应用Logistic模型预测草坪最大经济修剪量

通过测定草坪剪草量,应用Logistic模型,以各时段剪草量和各时段累计剪草量作为各时段和试验阶段的k值估计量,分析确定了草坪最大经济修剪量,并提出每次修剪标准应为 k/2,既可维持草坪生态系统平衡,又可保持草坪生产性能。     

运动场草坪最大持续修剪量的探讨

2001年3月1日～5月30日在深圳中学运动场草坪上结合草坪修剪,测定剪草量,以各时段剪草量和各时段累计剪草量作为各时段和试验阶段的k值估计量,用Logistic模型分析,试确定了该运动场草坪最大持续修剪量,并提出每次修剪标准应为k2,既可维持草坪生态平衡,又可保证其基本功能。     

草坪草药剂修剪的应用研究进展

药剂剪草又称化学剪草 ,是指利用生长调节物质或除草剂控制草坪草生长 ,达到减少草坪修剪的目的 ,从而降低养护管理成本。药剂剪草主要是基于化学药剂 (生长调节物质 )对草坪草的生物学效应。其效应在植株形态上表现为矮化、促蘖。化学药剂还使草坪草在内源激素、酶系统、代谢水平等方面发生深刻的变化。药剂剪草技术研究主要集中于高效低毒的药剂或药剂组配的筛选、药剂浓度的筛选。研究认为 ,不同的草种对化学药剂的敏感程度不同。为增强药效 ,可采取药剂混配、增加施药频率以及将药剂剪草和机械剪草有机结合起来等措施     

施肥对草地早熟禾草坪质量、剪草量及蒸散量的影响

通过盆栽试验,研究施肥对草坪颜色、剪草量、蒸散量及土壤中速效氮的影响。结果表明:施N肥能够明显改善草坪的颜色,增加草坪的剪草量,提高草坪的蒸散量;苗期施P肥将导致草坪剪草量明显增加;当土壤中速效N和速效P供应充足时,施K肥导致草坪颜色和剪草量明显降低。单施N肥能够加快土壤中铵态氮的硝化过程,氮磷钾平衡施肥则能够延缓土壤中铵态氮的硝化过程,降低土壤中硝态氮的含量,从而降低土壤中硝态氮淋失的风险。草坪的蒸散量与剪草量之间存在着显著的线性正相关(r=0.9965);控释肥料和常规肥料之间养分释放模式存在很大差异,使得施肥初期常规肥料处理草坪颜色、剪草量及蒸散量均高于控释肥料处理,施肥末期情况则相反。     

施肥对草地早熟禾草坪质量、剪草量及蒸散量的影响

通过盆栽试验。研究施肥对草坪颜色、剪草量、蒸散量及土壤中速效氮的影响。结果表明：施N肥能够明显改善草坪的颜色。增加草坪的剪草量，提高草坪的蒸散量；苗期施P肥将导致草坪剪草量明显增加；当土壤中速效N和速效P供应充足时。施K肥导致草坪颜色和剪草量明显降低。单施N肥能够加快土壤中铵态氮的硝化过程，氮磷钾平衡施肥则能够延缓土壤中铵态氮的硝化过程，降低土壤中硝态氮的含量，从而降低土壤中硝态氮淋失的风险。草坪的蒸散量与剪草量之问存在着显著的线性正相关(r=0．9965)；控释肥料和常规肥料之间养分释放模式存在很大差异。使得施肥初期常规肥料处理草坪颜色、剪草量及蒸散量均高于控释肥料处理，施肥末期情况则相反。     

贵州足球场草坪建植及优化管理模型研究

在一定的生境和管理条件下,以修剪高度、修剪次数和施Ｎ、Ｐ、Ｋ量为因素,利用二次正交回归设计,用模糊综合评分法评定草坪质量,最佳３因子水平为：修剪高度５－７．４ｃｍ,修剪次数４－６次／月,施Ｎ量为２．５－３．７ｇ（ｍ＾２．年）,施Ｐ、Ｋ量各为１．２５－１．８５ｇ／（ｍ＾２．年）,建立了草坪质量与养护３因子间的显相关回归模型。     

草地早熟禾草坪夏季施肥

氮肥用量是提高草地早熟禾草坪生长速率和修剪量的主要因素。含氮肥的磷酸二胺和尿素处理都能改善草地早熟禾草坪夏季颜色和盖度 ,提高草坪质量 ,但同时不同程度加重了草坪夏季病害 ,而施用磷酸二氢钾的处理提高了草坪的抗病性。     

贵州足球场草坪建植及化管理模型研究

在一定的生境和管理条件下,以修剪高度、修剪次数和施N、P、K量为因素,利用二次正交回归设计,用模糊综合评分法评定草坪质量,最佳3因子水平为:修剪高度5～7.4cm,修剪次数4～6次/月,施N量为2.5～3.7g/(m2·年),施P、K量各为L25～1.85g/(m2·年),建立了草坪质量与养护3因子间的显著相关回归模型.     

建坪与管理因素对运动场草坪密度影响的研究

以修剪高度、播种量、修剪频率和施Ｎ量为因素，利用四因素饱和Ｄ－最优设计，对运动草坪密度进行探讨，最佳四因素水平为，修剪高度４．５ｃｍ，播种量１５ｇ／ｍ＾２，修剪频率５次／月，施Ｎ量６．７８ｇ／ｍ＾２。并建立了草坪密度与建坪四因素显著相关的回归模型。     

灌溉量和修剪高度对草地早熟禾草坪维持景观时长的影响

以草地早熟禾品种凯蒂(Katie)为供试材料,在室内进行盆栽试验,研究不同灌溉量和不同修剪高度对草地早熟禾草坪维持景观时长的影响,为草坪节水灌溉提供科学依据。结果表明:在同一修剪高度条件下,分别用灌溉量相当于田间持水量的85%,70%和55%对供试材料进行处理,结果彼此间存在显著性差异,灌溉量的增加促进地下植物量不断增加,草地早熟禾草坪的维持景观时长相应增加,灌溉量对草地早熟禾维持景观时长起积极影响,但灌溉量大于等于相当于田间持水量85%时,草地早熟禾草坪维持景观时长却不再有显著增加;同时,修剪草坪高度对草地早熟禾草坪景观时长有一定影响,研究发现随修剪高度的提高,草坪维持景观的时长在缩短,并且修剪高度为3cm时,能使草地早熟禾草坪维持景观时长达到最大值。     

商会自治的基石——商会自治规范研究

在现代法律秩序中,商会自治规范是制定法的基础和必要的补充,甚至在某些方面替代了制定法;商会自治规范主要包括商会组织规范、行为规范、惩罚规范以及争端解决规范等;其效力仅及于其内部成员;商会自治规范和制定法之间存在冲突,但也存在整合的基础。     

癸氧喹酯干混悬剂含量测定的改进

采用高效液相色谱法测定癸氧喹酯干混悬剂的含量,在2-250μg/mL范围内,峰面积的常用对数与进样量浓度的常用对数呈良好的线性关系,R^2=1(n=5),平均回收率为99.24%~99.51%,RSD在0.05%~0.28%。此方法分析时间短,样品前处理简便、定量结果准确,重现性好,结果满意,为其质量控制提供了依据。     

猪毛色遗传的研究进展

本文概述了猪的毛色类型、猪的毛色遗传模式,着重综述了猪毛色基因分子基础的研究进展,指出存在问题并就未来发展方向做了思考。     

Comparison of 2 methods of centesis of the bursa of the biceps brachii tendon of horses

REASONS FOR PERFORMING STUDY: Centesis of the bicipital bursa using an 8.9 cm long spinal needle has been reported but the alternative of employing a 3.8 cm long hypodermic needle requires validation. OBJECTIVE: To compare the efficacy of 2 different methods of centesis of the bicipital bursa and to evaluate the usefulness of ultrasonographic imaging to determine the location of solution administered when centesis of the bursa is attempted. METHODS: For Trial 1, 6 clinicians, who had no previous experience of centesis of the bicipital bursa, attempted to inject a solution composed of an aqueous radiopaque contrast medium and physiological saline solution (PSS) into the bicipital bursae of 2/12 horses using the previously described distal approach to inject one bursa and a proximal approach to inject the contralateral bursa. The bicipital tendon and bursa were examined ultrasonographically before and after injection; and both shoulders were examined radiographically to identify the location of the medium. In Trial 2, another 6 clinicians, also with no previous experience of centesis, repeated Trial 1, using 6 horses, but the radiopaque contrast medium was mixed with air instead of PSS. RESULTS: Accuracy of centesis using the proximal approach was 39% and that of the distal approach 28%. Ultrasonographic examination of the shoulder allowed the location of solution and air to be accurately predicted in all 12 shoulders examined. CONCLUSIONS: Clinicians who have had no previous experience performing centesis of the bicipital bursa are unlikely to be successful in centesis using either approach. Radiographic examination after injecting a radiopaque contrast medium may be necessary to assess the success of centesis especially if bursal fluid is not obtained during centesis. Injecting air along with the radiopaque contrast medium provides more accurate ultrasonographic confirmation of centesis and better radiographic definition than does injection without air.     

不同样本商品蜂蜜中硒含量的测定

用硝酸和高氯酸消化蜂蜜,使硒游离出来,在微酸性环境下,硒和2,3-二氨基萘(DAN)生成有较强荧光的物质,用环己烷萃取,在激发波长378nm,荧光波长518nm处测定其荧光强度。蜂蜜中硒含量范围:0.10～0.82μg/g。表明:蜂蜜应视为天然富硒营养品。     

乳酸杆菌益生作用机制的研究进展

乳酸杆菌作为益生菌广泛用于人和动物。本文综述了乳酸杆菌改善宿主健康的机制。乳酸杆菌可通过产生抗菌物质如乳酸、过氧化氢、细菌素,或者通过竞争营养或肠道黏附位点来抑制致病菌;通过诱导黏附素的分泌或阻止细胞凋亡而增强肠道的屏障功能,从而保护肠道。文章重点讨论了乳酸杆菌表面成分（表面蛋白、脂磷壁酸和肽聚糖）与肠道受体（Ｃ型凝集素受体、Ｔｏｌｌ样受体和 Ｎｏｄ样受体）,阐述了他们结合后启动免疫调节信号,调控肠道免疫功能以发挥改善健康作用的机制。     

中华人民共和国农业部公告 第267号

为贯彻落实《兽药生产质量管理规范》(简称《兽药GMP》),进一步推动兽药GMP实施进程,我部制定了《兽药生产质量管理规范检查验收办法》,现予公告。本公告自2003年6月1日起施行。附件:兽药生产质量管理规范检查验收办法二○○三年四月十日第一章 总则 第一条 为推动《兽药生产质量管理规范》(以下简称兽药GMP)的实施,规范兽药GMP检查验收工作,制定本办法。 第二条 农业部负责全国兽药GMP管理和检查验收工作;负责制修订兽药GMP检查验收管理规定;负责兽药GMP检查员队伍建设和监督管理工作,负责国际兽药贸易中GMP互认工作。 …     

鸡败血支原体垂直传播模式及其阻断方法

以国际标准强毒Ｒ株人工感染非免疫产蛋鸡,定时扑杀,分别从鼻窦、眶下孔、气管、肺、气囊、卵巢和输卵管分离ＭＧ,并收集感染鸡所产蛋分离ＭＧ。结果表明,人工感染４８小时后上、下呼吸道及肺已被全面感染,９６小时气囊已被感染,１２０小时输卵管已能分离到ＭＧ,卵巢始终分离不到ＭＧ。人工感染鸡自１４４小时便能在其所产蛋中分离出ＭＧ。药物治疗能在７２小时内消除感染,油乳剂苗则需２４天后逐渐降低蛋内ＭＧ分离率,药物卵内注射、种蛋药浴、高温处理均能杀死卵内ＭＧ,但以研制的种蛋浸泡剂药浴效果为最好。     

Effects of size of ingestively masticated fragments of plant tissues on kinetics of digestion of NDF

Ingestively masticated fragments were collected and sized via sieving. Different sizes of esophageal masticate and ruminal digesta fragments, and ground fragments of larger masticated pieces were incubated in vitro, and undigested NDF remaining at intervals of up to 168 h of incubation was determined. The ruminal age-dependent time delay (tau) for onset of digestion of NDF was positively correlated (P < 0.004) with the mean sieve aperture estimated to retain 50% of the fragments between successive sieve apertures (MRA). Degradation rate of potentially degradable NDF (PDF) and level of indigestible NDF were not related (P > 0.10) to MRA of masticated and ground fragments. Estimates of tau were positively related to MRA, with slopes of bermudagrass < corn silage < ruminal fragments of corn silage. It was concluded that fragment size-, and consequently, ruminal age-dependent onset of PDF degradation of a mixture of different fragment sizes results in an age-dependent rate of degradation of the more rapidly degrading of two subentities of PDF. Models are proposed that assume a tau before onset of simultaneous degradation of PDF from two pools characterized as having gamma-modeled age-dependency and age-constant rates. The ruminal age-dependent pool seems to be associated with the faster-degrading pool, and its rate parameter increases with range in MRA in the population of fragments. Conceptually, the ruminal age-dependent rate parameter for PDF degradation seems to represent a composite of several effects: 1) effects of the size-dependent tau; 2) range in MRA of the population of ingestively masticated fragments; and 3) subentities of PDF that degrade via more rapid age-dependent rates compared with subentities of PDF that degrade via age-constant rates. The estimated fractional rates of ruminative comminution of ingestively masticated fragments (0.060 to 0.075/h) were of a magnitude similar to the mean fractional rates of PDF digestion (0.030 to 0.085/h), which implies that ruminative comminution may be first-limiting to fractional rate of PDF digestion. The in vivo roles of ingestive and ruminative mastication of fragments on PDF degradation must be considered in any kinetic system for estimating PDF digestion in the rumen. These results and others in the literature suggest that the rate of surface area exposure rather than intrinsic chemical attributes of PDF may be first-limiting to degradation rate of PDF in vivo.