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1.
Second-order schedules of drug injection.   总被引:2,自引:0,他引:2  
Key-press responding of squirrel monkeys produced intravenous injections of cocaine under two simple types of schedule. Under a fixed ratio schedule, every 30th response produced an injection; steady responding at high rates of over one per second were maintained during each fixed-ratio component. Under a fixed-interval schedule, the first response occurring after a fixed time of 5 min produced an injection; there was a pause at the start of each interval and then progressively increasing responding until cocaine was injected at the end of the interval. Both squirrel monkeys and rhesus monkeys also were studied under second-order schedules of drug injection. Under one type of second-order schedule, studies only in squirrel monkeys, completion of each fixed-interval component produced only a 2 sec light; completion of the 10th fixed-interval component produced the brief light and an intravenous injection of cocaine. Under a second type of second-order schedule, each fixed-ratio component completed during a fixed time interval (5 or 60 min) produced only a 2-sec light; the first fixed-ratio component completed after the interval of time elapsed produced the brief light and an intravenous (squirrel monkeys) or intramuscular (rhesus monkeys) injection of cocaine. Under both types of second-order schedules, repeated sequences of responding were maintained during each session and characteristic fixed-interval or fixed-ratio patterns of responding were controlled by the brief visual stimuli.  相似文献   

2.
8-Oxo-7,8-dihydroguanine was specifically oxidized by iodine with aqueous KI. Under acidic conditions, the major product was dehydro-guanidinohydantoin. Under basic conditions, two diastereoisomers of spirohydantoin were chiefly obtained. In addition, unstable diimine was detected for the first time.  相似文献   

3.
Bioremediation potential of Phanerochaete chrysosporium strains NCIM 1073, NCIM 1106 and NCIM 1197 to decolourise molasses in solid and liquid molasses media was studied. Strains varied in the pattern of molasses decolourisation on solid medium by Giant colony method. Under submerged cultivation conditions, strain NCIM 1073 did not decolourise molasses while, strains NCIM 1106 and NCIM 1197 could decolourise molasses up to 82% and 76%, respectively. Under stationary cultivation conditions, none of the strains could decolourise molasses. This was overcome by increasing the surface area of the culture in flat bottom glass bottles under stationary cultivation conditions. Under submerged cultivation conditions, growth was more or less same in all strains. However, the lignin peroxidase and manganese peroxidase activities were significantly less in the strain NCIM 1073. Under stationary cultivation conditions, none of the strains could produce enzymes lignin peroxidase, manganese peroxidase and laccase. However, all of them could produce lignin peroxidase and manganese peroxidase when cultivated in flat bottom glass bottles under stationary cultivation conditions.  相似文献   

4.
Based on quantitative measurement of components of field resistance of potatoes to late blight, a multiple linear regression equation is derived for laboratory estimation of Area Under Disease Progress Curve. The equation accounts for 82% of variation in Area Under Disease Progress Curve. Transformation of data or inclusion of more terms do not improve the equation significantly. The method is suggested as a replacement or supplement to field testing.  相似文献   

5.
Summary At high salinities and high temperatures, the growth rate of Pterocladia was high, the tips of branch initials were dilated and holdfasts broadened. By the end of the fourth week bleaching of the whole plant was complete.Under low salinities and low temperatures, the rate of vegetative growth was decreased, the cuticle was thin and food reserve was centrally accumulated in the cells.Under high salinities and low temperatures, the rate of growth was greatly reduced and cells were devoid of food reserve. Defoliation of lateral branches was frequent.Under low salinities and high temperatures, the rate of growht was rather high and cells were relatively large.  相似文献   

6.
Bean plants were exposed to salinity either during the lightor the dark period of the day. Under conditions of relativelymild evapotranspirative demand of the atmosphere, transpirationduring salt absorption did not markedly affect salt uptake orplant growth. In all cases duration of exposure to salinitywas the main factor. Under the experimental conditions, salinityreduced the transpiration rate. In these experiments full adjustmentto salinity was not achieved.  相似文献   

7.
目的总结无张力疝修补治疗腹股沟疝56例的效果。方法局麻下、使用聚丙烯编织而成的平片对56例各类腹股沟疝患者进行无张力修补治疗。结果与在硬麻或全麻下与传统的修补方法相比,具有手术适应证广、方法简单、创伤小,恢复快,并发症少和复发低率。结论应用国产的平片修补腹股沟疝效果良好,价格便宜,局麻下施行无张力疝修补术适合在基层医院推广。  相似文献   

8.
The phase character of lipid peroxidation has been found in the rabbit adrenal cortex in the process of adaptation to extreme loads. Under acute stress the activation of lipid peroxidation is directly dependent on the hormonal synthesis processes. Under conditions of the prolonged stress factor an enhancement of the lipid peroxidation intensity in the adrenal cortex coincides with a decrease in the steroidogenesis rate.  相似文献   

9.
Inhibition of ferritin reduction by pyrazolo(3,4d)pyrimidines   总被引:4,自引:0,他引:4  
The characteristics of inhibition of the ferritin reductase function of xanthine oxidase by three pyrazolopyrimidines is described. Under anaerobic conditions, the ferritin reduction coupled to hypoxanthine oxidation was inhibited by the three pyrazolopyrimidines tested, 4-hydroxypyrazolopyrimidine, 4,6-dihydroxypyrazolopyrimidine, and 4-mercaptopyrazolopyrimidine. Under the same conditions, four purine analogs were devoid of inhibitory activity, and 8-azaguanine and 8-azaadenine were weakly inhibitory.  相似文献   

10.
Growth of human clinical isolates of Streptococcus constellatus, Strep. intermedius and Strep. anginosus in HCl-, acetate and lactate acidified media was investigated. Under aerobic conditions, Strep. constellatus and Strep. anginosus were significantly more tolerant to all the acidulants than was Strep. intermedius. Under anaerobic conditions, Strep. anginosus and Strep. intermedius were significantly more tolerant to acetic acid (pH < 4.5) than Strep. constellatus  相似文献   

11.
Effects of abscisic acid on flowering in Pharbitis nil   总被引:1,自引:0,他引:1  
Under continuous light, flowering of Pharbitis seedlings wasnot induced by abscisic acid (ABA) treatment. Under short daytreatment, flowering was slightly enhanced by ABA at 0.2 and0.4 mg/liter. Stem elongation was considerably inhibited by25 and 50 mg/liter of ABA irrespective of day length. (Received October 21, 1972; )  相似文献   

12.
利用实验生态学方法,对攀缘生长与伏地生长的薇甘菊(Mikania micrantha)的形态特征、生物量分配和繁殖特征进行了比较研究。结果表明:在潮湿生境条件下,攀缘生长的植株与伏地生长的植株相比对主茎的生物量投资较大,而对分枝茎的生物量投资则相对较小;但在干旱生境条件下,攀缘生长的植株对主茎和分枝茎的生物量投资均较伏地生长的植株小。在潮湿与干旱生境中,攀缘植株的繁殖投资分别为0.429g·g-1和0.342g·g-1,显著高于相同生境中的伏地植株。在薇甘菊种群的补充与更新过程中,攀缘生长的植株以有性生殖占主导地位,在潮湿与干旱生境中产生的个体分别占种群数量的84.7%和62.6%;伏地生长的植株则主要以无性(克隆)繁殖为主,在潮湿与干旱生境中有性生殖产生的个体仅占种群数量的40.4%和35.9%。生长方式与土壤水分二因子互作效应对薇甘菊的生物量分配和繁殖指标影响均达到显著水平(P〈0.05)。通过研究得出以下结论:不同生长方式的薇甘菊对环境条件具有不同的生长与繁殖适应对策。  相似文献   

13.
Under static growth conditions, hyperpiliated, nontwitching pilT and pilU mutants of Pseudomonas aeruginosa formed dense biofilms, showing that adhesion, not twitching motility, is necessary for biofilm initiation. Under flow conditions, the pilT mutant formed mushroom-like structures larger than those of the wild type but the pilU mutant was defective in biofilm formation. Therefore, twitching motility affects the development of biofilm structure, possibly through modulation of detachment.  相似文献   

14.
Under starvation conditions, rhodopsin-containing halobacteria show a light-accelerated death under aerobic conditions. This is attributed to photooxidative processes. Under anaerobic conditions, halobacteria die rapidly in the dark, and light prevents death. Since it has been shown by others that lightdriven ATP synthesis can occur under anaerobic conditions, it is postulated that rhodopsin-mediated photophorylation is of survival value for this organism in the brines in which it lives, especially because the solubility of oxygen is low in highly saline waters and anaerobic conditions can often develop.  相似文献   

15.
通过对不同光照条件下桂花幼苗的冠形、分枝率、叶片在树冠中的空间分布等特征进行研究,结果表明桂花幼苗构型发生了明显的可塑性适应:其树冠对光照条件的变化有显著的可塑性响应。在林隙中的幼苗受光的间歇性影响,总体分枝率明显小于全光、林冠下的幼苗分枝率。全光的幼苗叶片集中于二级枝,叶片长度和叶片面积相对较小,对光照利用充分;而林隙中的幼苗叶片集中于一级枝,避免处于植冠内侧受到遮蔽,表现出较大的叶片长度和叶面积;林冠下的叶片较均匀分布在一、二级枝上,叶片总数量较少,枝条高生长较全光下明显。幼苗在总体分枝格局中表现出独自的特点,即强光环境下产生短枝和高分枝率,在适度庇荫条件下产生长枝及低分枝率,在强度庇荫条件下以较长枝和较高分枝率来同时满足高生长和横向生长的需求。  相似文献   

16.
In maize mitochondria the effect of the herbicide amiprophosmethyl was studied on massive and limited Ca2+-loading and on mitochondrial energy transduction. Under massive Ca2+-loading conditions amiprophosmethyl inhibited the Ca2+ transport system directly without a significant effect on the respiratory chain, the membrane potential or Ca2+ efflux. Under limited Ca2+-loading conditions an increased Ca2+ efflux was noted, which could be partially responsible for the inhibition of the net Ca2+ accumulation.  相似文献   

17.
Myocardium has been investigated in 68 human fetuses and newborns suffered from intrauterine acute and prolonged hypoxia, occurred as a result of various maternal, fetal and placental diseases. Under acute hypoxia only reactive changes of the contractile myocardium appear. They are demonstrated as degeneration of muscle fibers and appearance of scattered foci of necrosis in cardiomyocytes. Under a prolonged hypoxia, besides analogous reactive changes, compensatory hypertrophy of some part of cardiomyocytes is noted; this is manifestation of a compensatory-adaptive reaction of the myocardium.  相似文献   

18.
氧化还原条件对湿地土壤磷吸附与解吸特性的影响   总被引:6,自引:0,他引:6  
采用室内模拟试验研究了氧化还原条件对盘锦天然湿地土壤磷吸附与解吸特性的影响,并对磷的吸附与解吸过程进行拟合。结果表明,氧化或还原条件下Langmuir模型和Freundlich模型均能较好地拟合磷的等温吸附曲线,且Langmuir方程的拟合效果好于Freundlich方程。淹水还原条件下,湿地土壤对磷的最大吸附量和解吸率比淹水前分别降低了9.5%和16.3%;吸附解吸平衡浓度升高,平均增加158.8%。淹水后土壤活性铁含量明显升高,淹水前后活性铁变化与吸附解吸平衡浓度变化之间的相关性达到了显著水平,与土壤中磷的最大吸附量和解吸率变化的相关性不显著,表明活性铁含量的变化是淹水还原条件下影响土壤磷吸附解吸平衡浓度变化的主要因素。  相似文献   

19.
玉米根系水流导度差异及其与解剖结构的关系   总被引:3,自引:0,他引:3  
在人工气候室水培条件下,从单根水平研究了不同水分条件下玉米根系水流导度的基因型差异及解剖结构之间的关系.结果表明,抗旱性的杂交种户单四号具有水流导度上的杂种优势现象,不抗旱的父本803根系水流导度最低,3个品种根系水流导度大小为F1代户单四号>母本天四>父本803;水分胁迫普遍降低了根系直径、导管直径和皮层厚度.同时,玉米品种根系的解剖结构和根系水流导度有关,正常水分条件下,根系导管直径与3个玉米品种的根系水流导度呈正相关,胁迫条件下则呈负相关.无论是在胁迫还是正常水分条件下,根系皮层厚度占根系直径的比例与根系水流导度都呈负相关,说明根系皮层是根系吸收水分的主要阻力部位.  相似文献   

20.
初征  郭建平 《应用生态学报》2018,29(6):1885-1892
为探求东北玉米未来如何更好地适应气候变化,本研究采用抗逆品种和推迟播种期两种适应措施,结合区域气候模式模拟的2010-2099年间RCP4.5、RCP8.5两种浓度路径逐日气象资料,分析了不同气候变化情景下东北玉米适应措施的生产潜力变化.结果表明: 2010-2099年间,东北区玉米气候生产潜力的空间分布特征基本为东南向西北减小的趋势,RCP4.5情景下东北玉米生产潜力高于RCP8.5情景,且RCP8.5情景出现极低值年份明显多于RCP4.5情景.所有抗逆品种的玉米生产潜力均高于原有品种,在RCP4.5情景下,耐高温品种的玉米生产潜力更高,在RCP8.5情景下,耐旱品种表现更好,双耐(耐高温、耐旱)品种的玉米生产潜力在2种气候变化情景下均最高.RCP4.5情景下,推迟播种均出现增产情况,其中,推迟30~40 d播种的玉米增产率达到最大;RCP8.5情景下,部分地区出现减产情况.说明适当推迟播种期有利于提高玉米气候生产潜力,但地区间存在差异.  相似文献   

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