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1.
水稻苗床土壤调酸后对土壤酶活性及一些营养元素的影响   总被引:4,自引:0,他引:4  
水稻苗床土壤调酸后对土壤酶活性及一些营养元素的影响唐咏,梁成华,张中原,李焕珍(沈阳农业大学,110161)(沈阳市土肥工作站,110034)EffectsofSoilAcidificationonEnzymeActivitiesandNutrien...  相似文献   

2.
长白山珍稀植物-草苁蓉于英赵淑春修荆昌(吉林农业大学野植教研室,长春130118)(吉林省园艺特产管理站)长白山珍稀野生植物草苁蓉(BoschniakiarossicaFedtschetFlerov),系列当科(Oroban-chaceae)植物,俗...  相似文献   

3.
InductionofRatProlactinomabyβ-EstradiolandItsRelationtoExpressionofc-mycOncogene¥XURong-kun(许荣琨);GUOChuan-hai(郭传海);HUANGMan-y...  相似文献   

4.
辽宁省灾害区划初探   总被引:2,自引:0,他引:2  
辽宁省灾害区划初探尹功成,梁文举(辽宁省农业区划研究所,沈阳110031)(中国科学院沈阳应用生态研究所,110015)AnApproachtoCalamityDivisioningofLiaoningProvince¥.YinGongcheng(LiaoningInslituteofAgri-culturalDivisioning,Shenyang110031),LiangWenju(InsliluteofAppliedEcology,AcademiaSinica,Shenyang110015).ChineseJournalofEcology,1993,12(4):61-65.NaturalcalamitiesoccurwhenvariOusnaturalphenomnaendangerlife,mindsandproperties,butsomepotentialenvironmentaldisasterssuchasrnan-madeandanthropogenousnaturaldisastersdevelopslow-lyandprofoundly,whlchareunobviousandnotr  相似文献   

5.
FactorsAffectingElectro-FusionandElectro-ActivationInSerialNuclearTransplantationInGoat(Carpahircus)EmbryoWANGYu-ge(王玉阁);ZOUX...  相似文献   

6.
应用免疫组织化学及图像分析技术对50例乳腺癌的c-erbB-2癌基因表达与细胞形态定量及DNA含量的关系进行了分析。结果显示:(1)c-erbB-2阳性乳腺癌细胞平均DNA含量及倍体数明显高于c-erbB-2阴性者,且以非二倍体细胞为主;(2)c-erbB-2阴性乳腺癌细胞平均核面积(NA)、核周长、核直径及核浆比例均大于c-erbB-2阴性者。术后5年内死亡的c-erbB-2阳性乳腺癌细胞NA值最大,c-erbB-2阳性且有淋巴结转移者细胞NA值亦较大,核形状因子偏离“1”更远。表明c-erbB-2表达与乳腺癌细胞的分裂及分化关系密切。  相似文献   

7.
白介素-18     
白介素-18日本研究者UshioS等(1996)根据IFN-γ诱导因子(IGIF)的结构特征和功能,将它命名的白介素-18(IL-18)。Hyogo医学院细菌学系Okamura等(1995)从内毒素休克小鼠肝脏里克隆了小鼠IL-18cDNA,其ORF...  相似文献   

8.
系统感染TMV的番茄叶胞外提取液经冰冻干燥浓缩、-20℃丙酮沉淀、离子交换柱层析和凝胶柱层析纯化,获得4种β-N-乙酰氨基己糖苷酶。这些酶是由75kD亚基构成的电荷异构体(chargeisomer),用过碘酸-Schiff反应证明是糖蛋白,以D-硝基苯-N-乙酰-β-D-氨基葡萄糖苷(pNP-β-D-GlcNAc)和p-硝基苯-N-乙酰-β-D-氨基半乳糖苷(pNP-β-D-GalNAc)为底物,这些酶具有相似的性质。N-乙酸氨基葡萄糖(GlcNAc)和N-乙酰氨基半乳糖(GalNAc)是这些酶的竞争性抑制剂,Ag+和Hg2+是它们的强抑制剂,Fe2+、Fe3+和Cu2+也抑制其活性。  相似文献   

9.
c-mpl原癌基因编码促血小板生成素受体郭树华,贺福初,吴祖泽(北京放射医学研究所,北京100850)c-mpl原癌基因是v-mpl(myeloProliferativeleukemiavirus,MPLV)的正常细胞的对应物.人的全长c-mplcD...  相似文献   

10.
6-Dimethylaminopurine(6-DMAP)SpontaneouslyInducesInterphaseTransitionOfMetaphaseMouseOocytes¥SUNQing-yuan(孙青原);GAOShao-rong(高...  相似文献   

11.
稻—鱼—蛙立体农业生态效益的研究   总被引:9,自引:0,他引:9  
我国是一个稻米生产大国 ,古代劳动人民早已认识到稻田中的鱼、蛙与水稻生长的互利关系。三国时代就有稻田养鱼的记载 :“郫县子鱼黄鳞赤尾 ,出稻田可以作酱”;宋朝诗人辛弃疾的词句 :“稻花香里说丰年 ,听取蛙声一片”,生动地描述了那种自然景象。但是到目前为止 ,对稻 -鱼 -蛙共生生态系统的系统研究还较缺乏。本文旨在通过在稻田中放养美国青蛙及草鱼 ,进行立体种养殖来分析探讨稻 -鱼 -蛙立体农业的生态效益 ,为该项技术的深入研究、生产的推广普及提供一些理论依据。放草鱼夏花 2 0 0尾 ,进行经济效益的比较试验。1 .3 秧苗的栽插与鱼…  相似文献   

12.
We have developed novel stereoscopic wearable multimodal intraoperative imaging and display systems entitled Integrated Imaging Goggles for guiding surgeries. The prototype systems offer real time stereoscopic fluorescence imaging and color reflectance imaging capacity, along with in vivo handheld microscopy and ultrasound imaging. With the Integrated Imaging Goggle, both wide-field fluorescence imaging and in vivo microscopy are provided. The real time ultrasound images can also be presented in the goggle display. Furthermore, real time goggle-to-goggle stereoscopic video sharing is demonstrated, which can greatly facilitate telemedicine. In this paper, the prototype systems are described, characterized and tested in surgeries in biological tissues ex vivo. We have found that the system can detect fluorescent targets with as low as 60 nM indocyanine green and can resolve structures down to 0.25 mm with large FOV stereoscopic imaging. The system has successfully guided simulated cancer surgeries in chicken. The Integrated Imaging Goggle is novel in 4 aspects: it is (a) the first wearable stereoscopic wide-field intraoperative fluorescence imaging and display system, (b) the first wearable system offering both large FOV and microscopic imaging simultaneously, (c) the first wearable system that offers both ultrasound imaging and fluorescence imaging capacities, and (d) the first demonstration of goggle-to-goggle communication to share stereoscopic views for medical guidance.  相似文献   

13.
Although binocular disparity can in principle provide absolute depth information, perceived stereoscopic depth depends on the relative disparities between points and their spatial arrangement. An example of this is the stereoscopic anisotropy--observers typically perceive less depth for stereoscopic surfaces when depth varies in the horizontal direction than in the vertical direction. We investigated whether this anisotropy also affects manual pointing. Participants were presented with stereograms depicting surfaces that were slanted in depth about either a horizontal axis (inclination) or a vertical axis (slant), and were asked either to point to the edge of a surface, or to estimate its inclination or slant. For both tasks, a clear anisotropy was observed, with participants perceiving greater depth, and also pointing out steeper surfaces, for inclined surfaces than for slanted surfaces. We conclude that both perception and the control of action are subject to a similar stereoscopic anisotropy, and that performance on the two tasks relies on similar depth processing mechanisms.  相似文献   

14.
进入21世纪,农业节能减排逐渐引起人们的关注。运用能源碳排放计算模型,对德州市2003-2008年农业碳源、碳汇进行计算分析,结果表明:(1)目前德州市农业碳源现状为7.29TgCO2eq.a-1,其中由农业能源消费、土壤呼吸、化肥施用和牲畜饲养造成碳排放分别为2.81、2.12、0.93和1.43TgCO2eq.a-1;(2)农业碳汇现状能力为9.24TgCO2eq.a-1,包括由于土地利用变化造成的碳排放4.73TgCO2eq.a-1和通过施用有机肥和实施秸秆还田的固碳能力4.51TgCO2eq.a-1;(3)碳汇能力较碳源释碳量有所盈余,具有发展低碳农业的潜力。从减源、增汇两个方面提出德州市未来发展低碳农业的相关措施,如调整农业产业结构,改进土地利用方式、实行保护性耕作、提倡农村可再生能源利用、推广立体种养模式,发展种养结合的循环农业等。  相似文献   

15.
利用微机化的伪随机点立体图对发生器进行双眼体视的心理物理实验,研究交替呈现的随机点体图对(RDS)在达到双眼融合形成立体感知时信息输入的时间特性.实验结果表明,当RDS的交变频率达到4.8Hz以上时就能达到双眼的信息融合产生立体感知,但当交变频率低于62.5Hz时有图形的闪烁感.当交变频率等于62.5Hz时则产生稳定而清晰的立体感知.一幅RDS图对中的L(左)和R(右)图的呈现时间及其之间的交变时间的长短均对双眼的融合和立体感的形成有影响.L和R图的呈现时间和交变时间还存在一定的关系,以立体感形成为条件,如增大一定值的L和R图的呈现时间,则它们之间的交变时间必须相应减小,反之亦然.实验结果提示,双眼立体感知的形成不涉及单眼图象的长时记忆和短时记忆,仅有瞬时的视觉存储.  相似文献   

16.
双眼倾斜效应中频率和相对距离乘积的恒常性   总被引:1,自引:1,他引:0  
双眼协同的功能不仅是扩大视野,而且更为重要的是人和动物获得对环境特有的立体感觉。但立体视觉信息处理机制至今尚不清楚,有待深入研究。 本文利用自己研制的一种多功能立体图形发生器产生的亮度以正弦波调制的光栅条纹作为刺激图形,设计并做了一系列有关频差倾斜现象;其次,分别对不同中心频率和不同观察距离下,左、右刺激器处于与被试者不同距离下频差倾斜观象中的频差与倾斜度的关系进行了研究。结果表明,对于频率差分析存在着频率和相对远近乘积的恒常性,这是判断物体精细凸凹的一种global stereopsis性质的心理规律。  相似文献   

17.
To investigate the long-term surface microstructure of a synthetic auditory ossicle (Apaceram) composed of dense hydroxyapatite (HA), thin HA disks were implanted subcutaneously into the interscapular regions of 12 rats. After 6, 14 and 20 months, implanted HA surfaces were observed using stereoscopic microscopy, scanning electron microscopy (SEM) and laser-Raman spectrometry. Visual observation by SEM at 6 months and by stereoscopic microscopy at 14 months indicated a progressive degradation of the HA disk surfaces implanted in the subcutaneous tissue. Visual observation by SEM at 14 and 20 months and by stereoscopic microscopy at 20 months indicated a progressive redeposition on the surfaces of the implants. Raman spectra compared half-peak breadths of v1 signal (PO4(3-), 960 cm(-1)) on the gray and white surface areas of implanted HA disks observed by stereoscopic microscopy. Analysis demonstrates that demineralization at 14 months and remineralization at 20 months occur on the gray areas; demineralization at 6 months and remineralization at 14 months occur on the white areas.  相似文献   

18.
体视感觉“崩溃”的阀值   总被引:1,自引:1,他引:0  
视差是产生体视感觉的主要因素.但视差过大时这种体视感觉也不能存在.这时随着双眼视差的增大从融合为单一像到成复像,而引起体视“崩溃”.本文对正常人和体视欠缺者用心理物理试验方法结合视觉诱发电位(VEP)分析,测量了人眼体视“崩溃”的视差上限阈值.并在改变刺激图形亮度和面积时加以比较.我们的结果表明正常人体视上限阈值,其视差高于2度,在某些情况下这个“崩溃”阈值达到3度.体视欠缺者的“崩溃”阈值约为1.5度.亮度和面积变小会使体视“崩溃”阈值下降,但在这种情况下体视欠缺者的“崩溃”阈值不会下降.可以认为1.5度是人的最低上限阈值·体视存在时VEP的N峰潜伏期约为220—300ms,P_3峰在280—340ms之间.无体视现象(视差为零和过大)这两个峰的潜伏期明显加大.  相似文献   

19.
We present a simple model which can account for the stereoscopic sensitivity of praying mantis predatory strikes. The model consists of a single “disparity sensor”: a binocular neuron sensitive to stereoscopic disparity and thus to distance from the animal. The model is based closely on the known behavioural and neurophysiological properties of mantis stereopsis. The monocular inputs to the neuron reflect temporal change and are insensitive to contrast sign, making the sensor insensitive to interocular correlation. The monocular receptive fields have a excitatory centre and inhibitory surround, making them tuned to size. The disparity sensor combines inputs from the two eyes linearly, applies a threshold and then an exponent output nonlinearity. The activity of the sensor represents the model mantis’s instantaneous probability of striking. We integrate this over the stimulus duration to obtain the expected number of strikes in response to moving targets with different stereoscopic disparity, size and vertical disparity. We optimised the parameters of the model so as to bring its predictions into agreement with our empirical data on mean strike rate as a function of stimulus size and disparity. The model proves capable of reproducing the relatively broad tuning to size and narrow tuning to stereoscopic disparity seen in mantis striking behaviour. Although the model has only a single centre-surround receptive field in each eye, it displays qualitatively the same interaction between size and disparity as we observed in real mantids: the preferred size increases as simulated prey distance increases beyond the preferred distance. We show that this occurs because of a stereoscopic “false match” between the leading edge of the stimulus in one eye and its trailing edge in the other; further work will be required to find whether such false matches occur in real mantises. Importantly, the model also displays realistic responses to stimuli with vertical disparity and to pairs of identical stimuli offering a “ghost match”, despite not being fitted to these data. This is the first image-computable model of insect stereopsis, and reproduces key features of both neurophysiology and striking behaviour.  相似文献   

20.
Binocular vision is obviously useful for depth perception, but it might also enhance other components of visual processing, such as image segmentation. We used naturalistic images to determine whether giving an object a stereoscopic offset of 15-120 arcmin of crossed disparity relative to its background would make the object easier to recognize in briefly presented (33-133 ms), temporally masked displays. Disparity had a beneficial effect across a wide range of disparities and display durations. Most of this benefit occurred whether or not the stereoscopic contour agreed with the object’s luminance contour. We attribute this benefit to an orienting of spatial attention that selected the object and its local background for enhanced 2D pattern processing. At longer display durations, contour agreement provided an additional benefit, and a separate experiment using random-dot stimuli confirmed that stereoscopic contours plausibly contributed to recognition at the longer display durations in our experiment. We conclude that in real-world situations binocular vision confers an advantage not only for depth perception, but also for recognizing objects from their luminance patterns and bounding contours.  相似文献   

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