A randomised clinical trial to evaluate the effect of a 67 % sodium bicarbonate-containing dentifrice on 0.2 % chlorhexidine digluconate mouthwash tooth staining.

Background: Gingivitis can develop as a reaction to dental plaque. It can be limited by curtailing plaque build-up through actions including tooth brushing and the use of medicinal mouthwashes, such as those containing chlorhexidine digluconate (CHX), that can reach parts of the mouth that may be missed when brushing. This study aimed to compare dental stain control of twice-daily brushing with a sodium fluoride (NaF) dentifrice containing 67 % sodium bicarbonate (NaHCO3) or a commercially available NaF silica dentifrice without NaHCO3, while using a mouthwash containing 0.

Playback of colony sound alters the breeding schedule and clutch size in zebra finch (Taeniopygia guttata) colonies.

The hypothesis that social stimulation, derived from the presence and activities of conspecifics, can hasten and synchronize breeding in colonies of birds was tested. A modified playback/recorder system was used to continuously exaggerate the amount of colony sound available to zebra finches throughout their courtship period. Males that heard 'sound supplements' generated from their own colony sang more than males in control colonies that did not receive playback; males that heard samples from a different colony, sang at an intermediate level.

Prey choice by marten during a decline in prey abundance.

We examined variation in diet choice by marten (Martes americana) among seasons and between sexes and ages from 1980-1985. During this period prey populations crashed simultaneously, except for ruffed grouse (Bonasa umbellus) which was common at the beginning and end of the study, and masked shrews (Sorex cinereus) which were abundant in 1983. Marten were catholic in selection of prey and made use of most available mammalian prey, ruffed grouse, passerine birds, berries, and insects.

Predator foraging success and habitat complexity: quantitative test of the threshold hypothesis.

Numerous studies have demonstrated a negative relationship between increasing habitat complexity and predator foraging success. Results from many of these studies suggest a non-linear relationship, and it has been hypothesised that some "threshold level" of complexity is required before foraging success is reduced significantly. We examined this hypothesis using largemouth bass (Micropterus salmoides) foraging on juvenile bluegill sunfish (Lepomis macrochirus) in various densities of artificial vegetation.