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81.
Exergy, the thermodynamic function that represents the distance of an open system from equilibrium, is proposed as an ecological indicator for summarizing the complex dynamics occurring in a disturbed community during its recovery processes. These complex dynamics can be difficult to capture by using classical indices. In this study, we sampled macrobenthos using the BACI scheme (before versus after; control versus impact) in tidal wetlands of west Chongming Island, China, an area that has been disturbed by ecological engineering measures. Exergy storage is estimated for benthic communities. The control area is proposed as dynamic reference for estimating local exergy storage of the benthic community. Three different methods were used for estimating exergy on the basis of coefficients: (a) taken for taxa groups; (b) estimated from coding genes given for broad taxonomic groups; and (c) estimated from genome size taken as close as possible to the taxonomic level of the species, providing a basis for inferring similarities. We found a decrease of local exergy content in the disturbed area 9 days after the disturbance. Subsequently, the reference exergy of the benthic community increased (i.e. in the surrounding control area) in accordance with the proposed hypothesis regarding the dynamics of exergy storage during a system's development. Estimates of local exergy arrived at using the three methods provided comparable results. Based on this, we then discuss the feasibility of using the more readily available genome size data for estimating exergy. This result may have important implications for broader application of this indicator to biological systems. Moreover, the adjacent control samples seem to represent an appropriate dynamic reference for estimating the local exergy of disturbed communities. We found that exergy was a useful indicator that integrates the processes underlying the recovery of the benthic community after disturbance. 相似文献
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83.
Exogenous eFSH, follicle coasting, and hCG as a novel superovulation regimen in mares 总被引:3,自引:0,他引:3
S.A. Welch MS D.J. Denniston PhD J.J. Hudson DVM MS J.E. Bruemmer PhD P.M. McCue DVM PhD E.L. Squires PhD 《Journal of Equine Veterinary Science》2006,26(6):262-270
The objective of this study was to evaluate various equine follicle-stimulating hormone (eFSH) treatment protocols and the effect of “follicle coasting” on ovulation and embryo recovery rates in mares. Cycling mares (n = 40) were randomly assigned to one of four groups 7 days after ovulation: (1) 12.5 mg eFSH twice daily until follicles were 35 mm or larger; (2) 12.5 mg eFSH twice daily until follicles were 32 mm or larger; (3) 12.5 mg eFSH twice daily for 3.5 days followed by 12.5 mg eFSH enriched with luteinizing hormone (LH) twice daily until follicles were 35 mm or larger; and (4) 25 mg eFSH once daily until follicles were 32 mm or larger. Mares in groups 1 and 3 were injected with human chorionic gonadotropin (hCG) (2500 IU intravenously) at the end of eFSH treatment, whereas mares in groups 2 and 4 were given hCG approximately 42 and 54 hours, respectively, after the last eFSH treatment (“follicle coasting”). Nonsurgical embryo collection was performed 6.5 to 7.5 days after ovulation. Each mare experienced a nontreated estrous cycle before being reassigned to a second treatment. Ovulation rates for mares in treatment groups 1 to 4 were 3.3 ± 0.4, 4.1 ± 0.4, 3.5 ± 0.4, and 2.8 ± 0.4 (mean ± SEM; P < .05), respectively. One or more embryos were recovered from more than 80% of mares in each treatment group, and embryo recovery rate per flush was similar among treatment groups (1.9 ± 0.3, 2.6 ± 0.3, 1.9 ± 0.3 and 1.9 ± 0.3, respectively; P > .05). The overall embryo recovery rate was 2.1 ± 1.5 embryos per flush. In summary, ovulation rate was higher for mares treated with eFSH (3.4 ± 0.4) compared with non-treated controls (1.1 ± 0.2). Ovulation rate in mares in which hCG was delayed (follicle coasting) was higher (P < .05) when treatments were given twice per day versus once per day. Administration of equine luteinizing hormone (eLH) in conjunction with eFSH did not have an advantage over mares treated only with eFSH. 相似文献
84.
85.
退化人工草地更新效果观测 总被引:7,自引:2,他引:5
利用草地建植方法,对175.7hm^2退化人工草地进行了更新改良,结果,当年平均干草产量达3570kg/hm^2比未更新地带提高2058kg/hm^2;播种牧草相对重量65.9%,未更新地带15.1%,优势度由重建前的27.0%上升至61.8%,恶性杂草竞争力下降,基本形成白叶+黑麦草+鸭茅+画眉草+红三叶+狗尾草+白茅+蒿类的格局。 相似文献
86.
LiuZemin LiYongzhao HuangWeitong 《农业科学与技术》2000,1(2):10-12
A major component rice varietv of Xiangwanxian 9 (a late Indica variety) with 13.1%, 15.6% and 18.3% of the moisture was respectively mixed with three ad-ditive varieties in 13% of moisture at ration of 7:3 for processing assorted rices. Head rice recovery of the treatments was determined 24 hours later. Analysis indicated sig-nificant differences exist in the effects produced by the component varieties, their moistures and the component variety moisture. 相似文献
87.
“一江两河”中部流域是西藏沙漠化最为严重的地区之一,草地的沙化对于生态环境的恶化和畜牧业生产造成很大的不利影响。通过对这一地区草地的现状分析,划分了沙化草地类型,并通过示范试验结果分析,探讨了沙化草地恢复的主要措施。 相似文献
88.
梅花品种抗寒性的比较分析 总被引:3,自引:1,他引:2
张启翔 《北京林业大学学报》1985,(2)
用电导法和生长法测定了梅花38个主要代表品种的抗寒性,并对梅花的系统、类、型的抗寒性进行了比较。结果表明,杏梅系统比真梅系统抗寒,真梅系统的直脚梅类和垂枝梅类比龙游梅类抗寒。在直脚梅类的六个型中,玉蝶型和绿萼型抗寒性较强,朱砂型抗寒弱。垂枝梅类的‘骨红垂枝’同直脚梅类的朱砂型抗寒性相似。对梅花品种抗寒性的季节性变化、同型及同品种在不同栽培地区的差异及其枝条脱水等也进行了一些讨论。提出了在北京地区引种栽培梅花的几点意见。 相似文献
89.
Niu Chen Li Yun 《中国林学(英文版)》2006,8(1):32-34
Conventional methods of DNA recovery from agarose gel generally require expensive equipment, extended elution times, or considerable handling of the sample after elution. We developed a simple protocol for a quick and effective recovery of DNA from agarose gels with good yield and quality. Using a Sephadex resin filled spin column, DNA fragments of 500 bp to 6 kb in an agarose gel slice were easily recovered by a 2 min centrifugation. The recovery efficiencies were over 40%-50% and the eluted DNA can be used directly for downstream application, such as polymerase chain reactions (PCR) and restriction enzyme digestion. This method could also be used to recover large DNA fragment (48 kb) without degradation. The use of Sephadex helps to remove small molecular impurities from agarose and it also reduces the chance of clogging the column filter caused by direct contact with agarose. 相似文献
90.
《Veterinary anaesthesia and analgesia》2022,49(6):624-633
ObjectiveTo evaluate the effects of detomidine or romifidine on cardiovascular function, isoflurane requirements and recovery quality in horses undergoing isoflurane anaesthesia.Study designProspective, randomized, blinded, clinical study.AnimalsA total of 63 healthy horses undergoing elective surgery during general anaesthesia.MethodsHorses were randomly allocated to three groups of 21 animals each. In group R, horses were given romifidine intravenously (IV) for premedication (80 μg kg–1), maintenance (40 μg kg–1 hour–1) and before recovery (20 μg kg–1). In group D2.5, horses were given detomidine IV for premedication (15 μg kg–1), maintenance (5 μg kg–1 hour–1) and before recovery (2.5 μg kg–1). In group D5, horses were given the same doses of detomidine IV for premedication and maintenance but 5 μg kg–1 prior to recovery. Premedication was combined with morphine IV (0.1 mg kg–1) in all groups. Cardiovascular and blood gas variables, expired fraction of isoflurane (Fe′Iso), dobutamine or ketamine requirements, recovery times, recovery events scores (from sternal to standing position) and visual analogue scale (VAS) were compared between groups using either anova followed by Tukey, Kruskal-Wallis followed by Bonferroni or chi-square tests, as appropriate (p < 0.05).ResultsNo significant differences were observed between groups for Fe′Iso, dobutamine or ketamine requirements and recovery times. Cardiovascular and blood gas measurements remained within physiological ranges for all groups. Group D5 horses had significantly worse scores for balance and coordination (p = 0.002), overall impression (p = 0.021) and final score (p = 0.008) than group R horses and significantly worse mean scores for VAS than the other groups (p = 0.002).Conclusions and clinical relevanceDetomidine or romifidine constant rate infusion provided similar conditions for maintenance of anaesthesia. Higher doses of detomidine at the end of anaesthesia might decrease the recovery quality. 相似文献