuations in diet over the maternity season. Dipteran (fly) species dominated the diet early in the season, replaced later by species of mayfly. Because our methodology provides species-level identification of prey, we were able to isolate environmental indicator species in the diet and draw conclusions about the location and type of their foraging habitat and the health of these aquatic systems. The species detected suggested that the bats use variable habitats; members of one agricultural roost foraged on insects originating in rivers or streams while those in another agricultural roost and the forest roost fed on insects from pond or lake environments. All source water for prey was of fair to good quality, though no species detected are intolerant of pollution thus the habitat cannot be classified as pristine. Our study outlines a model system to investigate the abiotic and biotic interactions between habitat factors through this simple food chain to the top predator. [ABSTRACT FROM AUTHOR]

The imaging findings of a case of metastasing meningioma are described. The case illustrates a number of rare and interesting features. The patient presented with haemoptysis 22 years after the initial resection of an intracranial meningioma. CT demonstrated heterogeneous masses with avid peripheral enhancement without central enhancement. Blood supply to the larger lesion was partially from small feeding vessels from the inferior pulmonary vein. These findings correlate with a previously published case in which there was avid uptake of fluoro-18-deoxyglucose peripherally with lesser uptake centrally. The diagnosis of metastasing meningioma was confirmed on percutaneous lung tissue biopsy. [ABSTRACT FROM AUTHOR]

When calves are weaned abruptly off large amounts of milk, weight gain is reduced as a result of low intake of starter. We compared gradual and abrupt weaning of 40 calves allowed to drink up to 12 kg of milk/d by automated feeders, housed in groups of 4, and weaned at 41 d abruptly or over 3 gradual weaning periods (4, 10, or 22 d), with one calf within each group randomly allocated to each treatment, balancing for sex and birth weight. During the milk-feeding period, the calves weaned over 22 d drank the least milk and ate the most starter, but these calves had the lowest total digestible energy intake and weight gains. The abruptly weaned calves had the highest digestible energy intakes and weight gains during the period before weaning. During the 9 d following weaning, the calves weaned over 22 and 10 d ate more starter and had better weight gains than abruptly weaned calves and those weaned over 4 d. Abruptly weaned calves lost weight during this period. In summary, gradual weaning improved starter intake, but because of reduced milk availability, this resulted in reduced total digestible energy intake before weaning. Weaning over 10 d resulted in the best overall weight gains over the study. [ABSTRACT FROM AUTHOR]