33 research outputs found

    Investigating of Integrated Weed Management in Broomcorn (Sorghum bicolor) Farms in Miyaneh Region

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    The experiment was carried out as randomized complete block design in factorial with three replications to evaluate of the possibility of integrated weed management in Broomcorn (Sorghum bicolor) yield. Treatments were included herbicides (Foramsulfuron, Bromoxynil+MCPA and 2,4-D+ MCPA), application dose (recommendation dose, 25% less and more than recommended doses for corn farms) and mechanical control (with or without cultivation). The result indicated all factors including herbicides, application doses and cultivation were significantly influenced weeds density and dry weight. The best herbicide in weeds density and dry weight  decreasing percentage was Foramsulfuron treatment. Cultivation treatment was significantly influenced weeds control. The best doses were 25% more recommended dose and recommended dose on weeds density and dry weight  decreasing percentage

    Evaluation of parametric models with estimating the prediction error by apparent loss method in analyzing survival of colorectal patients

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    Abstract Background: Colorectal cancer is the most common gastrointestinal cancer. Investigating the factors that predict survival time for these patients is important.The purpose of this study was comparison of parametric models by estimating the prediction error and also identifying the effective factors on predicted survival time of patients with colorectal cancer. Materials and Methods: This cohort study was conducted with 600 patients who were suffered from colorectal cancer in Taleghani Hospital of Tehran between 2001 to 2005 and they were followed up for at least 5 years. For identifying the effective factors on survival time, of the patients we analyzed the data by some parametric models such as Weibull, Exponential and Log logistic and compared these models with the estimation of prediction error by apparent loss method. Results: Among 600 patients there was 344 men (57.3%) and 256 wemon (47.7%). Of total, 151 patients were died that 62.3% of them were men. Univariate analysis showed that the effect of BMI, sex, staging of tumor, tumor site were significant but in multivariate model staging of tumor and BMI were significant. By the estimation of prediction error, the best model was Log logistic . Conclusion: With respect to the importance of survival time prediction, we found that we can use the prediction error to compare the parametric models. In addition, because of effectiveness of tumor stages and BMI in the patients’ survival time, survival time could be increased by an on-time diagnosis and an appropriate controled diet

    Allelopathic and autotoxicity effects of barley (Hordeum vulgare L. ssp. vulgare) root exudates

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    The allelopathic activity of barley (Hordeum vulgare L. ssp. vulgare) root exudates was studied by comparing their effects on seedling establishment in barley itself and in two weed species, Bromus diandrus Roth. and Lolium rigidum Gaudin, using an original laboratory protocol, named ‘seed-after-seed’. In this protocol, the donor and the receiver species of watersoluble allelochemicals are grown one after the other in the same dishes, in conditions reducing resource competition between both species. Growth of all receptive species (weeds and barley) was inhibited in a dose-dependent manner, when using increasing barley seed densities (0, 8, 19 and 25 seeds per Petri dish). In our conditions, the barley varieties and landraces exhibited different allelopathic activities against weeds or barley. The allelopathic potential of the barley root exudates was also dependent on the receiver species. Indeed, the released allelochemicals proved to be more toxic against the weed plants than on barley itself. Furthermore, the toxicity of the allelochemicals increased after their release by roots, between day 0 and day 6. These allelochemicals might contribute to the plant community dynamics and their usefulness as bio-herbicides deserves further consideration
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