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911.
Differences of raw cork quality, in terms of thickness and porosity, were observed in productive cork oak (Quercus suber L.) stands in the Nebrodi and Iblei mountains of Sicily in relation to stand density. Five study areas were chosen across a range of different stand density satisfying specific sampling requirements among two managed cork oak woods.Analysis of variance using Fisher–Snedecor‘s F test (p < 0.05) were used to identify statistically significant differences of cork quality and sylvicultural, dendrometric and cork stripping parameters between study areas within each stand. Relationships between cork quality and sylvicultural and dendrometric parameters were also tested using Pearson's correlation coefficient (r). Results shown that sylvicultural practices are a key factor influencing cork quality: statistically significant differences in cork thickness and crown area were observed between areas at different stand density; positive correlations were found between cork thickness and crown area in lower density study areas favouring a significant vegetative activity; negative correlations were found between parameters of cork stripping (cork stripping coefficient, cork stripping surface, maximum height of cork stripping) and cork thickness. No correlations were found between cork porosity and dendrometric or sylvicultural parameters, demonstrating the probable genetic origin of cork porosity. Results shown that cork quality parameters and stand attributes may be used in sustainable management models of cork oak forests.  相似文献   
912.
采用平皿法和液体稀释法对急性支气管炎验方制剂进行体外抗菌试验。以急性支气管炎验方制剂药液灌胃给药测定其对小鼠的无毒剂量,同时测定甲型溶血性链球菌、金黄色葡萄球菌、百日咳杆菌标准株对小鼠的最小致死量(MLD)。通过腹腔注射不同菌株(MLD 0.5mL)感染小鼠,以急性支气管炎验方制剂药液治疗。体外抗菌试验表明,急性支气管炎验方制剂对甲型溶血性链球菌、金黄色葡萄球菌、百日咳杆菌标准株均有不同程度的抑制和杀灭作用。药效学实验表明,该验方制剂对人工感染小鼠有不同程度的保护作用,与对照组比较差异显著。说明该验方可以进行临床治疗试验。本实验为扩大应用范围及成果转化奠定了基础。  相似文献   
913.
西藏农村远程教育与信息服务体系是实现西藏农牧业跨越式和可持续发展、增加农牧民收入和促进农村经济、文化快速发展的重要平台。在基于西藏农牧业教育、农村信息化建设的现状的条件下,通过对农村远程教育与信息化服务所面临的主要问题的分析,提出了西藏农村远程教育与信息服务体系发展的对策。  相似文献   
914.
水飞蓟素的药理学研究进展   总被引:6,自引:0,他引:6  
系统查阅近年来有关水飞蓟素的药理学研究报道,总结了草本植物水飞蓟的活性成分--水飞蓟素的药理学研究进展,综述了水飞蓟素的成分对免疫系统的调节作用、抗肝纤维化、对乳腺癌细胞系的抑制作用、对糖尿病大鼠主动脉非酶糖化及氧化的抑制作用、预防顺铂肾毒性而不影响其抗癌活性、对糖尿病植物神经病变以及保护肝细胞膜,促进被损伤肝细胞合成DNA及结构蛋白等药理作用.本文还展望了水飞蓟素的良好应用前景.  相似文献   
915.
Total porosity and width, length and irregularity of elongated pores from thin sections, prepared from undisturbed Ap horizon samples taken from a zero versus conventional-tillage field experiment, were analysed by means of a Quantimet 720 System 23 image analysing computer. Both total porosity and elongated pore area were significantly higher in conventionally-tilled plots. On the contrary, both the total number of pores and the proportion of elongated pores were significantly higher in no-tilled plots. Thus, zero tillage reduced the size of pores. Conventional tillage caused an increase in the length of a few large, elongated pores which also showed very strong irregularity. In samples from no-tilled plots the total length of elongated pores was smaller, but these pores were more numerous and more regular than in samples from conventionally-tilled plots. Consequently, soil conditions for root growth were better.  相似文献   
916.
Time series (1825–1973) of the Atlantic bluefin tuna, Thunnus thynnus, landings from the trap fishery of Sardinia (W. Mediterranean) were analyzed to identify (i) patterns of catch variability in the historical traps of Isola Piana, Portoscuso and Porto Paglia, and (ii) effects of three local environmental variables: Mining, Run-off and Sea Surface Temperature.We applied different time series analysis techniques: auto-correlation functions, spectral analysis and Dynamic Factor Analysis (DFA). Moreover, an asymmetrical design using a Before/After and Control/Impact location approach was used to test the perturbations due to mining processes that have characterized the fishery area.A sharp decreasing trend of Porto Paglia trap landings beginning in 1880, coincided with mechanized mining. This result was confirmed by the ANOVAs contrasting Before vs. After (P < 0.01) and Controls vs. Impact location (P < 0.01).We found a slight cyclical behaviour in the same time series. Spectral analysis highlighted that pattern synchronized with the Run-off cycles with periods corresponding to 7 years. We hypothesized that the effect of Run-off from watershed mine tailing dams creates a pulsing boundary ‘reflective’ effect for tuna migration schools on the in-shore trap of Porto Paglia, resulting in a periodic oscillation of captures.We have identified (i) a reversal of trends in captures between Portoscuso and Isola Piana traps and (ii) significant differences of the monthly distribution of capture events and timing of landings (P < 0.01) with a higher proportion now in May, rather than in June as in the past. We assume there is a relationship with climatic changes because warmer waters can induce precocity in gonad maturation. DFA did not show any significant differences among environmental factors and landings probably because the cyclical component in Run-off is masked. We emphasize the importance of Mediterranean traditional traps as ‘sentinels’ of the homing reproductive behaviour of bluefin tuna and we argue the case for a plan to link the remaining traps in a common monitoring network.  相似文献   
917.
The evaluation of Tiber River quality, in a stretch including a sewage treatment plant, has been carried out by the contemporary evaluation of water effect on Daphnia and benthic macroinvertebrates community structure. To achieve a good status of a river water by the end of 2015, as provided in the Water Framework Directive (WFD) 2000/60/EC, is necessary to know the quality starting point. To this end, several endpoints are expected by the WFD, including Daphnia toxicity test and macroinvertebrate community analysis. River water sampling was conducted in the four seasons, from upstream to downstream a sewage treatment plant. I endpoint. At the outfall of the sewage treatment plant, river water showed very high acute toxicity to Daphnia only in summer; some toxic effect can be found also upstream in spring. Results at the outfall were consistent with the hypothesis that disinfectants, mainly used in summer to treat discharging waters, are responsible of river water acute toxicity: Daphnia tests with each disinfectant (NaClO, PAA, ClO2) showed high toxicity. River waters were also utilized in Daphnia reproduction tests. Samples at the outfall (excluding the summer one, undoubtedly toxic) caused slight reduction in survival and fecundity. Disinfectants were also checked in reproduction tests. Still at NOEC24h, they caused a significant toxicity on both death rate and reproduction. II endpoint. Macroinvertebrate benthic community composition was evaluated upstream and downstream the sewage treatment plant, on these data Extended Biotic Index (EBI), was determined to get a score as quality class. A reduction of water quality score was found downstream the plant, one season delayed (autumn) respect the acute test on Daphnia. Effect of disinfectant discharge, river dilution capability on a short spatial scale and use of different endpoints are discussed in term of river stretch quality.  相似文献   
918.
In wine making, the bacteriolytic activity of lysozyme has primarily been used to control the malolactic fermentation in wines. The use of lysozyme in musts before settling and the beginning of the alcoholic fermentation to inhibit the growth of lactic acid bacteria could be very beneficial. In a resistance test carried out in MT/b broth, lysozyme had greater antimicrobial activity toward Oenococcus oeni than Lactobacillus species. Several strains of wine bacteria belonging to Oenococcus proved sensitive to the bacteriolytic activity of lysozyme at low concentrations in both synthetic medium (MT/b) (50 mg/L), white must, or red must made with or without the skins (100 mg/L). Lactobacillus and Pediococcus strains survived at lysozyme concentrations of 200-500 and 500 mg/L, respectively, in MT/b and musts. Suspended solids in unclarified musts may strongly bind to lysozyme thereby causing its removal by filtration or centrifugation. One hour after lysozyme was added to musts, it was quantified by HPLC and found after centrifugation to be 40-50% and only 10% in musts made with or without the skins, respectively. Although appreciable amounts of lysozyme were bound to wine components, this did not appear to be a serious hindrance to lysozyme activity.  相似文献   
919.
杨文才  拉巴  魏巍 《作物杂志》2016,32(5):75-45
在海拔4 300m的西藏河谷农区,进行了N、P配合施肥对混播燕麦与箭筈豌豆产量及品质影响的研究。结果表明:刈割期为燕麦乳熟期/箭筈豌豆结荚期,混合饲草产量最高,饲草粗蛋白、粗脂肪含量较高,而酸性洗涤纤维(ADF)与中性洗涤纤维(NDF)较低。N、P及其互作对混播燕麦与箭筈豌豆株高、产量、养分含量的影响显著;在相同施P水平下,随着N的增加,干草产量、株高和粗蛋白呈现先增后减的变化趋势;粗脂肪、ADF和NDF含量随氮肥施用量的增加有不同程度的降低;在相同施N水平下,随磷肥施用量的增加,粗蛋白、粗脂肪、ADF呈增加的趋势,而NDF逐渐降低。施用氮(纯N)140kg/hm 2、磷(P2O5)60kg/hm 2处理组合干草产量最高为16 636kg/hm 2,比不施肥对照组增产60.47%;蛋白质含量最高达18.42%。说明N、P施用量分别为140kg/hm 2、60kg/hm 2可作为该地区燕麦与箭筈豌豆混播种植的推荐施肥量。  相似文献   
920.
为解决东北黑土区因不合理耕作导致的土壤结构性状变差及有机碳含量下降的问题,该研究于2015年开始,在黑龙江省哈尔滨市东北农业大学向阳试验基地开展。设置免耕+秸秆还田(NTS)、免耕(NT)、翻耕+秸秆还田(CTS)、翻耕(CT)4种处理,于2018、2019年采集土样,研究免耕措施及秸秆还田对东北薄层黑土区0~10、>10~20 cm土壤团聚体稳定性、土壤有机碳含量、各粒径团聚体内有机碳含量影响。结果表明:2018和2019年0~10、>10~20 cm土层NTS处理>5 mm水稳性团聚体百分比含量及平均重量直径(MWD)显著高于其他3种处理,NTS及NT处理土壤有机碳含量显著高于CTS及CT处理(P?<0.05),4种处理各粒径水稳性团聚体有机碳含量峰值总体出现在1~2 mm处,NTS及NT处理>5、2~5、1~2 mm有机碳贡献率整体高于CTS及CT处理。研究表明,免耕与秸秆还田有利于薄层黑土坡耕地耕层土壤团聚体稳定性的提高和各粒级下团聚体有机碳的积累,与其他3种处理相比,免耕+秸秆还田效果更佳。  相似文献   
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