Social Costs of Herbicide Resistance: The Case of Resistance to Glyphosate

Unlike in the pesticide and antibiotic resistance literature, potential social costs and externalities associated with herbicide resistance have not generally been considered by economists. The economics of managing herbicide resistance in weeds has focused on cost-effective responses by growers to the development of resistance at the individual farm and field level. Economic analyses of optimal herbicide use have focused on optimising farmer returns in the long run. Weeds have been considered less mobile, compared to insects and diseases, suggesting that externalities resulting from resistance spread will be minimal and any consequent social costs low. Glyphosate is the world's most widely used broad-spectrum non-selective herbicide. Declining glyphosate prices, the adoption of no-till and minimum-till systems and the adoption of glyphosate-tolerant crops, have combined to cause a rapid increase in the use of glyphosate, and resistance is now appearing. In this paper we argue that the increasing possibility of widespread glyphosate resistance, exacerbated in some situations by spread through resistance mobility, presents a case where social costs associated with glyphosate resistance need to be considered when assessing optimal use of this herbicide resource at the farm level. Possible social costs associated with the loss of glyphosate efficacy include potential failure of herbicide-resistant crop systems, reduced use of conservation tillage techniques, and potentially more reliance on herbicides with greater environmental and health risks.glyphosate resistance, herbicide resistance, social costs, externalities, resistance mobility, Crop Production/Industries,

Effective information and the influence of an extension event on perceptions and adoption

Perceptions are known to play an important role in the innovation adoption decision. Once influential perceptions have been identified, there is the potential for information to influence adoption by changing these perceptions. In this paper, the influence of an extension workshop targeting grain growers’ perceptions known to be associated with the adoption of integrated weed management and herbicide resistance management has been measured using regression analysis. Consistent with a Bayesian learning framework, the greatest influence on grower perceptions and intended adoption behaviour was observed where information could be delivered with a high degree of certainty and validity.Crop Production/Industries, Farm Management,

Keypad mobile phones are associated with a significant increased risk of microbial contamination compared to touch screen phones

The use of mobile phones in the clinical environment by healthcare workers has become widespread. Despite evidence that these devices can harbour pathogenic micro-organisms there is little guidance on how to reduce contamination. Recently touchscreen phones with a single flat surface have been introduced. We hypothesise that bacterial contamination of phones used in hospitals will be lower on touchscreen devices compared to keypad devices. Sixty seven mobile phones belonging to health care workers were sampled. The median colony count for touchscreen phones and keypad devices was 0·09 colony forming units (cfu)/cm2 (interquartile range (IQR) 0.05–0·14) and 0·77 cfu/cm2 (IQR range 0·45–3.52) respectively. Colony counts were significantly higher on the keypad phones (Fisher’s exact test p<0.001). Multivariate analysis showed the type of phone (keypad vs. touch screen) was associated with increased colony counts (F-statistic 14.13: p<0.001). Overall, nine (13%) phones grew either meticillin resistant Staphylococcus aureus or vancomycin resistant enterococci. Eight (24%) keypad phones were contaminated with these organisms compared with one touch screen phone (3%). Our data indicate that touchscreen mobile phones are less contaminated than their keypad counterparts, and they are less likely to harbour pathogenic bacteria in the clinical setting

Effect of herbicide resistance endowing Ile-1781-Leu and Asp-2078-Gly ACCase gene mutations on ACCase kinetics and growth traits in Lolium rigidum

4711-4718The rate of herbicide resistance evolution in plants depends on fitness traits endowed by alleles in both the presence and absence (resistance cost) of herbicide selection. The effect of two Lolium rigidum spontaneous homozygous target-site resistance-endowing mutations (Ile-1781-Leu, Asp-2078-Gly) on both ACCase activity and various plant growth traits have been investigated here. Relative growth rate (RGR) and components (net assimilation rate, leaf area ratio), resource allocation to different organs, and growth responses in competition with a wheat crop were assessed. Unlike plants carrying the Ile-1781-Leu resistance mutation, plants homozygous for the Asp-2078-Gly mutation exhibited a significantly lower RGR (30 per cent), which translated into lower allocation of biomass to roots, shoots, and leaves, and poor responses to plant competition. Both the negligible and significant growth reductions associated, respectively, with the Ile-1781-Leu and Asp-2078-Gly resistance mutations correlated with their impact on ACCase activity. Whereas the Ile-1781-Leu mutation showed no pleiotropic effects on ACCase kinetics, the Asp-2078-Gly mutation led to a significant reduction in ACCase activity. The impaired growth traits are discussed in the context of resistance costs and the effects of each resistance allele on ACCase activity. Similar effects of these two particular ACCase mutations on the ACCase activity of Alopecurus myosuroides were also confirmed

Laparoscopic Nissen fundoplication post-oesophageal stenting: an unusual case.

Laparoscopic Nissen fundoplication post-oesophageal stenting is uncommon and yet to be reported. We report the case of a 57-year-old palliative lady who underwent surgery for symptomatic relief of severe gastrooesophageal reflux post-oesophageal stenting. Surgery was carried out successfully with no complications. On the evening post-surgery she was able to lie supine for the first time in months without symptoms of reflux. In conclusion, surgery is still valuable and may play an important role, even in a palliative setting

A randomised trial comparing combination chemotherapy using mitomycin C, mitozantrone and methotrexate (3M) with vincristine, anthracycline and cyclophosphamide (VAC) in advanced breast cancer.

This paper describes a randomised clinical trial in patients with advanced breast cancer, comparing the regimen 3M, mitomycin C 7-8 mg m-2 (day 1), mitozantrone 7-8 mg m-2 (day 1 and 21), methotrexate 35 mg m-2 (day 1 and 21) given on a 42 day cycle with a standard anthracycline containing regimen, VAC, vincristine 1.4 mg m-2 (day 1), anthracycline (adriamycin or epirubicin) 30 mg m-2 (day 1), cyclophosphamide 400 mg m-2 (day 1) given on a 21 day cycle. Of a total of 217 patients, 107 were randomised to 3M and 110 to VAC and a mean of 5.5 courses was given per patient. The overall response rate (complete and partial) was 53% (95% Confidence Limits (CL): 43-62%) for 3M and 49% (CL; 39-58%) for VAC. The response according to sites of metastases was the same for both treatment groups. Symptomatic toxicity including alopecia, neuropathy, vomiting (P less than 0.001) and nausea (P less than 0.01) were significantly less for 3M. Myelosuppression including leucopenia (P less than 0.001) and thrombocytopenia (P less than 0.001) was significantly greater with 3M at day 21, although there was no difference in nadir counts in patients at special risk of myelosuppression and there was no evidence of an increase in infective or bleeding complications. There was no significant difference in the duration of response to 3M (10 months, CL 6-15) and VAC (11 months, CL 7-12), nor in survival (3M, 8 months, CL 6-12; VAC, 10 months, CL 8-12). These results indicate that 3M is as effective as, but has significantly less symptomatic toxicity than, an anthracycline containing regimen for the treatment of advanced breast cancer

Evidence for a vortex-glass transition in superconducting Ba(Fe0.9_{0.9}Co0.1_{0.1})2_{2}As2_{2}

Measurements of magneto-resistivity and magnetic susceptibility were performed on single crystals of superconducting Ba(Fe$_{0.9}$Co$_{0.1}$)$_{2}$As$_{2}$ close to the conditions of optimal doping. The high quality of the investigated samples allows us to reveal a dynamic scaling behaviour associated with a vortex-glass phase transition in the limit of weak degree of quenched disorder. Accordingly, the dissipative component of the ac susceptibility is well reproduced within the framework of Havriliak-Negami relaxation, assuming a critical power-law divergence for the characteristic correlation time $\tau$ of the vortex dynamics. Remarkably, the random disorder introduced by the Fe$_{1-x}$Co$_{x}$ chemical substitution is found to act on the vortices as a much weaker quenched disorder than previously reported for cuprate superconductors such as, e.g., Y$_{1-x}$Pr$_{x}$Ba$_{2}$Cu$_{3}$O$_{7-\delta}$.Comment: 10 pages, 8 figure