Quantitative results from Environmental Management Systems (EMS) at primary schools have rarely been examined in literature. This paper presents the monitoring results of environmental care in 39 primary schools in Northern South Africa. During 2 years, after the EMS was implemented in the curriculum and in the school's management, the progress of environmental performances of the participating schools has been measured, by means of detailed questionnaires, related to four environmental aspects: water, waste, energy and greening. At the beginning of the project, 50% of the schools performed well on water-related environmental actions. Two years later it was 76%. For waste-related activities the improvement was even stronger: from 50% to 100%. The environmental performances of the schools improved also for greening-related actions, from 50% at the start of the project to 64% two years later. Only energy-related activities did not improve significantly with only 24% of all schools performing well at the end of the survey period.In general, the introduction of an EMS succeeded in an improvement of the overall environmental performances of the schools, but cost-intensive activities were less successful than others. 相似文献
Distribution and size variation of thecosomatous pteropods from the eastern Banda and western Arafura Sea (Indonesia) were studied during the southeast and northwest monsoon seasons in 1984 and 1985, respectively. During the SE monsoon the pteropod community presents evidence of a zoogeographic boundary located roughly along the Banda Arc, separating a Java and Banda Sea fauna in the west from a mixed imported Pacific and local upwelling fauna in the east. During the NW monsoon the boundary was not present and the Java and Banda Sea fauna, with Indian Ocean influences, was found thoughout the area. The observed patterns match the seasonal movements of watermasses in the area, and it is concluded that taxonomic composition and morphological data of the pteropod fauna are finetuned tracers of hydrography. 相似文献
One of the most important measures of offspring performance is growth rate, which is often traded off against another important survival trait, immune function. A particular feature of ostrich chicks maintained in farmed environments is that cohorts of chicks vary widely in size. As parents can have a profound effect on the phenotype and fitness of their offspring, we investigated whether chick growth and immune defence were related to variation in levels of immune defence in their genetic parents. As secondary sexual traits of sires could serve as indicators of male quality, and be used in female mating decisions, we also investigated whether chick growth rate and immune defence were related to male plumage and integumentary colouration. We found that offspring growth rates and humoral responses were related to the humoral responses of their parents, suggesting that at least some components of humoral immune capacity are heritable. The white colour of male ostrich feathers was correlated to the humoral response and growth rate of their offspring, suggesting that this visual cue involved in the male courtship display could serve as an important signal to females of male quality, thereby forming the basis of mate choice in this species. 相似文献
A tradeoff between immune response and life history traits, in particular growth rate, has been documented in various bird
species. Ostriches are fast-growing birds and a typical feature of cohorts is that offspring often differ greatly in size.
We investigated the relationship between hatching date and growth rate of chicks and both cell-mediated (measured using a
phytohaemagglutinin (PHA) injection) and humoral immune responses in ostrich chicks maintained on a research farm. Chicks
with higher growth rates had intermediate responses to both diphtheria and tetanus toxoids. By contrast, no relation between
growth rates and responses to PHA injection were found. We conclude that chick growth rate variation may be explained beyond
a certain threshold by a tradeoff between the humoral response and growth. Both responses to PHA injection and humoral responses
in chicks were found to decrease with chick hatching date. Within the context of ostrich farming, these results could partially
explain size variations observed in cohorts of chicks, as well as high mortality rates during their first 3 months of age. 相似文献
The ability of a plant cytochrome P450 to bind and metabolise plant endogenous molecules and xenobiotics was investigated.
The work was performed on the yeast-expressed CYP73A1, a cinnamate 4-hydroxylase isolated fromHelianthus tuberosus. CYP73 controls the general phenylpropanoid pathway and is likely to be one of the most abundant sources of P450 in the biosphere.
The enzyme shows a high selectivity toward plant secondary metabolites. Nevertheless, it oxygenates several small and planar
xenobiotics with low efficiency, including an herbicide (chlorotoluron). One xenobiotic molecule, 2naphthoic acid, is hydroxylated
with an efficiency comparable to that of the physiological substrate. This reaction was used to devise a fluorimetric test
for the rapid measurement of enzyme activity. A series of herbicidal molecules (hydroxybenzonitriles) are shown to bind the
active site without being metabolised. These molecules behave as strong competitive inhibitors of CYP73 with a Ki in the same micromolar range as the Km for the physiological substrate. It is proposed that their inhibition of the phenylpropanoid pathway reinforces their other
phytotoxic effects at the level of the chloroplasts. All our results indicate a strong reciprocal interaction between plant
P450s and xenobiotics. 相似文献
The electrodes in industrial precipitators collect many tons of dust daily, and the efficient transfer of this dust burden to the hoppers is a challenging problem in mechanical engineering. Many varieties of devices have been tried; hammers, vibrators, scrapers, water flushing, gas blasting, etc. Impact devices for this purpose are usually called “rappers.” Laboratory experiments described in this paper show that normal (perpendicular) rapping is more effective than shear rapping; that thick dust layers are more easily removed by rapping than thin ones; that rapping becomes easier with increasing temperature, within limits; and that the electrostatic forces acting upon the precipitated dust layer play an important role. Quantitative data are shown graphically. The relation of these results to previous studies by other investigators is discussed. 相似文献