The time factor in mortality: weather associations in a subtropical environment

 Mortality rates for a decade in Brisbane are analysed for dependence upon atmospheric factors. Time filters are applied to both the dependent and independent variables, and several models are developed to enable prediction, especially for weekly intervals. Statistically, deaths are observed to increase with colder and less humid weather with winds from a westerly, direction. Overall, taking account of both synoptic and seasonal influences, >90% of cumulative deviations from mean death rates are explained. Some differences are also noted in the association of death with the weather between sexes, age groups and causes of death. Received: 2 November 1995 / Accepted: 26 December 1996     

Response of predatory zooplankton populations to the experimental acidification of Little Rock Lake, Wisconsin

To assess the effects of lake acidification on large predatoryzooplankton, we monitored population levels of four limnetictaxa for 6 years in a lake with two basins, one of which wasexperimentally acidified (2 years at each of three levels: pH5.6, 5.2 and 4.7). Concentrations of phantom midge (Chaoborusspp.), the most abundant large predator, remained similar inthe treatment and reference basins until the fourth year (pH5.2) when they increased in the treatment basin. In contrast,Epischuru lacustris and Leptodora kindtii disappeared from limneticsamples, and water mites declined to near zero upon acidification.Treatment basin populations of E.Iacustris declined sharplyduring the second year of acidification. The nature of the declinesuggested sensitivity of an early life stage during the firstyear at pH 5.6. Leptodora kindtii showed no population responseat pH 5.6, but declined to essentially zero at pH 5.2. Treatmentbasin populations of water mites fluctuated until decliningin the fifth and sixth years (pH 4.7). These changes indicatea variety of direct and indirect responses to lake acidification.     

A combination plastic permeable film system for controlling post-harvest mushroom quality

Summary A combination of microporous and a relatively impermeable film was used to overwrap mushrooms. The modified atmosphere created by respiration could be controlled by adjusting the area of microporous film which in turn reduced the loss of mushroom quality assessed by developmental stage, colour, weight loss and disease incidence.