大棕幅下丘神经元对双声刺激的前掩蔽效应

以回声定位蝙蝠作为实验动物,研究下丘神经元对双声刺激听反应的前掩蔽效应。结果表明,蝙蝠下丘神经元对双声刺激听反应存在明显的前掩蔽效应。并且随双声间隔时间的缩短,神经元对探测声强度的敏感性增强;掩蔽效应的强弱与双声的相对强度和间隔时间有关,即前掩蔽效应随掩蔽声强度的降低而减弱,随探测声强度的减小和双声间隔时间的缩短而增强。推测下丘神经元对探测声的反应特性与其突触后电流的状态相关联。     

少数民族聚居地新农村经济建设的成功典范——长榔河流域“资丘皱皮木瓜”经济发展刍议

近年来,湖北省长阳土家族自治县榔坪镇大力推行"木瓜战略",使该镇农业结构得到合理调整,生态环境明显改善,经济实力迅速提升。本文探讨长榔河流域"资丘皱皮木瓜"经济的发展及其带给我们的启示。     

声负载增加导致老年鼠下丘神经元潜伏期波动性加强

基于我们先前的研究,主要探讨了小鼠下丘神经元声反应伏期的年龄相关性改变.自由声场条件下,声刺激为特征频率的短纯音(40 ms),呈现率为0.5～20 Hz共8种.结果显示,幼年鼠和成年鼠中,潜伏期随呈现率升高而单调递增的神经元分别点62.8%(22/35)和66.7%(22/23),而老年鼠中只占33.3%(11/33),但非单调比则达66.7%(22/23).我们的初步结果提示,老年性听力低下可能与大声负载条件下听中枢神经元的时相表征稳定性下降有关.     

艺术创作主体的精神蓄养

艺术家创作前的精神状态不应该是抑郁沉滞和意乱心烦的,而应该是充满生机勃勃的生命力和创造力;不是利欲满怀的心胸,而应该是"万虑消沉"的"林泉之心",一种排除主观欲念和成见的虚静内心,而这纯洁、闲适的虚静之心需要艺术家在生活中、创作前进行一番精神蓄养,这种蓄养过程就是艺术创作主体的精神准备。因艺术作品所属不同文化和民族性的思维方式有差异,西方的艺术家于创作前的精神蓄养过程则与东方的艺术家似有差异。     

海底湖泊 坠落深海的蓝宝石

<正>闭上眼睛试想这样一个画面:一汪汪的湖水,每个湖都不大,错落地点缀在大地上。一阵风吹过,湖水泛起一圈圈涟漪,轻拍着堤岸。不管是在沙漠还是在草原,这定是一个水草丰美,生意盎然的地方。如果将这个场景平移至一千米以下的深海,你是否会觉得不可思议:海洋是一个由咸水充满的水体,不管是湖泊还是河流,一旦汇入海洋,就与海水融为一体,哪还有海水和湖水之分呀。这些湖泊是如何存在于海底的呢?又是在什么时候形成的呢?它们是否也如陆地湖泊     

Topography of acoustic response characteristics in the midbrain inferior colliculus of Kunming mouse

Topography of acoustic response characteristics of the midbrain inferior colliculus(IC)of the Kunming mouse was studied by using extracellular recording techniques.The characteristic frequency(CF)range represented in the different divisions of the IC differed markedly:4-15 kHz in the dorsal cortex(DC),10-70 kHz in the central nucleus(CN),and 4-35kHz in the external cortex(EC).The CF in the CN increased from dorsal and lateral to ventral and medial,higher CFs represented at its ventromedial part and lower CFs at its dorsal part.The isofrequency contours of CFs were incurvate.Minimum thresholds(MT)of the auditory neurons in DC and the central part of CN were lower(about 10dB SPL),but considerably higher in the dorsal and ventral region of EC.Results suggest that each of the divisions in the mouse IC may have different auditory functions.     

Nitric oxide produced by cumulus cells stimulates maturation of mouse oocytes

The effect of sodium nitroprusside (SNP), a donor of nitric oxide, on meiotic maturation of mouse oocytes was studied by injecting N^w-nitro-L-arginine methyl ester (L-NAME) intra-peritoneal (ip), a nitric oxide synthase inhibitor, or culturing oocytes in the medium supplemented with L-NAME or hypoxanthine (HX) to arrest the spontaneous oocyte maturation in vitro. The results showed that the inhibitory effect of L-NAME by injecting 10 mg/kg ip on extrusion of the first polar body only could be reversed by injecting 2.5 mg/kg SNP with L-NAME simultaneously (P < 0.05). Half an hour later ten mice died when given 10 mg/kg SNP ip. The treatment of some concentrations of SNP (10^–7, 10^–6, 10^–5mol/L) significantly stimulated meiotic maturation to metaphase Ⅱ stages in cumulus enclosed oocytes in the presence of HX. However, other concentrations of SNP (10^–8, 10^–4, 10^–3 mol/L) had no effect on HX-arrested oocyte meiotic maturation. The optimal concentration of SNP on CEOs had no effect on DOs. The dose of 10^–3 mol/LL-NAME demonstrated a significant suppression in formation of PB₁, but not in GVBD. This inhibition was reversed by the addition of SNP. These results indicated that the physiological levels of NO produced by cumulus cells could stimulate meiotic maturation of mouse oocytes both in vivo and in vitro.     

泥炭沼泽微地貌特征及其形成的水动力机制

草丘微地貌是泥炭沼泽重要的景观特征之一，根据对中国和白俄罗斯不同类型泥炭沼泽的野外观测，分析草丘微地貌的类型，结构和形态，论述了其发育和分布的基本规律，并对草丘微地貌形成的水动力机制做了初步探讨。     

低丘缓坡土地开发建设潜力调查研究——以广西壮族自治区玉林市为例

<正>掌握全市低丘缓坡土地数量及分布情况,充分发挥其资源优势,全面促进低丘缓坡土地资源的开发利用,对于地区经济发展、社会发展具有重要意义。为此,玉林市开展了低丘缓坡土地开发建设潜力调查。一、技术性分析以区为单位,应用GIS技术,将该区域最新的土地利用变更调查、土地利用总体规划及其他相关规划成果数据进行叠加分析,提取低丘缓坡土地空间分布信息,统计可利用低丘缓坡的地类、面积。     

丘逢甲的传统文化意识与两岸统一思想

四百年前，客家人从粤东、闽南、赣南、闽西一带渡过险恶的黑水沟来到台湾，“开山打林”、“咬姜啜醋”，经过拓垦、聚居、生息、繁衍，为子孙开创出一片土地，成为台湾客家人。丘逢甲的祖先本是由中原为躲避战乱而南迁的客家人，在宋朝时迁居于福建邵武、宁化、上杭。清朝乾隆中叶，丘逢甲的祖父丘仕俊(公元1756—1828年)随着镇平的客家乡亲，不顾险峻渡海来台定居。