Predicting effective doses for the joint action of two fungicide applications   总被引：1，自引：0，他引：1  

N. D. Paveley †  J. M. Thomas  T. B. Vaughan  N. D. Havis  D. R. Jones 《Plant pathology》2003,52(5):638-647

A function was derived to predict fungicide efficacy when more than one application of a single active ingredient is made to a crop, given parameters describing the dose–response curves of the component single-spray applications. In the function, a second application is considered to act on that proportion of the total pathogen population which was uncontrollable at the time of the first application (represented by the lower asymptote of the dose–response curve for the first treatment), plus any additional part of the population which survived the first application as a result of a finite dose being applied. Data to estimate the single-spray dose–response curve parameters and validate predictions of two-spray programme efficacy were obtained from separate subsets of treatments in four field experiments. A systemic fungicide spray was applied to wheat at a range of doses, at one or both of two times (t₁ and t₂), in all dose combinations. Observed values of the area under the disease progress curve (AUDPC) for septoria leaf blotch (Mycosphaerella graminicola) were used to construct response surfaces of dose at t₁ by dose at t₂ for each culm leaf layer. Parameters were estimated from single-spray and zero-dose treatment data only. The model predicted a high proportion (R² = 71–95%) of the variation in efficacy of the two-spray programmes. AUDPC isobols showed that the dose required at t₂ was inversely related to the dose at t₁, but the slope of the relationship varied with the relative timings of t₁ and t₂ in relation to culm leaf emergence. Isobols were curved, so the effective dose – the total dose required to achieve a given level of disease suppression – was lower when administered as two applications.  相似文献   

有效碳数法研究及其在农药气相色谱分析中的应用   总被引：2，自引：0，他引：2  

刘绍仁  叶纪明 《农药科学与管理》1997,18(4):5-9

有机化合物结构与其所含有的有效碳数有一定的关系，本文给出了２０类结构化合物及其所含有有效碳数的关系，并对理论计算值和实测值进行了比较，结果十分接近，利用有效碳数法可以设计农药分析实验方案和无标样的情况下测定农药杂质含量。  相似文献   

A perspective on the measurement of time in plant disease epidemiology   总被引：2，自引：1，他引：2  

D. J. Lovell †  S. J. Powers  S. J. Welham  S. R. Parker 《Plant pathology》2004,53(6):705-712

The growth and development of plant pathogens and their hosts generally respond strongly to the temperature of their environment. However, most studies of plant pathology record pathogen/host measurements against physical time (e.g. hours or days) rather than thermal time (e.g. degree-days or degree-hours). This confounds the comparison of epidemiological measurements across experiments and limits the value of the scientific literature.  相似文献   

Black carbon estimation in French calcareous soils using chemo‐thermal oxidation method     

G. Caria  D. Arrouays  E. Dubromel  C. Jolivet  C. Ratié  M. Bernoux  B. G. Barthès  D. Brunet  C. Grinand 《Soil Use and Management》2011,27(3):333-339

We studied the black carbon (BC) content of ca. 405 samples from French topsoil and artificial soil and carbonate mixtures. Our protocol involved three main steps: (i) decarbonation by HCl, (ii) elimination of non‐pyrogenic organic carbon in a furnace at 375 °C, and (iii) quantification of residual carbon by CHN analysis. BC content increased for calcareous soils according to their carbonates content. Subsequent analyses confirmed the existence of a methodological artefact for BC determination only in calcareous soils. Decarbonation changes the thermal properties of organic matter, creating more recalcitrant carbon than in the initial sample. Higher CaCO₃ and organic carbon content results in a more pronounced artefact. The reversal of the first two steps of the chemo‐thermal oxidation method (i.e. thermal oxidation before soil decarbonation) eliminates this artefact. Overall, our results suggest that BC content may have been overestimated in a large number of studies on calcareous soils.  相似文献   

有效体育教学模式的创建与实施*     

张细谦 《上海交通大学学报(农业科学版)》2015,(1):106-109

有效体育教学的内涵主要包括三个方面，即，体育教学要重效果，体育教学要好效益，体育教学要高效率。有效体育教学模式是指在“健康第一”思想指导下相对稳定的一种教学程序，其创建步骤主要包括确立教学指导思想、明晰目标内涵、分析教学情境、编选教学内容、创设运作程式。有效体育教学模式的实施要全程渗透健康引领的价值观念，细化体育教学有效性的指标体系，加强教师的有效指导，激活学生的主体参与。  相似文献   

晋中市左权县作物土壤有效镁营养状况分析     

刘艳  姚延梼  李彩珍  陈菲儿  许建卿 《天津农业科学》2014,(8):38-41

以长治市左权县东隘口村土壤为研究对象,将48个分别来自玉米地、蓖麻地、谷子地、药材地内的不同土壤类型样品,用原子吸收分光光度计进行有效镁含量的检测。结果表明,试验区内,土壤有效镁含量处于中等水平,且有效镁含量与电导率呈现正相关关系。不同作物下的土壤有效镁含量无显著性差异,而在不同土壤类型间差异性显著。土壤缺镁时,可以施用硫酸钾镁。  相似文献   

Land surface temperature retrieval for arid regions based on Landsat-8 TIRS data:a case study in Shihezi,Northwest China   总被引：1，自引：0，他引：1  

Lei YANG  ;YunGang CAO  ;XiaoHua ZHU  ;ShengHe ZENG  ;GuoJiang YANG  ;JiangYong HE  ;XiuChun YANG 《干旱区科学》2014,(6):704-716

Scientific interest in geophysical information about land surface temperature （LST） is ever increasing, as such information provides a base for a large number of applications, including environmental and agricultural monitoring. Therefore, the research of LST retrieval has become a hot topic. Recent availability of Landsat-8 satel- lite imagery provides a new data source for LST retrieval. Hence, exploring an adaptive method with reliable ac- curacy seems to be essential. In this study, basing on features of Landsat-8 TIRS thermal infrared channels, we re-calculated parameters in the atmospheric transmittance empirical models of the existing split-window algorithm, and estimated the ground emissivity with the help of the land cover classification map of the study area. Further- more, a split-window algorithm was rebuilt by virtual of the estimation model of the updated atmospheric transmit- tance and the ground emissivity, and then a remote sensing retrieval for the LST of Shihezi city in Xinjiang Uygur autonomous region of Northwest China was conducted on the basis of this modified algorithm. Finally, precision validation of the new model was implemented by using the MODIS LST products. The results showed that the LST retrieval from Landsat-8 TIRS data based on our algorithm has a higher credibility, and the retrieved LST is more consistent with the MODIS LST products. This indicated that the modified algorithm is suitable for retrieving LST with competitive accuracy. With higher resolutions, Landsat-8 TIRS data may provide more accurate observation for LST retrieval.  相似文献   

黑曲霉菌渣资源化再利用途径分析     

陈秀龙  蔡冠杰  覃新导  彭黎旭 《热带作物学报》2011,31(6):24-27

黑曲霉菌渣是黑曲霉发酵法生产葡萄糖酸钠后产生的废弃物，其资源化利用已成为企业扩大生产亟需解决的问题。对该菌渣有效成分检测得知，该菌渣有害金属元素均小于城镇垃圾农用控制标准、有机-无机复混肥料控制标准和鱼粉、猪、家禽添加剂预混合饲料卫生指标，有机质含量符合有机肥料中的有机质含量指标，总糖、粗纤维、粗蛋白、脂肪等营养成分含量较多，同时也含有丰富的N、P、K、Ca、Mg、Fe等元素，可从有机肥料和禽畜饲料方向进行资源化利用，有利于减轻环境污染及实现变废为宝，具有积极的社会、经济和生态效益。  相似文献   

Quantitative sensory testing of the equine face     

Kata O. Veres-Nyéki  József Nyéki  Gábor Bodó  Claudia Spadavecchia 《Equine veterinary journal》2021,53(1):177-185

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The thermal antinociceptive effects of a high-concentration formulation of buprenorphine alone or followed by hydromorphone in conscious cats     

Kara L. Moreno  Elizabeth M. Scallan  Beatriz P. Monteiro  Paulo V. Steagall  Bradley T. Simon 《Veterinary anaesthesia and analgesia》2021,48(4):570-576

ObjectiveTo evaluate the thermal antinociceptive effects of a high-concentration formulation of buprenorphine alone or followed by hydromorphone in conscious cats.Study designRandomized, blinded, placebo-controlled crossover study design.AnimalsA total of six purpose-bred, adult female ovariohysterectomized Domestic Short Hair cats.MethodsCats were allocated into three treatments each consisting of two injections, subcutaneous then intravenous (IV) administration, 2 hours apart: treatment SS, two injections of 0.9% saline; treatment BS, buprenorphine (0.24 mg kg^–1, 1.8 mg mL^–1) and saline; and treatment BH, buprenorphine (0.24 mg kg^–1) and hydromorphone (0.1 mg kg^–1). Skin temperature (ST) and thermal threshold (TT) were recorded before (baseline) and for 24 hours following first injection. TT data were analyzed using mixed linear models and a Benjamini–Hochberg sequential adjustment procedure (p < 0.05).ResultsThere were no significant differences among treatments for baseline ST and TT values, treatment SS over time and between treatments BS and BH. Compared with baseline, TT was significantly increased at all time points in treatments BH and BS except at 2 hours in treatment BS. TT was significantly higher than SS at 3–18 hours and 4–12 hours for treatments BS and BH, respectively. Maximal increases in TT were 47.5 °C at 2 hours, 53.9 °C at 3 hours and 52.4 °C at 6 hours in treatments SS, BS and BH, respectively.Conclusions and clinical relevanceAdministration of IV hydromorphone following high-concentration buprenorphine provided no additional antinociception and decreased the duration of effect when compared with high-concentration buprenorphine alone. Alternative analgesics should be considered if additional analgesia is required after administration of high-concentration buprenorphine.  相似文献