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Heavy Machinery (heavy + machinery)

Distribution by Scientific Domains

Life Sciences	50%

Selected Abstracts

Methamphetamine use among Australian workers and its implications for prevention

DRUG AND ALCOHOL REVIEW, Issue 3 2008
Professor ANN M. ROCHE Director
Abstract Introduction and Aims. Little attention has been directed to the use of methamphetamine among Australian workers. To address this, a study was conducted that examined drug consumption patterns of the Australian work-force. Design and Method. A secondary analysis of the 2004 National Drug Strategy Household Survey (NDSHS) data was undertaken that focused on methamphetamine use among those in paid employment. Results. Methamphetamine use in the past 12 months was reported by 4.0% of workers compared to 2.2% of respondents not in the paid work-force. A larger proportion of male (4.8%) than female workers (3.0%) used methamphetamine. The highest prevalence occurred among 18,29-year-old workers (11.2%; males: 12.6%; females: 9.4%), and among workers in hospitality (9.5%), construction (5.4%) and transport (5.4%) industries and among tradespeople (6.5%). Significantly more methamphetamine users reported absenteeism compared to users of other illicit drugs and non-drug users. Among respondents reporting methamphetamine use, 13.4% reported absenteeism due to illicit drug use, while 56.8% reported absenteeism due to any illness or injury. Significantly more methamphetamine users (32.9%) reported going to work under the influence than users of other illicit drugs. Compared to users of other illicit drugs, methamphetamine users were also significantly more likely to drive a car, operate heavy machinery or abuse someone while under the influence. Discussion and Conclusions. The specific details of the profile of workers using methamphetamine and the impact it has on work performance allows for the development of targeted interventions and tailored prevention strategies previously not possible. [source]

Responses of ants to selective logging of a central Amazonian forest

JOURNAL OF APPLIED ECOLOGY, Issue 3 2000
H.L. Vasconcelos
Summary 1.,Relatively little information exists on the effects of logging on rain forest organisms, particularly in the Neotropics where logging operations have increased dramatically in recent years. In this study we determined experimentally the effects of selective logging of a central Amazonian forest on ground-living ants. 2.,The experimental design consisted of three 4-ha replicated plots representing control unlogged forest, forest logged 10 years prior to the start of the study (1987), and forest logged 4 years prior to the start of the study (1993). The logging operation removed 50% of the basal area of trees of commercial value, or about eight trees per hectare. This resulted in a significant decrease in canopy cover, and an increase in understorey vegetation density in logged plots relative to controls. 3.,Collection and identification of ants from a total of 360 1-m2 samples of leaf-litter revealed 143 ant species, of which 97 were found in the control plots, 97 in the plots logged in 1987, and 106 in those logged in 1993. Species richness, evenness and mean abundance (ants m,2) per plot did not vary among treatments. Most of the species found in the control plots were also present in the logged plots. However, population density of many species changed as a result of logging, an effect that persisted for at least 10 years after logging. Species commonly found in sites that were directly disturbed by logging (gaps and tracks) were rare in the undisturbed forest, as revealed by an additional collection of ants. 4.,These results suggest that the persistence of ant assemblages typical of undisturbed forest is likely to depend on the amount of structural damage incurred by logging. Thus management techniques that minimize logging impacts on forest structure are likely to help maintain the conservation value of logged forests for ground-dwelling ants. It is particularly important to minimize the extent of logging roads and tracks created by heavy machinery because these areas appear more prone to invasion by non-forest species. [source]

EVALUATING THE ECONOMIC COST OF ENVIRONMENTAL MEASURES IN PLANTATION HARVESTING THROUGH THE USE OF MATHEMATICAL MODELS

PRODUCTION AND OPERATIONS MANAGEMENT, Issue 3 2003
FELIPE CARO
An important issue being discussed for Chilean pine plantation policies is the application of environmental protection measures when managing its timber areas. Typical measures, already in place in more developed countries, include imposing riparian strips and protecting fragile soils from the use of heavy machinery. While environmental protection measures have been considered vital for decades, so far there has been almost no attempt to quantify both the benefits and costs of these measures. This paper attempts to measure the costs associated with the main measures which can help both the forestry firms and the government evaluate the cost impact of the new environmental protection regulations being studied. The analysis for different environmental scenarios is carried out by modifying a mixed integer LP, currently used for tactical planning by one forestry firm. [source]

The effect of soil compaction on germination and early growth of Eucalyptus albens and an exotic annual grass

AUSTRAL ECOLOGY, Issue 6 2009
ALISON K. SKINNER
Abstract Most agricultural land has been compacted to some degree by heavy machinery or livestock trampling. This legacy is expected to influence the success of tree seedling recruits in farmland areas where natural regeneration is being encouraged. We investigated the impact of soil compaction on seedlings of a woodland eucalypt (Eucalyptus albens) and an annual grass competitor (Vulpia myuros) in a laboratory experiment. Replicate soil cores were created at five bulk density levels; 1.0, 1.1, 1.2, 1.3 or 1.4 Mg m,3 with a soil water content of 20%. The depth of root penetration declined linearly with increasing bulk density, resulting in a decrease in root depth of around 75% in the most compacted soil compared with the least compacted soil for both species. Shoot length and primary root length did not vary between soil bulk density levels for either species, but seedlings responded to increasing levels of compaction with oblique (non-vertical) root growth. Results suggest that young seedlings of both E. albens and V. myuros will be more susceptible to surface drying in compacted than uncompacted soils and therefore face a greater risk of desiccation during the critical months following germination. Any competitive advantage that V. myuros may have over E. albens is not evident in differential response to soil compaction. [source]