冀、京、津产麦区小麦赤霉病菌原体形成期的气象要素演变特征与分析

根据河北省、北京市、天津市22个代表站1960—2000年逐日平均气温、降雨量、相对湿度以及日照时数等资料，运用统计学方法，分析了京、津、冀地区小麦赤霉病菌原体形成期各相关气象因子的年际、年代际变化及空间分布。结果表明，日平均气温≥12℃日数大部地区呈弱增加趋势，降雨量和雨日呈减少趋势，中部以南地区的日照条件向降低小麦抗病能力的方向转化；贴近度分析表明，塘沽一天津一保定以南地区秋季小麦赤霉病菌原体形成期的气候条件是最适宜或适宜小麦赤霉病发生。     

Reuse of domestic wastewater treated in macrophyte ponds to irrigate tomato and eggplant in semi-arid West-Africa: Benefits and risks

The scarcity of freshwater resources is a critical problem in semi-arid zones and marginal quality water is increasingly being used in agriculture. This paper aimed at evaluating the physico-chemical and biological risks on irrigated soils and fruits of macrophyte treated wastewater (TWW), the nutrients supply, and the effect on tomato and eggplant production in semi-arid Burkina Faso. During three years of experiments, treated wastewater was used, with fresh water as control, in combination with or without mineral fertilizer application at recommended rate (140 kg N/ha + 180 kg P₂O₅/ha + 180 kg K₂O/ha). The study revealed that the treated wastewater provided variable nutrients supply depending on year and element. The treated wastewater without mineral fertilizer improved eggplant yield (40% in average) compared to the freshwater. Both crops responded better to mineral fertilizer (52% for tomato and 82% for eggplant) and the effects of the treated wastewater and fertilizer were additive. As the N supply of TWW was very unsteady (8-227% of crop need), and P₂O₅ supply did not satisfy in whole crop need (3-58%) during any of the three years of experiment, we recommended that moderate N and P₂O₅ fertilizers be applied when irrigating with TWW in semi-arid West-Africa. On the contrary, the K₂O supply was more steady and close to crop requirement (78-126%) over the three years of experiment and no addition of K fertilizer may be needed when irrigated with TWW. Faecal coliforms and helminth eggs were observed in treated wastewater and irrigated soils at rate over the FAO and WHO recommended limits for vegetable to be eaten uncooked. Tomato fruits were observed to be faecal coliform contaminated with the direct on-foliage irrigation with treated wastewater. Our results indicate that treated wastewater can effectively be used as both nutrients source and crop water supply in market gardening in the semi-arid Sub-Saharan West Africa (SSWA) where freshwater and farm income are limiting. Yet consumers should properly cook or disinfect treated-wastewater irrigated vegetables before eating, and market gardeners should also be careful manipulating treated wastewater to avoid direct health contamination in this environment.     

兔骨髓间充质干细胞的分离培养及肝内示踪

通过分离培养兔骨髓来源的间充质干细胞(MSCs),示踪其肝内移植命运,为MSCs的细胞治疗肝脏疾病提供理论依据和试验支持.采取全骨髓贴壁培养法分离培养兔骨髓MSCs,利用携带增强型绿色荧光蛋白(EGFP)的慢病毒载体感染MSCs,选择最优转染效率,并移植入经D-氨基半乳糖诱导的急性/亚急性肝衰竭受体兔体内,荧光显微镜下...     

太阳自动跟踪系统中光电传感器的设计

针对现有光电传感器存在形式单一、跟踪精度不高、运行稳定性较差等不足,该文通过对光电传感器进行结构设计,设计了一种金字塔式和箱体式嵌套的粗-精跟踪光电传感器,其中箱体式可拆卸、单独使用,其内部的凹面镜利用反射作用有效减小了箱体高度,保证了跟踪过程中的跟踪精度和运行稳定性。在对该传感器的电路进行设计时,选取四运放集成电路LM324为核心,利用其比较作用来控制电机驱动执行机构,从而使聚光系统对准太阳。利用MATLAB/Simulink对模糊PID(proportional integration differentiation,比例-积分-微分)控制器建模和仿真,与PID控制相比,模糊PID控制曲线的响应时间较短,在0.1 s时给系统一个宽度为0.1的矩形脉冲干扰,在0.1~0.2 s之间系统的响应曲线、控制误差的响应曲线以及控制器的输出变化曲线呈现不同的变化;在0.2 s时,均达到稳定状态。通过分析可知,无论是否存在干扰,该控制方法均能使控制器迅速达到稳定状态,减少系统响应时间,从而减少系统的运行成本。该研究为太阳自动跟踪系统的稳定运行和跟踪精度的提高提供了参考。     

Fungicidal Control of Lophodermium seditiosum on Pinus sylvestris Seedlings in Swedish Forest Nurseries

During the 1990s, there were serious outbreaks of the pathogen Lophodermium seditiosum on pine seedlings in Swedish forest nurseries, even though the seedlings had been treated with the fungicide propiconazole. The present experiment was carried out to evaluate two other fungicides, fluazinam and azoxystrobin, as possible alternatives to propiconazole. In the tests, which were all carried out in the same forest nursery, seedlings were treated with either propiconazole, fluazinam or azoxystrobin, and the proportion of needles with ascocarps of L. seditiosum and the number of ascocarps per needle were recorded over the following 2 yrs. Seedlings treated with azoxystrobin already appeared healthier than control seedlings in September of the first year, and by November all azoxystrobin-treated seedlings had fewer ascocarps per needle compared with control seedlings. In autumn of the second year, there were no ascocarps on seedlings treated with fluazinam or azoxystrobin, whereas seedlings treated with propiconazole had similar numbers of ascocarps to non-treated control seedlings.     

拖拉机行走机构的研究现状

牵引附着性能是拖拉机最重要的性能之一,多年的研究表明,要提高牵引附着性能,进行保护性耕作,改善车辆在松软地面的通过性能,新的行走机构或装置就成为目前国内外研究的主要趋向。为此,介绍了国内外行走机构研究的现状,并指出了现存问题和今后发展的趋势。     

“乳黄消散”对临床型奶牛乳房炎治疗效果

为观察不同给药量的"乳黄消散"对临床型奶牛乳房炎的治疗效果,为临床治疗提供可靠依据,选取患临床型乳房炎的泌乳牛40头,随机分为3个试验组和1个对照组,每组10头牛。试验组分别用不同给药量的"乳黄消散"进行治疗(高、中、低剂量组给药量分别为1 500、1 000、500 g/d),"公英散"对照组给药量为500 g/d,观察并统计临床治疗效果、治疗前后乳汁LMT检测情况及细菌变化情况。结果显示,"乳黄消散"中剂量组治愈率及总有效率最高,极显著高于高剂量组和低剂量组,高剂量组治愈率和总有效率次之,低剂量组最低。试验组治愈率和总有效率均极显著高于对照"公英散"组。LMT检测结果显示,治疗前40个乳区均为强阳性"+++",治疗后均为"+、+或-"。乳汁细菌检测结果显示,治疗前主要为大肠杆菌、无乳链球菌、乳房链球菌和屎肠球菌等,治疗后3～5 d同一乳区细菌检测结果显示,试验组的细菌总转阴率达66.67%～100.00%,对照组细菌总转阴率达50.00%～100.00%。综合考虑,"乳黄消散"中剂量组临床治疗效果最佳。     

河北省花生果腐病病原鉴定及致病性研究

对河北省石家庄、保定等地的花生果腐病进行了调查和取样,并进行了病原菌的分离鉴定,基本明确了河北省花生果腐病主要是由茄镰刀菌[Fusarium solani（Mart.）Sacc.]和群结腐霉（Pythium.myriotylum Drechsl）复合侵染引起。同时进行了病菌回接试验,检验了2种病菌的致病性,结果表明,茄镰刀菌和群结腐霉菌单独接种均可致病,且茄镰刀菌致病力较强,但症状与田间表现有差异;复合接种发病的症状与田间发病症状相同。从回接发病的荚果上再次分离培养病原菌,发现与原分离病原物一致,说明茄镰刀菌和群结腐霉菌是河北省花生果腐病的主要致病菌。     

Development of two telemetry-based systems for monitoring the feeding behaviour of Atlantic salmon (Salmo salar L.) in aquaculture sea-cages

Two novel acoustic transmitter tags intended to reflect feeding behaviours in farmed Atlantic salmon (Salmo salar L.) were developed and tested in this study. Using information from the literature and video recordings of feeding salmon, measurements of swimming depth and motion (acceleration) were identified as two promising sensing principles on which to base the tag development. Video footage and laboratory studies were used to develop corresponding algorithms that translated depth and acceleration measurements into compound parameters reflecting the different aspects that discern feeding activity from other activities. Field tests performed in a sea-farm were used to verify the functionality of the tags, and indicated that both tag types had potential in distinguishing between feeding and non-feeding behaviour. Additionally, both depth- and acceleration-based tags were seen to have applications to fish monitoring and farm management beyond that of observing feeding in salmon, in giving recordings of the vertical swimming behaviour of fish over extended periods of time as well as indications of the activity changes of fish due to external influences. These results suggest that fish telemetry using sensor-based transmitter tags could represent a useful tool in future fish farm management.     

红地球葡萄贮藏中致病菌鉴定及发生规律研究

[目的]研究红地球葡萄贮藏过程中主要腐烂致病菌及其发病规律,为确定红地球葡萄贮藏过程中的病害提供方法。[方法]使用Martin培养基分离致病菌,PDA培养基鉴定,再将鉴定后的致病菌反接研究侵染规律。[结果]确定红地球葡萄贮藏过程中灰霉菌、交链孢菌、青霉菌3种主要致病菌。其中,灰霉菌在红地球葡萄果粒、果梗检出机率均较高,其次是交链孢菌,而青霉菌果粒、果梗检出频率均较低。灰霉菌、交链孢菌于葡萄果梗、果粒上在有伤和无伤条件下均可侵入红地球葡萄组织;青霉菌在果粒上有伤或无伤均可侵入,在果梗上只有在有伤时才可侵入。灰霉菌和交链孢菌在冷藏保鲜过程中表现较高活力,是主要危害致病菌。[结论]为防止贮藏红地球葡萄腐烂病害发生提供了一定的科学依据。