Asymmetric Exhaustive Service Polling System with Bernoulli Feedback

This paper studies asymmetric exhaustive service polling system with Bernoulli feedback,gives the distributions of queue lengths and sojoun times,and obtains some other results,in stationary condition.     

阴地厥提取物对运动训练大鼠不同组织抗氧化水平的影响

【目的】探讨阴地厥提取物(Scepteridium ternatumextract,STE)对运动训练大鼠心、肝、肾、脑、股四头肌等组织抗氧化水平的影响。【方法】将24只SD雄性大鼠随机分为安静对照组、运动对照组及运动+STE组,后2组大鼠进行7周的大强度跑台耐力训练,安静对照组自由活动不进行跑台训练,运动+STE组大鼠每天灌胃STE100mg/kg,其他2组灌服相同体积的生理盐水,每周最后1天测各组大鼠的体质量。第8周第1天取运动对照组和运动+STE组大鼠心、肝、肾、脑、股四头肌等组织样品,匀浆后分别测试各组大鼠不同组织总抗氧化能力(T-AOC)及超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、谷胱甘肽过氧化物酶(GSH-Px)活性和丙二醛(MDA)、还原型谷胱甘肽(GSH)含量。【结果】运动+STE组和运动对照组大鼠体质量与安静对照组比较均呈下降的趋势,其中运动+STE组大鼠体质量变化无显著性差异(P0.05),而运动对照组大鼠体质量变化有显著性差异(P0.05)。运动+STE组大鼠各组织T-AOC、SOD、CAT、GSH-Px活性和GSH含量显著或极显著高于运动对照组。运动+STE组大鼠各组织(除脑组织外)MDA含量显著低于运动对照组(P0.05),而高于安静对照组。【结论】阴地厥提取物可以改善长时间大强度耐力运动大鼠心、肝、肾、脑、股四头肌等组织的抗氧化水平,维持各组织抗氧酶活性和GSH含量,降低脂质过氧化反应,减少MDA的生成。     

BRA-90花青素的生物活性研究

旨在探讨BRA-90花青素对肝损伤具有一定的保护作用和抗氧化作用,建立了一次性力竭游泳运动模型,采用邻苯三酚法检测各组小鼠肝脏组织中超氧化物歧化酶（SOD）的活性,分析比较给药组和对照组肝脏指标变化情况。结论得出BRA-90花青素具有一定抗氧化作用,为BRA-90花青素在各方面的进一步应用和开发提供实验依据。     

蛹虫草多糖对小鼠抗疲劳作用的研究

采用雄性ICR小鼠随机分组,分别灌胃蒸馏水、不同剂量的蛹虫草(Cordyceps militaris)多糖(低、中、高剂量组分别每天灌胃75、150、450mg/kg BW),40d后建立疲劳模型,比较力竭游泳时间、肝肌糖原水平、乳酸含量和机体相关的乳酸脱氢酶和超氧化物歧化酶活力。结果表明:高剂量蛹虫草多糖能够显著延长小鼠力竭游泳时间,中高剂量多糖显著提高小鼠肝肌糖原水平,有效的遏制运动后小鼠乳酸生成量,而低剂量多糖显著增加运动后小鼠乳酸脱氢酶活力,3个剂量的多糖均能提高运动后小鼠血清中超氧化物歧化酶的活力。     

湖北省几种旱地土壤供钾能力的研究

用黑麦连续耗竭栽培和盆栽棉花、田间小区种植棉花拖钾的办法,综合评价了湖北省七种旱地土壤的供钾能力。结果表明,黑麦从0—50厘米土层中累积吸钾为41.57—98.66毫克/100克士,说明供试土壤的供钾能力不同。棉花施用钾肥的效应,土壤间亦不同,可反映供试土壤供钾能力的上述差异。黑麦累积吸钾量中,有0—24%来自速效钾,来自缓效钾的占76—100%,缓效钾的含量及其释放速率与土壤粘粒矿物组成及其含量有关。     

普洱茶熟茶抗疲劳作用研究

探讨了普洱茶熟茶抗疲劳的作用。将昆明种小鼠随机分为4组（20只/组）,分别为空白对照组和普洱茶熟茶低、中、高剂量组,分别饲喂0.9%生理盐水和0.5、1.0、2.0 g/kg的普洱茶熟茶。按照小鼠体重给予不同体积的受试物,自由摄食与饮水。连续饲喂30 d后,每组选取10只小鼠进行负重游泳实验,记录小鼠力竭游泳时间;剩余小鼠检测血乳酸(BLA)、血尿素氮(BUN)、血乳酸脱氢酶(LDH)活力及肝糖元（LG）、肌糖元（MG）。结果表明,与空白对照组相比,普洱茶熟茶低、中、高剂量组小鼠负重游泳时间均有延长,BLA、BUN含量降低,LDH活力升高,MG、LG含量也有显著提高,且以高剂量的普洱茶熟茶抗疲劳作用最为明显。     

力竭追赶训练对中华倒刺鲃自由基清除能力的影响

在(25±1)℃条件下,设置静水对照组(C组)、力竭追赶训练1次/d组(E1组)、力竭追赶训练2次/d组(E2组),研究了每日不同训练次数的力竭追赶训练对中华倒刺鲃(Spinibarbus sinensis)(46.84 g±2.50 g,13.73cm±0.22 cm)生长和自由基代谢相关指标的影响,训练周期为21 d。结果显示,中华倒刺鲃体质量特定生长率、肥满度和肝指数均比对照组有极显著降低;中华倒刺鲃肝脏和白肌抗氧化酶对力竭训练产生了一定适应性,但超氧化歧化物酶(SOD)、谷胱甘肽过氧化物酶(GSH-PX)和过氧化氢酶(CAT)对力竭训练的敏感性不同;力竭训练对肝脏和白肌总抗氧化能力(T-AOC)无显著影响;在肝脏和白肌丙二醛(MDA)方面,E2组>C组>E1组;E2组血清谷丙转氨酶(ALT)活性显著高于对照组和E1组,而3组血清肌酸激酶(CK)活性差异不显著。结果表明,力竭追赶训练对生长具有明显抑制性,并且对中华倒刺鲃脂质过氧化反应有类似"毒物兴奋效应",肝脏和白肌对其表现出不同的抗氧化调节机制。     

Depletion of Soil Potassium under Exhaustive Cropping in Inceptisol and Alfisol

Pot-culture studies of intensive cropping without potassium (K) application, taking three successive crops of rice on Sonakhali (Inceptisol) and Ranibundh (Alfisol) soils, revealed that all the forms of soil K declined after the third crop compared to the corresponding initial soil status. A similar trend was also found for nonexchangeable K extracted sequentially and termed as Step K and CR-K (constant rate K). The CR-K contents showed little variations with cropping. Except for the potential buffering capacity of the soil for K at equilibrium (PBC^K ₀) values, all the quantity/intensity (Q/I) parameters, namely activity ratio of potassium (AR^K _e), labile K (–ΔK₀), specifically held K (K_X), and total labile pool of K (K_L) values, decreased in both the soils as they were subjected to repeated cropping. The PBC^K ₀ values changed to a smaller extent in both the soils. In both soils, the threshold levels for release of intermediate K in terms of activity ratio, exchangeable K, and K concentration in soil solution decreased after the third cropping as compared to the initial status. The dry-matter weight of rice, K concentration, and K uptake decreased with the cropping sequence. The difference in values of each parameter between initial status and the third crop was much wider in Inceptisol than in Alfisol.     

Soil phosphorus after 25 years of cropping with five rates of phosphorus application

Abstract

Rate of change of levels of various soil P forms as affected by P fertilizer application and crop removal is important for determining long term P fertilization policy. A rotation‐fertility experiment conducted for 25 years at the Purdue Agronomy Farm, West Lafayette, IN has provided data for calculating changes in soil P levels. Average annual P applications ranged from 0 to 54 kg/ha. Soil samples taken initially and after 25 years were analyzed for resin exchangeable P, Bray Pl, and total P. A linear relation between P applied minus P removed by cropping and Bray Pl indicated that Bray Pl increased one μg/g for every 17 kg net P/ha added. When P application on some plots was stopped for up to eight years, resin and Bray Pl levels decreased. The rate of decrease was greater the higher the P level at the time P application ceased. Increase in soil P level by fertilizer addition and decrease in P level by cropping appeared to be reversible processes.     

力竭追赶训练对两种鲤科鱼类生长和摄食代谢的影响

为了考查力竭训练对养殖鱼类生长能力和摄食代谢影响,在25℃条件下,测定了中华倒刺鲃(Spinibarbussinensis)和岩原鲤(Procypris rabaudi)幼鱼各自非训练组和训练组(力竭追赶训练1次/d,历时21 d)的生长参数和摄食代谢反应。结果显示:训练组中华倒刺鲃幼鱼的摄食率、饲料转化效率、特定体重生长率、特定体长生长率、摄食代谢峰值、峰值比率、SDA总耗能量和SDA系数都显著小于非训练组;静止代谢率、SDA时间及峰值时间与非训练组无显著性差异。训练组岩原鲤幼鱼的饲料转化效率、特定体重生长率、特定体长生长率、静止代谢率和摄食代谢峰值都显著小于非训练组,但摄食率、SDA时间、峰值时间、峰值比率、SDA总耗能量和SDA系数与非训练组无显著性差异。研究表明:力竭训练导致两种鱼类的生长率都显著下降;在力竭训练条件下两种鱼类采用的摄食代谢适应策略不尽相同。