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1.
生理生态学的原则是随着纬度的升高,物种分布的海拔高度将随之降低。但是,云南一些植物特征成分的分布却与之相反,它们的分布与云南残留的古夷平面的分布相似,即随着纬度的升高,其分布的海拔高度也随之升高。二者的区别是云南古夷平面分布的趋势线的仰角大于那些特征成分分布的趋势线的仰角。可能的原因是:相对于剧烈的地质运动,物种的适应能力总是相对滞后的,并且物种的分布也受到其生长特性的制约;根据分布区形成的原则,这些成分的发生应早于夷平面的隆起。  相似文献   

2.
浅谈果树病虫害综合防治技术研究   总被引:2,自引:0,他引:2  
在我国的农业生产的过程中,对于果树的病虫害综合防治是农业生产效益的根本保障,我国是一个农业大国,尤其是在我国的北方,果树的栽培更是有着悠久的历史,在近些年中由于技术的进步果树的品种更新的速度也在不断的加快,但是随之而来的就是果树的病虫害的问题,它对于果树的影响非常的大,直接在经济上给果农带来严重的损失,为了能够让果农的经济效益得到保障,对于果树的病虫害防治就显得极为重要。本文主要是对东北地区的果树病虫害的现状进行简要的分析,并对果树病虫害的综合防治技术进行研究找出适当的对策,希望能有所裨益。  相似文献   

3.
绪言自从1950年召开的研究巴甫洛夫生理学说问题的苏联科学院及苏联医学科学院的科学会议以后,则产生了根据巴甫洛夫学说讲授中学的人体解剖生理学的必要性. 巴甫洛夫的高级神经活动学说是他的生理学说的顶峰,是中学学生所必需获得的,巴甫洛夫有关高级神经活动的概念,可以在人体解剖生理课程中阐明,但是它的形成在动物学的课程中就应当开始.高级神经活动的概念,在说明关于有机体为统一的整体的较为总括性的概念中,是起一个主导作用的.学生自觉的掌握巴甫洛夫的“高级神经活动”概念,将会有助于学生树立辩证唯物主义的、无神论的世界观.学生具备了高级神经活动的概念,则给中学10年级学习心理学打下了良好的基础.一直到现在为止,在学校的人体解剖生理学课程中树立高级神经活动概念的方法的问题,尚未得到必要的解决.  相似文献   

4.
对于罗红来说,热爱自然始于被自然的征服,始于非洲的原野上“生命就在你身边奔流”的时候,发现了“那么多的生命可以跟人类如此之近,有多美好”。同时也始于被蹂躏的自然的伤痛。于是他的镜头,才可能在动物的世界里,创造出“那么多让人热血沸腾的故事”。从一个旁观者的角度,进入到撼人心魄的生物圈,然后又选择了从数千米的高空,俯瞰这个世界的美丽。距离的远近不是心灵远近的同义词,罗红大气、美丽的自然,说出了一个普通而又意味深长的哲理。以一种爱的力量在很近的心灵的距离俯瞰宏大的自然,世界才会呈现出完全不同的意味。当然,这样的一个过程,是漫长而艰巨的,也是值得的。[编者按]  相似文献   

5.
在中学阶段的生物教学中,科学素质教育的任务是什么?笔者认为科学素质教育应包括运用科学的方法、选择适当的实验材料、执着的钻研精神、敏锐的观察能力、实事求是的态度以及耐得住清贫和寂寞的生活方式的教育等。科学品质的培养则依赖于正确的思想观念的确立和高尚的道...  相似文献   

6.
当代手术室护士素质能力要求   总被引:1,自引:0,他引:1       下载免费PDF全文
素质原本是心理学的一个专门术语,是指人的一种较稳定的心理特征。素质广义的解释分先天与后天两方面。先天的自然性的一面,是指人在某些方面的与生俱来的特点和原有基础,即天生的感知器官,神经系统,特别是大脑结构和功能上的一系列特点而言;素质的后天的社会性的一面是主要的,是指通过不断的培养、教育、自我修养、自我磨练而获得的一系列知识技能、行为习惯、文化涵养、品质特点的总和。护士的素质包括思想品质素质和专业素质两个方面。而对于手术室护士的素质就有更高更广泛的要求,特别是对于当代手术室护士的素质能力,只有提高了手术室护士的素质,才能改善医院手术室的护理质量,更好的适应当代手术室的工作要求。如何提高手术室护士的素质能力,是摆在我们面前的重要课题,作者结合多年担任手术室护士和护士长的经验就手术室护士应具有的素质能力,提高手术室护士素质的途径和方法做如下探讨。  相似文献   

7.
生物催化是指将酶或生物有机体用于有用的化学转化的过程,在人们对传统化学催化的环境影响抱有忧虑的情况下,生物催化提供了一种有吸引力的选择。在过去的几十年里,对生物催化剂的研究每出现一次大的进步,生物催化的发展就会出现一次高潮。因此,生物催化剂的发现与改造已成为当今研究的热点。宏基因组文库技术的出现克服了许多微生物不可培养的障碍,人们能够从自然资源中获得丰富的潜在的生物催化剂。而基于理性设计的分子改造技术的发展,可以使得人们对潜在的生物催化剂进行快速而有效的改造以满足工业化生产的需求。随着生物催化剂发现与改造的手段不断进步,更多的优良生物催化剂得到了广泛的应用,生物催化在工业生产中也得到了更深入的应用。结合作者的研究工作,总结了生物催化剂发现与改良的一些研究进展,以为获得更多优良的、能够实现工业应用的生物催化剂奠定理论基础。  相似文献   

8.
《化石》1977,(4)
当人们走进自然历史博物馆,看到巨大的恐龙骨架时,总是情不自禁地问道:这条恐龙有多少吨重?这就产生了怎样测量恐龙体重的问题。过去很长的一个时期,人们是依据恐龙骨架的大小,它的脚印的大小和凹陷的深浅,参考现代的一些脊椎动物的重量,作大体上的推测。例如要测量的恐龙骨架与现代的印度象差不多,就估计恐龙的体重约为5吨左右。显然这种方法并不准确。后来,有些研究恐龙的科学家不断提出测量恐龙体重的方案。目前,在我国普遍认为行之有效的测量恐龙体重的方法,是采用美国科尔伯特改进的用复原模型测量的方法。他的方法是,根据一个简单的物理学原理:体积×比重=体重。体积是用要测量的恐龙的复原模型求出来的。首先要依据待测恐龙的骨架的尺度,作出一个一  相似文献   

9.
医院的对外宣传工作的目的是为了更好的介绍医院,展示医院,树立医院在社会公众心中的良好形象。使更多的人们了解医院的专业性,服务大众的水平,医院的各项惠民政策,医疗科普知识等。建立健康的、和谐的医患关系,推动医疗卫生事业的蓬勃发展。本文从医院对外宣传存在的问题,新时期医院对外宣传的实践路径进行了简单的论述。  相似文献   

10.
许多国家都有了自己的国花。如朝鲜的金达莱,日本的樱花,英国的蔷薇,法国的百合花,美国的山杞花,德国的矢车菊,意大利的雏菊,加拿大的糖槭花,西班牙的石榴花,希腊的橄榄花,爱尔兰的酢浆草花,墨西哥的仙人掌花。这些花,或因原产于所在的国家,或因遍植于该国,或与该国人民  相似文献   

11.
Aquaporins: water channel proteins of the cell membrane   总被引:37,自引:0,他引:37  
Aquaporins (AQP) are integral membrane proteins that serve as channels in the transfer of water, and in some cases, small solutes across the membrane. They are conserved in bacteria, plants, and animals. Structural analyses of the molecules have revealed the presence of a pore in the center of each aquaporin molecule. In mammalian cells, more than 10 isoforms (AQP0-AQP10) have been identified so far. They are differentially expressed in many types of cells and tissues in the body. AQP0 is abundant in the lens. AQP1 is found in the blood vessels, kidney proximal tubules, eye, and ear. AQP2 is expressed in the kidney collecting ducts, where it shuttles between the intracellular storage sites and the plasma membrane under the control of antidiuretic hormone (ADH). Mutations of AQP2 result in diabetes insipidus. AQP3 is present in the kidney collecting ducts, epidermis, urinary, respiratory, and digestive tracts. AQP3 in organs other than the kidney may be involved in the supply of water to them. AQP4 is present in the brain astrocytes, eye, ear, skeletal muscle, stomach parietal cells, and kidney collecting ducts. AQP5 is in the secretory cells such as salivary, lacrimal, and sweat glands. AQP5 is also expressed in the ear and eye. AQP6 is localized intracellular vesicles in the kidney collecting duct cells. AQP7 is expressed in the adipocytes, testis, and kidney. AQP8 is expressed in the kidney, testis, and liver. AQP9 is present in the liver and leukocytes. AQP10 is expressed in the intestine. The diverse and characteristic distribution of aquaporins in the body suggests their important and specific roles in each organ.  相似文献   

12.
It is noteworthy that in the rat the early postnatal life is marked by an activation of both the corticostimulating function of the adenohypophysis in neonates of both sexes and of the gonadostimulating function mainly in males. In order to specify if such neuroendocrine variations are temporally correlated with changes in the hypothalamic metabolism of neurotransmitters, the hypothalamic metabolism of serotonin (5 HT), norepinephrine (NE), and dopamine (DA) and the hypothalamic content of neuropeptide Y (NPY) have been investigated in newborn rats of both sexes, delivered at term by cesarean section, as well as changes in the activity of both the hypothalamo-pituitary adrenal axis (HPA) and the hypothalamo-pituitary gonadal axis (HPG). Experimental data suggested that 1) in males a rise in hypothalamic metabolism of 5 HT, NE and DA occurs during the first two hours after delivery, whereas in females, only the metabolism of NE increases. Moreover, the postnatal metabolism of NE was higher in females than in littermate males; 2) NPY content of the hypothalamus, which was at birth significantly higher in males than in females, dropped in the former but not in the latter; 3) in newborn males, an early surge of plasma testosterone occurs, suggesting postnatal activation of the HPG axis; on the other hand, in females, a late and slight increase in plasma estradiol is observed; 4) in early postnatal life, a sex-independent rise in plasma ACTH and adrenal and plasma corticosterone levels suggest a comparable activation of the HPA axis in newborns of both sexes. In conclusion, the early postnatal activation of the corticostimulating function in neonates of both sexes and that of the gonadostimulating function, mainly in males, could be temporally correlated with a rise in the hypothalamic metabolism of two neurotransmitters, 5 HT and NE, and of NPY content. According to our data, a sex-dependent metabolsim of neurotransmitters in the hypothalamus is already apparent in early postnatal life.  相似文献   

13.
啮齿动物作用下退耕地山杏种子扩散与贮藏的季节变化   总被引:2,自引:0,他引:2  
啮齿动物对植物种子的取食和扩散影响种子的时空分布,继而影响种子的萌发和幼苗建成,因而在森林更新中起着重要作用.在国有济源市愚公林场,选择退耕地生境,于春季、夏季、秋季分别释放人工标记的山杏种子,观察啮齿动物扩散与埋藏山杏种子的季节性差异.结果表明:1)退耕地中的啮齿动物主要包括大林姬鼠、社鼠、黑线姬鼠;2)山杏种子扩散速率在春季显著慢于夏季,夏季显著慢于秋季;3)种子搬运量受季节和种子状态交互作用影响,春季显著少于夏季,夏季显著少于秋季;4)不同季节种子平均搬运距离不同,秋季不同状态种子的搬运距离均大于春季和夏季;5)啮齿动物对山杏种子的贮藏点大小多为1粒种子,少量为2、3粒种子,且贮藏点大小与季节间存在显著的交互作用,春季单粒种子的贮藏点数量显著少于夏季和秋季,而夏季与秋季的贮藏点则倾向于多粒种子;6)在夏季和秋季各有5枚(共释放1800枚)被啮齿动物分散贮藏的山杏种子建成幼苗.  相似文献   

14.
We have measured the endogenous TRH concentration in the pineal and 9 brain regions of a seasonal hibernator, the golden-mantled ground squirrel, during euthermia and hibernation in order to investigate the possibility that changes in TRH concentration might occur in association with naturally-occurring changes in CNS-mediated physiological and behavioral processes. Regional TRH content was assessed by radioimmunoassay in adult animals that were killed during euthermia in the mid-portion of each season and during hibernation in mid-winter. No significant changes in TRH concentration related to season or to hibernation versus euthermic state were noted in the hippocampus, brainstem, or cerebellum. In the olfactory bulb, preoptic area, and pineal, seasonal variation within euthermic groups was evident. During hibernation, statistically significant decreases in TRH content occurred in the forebrain, olfactory bulb, hypothalamus, septum, preoptic area, and midbrain. Significant fluctuations during hibernation were also observed in the pineal. In this structure, TRH concentration varied in relation to the phase of the hibernation bout. TRH content in the last quarter of the bout was three times greater when compared to values observed in the first quarter of the bout. These results suggest that TRH may be involved in the control processes attributed to these regions and support a role for TRH in the neural control of hibernation.  相似文献   

15.
Sex differences in the morphology and function of the hippocampus have been reported in several species, but it is unknown whether a sexual dimorphism exists in glial fibrillary acidic protein (GFAP) expression in the rat hippocampus. We analyzed GFAP immunoreactivity in the hippocampus of intact adult male rats as well as in females during diestrus and proestrus phases of the estrous cycle. We found that in CA1, CA3, and dentate gyrus, GFAP immunoreactivity was higher in proestrus females as compared with males and diestrus females. In CA1, a similar GFAP immunoreactivity was found in males and in diestrus females, but in dentate gyrus, males presented the lowest GFAP content. Interestingly, differences in astrocyte morphology were also found. Rounded cells with numerous and short processes were mainly observed in the hippocampus during proestrus whereas cells with stellate shape with few and long processes were present in the hippocampus of males and diestrus females. The marked sex and estrous cycle-dependent differences in GFAP immunoreactivity density and in astrocyte number and morphology found in the rat hippocampus, suggest the involvement of sex steroid hormones in the sexually dimorphic functions of the hippocampus, and in the change in its activity during the estrous cycle.  相似文献   

16.
松嫩平原全叶马兰种群不同龄级分株的生长策略   总被引:12,自引:3,他引:9  
杨允菲  李建东 《应用生态学报》2003,14(12):2171-2175
全叶马兰为根蘖性多年生草本菊科植物,种群由3个龄级无性系分株组成,在松嫩平原6月份,是全叶马兰营养生长的旺盛期,研究结果表明,分株的生长与生产力以1龄级最低,2、3龄级依次增高,3个龄级分株的生物量分配均为茎>叶>主根,叶的生物量分配为1龄级>2龄级>3龄级,茎和主根的均为1龄级<2龄级<3龄级,3个龄级分株总重与分株高度、分株叶重与茎重、分株主根重与枝条重之间均为幂函数异速生长规律,主根的生物量分配则随着分株高度的增加呈线性减少,全叶马兰无性系分株的生长与分配策略是在分株幼小时将较多的物质分配给叶,以保证物质生产器官叶的建造上,随着分株生长逐渐将生产的物质分配到茎和主根的生长与贮藏;分株不向主根投入较多的能量,但在分株幼小时向主根中分配的物质相对较多,随着分株的生长则按比例较小,并保持相对稳定的分配比率  相似文献   

17.
目的:研究复合疲劳大鼠血液、肌肉、肝脏和脑中矿物元素代谢变化的影响。方法:将30只大鼠随机分为正常对照组、食物限制组和复合疲劳组。经过5天的实验干预后,提取动物的血液、腓肠肌、肝脏和脑,并利用原子吸收分光光度法测量各组织中的钾(K)、钙(Ca)、镁(Mg)、铁(Fe)、锌(Zn)和铜(Cu)。结果:相对正常对照组和食物限制组,复合疲劳大鼠的肌肉、肝脏和脑中的K(P<0.01)和肝脏中的Fe(P<005)明显升高,血液中的Cu(与正常对照组比较P<0.01,与食物限制组比较P<0.05)明显下降;与对照组相比,复合疲劳大鼠的血液中的K明显升高(P<0.05),血液中的Mg和Zn(P<0.05),肌肉中的Ca、Mg和Zn(PCa<0.05,PMg<0.05,PZn<0.01),肝脏中的Ca和Zn(PCa<0.01,PZn<0.05),以及脑中的Fe、Mg和Zn(PFe<0.05,PMg<0.05,PZn<0.01)明显降低。结论:在复合疲劳状态下,大鼠血液、肌肉、肝脏和脑中的K、Ca、Mg、Fe、Zn和Cu代谢发生变化,可能在疲劳的发生与缓解中发挥作用。  相似文献   

18.
Dichoroacetate (DCA) and trichloroacetate (TCA) are by-products formed during chlorination of the drinking water and were found to be hepatotoxic and hepatocarcinogenic in rodents. In this study, the abilities of the compounds to induce oxidative stress and phagocytic activation have been studied in B6C3F1 mice. Groups of mice were administered 300 mg/kg of either DCA or TCA, p.o, and were sacrificed after 6 or 12 h. Peritoneal lavage cells (PLCs) were isolated and assayed for superoxide anion (SA) production, and hepatic tissues were assayed for the production of SA, lipid peroxidation (LP), and DNA-single strand breaks (SSBs). TCA resulted in significant production of SA in the PLCs, and in the production of SA, LP, and DNA-SSBs in the hepatic tissues, 12 h after dosing, as compared with the control. DCA administration, on the other hand, resulted in significant increases in the productions of LP and DNA-SSBs in the hepatic tissues at both time points, and in SA production in PLCs and hepatic tissues, 6 h after dosing. However, DCA-induced increases in SA production in PLC and hepatic tissues declined at the 12-h time point, reaching control level in the hepatic tissues. These results may implicate the contribution of phagocytic activation to the induction of oxidative stress in the hepatic tissues and also the role of SA production in the induction of LP and/or DNA damage in those tissues, in response to the compounds. The results also suggest studying the involvement of these mechanisms in the long-term hepatotoxicity/hepatocarcinogencity of the compounds.  相似文献   

19.
Recent coral spawning observations in the central Red Sea show that most scleractinian species release their gametes in the spring, with a majority of species spawning in April. There is, however, a lack of reproductive data for several other coral species, as well as a general lack of data for other invertebrates. Here, we document the detailed timing of spawning for 13 scleractinian coral species, one sea anemone, and six echinoderms from an inshore reef off the coast of Thuwal, Saudi Arabia, in the spring between April and June 2014. Furthermore, inferred from the presence of mature gametes, we report the month of spawning for three additional coral species in the spring. Seven scleractinian coral species were inferred to release their gametes in a second reproductive season, in the autumn, between September and November. This is the first report of a second spawning season in the Arabian region. Biannual spawning has so far been reported on the Great Barrier Reef, in Western Australia, in Indonesia, in Malaysia, in Palau, in Thailand, in Taiwan, and in Western Samoa.  相似文献   

20.
According to data of observations in 2002–2004, differences in the pattern of diurnal fluctuations in the total content and fractional composition of lipids in muscles of mature specimens of kilka Clupeonella cultriventris from the Rybinsk Reservoir in the feeding and spawning periods were revealed. It was established that the feeding intensity in kilka considerably changes throughout 24 h in both periods of the annual cycle, while diurnal fluctuations in the fatness of muscles are distinctly manifested only in the reproductive period and have a dissimilar pattern in specimens of different sexes. In females and males, they are determined mainly by the change in the content of the fraction of reserve lipids-triacylglycerols, as a rule, by its increase in the light hours of the day, several hours after an increase in the feeding activity of fish. The pattern of diurnal fluctuations of the level of lipid fractions (phospholipids, triacylglycerols, cholesterol, and its ethers) in kilka’s muscles differs from that in the feeding period. Possible causes of the change of diurnal variations of the considered indices of lipid metabolism in kilka at an increase in the endocrine activity of its body in the reproductive period is discussed.  相似文献   

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