以球果量、雄花量等数量性状对油松优良无性系的再选择

本研究对油松无性系种子园 2 2个无性系的球果量和雄球花量进行观测调查 ,并对数据进行处理。通过无性系内和无性系间的方差分析、聚类分析和秩序排序法对各无性系进行分类和排序。研究结果表明 :无性系间球果量和雄球花量的差异极显著 ,而无性系内差异不显著。并筛选出 1 61 #,6#,2 9#,63 #,78#5个球果数量大 ,占总数的 46% ,雄花量高 ,占总数的 5 7.6%的无性系为优良无性系     

鲁山县集雨工程建设的做法与经验

鲁山县为了解决丘陵区干旱缺水问题,在田间地头大量建设集雨工程,拦蓄地表径流,涝时蓄水,旱时灌溉,有效地解决了丘陵区的水源问题。介绍了主要做法和经验。     

提高农业国际竞争力的关键在于创新

经济一体化和贸易自由化是世界经济的发展趋势。中国已经加入世界贸易组织,农业作为基础产业必然要参与国际竞争。中国农业在国际经济舞台上参与激烈的国际竞争,既有一定的竞争优势,同时在很多方面又存在明显的劣势。我们必须根据国情,选择适当的战略,趋利避害、扬长避短。以求     

高产奶牛福利

近20年，荷斯坦牛成为优势奶牛品种，营养改善促使奶牛产奶量大幅度增加，工厂化管理致使奶牛运动量减少、生产性疾病频发，奶牛康乐受到严重威胁，因此，改善高产奶牛福利的呼声高涨。本文以生产性疾患为中心，从规模化生产、遗传改良、畜舍环境等角度讨论了高产奶牛的福利问题。     

PGF2αeCG及hCG 3种生殖激素联用对母犬发情、卵泡发育及胚胎着床的影响

给休情期性成熟母犬肌注 PGF2α(0 .5 m g/ kg) ,2 4 h后肌注 e CG(5 0 IU/ kg) ,再经 12 0 h后肌注 h CG(2 0 U/ kg) ,诱导其发情。将诱导发情的母犬与公犬交配 ,于交配后 16 d,摘取卵巢、子宫 ,观察其卵泡发育和胚胎着床情况。结果表明 ,药物处理可明显促使母犬提前结束休情期而进入发情期 (9/ 10 ) ,促进卵巢内卵泡发育 (P<0 .0 1) ,并使更多的胚胎着床 ,每只母犬子宫胚胎着床点为 (17.4± 2 .2 )个 ,提示 3种生殖激素联合应用可提高母犬繁殖率     

新颖三相异步电动机错相和缺相保护电路

从理论上分析了错相及缺相判别原理，提出了新颖保护电路，其线路简单、实用。     

Study on adherent precursors from human cord blood

AIM: To confirm the existence of the endothelial progenitor cells in human cord blood and to study its differentiation and development process. METHODS: The mononuclear cells in human cord blood were isolated using lymphocyte separation solution. Then the mononuclear cells were cltured in MCDB131 containing 20% fetal bovine serum. The effects of 5 μmol/L dexamethasone, the extract from bovine brain, insulin and hypoxanine on the proliferation and differentiation of the adherent cells were observed. The morphology of the adherent cells were examined twice daily by inverted phase contrast microscope. CD34 and CD14 expression were determined by FACS. Immunohistochemistry was used to confirm the expression of factor Ⅷ. RESULTS: The proliferative endothelial progenitor cells existed within the CD34^-adherent mononuclear cells of human cord blood. Dexamethasone and hypoxanine decreased the number of spindle-shaped cells and caudated cells. Bovine brain extract, insulin and FCS enhanced the number of spindle-shaped cells and caudated cells. CONCLUSION: The existence of endothelial progenitor cells within the CD34 - adherent monouclear cells of the human cord blood was observed and these cells were able to differentiate into endothelial-like cells in vitro.     

Ginkgo biloba extract enhances c-jun expression and attenuates motoneuron death induced by root avulsion

AIM: To investigate the influence of Ginkgo biloba extract (EGb761) on c-jun expressions and motoneurons survival following root avulsion. METHODS: One hundred and eighty adult Sprague-Dawley female rats were randomly divided into control and EGb761 groups. Immediately after avulsion of C5-T1 nerve roots, the rats were injected ip with either 1 mL of EGb761 25 mg·kg^-1·d^-1 or the same volume of normal saline, and the treatment repeated everyday. At 4 h to 6 weeks following avulsion, the C7 spinal segments of all rats were collected and prepared for c-jun immunocytochemistry and neutral red stain. The numbers of c-jun positive and survival motoneurons were counted and compared between two groups at each time point. RESULTS: In control rats following avulsion, c-jun positive motoneurons appeared at 4 h, reached its maximum at 1 d and declined to 2 weeks. Avulsion-induced motoneurons death started at 2 weeks, climbed to its maximum at 4 weeks-6 weeks. In EGb761 treated rats, both numbers of c-jun positive and survival motoneurons were more than that in control group at each time point. CONCLUSION: EGb761 attenuates avulsion-induced motoneurons death, and this effect may be related to up-regulation of c-jun gene in avulsed motoneurons.     

Expression of vascular endothelial growth factor in chronic inflammatory mucosa of lacrimal sac

AIM: To study the expression of vascular endothelial growth factor (VEGF) in inflammatory mucosa of lacrimal sac. METHODS: Immunohistochemical S-P method was used to examine the expression of VEGF in the mocusa from 12 patients with chronic dacryocystitis and 8 volunteers. RESULTS: The positive rates of VEGF expression in different parts of the mocusa were: basal lamina: 44.3%±7.6％; surface epithelium: 16.9%±4.6％; connective tissue: 15.2%±4.9％, all normal mocusa of 8 cases were negative. There was a significant difference between the two groups (P<0.01), a significant difference among each part of the chronic inflammatory mocusa of lacrimal sac. CONCLUSION: VEGF may play an important role in hyperplasia of inflammatory mucosa of lacrimal sac.     

土壤易氧化有机碳与溶解性有机碳对荒漠草地沙漠化过程中土壤碳库变异的表征

以干旱、半干旱地区荒漠草地不同沙漠化阶段土壤为研究对象,研究不同沙漠化阶段土壤易氧化有机碳与溶解性有机碳含量和分配比例变异规律,分析不同沙漠化阶段土壤碳库指数变化,探讨荒漠草地沙漠化过程中土壤易氧化有机碳与溶解性有机碳对土壤碳库的表征作用。结果表明,随着荒漠草地沙漠化程度的加剧,易氧化有机碳含量表现出一定的波动性,但整体呈下降趋势,溶解性有机碳含量呈线性下降。易氧化有机碳和溶解性有机碳分配比例均在荒漠草地达到最大值,在半固定沙地达到最小值。利用易氧化有机碳含量计算的土壤碳库管理指数随荒漠草地沙漠化程度增加表现出先下降后上升趋势,利用溶解性有机碳含量计算的土壤碳库管理指数呈线性下降趋势。易氧化有机碳、溶解性有机碳含量与土壤有机碳均显著正相关,但溶解性有机碳的相关系数略高于易氧化有机碳。通过比较活度敏感指数和碳库管理指数敏感指数发现,荒漠草地逆向演替至固定沙地过程中,易氧化有机碳的各项敏感指数均高于溶解性有机碳。固定沙地演替至流动沙地过程中,溶解性有机碳的各项敏感指数均高于易氧化有机碳,表明易氧化有机碳能够较好地表征荒漠草地沙漠化前期土壤碳库变化,而荒漠草地沙漠化中期和后期利用溶解性有机碳表征效果更好。