玉米地膜复合覆盖栽培技术

地膜覆盖栽培是有效保持寒旱区土壤水热条件、促进作物生产的措施之一。为解决长期覆盖普通地膜造成的土壤地膜残留污染及生物降解地膜破裂,且成本高的问题,通过多年试验研究,从地膜选择、肥料配比、绿色地膜复合覆盖技术、田间管理、地膜回收、秸秆与生物降解地膜还田等方面总结了寒旱区玉米普通地膜与生物降解膜覆盖栽培技术。     

标记辅助导入中不同背景选择方法的比较

模拟比较了随机选择、标记值选择及BLUP选择3种背景选择方法在标记辅助导入(利用标记辅助将供体群中的一个有利QTL等位基因导入到受体群中)的选择效果。前景选择是借助与目标基因连锁的两侧标记对目标基因进行间接选择。研究结果表明,在背景选择中,利用标记值选择能使受体基因组很快得到恢复,2个世代的回交就能恢复90%以上,4个世代的回交就能完全恢复。利用BLUP选择虽然不能使受体基因组迅速全部恢复,但能使特定的背景性状得到最大的遗传进展。     

杂草对作物产量损失预测的复合函数模型

本文根据杂草与作物在田间竞争所表现出的三大特征，应用幂函数与双曲线函数的复合模型（y=d^r/（a＋bd^l）来模拟杂草密度与作物产量间的关系，通过对7组不同来源的杂草与作物竞争资料的模拟，证明幂双曲线函数复合模型具有实际的生物学意义，能准确地描述多种杂草和多种作物间的竞争关系，预测杂草为害作物可能造成的产量损失。为杂草的经济防除和进一步建立杂草防除的生态经济阚值模型提供科学的依据。     

A study to evaluate buprenorphine at 40 μg kg(-1) compared to 20 μg kg(-1) as a post-operative analgesic in the dog

ObjectiveComparison of the analgesic effect of buprenorphine at 20 or 40 μg kg^?1.Study designAn investigator ‘blinded’, randomised study.AnimalsTwenty six dogs presented for ovariohysterectomy.MethodsDogs were premedicated intramuscularly with acepromazine 0.03 mg kg^?1 and buprenorphine at either 20 (B20, n = 12) or 40 μg kg^?1 (B40, n= 14) followed by anaesthetic induction with propofol and maintenance with isoflurane. During anaesthesia non invasive blood pressure, heart rate, respiratory rate, blood oxygen saturation, inspired and expired volatile agent, end-tidal carbon dioxide and ECG were recorded. Pain and sedation were assessed using interactive VAS scores; mechanical nociceptive thresholds were measured at the wound and hindlimb - all were assessed before and up to 22 hours after administration. Carprofen was used for rescue analgesia.ResultsThere were no significant differences between the two groups for any of the parameters examined. Rescue analgesia was required around 5 hours after administration of buprenorphine in a significant number of animals. Sedation was good preoperatively and scores decreased over time postoperatively. Hock thresholds did not change over time; wound thresholds decreased significantly compared to the baseline value from 3 hours onwards.ConclusionsAdministration of buprenorphine at either 20 or 40 μg kg^?1 IM with acepromazine provided good pre-operative sedation. Cardiovascular and respiratory values remained within clinically acceptable limits during anaesthesia. There was no evidence that increasing dose increased adverse events that may be associated with opioid administration (e.g. bradycardia and respiratory depression).Clinical relevanceIncreasing the dose of buprenorphine from 20 to 40 μg kg^?1 did not provide any benefits with respect to analgesia after ovariohysterectomy as assessed using the VAS scoring system.     

A quick and efficient screen for resistance to iron toxicity in lowland rice

Iron (Fe) toxicity is a major stress to rice in many lowland environments worldwide. Due to excessive uptake of Fe²⁺ by the roots and its acropetal translocation into the leaves, toxic oxygen radicals may form and damage cell structural components, thus impairing physiological processes. The typical visual symptom is the “bronzing” of the rice leaves, leading to substantial yield losses, particularly when toxicity occurs during early vegetative growth stages. The problem is best addressed through genotype improvement, i.e., tolerant cultivars. However, the time of occurrence and the severity of symptoms and yield responses vary widely among soil types, years, seasons, and genotypes. Cultivars resistant in one system may fail when transferred to another. Better targeting of varietal improvement requires selection tools improving our understanding of the resistance mechanisms and strategies of rice in the presence of excess iron. A phytotron study was conducted to develop a screen for seedling resistance to Fe toxicity based on individual plants subjected to varying levels of Fe (0–3000 mg L^–1 Fe supplied as Fe(II)SO₄), stress duration (1–5 d of exposure), vapor‐pressure deficit (VPD; 1.1 and 1.8 kPa), and seedling age (14 and 28 d). Genotypes were evaluated based on leaf‐bronzing score and tissue Fe concentrations. A clear segregation of the genotypic tolerance spectrum was obtained when scoring 28 d old seedlings after 3 d of exposure to 2000 mg L^–1 Fe in a high‐VPD environment. In most cases, leaf‐bronzing scores were highly correlated with tissue Fe concentration (visual differentiation in includer and excluder types). The combination of these two parameters also identified genotypes tolerating high levels of Fe in the tissue while showing only few leaf symptoms (tolerant includers). The screen allows selecting genotypes with low leaf‐bronzing score as resistant to Fe toxicity, and additional analyses of the tissue Fe concentration of those can identify the general adaptation strategy to be utilized in breeding programs.     

酥枣高粱复合果酒的工艺研究

[目的]探讨酥枣高粱复合果酒的制作方法,并优化其工艺条件.[方法]以酥枣和高粱作为原料制作酥枣高粱复合果酒,用小曲进行发酵;通过单因素试验和正交试验研究原料添加量比、发酵的温度、发酵时间和小曲的接种量对复合果酒的影响.[结果]试验确定了最优发酵条件为:原料添加量比为4:1、发酵温度为28℃、发酵时间为10 d、小曲接种量为0.4％,在此条件下得出的酥枣高粱复合果酒色泽鲜亮透明、酸甜适中、酥枣和高粱的香气浓郁.[结论]酥枣高粱复合果酒有很高的营养价值,研究可为复合果酒的开发提供参考依据.     

巧用EXCEL完成试卷成绩分析

在教学过程中 ,教师对学生的试卷成绩分析要花费很多的时间和精力 ,因为首先要登录学生姓名 ,填入每个学生的成绩 ,然后对学生的成绩进行各种统计 ,如查找出最高分、最低分、各分数段的频度等 ,可以说试卷成绩分析是一个很繁锁的过程。这时可借助OFFICE办公软件的EXCEL强大的电子表格及数据文字处理功能来完成试卷分析 ,使得教师的试卷分析工作变得轻松和简单。     

学籍微机管理系统的研制

本系统根据学生学籍管理的目标和任务,利用FOXBASE 2.1数据库管理系统编制而成。该系统具有对数据的录入和维护(修改、删除及追加)、统计与查询、打印输出等功能;对学生基本情况、在校成绩、综合测评、升留级情况及毕业、肄业等项目进行统计管理。     

木材纤维/铜纤维复合中密度纤维板

试验分析了铜纤维的施加比例对木材纤维／铜纤维复合中密度纤维板物理力学性能和电磁屏蔽效能的影响。结果表明，铜纤维的施加比例对复合中密度纤维板的力学性能影响显著，在木材纤维／铜纤维混合原料中施加一定量的异氰酸酯胶，可显著改善复合中密度纤维板的胶合性能，其胶合强度可以达到国家标准的要求。铜纤维施加比例对复合中密度纤维板的电磁屏蔽效能影响显著，铜纤维在中密度纤维板中的复合位置对电磁屏蔽效能影响较显著，当中密度纤维板双表面复合铜纤维且施加比例为3时其电磁屏蔽效能可达到60dB以上。     

学生考试分数的几种分析方法

对学生考试分数的分析方法有图形分析法、项目分析法和整体分析法。图形分析法是通过作考试分数的频率分布图来完成；项目分析法则是针对试题和试卷的难度而言；整体分析法是在建立数学模型的基础上，从信度和效度两方面加以测量，一般要求信度在0．9以上，效度在0．8以上。