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21.
内蒙古阿拉善盟草原疯草危害调查   总被引:6,自引:0,他引:6  
采用现场调查和资料收集相结合的方法,对内蒙古阿拉善盟的阿拉善左旗、阿拉善右旗和额济纳旗3个旗疯草的种类、分布、危害及防治对策进行了调查研究。结果表明:阿拉善盟有疯草7种,其中棘豆属有毒植物3种,黄芪属有毒植物4种,分布面积超过139.33万hm^2,危害最严重的是小花棘豆和变异黄芪,给当地畜牧业造成了极大的危害,并就如何综合利用疯草提出了几点措施。  相似文献   
22.
以天童国家森林公园常绿阔叶林主要组成树种为研究对象,通过测定其各组分生物量,建立了实测生物量与材积之间的回归模型,结果表明:主要组成树种各组分生物量与其材积之间存在着密切的相关关系,各主要树种材积与生物量的回归模型存在差异;回归方程精度较高,用于根据地区常绿阔叶林主要树种材积推算其生物量是可行的。  相似文献   
23.
达明珠 《木材工业》2005,19(1):33-34,39
介绍了原木蒸煮废水的处理方法,提出氧化塘法是小型木材加工厂处理该废水的最佳选择,并用实例简单介绍了氧化塘的设计选型问题.  相似文献   
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A peroxidase isozyme (BP) was purified to homogeneity from broccoli stems ( Brassica oleraceae var. maraton) discarded from industrial processing wastes. BP specific activity was 1216 ABTS [2,2'-azinobis(3-ethylbenzthiazoline-6-sulfonic acid)] units/mg, representing 466-fold that of crude extract. BP is a monomeric glycoprotein containing 16% carbohydrates, with a molecular mass of 49 kDa and an isoelectric point close to 4.2. From kinetic data it showed a two-substrate ping-pong mechanism, and the catalytic efficiency measured as the rate-limiting step of free BP regeneration was 3.4 x 10(6) M(-1) s(-1). The ABTS K m value was 0.2 mM, which was about 20 times lower than that reported for acidic commercial horseradish peroxidase (HRP). Assessment of BP secondary structure showed 30% helical character, similar to HRP and cytochrome c peroxidase. BP lost only 25% activity after 10 min of heating at 55 degrees C and pH 6; it was stable in the pH range from 4 to 9 and showed an optimum pH of 4.6 using ABTS as substrate. BP was active on substrates normally involved in lignin biosynthesis, such as caffeic and ferulic acids, and also displayed good catechol oxidation activity in the presence of hydrogen peroxide. Reverse micellar extraction was successfully used as potential large-scale prepurification of broccoli peroxidase, achieving a purification factor of 7, with 60% activity yield. Stems from the broccoli processing industry have a high potential as an alternative for peroxidase purification.  相似文献   
26.
The objectives were (i) to evaluate the effect of temperament, determined by modified 2‐point chute exit and gait score, on artificial insemination (AI) pregnancy rates in beef heifers following fixed time AI and (ii) to determine the effect of temperament on cortisol, substance‐P, prolactin and progesterone at initiation of synchronization and at the time of AI. Angus beef heifers (n = 967) at eight locations were included in this study. At the initiation of synchronization (Day 0 = initiation of synchronization), all heifers received a body condition score (BCS), and temperament score (0 = calm; slow exit and walk or 1 = excitable; fast exit or jump or trot or run). Blood samples were collected from a sub‐population of heifers (n = 86) at both synchronization initiation and the time of AI to determine the differences in serum progesterone, cortisol, prolactin and substance‐P concentrations between temperament groups. Heifers were synchronized with 5‐day CO‐Synch+ controlled internal drug release (CIDR) protocol and were inseminated at 56 h after CIDR removal. Heifers were examined for pregnancy by ultrasound 70 days after AI to determine AI pregnancy. Controlling for synchronization treatment (p = 0.03), facility design (p = 0.05), and cattle handling facility design by temperament score interaction (p = 0.02), the AI pregnancy differed between heifers with excitable and calm temperament (51.9% vs 60.3%; p = 0.01). The alley‐way with acute bends and turns, and long straight alley‐way had lower AI pregnancy rate than did the semicircular alley‐way (53.5%, 56.3% and 67.0% respectively; p = 0.05). The serum hormone concentrations differed significantly between different types of cattle handling facility (p < 0.05). The cattle handling facility design by temperament group interactions significantly influenced progesterone (p = 0.01), cortisol (p = 0.01), prolactin (p = 0.02) and substance‐P (p = 0.04) both at the initiation of synchronization and at the time of AI. Inter‐ and intra‐rater agreement for temperament scoring were moderate and good (Kappa = 0.596 ± 0.07 and 0.797 ± 0.11) respectively. The predictive value for calm and pregnant to AI was 0.87, and excited and non‐pregnant to AI was 0.76. In conclusion, the modified 2‐point temperament scoring method can be used to identify heifers with excitable temperament. Heifers with excitable temperament had lower AI pregnancy. Further, cattle handling facility design influenced the temperament and AI pregnancy.  相似文献   
27.
Abstract. Four experimental diets were formulated to resemble practical rainbow trout, Salmo gairdneri Richardson, grower feeds based on medium and moderate lipid inclusions of 10 and 14% (standard energy levels) to relatively 'high energy' diets containing 18 and 22% lipid respectively. Each of these diets was isonitrogenous with a defined protein content of 42%. During a 10-week growth trial period, juvenile rainbow trout of initial mean weight of 10g were fed each ration to satiation. At the end of the study, there was a significant gain (P> 0.05) in the mean live weights of fish receiving the higher energy diets associated with improved feed conversion ratio (FCR) and net protein utilization (NPU). Although there was a declining trend in voluntary food intake relative to body weight with increasing dietary lipid content, this was insufficient to prevent greater deposition of body fat.
The results are discussed in relation to practical trout feeds in order to achieve a desired growth performance and acceptable body composition with intensive feeding regimes.  相似文献   
28.
[Objective]This study was conducted to obtain a new high-efficiency acaricide mixture.[Method]The synergism acaricidal of diafenthiuron and fenbutatin-oxide against carmine spider mite was investigated,and the optimal ratio of both acaricides were determined by means of co-toxicity factors and co-toxicity coefficients(CTC).[Result]At 24 h post-treatment,the LC50values of diafenthiuron and fenbutatin-oxide against T.cinnabarinus female adults were 154.67 and 93.26 mg/L,respectively,and the synergistic mass ratios of diafenthiuron and fenbutatin-oxide ranged from 1:0.06 to 1:0.87,and the optimal diafenthiuron-to-fenbutatin-oxide ratio was 1:0.39 with the LC50and CTC of 67.87 mg/L and 188.93(CTC significantly above 100 strongly indicated synergism),respectively,and the toxicity relative to diafenthiuron and fenbutatin-oxide was 2.28 and 1.37 times,respectively.[Conclusion]The joint acaricidal action of diafenthiuron and fenbutatin-oxide strongly indicates synergism.These findings proved scientific theoretical basis for mixing diafenthiuron and fenbutatin-oxide to control spider mites and developing a new synergisic acaricide.  相似文献   
29.
为了检测牛GDF-9基因mRNA在怀孕期牛生殖系统的表达情况,为GDF-9基因在雌性动物繁殖上的研究提供一定的理论依据。本试验根据GenBank中报道的牛GDF-9基因序列设计引物,从牛卵巢、输卵管、子宫、肾脏中提取RNA,采用RT-PCR技术进行cDNA扩增,扩增产物与载体pGM-T连接,转化大肠杆菌DH5α,筛选阳性克隆,测序。结果表明,已成功克隆的阳性重组子经测序鉴定其片段大小与预期大小完全一致,为264 bp。序列同源性分析比较表明,该cDNA及其推导的氨基酸序列与绵羊GDF-9cDNA和氨基酸序列同源性分别为97%和94%。以-βactin为内参照物,采用RT-PCR技术进行半定量分析,通过检测比较牛GDF-9基因在卵巢、输卵管、子宫、肾脏组织中mRNA的表达情况。结果表明,牛GDF-9基因在卵巢中表达量最高,在输卵管、子宫、肾脏中均有表达,但表达量不高。  相似文献   
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