Western Australian primary school teachers knowledge about childhood asthma and its management

A total of 164 primary school teachers from Perth, Western Australia anonymously completed a survey of their knowledge and attitudes about asthma. These teachers were active in assisting children with asthma management but most (91.5%) felt that they did not know enough about asthma. Attitudes toward children with asthma were positive; 97% agreed that such children should be encouraged to participate in sporting activities. Specific knowledge about asthma management and medications was, however, poor. This large sample of Western Australian teachers knew more than their European counterparts but asthma training is needed and should be targeted at improving knowledge of both regular and emergency treatments for asthma.

Free volume and water uptake in a copolymer hydrogel series

A copolymer of X-hydroxyethyl methacrylate (HEMA) with 2-ethoxy ethyl methacrylate (EEMA) was synthesized and the molecular mobility, free volume, and density properties examined as a function of composition. These properties were correlated with the equilibrium water uptake in order to determine which of the properties were most influential in causing high water sorption, as these materials are suitable candidates for hydrogel systems. It was found that the polar HEMA repeat unit results in a rigid, glassy sample at room temperature due to the high degree of hydrogen bonding between chains whereas high EEMA content leads to rubbery samples with subambient glass transition temperatures. The free volume properties on the molecular scale measured by positron annihilation Lifetime spectroscopy (PALS) showed that higher HEMA content led to smaller, fewer holes and a lower free volume fraction than EEMA. Therefore the high water uptake of HEEMA-containing copolymers is largely related to the high polarity of the HEMA unit compared to EEMA, despite the low content of free volume into which the water can initially diffuse. Trends in density with copolymer composition, as measured on a macroscopic level, differs to that seen by PALS and indicates that the two techniques are measuring different scales of packing. (C) 1998 John Wiley & Sons, Inc.

A mathematical model for estimating the extent of solute- and water-flux heterogeneity in multiple sample percolation experiments

Multiple sampling is widely used in vadose zone percolation experiments to investigate the extent in which soil structure heterogeneities influence the spatial and temporal distributions of water and solutes. In this note, a simple, robust, mathematical model, based on the beta-statistical distribution, is proposed as a method of quantifying the magnitude of heterogeneity in such experiments. The model relies on fitting two parameters, alpha and zeta to the cumulative elution curves generated in multiple-sample percolation experiments. The model does not require knowledge of the soil structure. A homogeneous or uniform distribution of a solute and/or soil-water is indicated by alpha = zeta = 1, Using these parameters, a heterogeneity index (HI) is defined as root 3 times the ratio of the standard deviation and mean. Uniform or homogeneous flow of water or solutes is indicated by HI = 1 and heterogeneity is indicated by HI > 1. A large value for this index may indicate preferential flow. The heterogeneity index relies only on knowledge of the elution curves generated from multiple sample percolation experiments and is, therefore, easily calculated. The index may also be used to describe and compare the differences in solute and soil-water percolation from different experiments. The use of this index is discussed for several different leaching experiments. (C) 1999 Elsevier Science B.V. All rights reserved.

Habitat structure and egg distributions in the processionary caterpillar Ochrogaster lunifer: lessons for conservation and pest management

1. The spatial and temporal distribution of eggs laid by herbivorous insects is a crucial component of herbivore population stability, as it influences overall mortality within the population. Thus an ecologist studying populations of an endangered butterfly can do little to increase its numbers through habitat management without knowledge of its egg-laying patterns across individual host-plants under different habitat management regimes. At the other end of the spectrum, a knowledge of egg-laying behaviour can do much to control pest outbreaks by disrupting egg distributions that lead to rapid population growth. 2. The distribution of egg batches of the processionary caterpillar Ochrogaster lunifer on acacia trees was monitored in 21 habitats during 2 years in coastal Australia. The presence of egg batches on acacias was affected by host-tree 'quality' (tree size and foliar chemistry that led to increased caterpillar survival) and host-tree 'apparency' (the amount of vegetation surrounding host-trees). 3. In open homogeneous habitats, more egg batches were laid on high-quality trees, increasing potential population growth. In diverse mixed-species habitats, more egg batches were laid on low-quality highly apparent trees, reducing population growth and so reducing the potential for unstable population dynamics. The aggregation of batches on small apparent trees in diverse habitats led to outbreaks on these trees year after year, even when population levels were low, while site-wide outbreaks were rare. 4. These results predict that diverse habitats with mixed plant species should increase insect aggregation and increase population stability. In contrast, in open disturbed habitats or in regular plantations, where egg batches are more evenly distributed across high-quality hosts, populations should be more unstable, with site-wide outbreaks and extinctions being more common. 5. Mixed planting should be used on habitat regeneration sites to increase the population stability of immigrating or reintroduced insect species. Mixed planting also increases the diversity of resources, leading to higher herbivore species richness. With regard to the conservation of single species, different practices of habitat management will need to be employed depending on whether a project is concerned with methods of rapidly increasing the abundance of an endangered insect or concerned with the maintenance of a stable, established insect population that is perhaps endemic to an area. Suggestions for habitat management in these different cases are discussed. 6. Finally, intercropping can be highly effective in reducing pest outbreaks, although the economic gains of reduced pest attack may be outweighed by reduced crop yields in mixed-crop systems.

Simultaneous X-ray imaging of plant root growth and water uptake in thin-slab systems

Direct and simultaneous observation of root growth and plant water uptake is difficult because soils are opaque. X-ray imaging techniques such as projection radiography or Computer Tomography (CT) offer a partial alternative to such limitations. Nevertheless, there is a trade-off between resolution, large field-of-view and 3-dimensionality: With the current state of the technology, it is possible to have any two. In this study, we used X-ray transmission through thin-slab systems to monitor transient saturation fields that develop around roots as plants grow. Although restricted to 2-dimensions, this approach offers a large field-of-view together with high spatial and dynamic resolutions. To illustrate the potential of this technology, we grew peas in 1 cm thick containers filled with soil and imaged them at regular intervals. The dynamics of both the root growth and the water content field that developed around the roots could be conveniently monitored. Compared to other techniques such as X-ray CT, our system is relatively inexpensive and easy to implement. It can potentially be applied to study many agronomic problems, such as issues related to the impact of soil constraints (physical, chemical or biological) on root development.

Alleviation of dormancy in annual ryegrass (Lolium rigidum) seeds by hydration and after-ripening

The effect of hydration (priming) treatment on dormancy release in annual ryegrass seeds from two populations was investigated. Hydration duration, number, and timing with respect to after-ripening were compared in an experiment involving 15 treatment regimens for 12 wk. Seeds were hydrated at 100% relative humidity for 0, 2, or 10 d at Weeks 1, 6, or 12 of after-ripening. Dormancy status was assessed after each hydration treatment by measuring seed germination at 12-hourly alternating 25/15 C (light/dark) periods using seeds directly from the hydration treatment and seeds subjected to 4 d postpriming desiccation. Seeds exposed to one or more hydration events during the 12 wk were less dormant than seeds that remained dry throughout after-ripening. The longer hydration of 10 d promoted greater dormancy loss than either a 2-d hydration or no hydration. For the seed lot that was most dormant at the start of the experiment, two or three rather than one hydration event or a hydration event earlier rather than later during after-ripening promoted greater dormancy release. These effects were not significant for the less-dormant seed lot. For both seed lots, the effect of a single hydration for 2 d at Week 1 or 6 of after-ripening was not manifested until the test at Week 12 of the experiment, suggesting that the hydration events alter the rate of dormancy release during subsequent after-ripening. A hydrothermal priming time model, usually used for modeling the effect of priming on germination rate of nondormant seeds, was successfully applied to dormancy release resulting from the hydration treatments.

Sheep rumen digestion and transmission of weedy Malva parviflora seeds

The effect of sheep digestion and mastication on Malva parviflora L. seed transmission, viability and germination was investigated. Mature M. parviflora seeds were subjected to 2 seed treatments: 'scarified', where the hard seed coat was manually cut to allow inhibition, and 'unscarified', where the hard seed coat was not cut. Seeds were placed directly into the rumen of fistulated sheep and removed at 0, 12, 24, 36 and 48 h of rumen digestion. After 12 h of in sacco exposure to digestion in the rumen, the germination of seeds that were initially scarified dropped from 99.2 to 1.4% and longer exposure periods produced no germinable seeds. In contrast, seeds that were unscarified when placed in the rumen produced over 92% germination regardless of in sacco digestion time, although manual scarification after retrieval was essential to elicit germination. In a second experiment, unscarified seeds (29000) were fed in a single meal to fistulated sheep and feces were collected at regular intervals between 6 and 120 h after feeding. Fecal subsamples were taken to determine number of seeds excreted, seed germination on agar and seed germination from feces. Major seed excretion in the feces commenced after 12 h and continued until 144 h, with peaks between 36 and 72 h after consumption. Although mastication and gut passage killed the majority of unscarified seeds, about 20% were recovered intact and over 90% of these recovered seeds were viable and could, thus, potentially form an extensive seed bank. A few excreted seeds (1%) were able to germinate directly from feces, which increased to a maximum of 10% after subsequent dry summer storage (3 months). Through information gained in this study, there is a potential to utilise livestock in an integrated weed management program for the control of M. parviflora, provided additional measures of weed control are in place such as holding periods (> 7 days) for movement of livestock from weed infested areas.

Orofacial granulomatosis: A diagnostic problem for the unwary and a management dilemma. Case reports

Orofacial granulomatosis is a condition that, may be difficult to diagnose for those unfamiliar with the entity. This paper describes two cases and addresses the presentation, pathogenesis and treatment. The clinical recognition of his condition is important as is the subsequent investigation by an appropriate specialist. Management of patients needs to take into account the results of further investigations, the patient's expectations, and the severity of the condition.

Diabetes, hyperglycemia and the management of cerebrovascular disease

Purpose of review Hyperglycemia is frequent in patients with cerebrovascular disease. This review article aims to summarize the recent evidence from observational studies that examined the adverse cerebrovascular effects of dysglycemic states as well as interventional studies assessing intensive management strategies for hyperglycemia. Recent findings In recent years, diabetes, prediabetic states and insulin resistance and their association with cerebrovascular disease were an important focus of research. The cerebrovascular consequences of these metabolic abnormalities were found to extend beyond ischemic stroke to covert brain infarcts, other structural brain changes and to cognitive impairment with and without dementia. Interventional studies did not reveal that more intensive management of chronic hyperglycemia and of hyperglycemia in the setting of acute stroke improves outcome. There is clear evidence, however, that the overall management of multiple risk factors and behavior modification in patients with dysglycemia may reduce the burden of cerebrovascular disease. Summary Observational studies reveal the growing burden and adverse cerebrovascular effects of dysglycemic states. Currently available interventional studies assessing more intensive strategies for the management of hyperglycemia did not prove, however, to be effective. We discuss the current evidence, pathophysiological considerations and management implications.