不同时间尺度下温室无土栽培番茄蒸散规律研究     

孙国祥  汪小旵  李永博  陈满  楼恩平  狄娇 《灌溉排水学报》2015,34(3)

采用试验测量法,以温室环境参数为变量,建立了不同时间尺度下番茄蒸腾量和椰糠水分蒸发量回归模型以分析温室无土栽培番茄蒸腾规律和椰糠水分蒸发规律。结果表明,1h、1d时间尺度下番茄蒸腾量回归模型的决定系数分别为0.673 8、0.801;68d(整个试验周期)时间尺度下,1号番茄累积蒸腾量与累积有效积温、累积辐射积的拟合决定系数分别为0.998 4、0.993 6。1d时间尺度下,椰糠水分蒸发量特性方程的回归系数为0.891;58d(整个试验周期)时间尺度下,椰糠累积水分蒸发量与累积有效积温和累积辐热积回归方程的决定系数分别为0.999和0.992 7。随着时间尺度增大,番茄蒸腾量和椰糠水分蒸发量与环境参数的相关性显著提高。  相似文献   

基于无线传感器网络的水质监测系统研究     

黄亦磊  郁炜  叶国聪  周凯杰  赵金鑫 《湖南农机》2015,(3):51+53

针对国内外水质环境研究中水质样品异地监测分析存在的巨大缺陷,研究了水质自动监测系统。文章介绍了基于无线通讯传感器网络的简易水质自动监测系统,实现水质数据自动采集和实时上传,可以实现对钱塘江源头水质（衢州水质）进行更好的监测及保护。  相似文献   

Behaviour in one fast-growing and one slower-growing broiler (Gallus gallus domesticus) hybrid fed a high- or low-protein diet during a 10-week rearing period     

A. Wallenbeck  S. Wilhelmsson  L. Jönsson  S. Gunnarsson  J. Yngvesson 《Acta Agriculturae Scandinavica, Section A - Animal Sciences》2016,66(3):168-176

This study compared behavioural time budgets, presence of comfort behaviours and social behaviours in two different broiler genotypes (the fast-growing Ross 308 (R) and the slower-growing Rowan Ranger (RR)) fed organic diets with high (17.0% crude protein (CP)) or low (14.5% CP) protein content during a 10-week rearing period. 429-day-old chicks (218 R and 211 RR, respectively) were included in the study and behaviour was recorded at 2, 6 and 9 weeks of age. The results showed no effect of diet treatments but that R broilers were less active and sat, ate and drank more frequently than RR broilers, which stood and perched more frequently. However, both hybrids showed decreasing activity and foraging behaviour with increasing age, while time spent eating and sleeping was approximately similar over the entire rearing period.  相似文献   

食品安全与食品低温流通中的温度监控     

徐倩  谢晶 《上海海洋大学学报》2007,(2):180-184

食品的温度监控是一种有效的保证食品安全及保持冷藏链完整的手段,对冷冻冷藏食品在低温流通过程中实行温度监控是非常有必要的。目前,我国冷藏运输中的温度管理情况并不乐观,消费者获得的货物通常不能达到预计的要求。要解决这一问题,必须要借助于时间-温度指示器等来对其整个运输过程进行温度监控。本文对温度立法的必然性和前景,温度监控的重要性、原理以及在冷藏运输中的应用作了较详尽的介绍,并列举了几种国外时间-温度指示器的工作原理。  相似文献   

Assessing the within-herd prevalence of Coxiella burnetii milk-shedder cows using a real-time PCR applied to bulk tank milk     

Guatteo R  Beaudeau F  Joly A  Seegers H 《Zoonoses and public health》2007,54(5):191-194

Thirty-seven bulk tank milk (BTM) and individual milk samples of all contributing cows were tested for Coxiella burnetii detection by a real-time PCR assay and used to assess the relationship between the BTM PCR-response and (i) the within-herd prevalence of milk-shedder cows and (ii) the proportion of heavy milk-shedder cows. The within-herd prevalence of milk-shedder cows (i) was found to be significantly higher in herds with a positive BTM and (ii) increased significantly with the estimated titre in Coxiella burnetii obtained in positive BTM. The proportion of heavy milk-shedder cows among the milk-shedder cows increased significantly with an increased estimated titre in Coxiella burnetii in positive BTM. Therefore, a real-time PCR assay applied to BTM samples collected repeatedly over time appears to be a valuable tool to assess on a larger scale the status of herds towards Coxiella shedding, and to evaluate the efficiency of control actions aimed at controlling and/or preventing Coxiella shedding in dairy herds.  相似文献   

Effects of 2 concentrations of sodium citrate on coagulation test results, von Willebrand factor concentration, and platelet function in dogs     

Morales F  Couto CG  Iazbik MC 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2007,21(3):472-475

BACKGROUND: Blood collection tubes containing 3.2% (0.109 M) sodium citrate, instead of 3.8% (0.129 M) sodium citrate, have recently become available in the United States. These tubes are visually indistinguishable from the traditional 3.8% sodium citrate tubes, except for wording on the label. Consequently, samples for hemostatic evaluation are frequently collected in tubes containing the lower concentration of sodium citrate. HYPOTHESIS: Results of hemostasis assays are different in samples collected in 3.2% versus 3.8% sodium citrate. ANIMALS: Twenty healthy dogs. METHODS: This study aimed at determining whether results of standard coagulation tests, von Willebrand factor concentration (vWF:Ag), and platelet function with the platelet function analyzer PFA-100a were affected by the different concentrations of sodium citrate. Blood samples were collected in tubes containing either 3.2% or 3.8% sodium citrate concentrations and processed routinely for coagulation assays (one-stage prothrombin time [OSPT], activated partial thromboplastin time [aPTT], fibrinogen concentration, and platelet count), vWF:Ag, and platelet function assays with a PFA-100. RESULTS: There was no significant difference between samples collected in 3.2% versus those collected in 3.8% sodium citrate for OSPT, aPTT, fibrinogen concentration, platelet count, or vWF:Ag. The closure times with collagen/adenosine diphosphate were significantly shorter (66 +/- 8.1 versus 74.8 +/- 9.7 seconds; P < .0001) with the 3.2% than with 3.8% sodium citrate concentration, and the hematocrit was significantly higher (47.9 +/- 5.6 versus 46.0 +/- 4.7 seconds; P = .03) in samples collected in 3.2% than in those collected in 3.8% sodium citrate. CONCLUSIONS AND CLINICAL IMPORTANCE: There is no clinically relevant effect of collection of blood into 3.2% or 3.8% sodium citrate.  相似文献   

基于"3S"技术的甘肃子午岭自然保护区土地利用变化研究   总被引：1，自引：0，他引：1  

焦明  张世强  刘勇  张培栋  张小文 《草业科学》2007,24(11):14-17

以甘肃省子午岭自然保护区为研究对象,运用"3S"技术,对研究区的地形图、不同时相的TM遥感影像进行数据预处理,并分类提取了研究区2个时段的土地利用信息.对分类信息进行统计分析后并与实地调查数据进行比较,结果表明,近20年来甘肃子午岭自然保护区的森林覆盖面积在稳步提高,乔木林面积明显增加.为甘肃子午岭自然保护区工程的建设提供了基础信息,为林区植物种群生长及分布调查研究提供了宏观数据,并且输出了研究区不同时相土地利用专题图.  相似文献   

Optimising cutting method and timing for the control of Abutilon theophrasti seed production     

Farnaz Kordbacheh  Charles L. Mohler  Alan G. Taylor  Anna S. Westbrook  Hamid Rahimian-Mashhadi  Hassan M. Alizadeh  Antonio DiTommaso 《Weed Research》2023,63(1):34-44

Abutilon theophrasti (velvetleaf) is a widespread and problematic annual weed. Greenhouse and field experiments were conducted to investigate the effects of different cutting methods on the viability of A. theophrasti seeds. Three cutting methods were assessed: (1) Entire plant cut and dried (EPD)—plants were cut at soil level and dried with capsules attached on the greenhouse bench or soil surface for 4 weeks; (2) capsules detached and dried (CD)—capsules were removed from plants and dried for 4 weeks; and (3) capsules detached and tested while fresh (CF)—a control treatment. Before drying, the developmental stage (stage one, dark green; stage two, light green; stage three, yellowish-green; or stage four, black with the slightly open capsule) and age (days after flowering, DAF) of each capsule was recorded. Seed viability was measured immediately in the CF treatment and after the 4-week drying period in the EPD and CD treatments. No seeds in the EPD and CD treatments were viable when harvested at the first developmental stage (1–8 DAF) in either experiment, but 100% of seeds in the CF treatment in the field were viable when harvested at 8 DAF. In both greenhouse and field experiments, seeds attained full viability at earlier harvest ages in CF than in EPD or CD treatments, suggesting that seeds might become viable relatively early in development but lose viability if allowed to dry. These findings could be applied to optimise late-season mechanical control of A. theophrasti.  相似文献   

光源、性别及光处理时间对草地贪夜蛾趋光行为的影响     

张亚南  刘雨欣  李梦瑶  姚梦语  魏国树 《植物保护学报》2023,50(4):1010-1015

为研发高效、精准的监测防控设备,利用八臂行为选择装置系统测定不同光源、性别和光处理时间下草地贪夜蛾Spodoptera frugiperda的趋光行为。结果显示,在紫外光（波长365 nm）、紫光（波长420～430 nm）、蓝光（波长465～475 nm）、绿光（波长525～535 nm）、黄光（波长585～595 nm）和红光（波长655～665 nm）6种波长光源下,草地贪夜蛾混合种群（雌雄成虫比为1∶1）对紫外光光源的趋光选择率最高,为25.61%,显著高于其他处理,其次为紫光和蓝光光源,趋光选择率分别为16.30%和8.82%,对红光的趋光选择率最低,为4.76%。在紫外光刺激下,草地贪夜蛾雌成虫的趋光选择率显著高于混合种群（雌雄成虫比为1∶1）,在红光刺激下,雄成虫的趋光选择率显著高于雌成虫。另外,在紫外光刺激下,光处理时间60 min草地贪夜蛾雌成虫的趋光选择率显著高于其他处理。表明光源与性别因素均影响草地贪夜蛾的趋光行为,光处理时间对草地贪夜蛾的趋光行为影响较小,且与光源及性别因素有关。  相似文献   

赤霉素浓度和温水浸种时间对猕猴桃不同品种种子萌发的影响     

伍梦婷  钟文奇  陶俊杰  陈双双  贾慧敏  徐小彪  黄春辉 《中国果业信息》2023,52(2)

以美味猕猴桃‘徐香’、中华猕猴桃‘宜黄2号’、毛花猕猴桃‘赣绿1号’和‘赣绿2号’4个猕猴桃品种的种子为试验材料,设置5个梯度的赤霉素浓度和5个浸种时间进行处理,通过统计种子萌发的发芽率、发芽势和发芽时滞,探讨赤霉素浓度和温水浸种时间对猕猴桃种子发芽的影响。结果表明：4种猕猴桃种子发芽率与发芽势均受赤霉素浓度和温水浸种时间的影响,其中‘徐香’的种子发芽率和发芽势最高,其次是‘赣猕1号’、‘赣猕2号’和‘宜黄2号’。‘徐香’、‘赣绿1号’和‘赣绿2号’、‘宜黄2号’种子发芽率最高所对应的赤霉素处理浓度和浸种时间组合分别为：0.6 g/L赤霉素+30 min温水浸种、0.4 g/L赤霉素+30 min温水浸种、0.6 g/L赤霉素+30 min温水浸种和0.6 g/L赤霉素+60 min温水浸种。不同品种猕猴桃发芽时滞也有一定差异,其中‘徐香’发芽最早,其次是‘宜黄2号’,‘赣绿1号’和‘赣绿2号’开始发芽最晚。  相似文献