21 research outputs found

    Conservation Agriculture Practices Increase Potentially Mineralizable Nitrogen: A Meta-Analysis

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    Potentially mineralizable nitrogen (PMN) is considered an important indicator of soil health. Cropping systems management can affect PMN. However, the effect size and relationship with crop yield across specific management practices remain uncertain. We conducted a quantitative review to understand how conservation agriculture management practices affect PMN including N fertilizer application, cropping system diversity, and tillage system as well as the relationship of crop yield with PMN. Data were extracted from 43 studies published in peer-reviewed journals, providing 494 paired comparisons of PMN and 26 paired comparisons of PMN and yield across selected crop management practices. In our meta-analysis, the effect size for each management practice was expressed as a response ratio, calculated as PMN or yield for the fertilizer application, high crop diversity, and no-till system to the no-fertilizer, less diverse crop system, and tillage system. On average, N-fertilized cropping systems had greater PMN: compared to no N fertilizer, inorganic N fertilizer had 22%, and manure had 34% higher PMN. Diverse cropping systems also had greater PMN: three or more different crops in rotation had 44% greater PMN than continuous cropping systems; cropping systems with a leguminous cover crop had 211% greater PMN than systems without cover crops. Compared to till systems, no-till systems had 13% higher PMN. Overall, conservation practices consistently increased both PMN and yield; however, the increase in PMN and yield were not correlated. Consistent with the use of PMN as a soil health indicator, this synthesis demonstrates that practices benefiting PMN also benefit yield

    Initial Results from the Royal College of Radiologists' UK National Audit of Anal Cancer Radiotherapy 2015

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    Aims: UK guidance was recently developed for the treatment of anal cancer using intensity-modulated radiotherapy (IMRT). We audited the current use of radiotherapy in UK cancer centres for the treatment of anal cancer against such guidance. We describe the acute toxicity of IMRT in comparison with patient population in the audit treated with two-phase conformal radiotherapy and the previous published data from two-phase conformal radiotherapy, in the UK ACT2 trial. Materials and methods: A Royal College of Radiologists' prospective national audit of patients treated with radiotherapy in UK cancer centres was carried out over a 6 month period between February and July 2015. Results: Two hundred and forty-two cases were received from 40/56 cancer centres (71%). In total, 231 (95%) underwent full dose radiotherapy with prophylactic nodal irradiation. Of these, 180 (78%) received IMRT or equivalent, 52 (22%) two-phase conformal (ACT2) technique. The number of interruptions in radiotherapy treatment in the ACT2 trial was 15%. Interruptions were noted in 7% (95% confidence interval 0–14%) of courses receiving two-phase conformal and 4% (95% confidence interval 1–7%) of those receiving IMRT. The percentage of patients completing the planned radiotherapy dose, irrelevant of gaps, was 90% (95% confidence interval 82–98%) and 96% (95% confidence interval 93–99%), in two-phase conformal and IMRT respectively. The toxicity reported in the ACT2 trial, in patients receiving two-phase conformal in the audit and in patients receiving IMRT in the audit was: any toxic effect 71%, 54%, 48%, non-haematological 62%, 49%, 40% and haematological 26%, 13%, 18%, respectively. Conclusions: IMRT implementation for anal cancer is well underway in the UK with most patients receiving IMRT delivery, although its usage is not yet universal. This audit confirms that IMRT results in reduced acute toxicity and minimised treatment interruptions in comparison with previous two-phase conformal techniques

    High avidity drives the interaction between the streptococcal C1 phage endolysin, PlyC, with the cell surface carbohydrates of Group A Streptococcus

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    Endolysin enzymes from bacteriophage cause bacterial lysis by degrading the peptidoglycan cell wall. The streptococcal C1 phage endolysin PlyC, is the most potent endolysin described to date and can rapidly lyse group A, C, and E streptococci. PlyC is known to bind the Group A streptococcal cell wall, but the specific molecular target or the binding site within PlyC remain uncharacterized. Here we report for the first time, that the polyrhamnose backbone of the Group A streptococcal cell wall is the binding target of PlyC. We have also characterized the putative rhamnose binding groove of PlyC and found four key residues that were critical to either the folding or the cell wall binding action of PlyC. Based on our results, we suggest that the interaction between PlyC and the cell wall may not be a high-affinity interaction as previously proposed, but rather a high avidity one, allowing for PlyC's remarkable lytic activity. Resistance to our current antibiotics is reaching crisis levels and there is an urgent need to develop the antibacterial agents with new modes of action. A detailed understanding of this potent endolysin may facilitate future developments of PlyC as a tool against the rise of antibiotic resistance.Bio-organic Synthesi

    Who are the expressive voters?

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    Brennan and Hamlin (1998) predict that moderates are more likely to be expressive rather than instrumental voters, but do not test this hypothesis. Greene and Nelson (2002) claim to reject this, by finding that extremists are as likely to vote as moderates. We argue that Greene and Nelson's study was not a complete test of Brennan and Hamlin's hypothesis and we extend their analysis to provide a more thorough test. Our results imply that there is some evidence to suggest that extremist non-voters are less likely to be instrumentally motivated, providing some support for the predictions of Brennan and Hamlin. Copyright Springer Science+Business Media, LLC 2007Voting, Expressiveness, Extremists,
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