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1.
针对保定市城区水系管理委员会2017年3月公布的黑臭水体河流中的一亩泉河7.23km的黑臭水体段为参考进行了勘查、取样与COD实验工作,从2019年4月12日到2019年5月29日进行了为期一个半月的时间。研究结果表明:保定市一亩泉河河流不同位置COD大小不同、污染原因不同。通过周围景观的变化、对采样点附近居民进行的走访和COD浓度的测定,对一亩泉河的水质状况和污染源进行了全面系统地分析。并为此提出了切实可行、经济有效、便于管理的控制方案。  相似文献   
2.
In this study, we identified a cluster of 14 avian β‐defensins (AvBD; approximately 66 kbp) in the Japanese quail, Coturnix japonica. Except for AvBD12 (CjAvBD12) and ‐13, the CjAvBDs coding sequences exhibited greater than 78.0% similarity to the respective orthologous chicken AvBD genes (GgAvBD). The putative amino acid sequence encoded by each CjAvBD contained six cysteine residues and the GXC (X1‐2) motif considered essential for the β‐defensin family. Each CjAvBDs also formed a sub‐group with the respective orthologous genes of various bird species in a phylogenetic tree analysis. Synteny between the CjAvBD cluster and GgAvBD cluster was confirmed. The CjAvBD cluster was mapped on the long‐arm end of chromosome 3 by linkage analysis based on single nucleotide polymorphisms (SNPs) of CjAvBD1 and CjAvBD12 (approximately 46kbp), as well as GgAvBD cluster. We also confirmed that CjAvBD1, ‐4, ‐5, ‐9, and ‐10 are transcribed in 20 tissues, including immune and digestive tissues. However, our experimental data indicated that the CjAvBD cluster lacks the AvBD3 and ‐7 loci, whereas the CjAvBD101α, ‐101β, and ‐101θ loci arose from gene duplication of the AvBD6 orthologous locus in the CjAvBD cluster after differentiation between Coturnix ‐ Gallus.  相似文献   
3.
Milk produced by the grazing system, referred to as “grazing milk” contains many components required for human health. The milk fatty acid (FA) profile is strongly associated with the diet on the farms. In the present study, based on the FA profile of farmer's bulk milk, we determined how to discriminate between milk produced on grazing and on a confinement system. A field survey was conducted four times (grazing and confinement season) in the Konsen (29 farms) and Okhotsk (25 farms) area in Hokkaido. Farmer's bulk milk samples and details of feeding management were collected and the FA profile of milk was measured. Milk produced during the grazing season contained less C16:0 and cis‐9 C16:0, and more C18:0, cis‐9 C18:1, trans‐11 C18:1, cis‐9,12 C18:2, cis‐9,trans‐11 C18:2 and cis‐9,12,15 C18:3 than milk produced during the confinement season. Discrimination analysis using 16 FA revealed that almost all milk samples were discriminated correctly (confinement season: 90% correct and 10% borderline, grazing season: 88% correct, 9% borderline and 3% incorrect). For farmers that were categorized incorrectly and were considered borderline in the grazing season, the dependency on pasture was low compared with that for farmers correctly discriminated. Therefore, to claim “grazing milk”, a high dependency on pasture is required for grazing dairy farmers.  相似文献   
4.
To clarify the effect of digesta weight in the reticulorumen on diurnal and seasonal fluctuations in herbage intake, six ruminally cannulated, non‐lactating dairy cows were grazed on perennial ryegrass/white clover pasture during morning and evening sessions in spring and autumn. The digesta weight of fresh matter, dry matter (DM) and fiber in the reticulorumen at the beginning and the end of each grazing session was lower in spring than in autumn (P < 0.01). Although the digesta weight was similar between the sessions at the beginning of grazing, it was greater for the evening than for the morning at the end of grazing (P < 0.01). The large particles proportion in the digesta was lower for the morning than the evening (P < 0.01), and it was lower in spring than in autumn (P < 0.01). The concentrations of volatile fatty acids in rumen fluid were generally higher in spring compared with autumn. The herbage DM intake during the evening was greater compared with the morning in both seasons (P < 0.01). However, there was no difference in herbage DM intake between seasons. The results showed that the rumen digesta fill was not the sole factor explaining diurnal and seasonal variation of herbage intake in grazing dairy cows.  相似文献   
5.
This study aimed to clarify diurnal fluctuations of herbage intake, ruminal fermentation of herbage carbohydrates and proteins, and digesta particulate weight in the rumen of grazing dairy cows. Six ruminally cannulated, non‐lactating dairy cows were grazed on perennial ryegrass/white clover pasture either in the morning (04.00 to 08.00 hours) or the evening (16.00 to 20.00 hours). Cows grazed in the evening spent more time (P < 0.01) and consumed more herbage (P < 0.01) compared with cows grazed in the morning. Higher (P < 0.05) daily mean concentrations of total volatile fatty acid, propionate and n‐butyrate in rumen fluid were observed for cows grazed in the evening compared with cows grazed in the morning. Although cows grazed in the evening ingested more crude protein compared with cows grazed in the morning, no significant difference in NH3‐N concentration in rumen fluid was observed between them. The ratio of purine‐derivative concentration to creatinine concentrations was higher (P < 0.01) in the urine of cows grazed in the evening than in cows grazed in the morning. These results clearly indicated that evening grazing was advantageous for dairy cows compared with morning grazing, in terms of ruminal fermentable energy intake and nitrogen utilization efficiency.  相似文献   
6.
Androgen induces production of male effect pheromone in female goats   总被引:1,自引:0,他引:1  
Previously we showed that the primer pheromone responsible for the "male effect" was produced in specific skin regions of castrated male goats by androgen treatments. In the present study, we examined whether androgen can also induce production of the male effect pheromone in female goats. Capsules containing dihydrotestosterone (DHT) or testosterone (T) were subcutaneously implanted into six ovariectomized (OVX) goats for 28 days. Small skin samples were collected from the head and rump regions, and the pheromone activity of their ether extracts was examined using a bioassay that monitors the electrophysiological manifestation of the hypothalamic gonadotropin-releasing hormone pulse generator as multiple-unit activity. Behaviors of OVX goats towards ovary-intact estrous goats were also examined before and at the end of DHT or T treatment. Before androgen treatment, neither the head nor rump skin samples in OVX goats showed pheromone activity. DHT treatment induced pheromone activity in the head skin sample of six OVX goats and in the rump skin sample of two OVX goats. Similar results were obtained by T treatment. In addition, OVX goats treated with T showed masculine-type sexual behaviors such as courtship and mounting behaviors towards the estrous goats. These results demonstrate that androgen is capable of inducing primer pheromone activity in the female and suggest that the synthesis pathway of the male effect pheromone exists in both sexes in the goat.  相似文献   
7.
8.
由于甘蔗收获机在收获过程中智能化水平较低,依靠人工操作很容易对甘蔗收获机的运行状态产生误判,从而造成物流通道堵塞、能源浪费、收割效率低。针对这些问题,提出一种基于主成分分析(PCA)、遗传算法(GA)和支持向量机(SVM)状态识别模型。首先,通过实地采集甘蔗收获机刀盘轴、行走轴、切段轴和风机轴扭矩和行驶速度特征信息,然后通过PCA进行数据降维,最后利用GA优化参数C、γ,使用每个特性信息来训练SVM,对甘蔗收获机运行状态进行分类。结果表明:PCA-GA-SVM状态识别模型对甘蔗收获机运行状态的识别准确率为93.75%,建模时间为3.688 s,与SVM(81.25%,9.487 s)、PCA-SVM(87.5%,5.817 s)和GA-SVM(90%,8.969 s)进行对比,该模型具有最高准确识别率和最快建模速度,具有较大的应用价值。  相似文献   
9.
In evergreen azaleas, major anthocyanins were detected from petals of wild species and cultivars by HPLC analysis. Depending on flower color, all samples were divided into three groups: red, purple or white, using the Japan color standard for horticultural plants. The chromatic components a* and b* values of red group samples showed a convergent distribution, whereas those of purple group samples showed a wider distribution. According to the HPLC analysis, red group samples had two to four major anthocyanins, and those of the purple group had two to six major ones. In contrast, no anthocyanins were detected in the white group petals, although anthocyanidins were detected. These results suggest that the anthocyanin constitution of the purple group flowers is more varied than that of the red group flowers, and this wider variety among purple flowers contributes to extending the diversity of flower color in evergreen azalea.  相似文献   
10.
高精度气动比例压力阀设计与特性分析   总被引:3,自引:1,他引:2  
设计了一种两级阀芯活塞式结构的以比例电磁铁为控制元件,采用电反馈闭环控制的高精度气动比例压力阀。该阀输出压力在0.6MPa内连续可调,且稳态精度可达0.25 kPa。建立了比例阀完整的非线性动态模型,分析了主要物理和几何参数对系统动态特性和控制性能的影响;构建了输出因子调整的模糊自适应比例加积分控制器,并利用ATmega16单片机实现了压力在设定范围内的快速高精度控制。实验结果表明,该阀在设计压力范围内具有良好的压力和流量特性;和传统PI算法相比,输出因子调整的模糊自适应算法在改善系统响应和控制稳定性的同时,显著提高了稳态控制精度,具有较高的效率和鲁棒性。  相似文献   
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