324 research outputs found
How can the crisis of liberalization trade be overcome?
Since the seventies the existing order of international economic relations has been exposed to ever stronger pressures. Access to foreign markets must once again be regarded as a scarce commodity, since the far-reaching removal of tariff barriers has been more than compensated for by non-tariff restrictions
Assessing Resilience of Pasture Production to Climatic Changes
Increasing temperatures and atmospheric carbon dioxide (CO2) concentrations, together with changes to rainfall patterns, will influence seasonal pasture production; however climate change projections for south eastern Australia are uncertain (CSIRO and BoM 2007). Despite this, climate change impact assessments generally rely on specific climate projections, but in this study an alternative approach was developed to test the resilience of production to incremental changes in climate
Modelling Adaptation and Mitigation Strategies for Southern Livestock Industries of Australia
Climate change will impact on the Australian grazing industries both through mitigation policies and the impact of warmer temperatures, increased atmospheric CO2 and changed rainfall patterns (Cullen et al. 2009; Eckard et al. 2010). Mechanistic models are useful tools to inform our understanding of the complex interactions between future climates and the soil, plant, animal and management in livestock production systems.
This paper summarises the results of a number of whole farm systems modelling studies investigating likely impacts of climate change, adaptation options and emissions implications for livestock production in southern Australia
Nitrogen Balances in High Rainfall, Temperate Dairy Pastures of South Eastern Australia
Nitrogen (N) fertilizer use on dairy pastures in south eastern Australia has increased exponentially over the past 15 years, causing increasing environmental concerns. Volatilisation, denitrification and leaching of N were measured for one year (1998-1999) in pastures receiving no N fertilizer (grass/clover), or 200 kg N/ha applied as urea (46%N) or ammonium nitrate (34.5%N). Nitrogen balances were calculated for each treatment.
Significantly more N was lost through volatilisation and denitrification when N was applied as urea compared to ammonium nitrate. Nitrate leaching losses were significantly greater with the application of N fertilizer, although the maximum loss was only 4.1 kg N/ha due to low rainfall between May and September. Nitrogen balances were -15, +87 and +82 kg N/ha per year for the grass/clover, 200 kg N/ha urea and 200 kg N/ha ammonium nitrate treatments, respectively. Given the large range in N losses and balances, there is opportunity for improving the N efficiency in dairy pastures, through lower stocking rates and more tactical use of grain and N fertilizer
Chitinase-Induced Airway Hyperreactivity and Inflammation in a Mouse Model of Nonallergic Asthma.
INTRODUCTION
Environmental exposure to mites and fungi has been proposed to critically contribute to the development of IgE-mediated asthma. A common denominator of such organisms is chitin. Human chitinases have been reported to be upregulated by interleukin-13 secreted in the context of Th2-type immune responses and to induce asthma. We assessed whether chitin-containing components induced chitinases in an innate immune-dependent way and whether this results in bronchial hyperresponsiveness.
MATERIALS AND METHODS
Monocyte/macrophage cell lines were stimulated with chitin-containing or bacterial components in vitro. Chitinase activity in the supernatant and the expression of the chitotriosidase gene were measured by enzyme assay and quantitative PCR, respectively. Non-sensitized mice were stimulated with chitin-containing components intranasally, and a chitinase inhibitor was administered intraperitoneally. As markers for inflammation leukocytes were counted in the bronchoalveolar lavage (BAL) fluid, and airway hyperresponsiveness was assessed via methacholine challenge.
RESULTS
We found both whole chitin-containing dust mites as well as the fungal cell wall component zymosan A but not endotoxin-induced chitinase activity and chitotriosidase gene expression in vitro. The intranasal application of zymosan A into mice led to the induction of chitinase activity in the BAL fluid and to bronchial hyperresponsiveness, which could be reduced by applying the chitinase inhibitor allosamidin.
DISCUSSION
We propose that environmental exposure to mites and fungi leads to the induction of chitinase, which in turn favors the development of bronchial hyperreactivity in an IgE-independent manner
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