Effects of detomidine or romifidine during maintenance and recovery from isoflurane anaesthesia in horses

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.     

云南岩溶地区石漠化生态恢复的思路

云南岩溶面积达11.09万km2,占全省国土面积的28.14%,是西南地区岩溶集中分布区,岩溶石漠化面积已达2.15万km2.分析云南岩溶的分布,以及岩溶地区生态脆弱给当地人民带来生产、生活的生态危机,并结合云南石漠化治理的成功经验,提出岩溶地区生态恢复的思路.     

次生阔叶林改建为食用菌原料林后的群落恢复和林分生长

选择12年生林相较好的天然次生阔叶林,通过择伐更新和皆伐人促更新2种经营方式定向培育食用菌原料林。研究发现,择伐经营的经济效益较高,且有利于群落的快速恢复,经过7a的封育,林分蓄积量已达到择伐前的水平。皆伐人促更新获得的食用菌材虽较择伐利用高出40%左右,但因经营强度过大,保留的幼树受损严重而不利于伐后林木的生长与恢复,封育期内蓄积增长量分别为择伐更新和对照未经营区的64 7%和73 41%。动态监测结果显示,采用择伐和皆伐人促更新措施后群落恢复较快。疏伐后因透光度的急剧增加,阳性和中性树种大量侵入,地面芽植物和1年生植物的比例增高。到第7a时,高位芽植物的比例已接近未经营区的状态,乔、灌、草各层的物种多样性指数高于未经营的天然阔叶林,物种均匀度则与其相近。研究还发现,2种更新经营方式对土壤养分的损失较小,经过7a的恢复,林地土壤肥力已基本达到原有天然林水平。     

植被恢复与重建过程中小流域降雨及水沙变化特征研究

以女儿寨小流域为研究对象，着重研究了植被恢复与重建过程中小流域系统的降雨和水沙变化特征，并对植被恢复过程中的总体减沙水平做了分析。结果表明：①受大气环流的影响，小流域年际降雨量差异较大；小流域降雨年内时间分布极为不均，集中性很大，主要集中在汛期（4-8月），但年内降雨量的月间分布趋势基本一致。②小流域迳流年际变化很大，迳流年内分配不均。迳流集中是该小流域迳流变化的一个显著特征：小流域的植被恢复与重建对洪峰的出现和洪峰流量具有明显的延缓和削减作用。③径流（Qi）主要来源于降水（Pi），二者呈明显的一元线型关系：Pi=115．7678＋2．7386Qi。④小流域的年输沙模数与年迳流量的变化规律基本一致，小流域年内产沙也高度集中，且与降水、迳流关系密切，小流域的土壤侵蚀主要由汛期的强降水引起。⑤随着小流域大面积、高标准的生态环境建设，1990年至2004年间小流域的输沙模数呈锐减之势，植被恢复与重建起到了显著的减沙效应。     

Root distribution pattern of the wild jack tree (Artocarpus hirsutus Lamk.) as studied by 32P soil injection method

Root distribution of the wild jack tree (Artocarpus hirsutus) was determined by selective placement of ³²P at various depths and lateral distances from the tree, in Kerala, India. In eight-and-a-half-year-old trees growing on a lateritic site, absorption of ³²P from a lateral distance of 75 cm and 30 cm depth was much greater than from 150 and 225 cm lateral distance and 60 and 90 cm depth. Root activity declined with increasing depth and lateral distance. Most of the physiologically active roots were concentrated within a radius of 75 cm and 30 cm depth, although the tap root might reach even deeper. Possibly, surface accumulation of feeder roots may cause considerable overlap of the tree and crop root zones in intercropping situations. However, as the tree roots seldom extend beyond 2.25 m laterally from the trunk, the effect of overlapping root zones and the associated competitive effects may not be a serious problem for intercropping during the first few years (<10 years after planting) of tree growth.     

不同破坏方式对固定沙丘植被的影响

通过对吉林省前郭县乌兰图嘎林场固定沙丘植被试验区采取限制放牧与过度放牧的对比调查，结果得出，控制放牧有利于固定沙丘植被的恢复，可有效地提高草牧场植被的多样性和异质性；而过度放牧通常是吉林省西部草牧场退化的最重要原因。     

宜昌公益林可持续经营条件与对策

在分析宜昌公益林可持续经营的制约因素与有利条件的基础上,依据公益林营造的基本原则,阐明了公益林营造途径和营造方法;同时以公益林恢复重建途径为指导,提出公益林恢复重建模式;并依照公益林保护原则,探索了宜昌公益林保护的基本思路,对宜昌公益林可持续经营具有现实指导意义。     

第二代杉木林养分动态研究

根据连续定位观测所取得的数据,对4个小集水区第二代10年生杉木人工林生态系统中的养分循环进行了研究.结果表明.集水区由降水输入的N、P、K、Ca、Mg等营养元素总计为59.285kg/hm2a,径流输出为38.938kg/hm2a,净积累量为20.347kg/hm2a.与该林分7年生时相比,净积累量提高了7.2%,说明集水区第二代杉木林生态恢复处于进展的变化过程.     

川南几种竹种退耕还林植被恢复研究

本文用空间代时间的方法研究了长宁县竹林退耕还林在时间序列上的植被恢复特点。除毛竹外,和一般树种相比,竹类恢复为森林的时间较短,3 a~5 a即可成林。但竹种类型间成林速度存在差异,丛生竹成林最快,散生竹较慢。梁山慈竹和硬头黄竹退耕后可以一次成林,毛竹退耕可先进行农林复合经营直到群落郁闭。随着竹林的恢复,草本层生物量逐渐减少,地被物层生物量增加,各竹种新生个体的生态位逐渐扩大。人工栽植5 a的毛竹扩散规律研究结果表明,随着毛竹栽植时间的延伸,毛竹产生的新竹数目增多,个体变大,距离变远(170 cm),也存在大小年变化。人工促进竹林植被恢复速度明显较快。     

木荷种子萌发及对干旱胁迫的响应

以不同渗透势的PEG(6000)溶液模拟干旱胁迫条件,研究木荷种子的萌发、幼苗生长和累积吸水率对干旱胁迫的响应。结果显示:木荷种子的萌发率、幼苗生长及累积吸水率与PEG溶液的渗透势之间呈显著的负相关关系,但渗透势为-0.3~-0.6 MPa时,种子的萌发率比对照要高一些。在渗透势达到-1.8 MPa时,仍有少量种子(5.2%)能萌发,说明木荷种子具有一定的抗干旱胁迫能力。另外,经PEG处理后复水,种子的萌发率均高于对照的32.4%,提示PEG处理可以打破木荷种子的休眠现象。