采用营养调控措施减少畜牧业对环境的污染

在我国畜牧业迅猛发展的今天，如何降低畜含生产对环境的污染已成为畜牧业可持续发展所面临的重要课题。本文在分析畜禽生产对环境危害的基础上，对应用平衡日粮营养、利用特殊调控剂、改进饲养方式等手段减少环境污染的原理进行了综述。     

论强制要约收购中股东利益的保护

强制要约收购是指当投资者持有某上市公司己发行股份达到一定比例时，收购人依法向全体股东发出收购要约的法律制度。对于收购人和目标公司管理层而言，股东处在弱势地位，因而需要在制度设计上给予特殊保护。对股东利益的保护需要通过规制收购人和目标公司管理层的行为得以实现。木文对此提出了一些建议。     

乙氧氟草醚、乙草胺和盖草能在苗圃中的应用

为了探讨乙氧氟草醚、乙草胺和盖草能在森林苗圃中的应用效果,进行马尾松Pinusmassoniana、火力楠Micheliamacclurei和乳源木莲Manglietiayuyuanensis苗圃化学除草正交试验。试验结果表明,乙氧氟草醚和乙草胺在苗圃播种后芽前期使用和苗期使用乙氧氟草醚、乙草胺和盖草能除草率达90%以上,持效期45～63d,同时对种子发芽出苗和苗木生长安全。采用20%乙氧氟草醚、90%乙草胺和10 8%盖草能,使用剂量为0 105mL·m-2进行化学除草,比人工除草减少除草用工59 1%～66 7%,降低除草成本46 8%～62 9%。表3参4     

钢筋混凝土梁的抗弯加固中碳纤维板用量研究

通过碳纤维板加固的4根足尺钢筋混凝土梁的试验研究,证明碳纤维板用量对加固梁的破坏模式和极限承载力有显著影响.在试验的基础上,根据界限破坏模式和延性问题提出了最小和最大碳纤维板使用面积的计算方法,并给出了相应的计算公式;采用Smith-Teng模型和修正的Cheng-Teng模型分析了碳纤维板加固钢筋混凝土梁时需要的粘贴长度,并通过简化修正得出了碳纤维板加固钢筋混凝土梁最小粘贴长度的计算公式.本文结果可供碳纤维板加固工程设计和施工参考.     

Discrimination and abundance estimation of wild and released abalone Haliotis diversicolor using stable carbon and oxygen isotope analysis in north-eastern Taiwan

The discrimination between wild and released Taiwan abalone Haliotis diversicolor was performed by stable carbon isotope analysis. Abalone samples were collected from Mao Aw Gulf in north-eastern Taiwan. Live abalone and dead shells were collected by divers with an 80 × 80 cm frame. The densities and amounts of wild and released abalone, as well as the survival rates of released abalone, in 1997 and 1998 were estimated. The age of the specimens was also determined from the specific temperature of each month and the inverse relationship between oxygen isotope values and temperatures. Results show that examining stable isotopic profiles proves to be a practical and feasible method for stock discrimination as well as density and abundance estimation. These data would be helpful in assessing the success of abalone culture and release programs, which aim to enhance this valuable marine resource.     

Tobacco cultivation as a driver of land use change and degradation in the miombo woodlands of south‐west Tanzania

Miombo woodlands support agriculture, biodiversity, and multiple ecosystem services across an extensive part of sub‐Saharan Africa. Miombo is frequently overutilised with deforestation and degradation resulting in significant land use and land cover change (LULCC). Understanding the drivers of LULCC is essential to achieving sustainable land management in miombo woodland regions. Within a remote miombo area of south‐west Tanzania in the Kipembawe Division, Mbeya Region, social survey and ecological data were used to identify the direct and indirect drivers of LULCC. Our findings show that tobacco (Nicotiana tabacum ) production results in an estimated annual deforestation rate of 4,134 ± 390 ha of undisturbed miombo woodland, of which 56.3 ± 11.8% is linked to the post‐harvest curing process. This deforestation represents 0.55 ± 0.06% of the wooded area of the Kipembawe Division. The perception of high incomes from tobacco cultivation has encouraged migration of both agriculturalists and pastoralists into the area, resulting in higher livestock numbers that lead to further degradation. Higher human populations need more woodland resources such as fuelwood and building materials and more farmland for food crops. Continued deforestation will reduce the long‐term profitability of tobacco cultivation due to a lack of fuel to cure the crop and could render production unviable. Action is urgently needed to conserve globally important biodiversity resources while enabling agricultural and pastoral activities to continue. Improved governance, together with sustainable land management strategies and diversification of livelihood strategies, can reduce dependence on tobacco cultivation and contribute to a sustainable future for this ecoregion.     

小剂量四氯化碳结合乙醇制备小鼠慢性肝损伤模型

通过腹腔注射70 g/L四氯化碳/橄榄油及自由饮用100 mL/L乙醇建立稳定的小鼠慢性肝损伤模型。选择昆明小鼠25只,试验组15只,对照组10只,试验组腹腔注射70 g/L四氯化碳并自由饮用100mL/L乙醇溶液,连续造模4周。结果试验组小鼠血清中ALT、AST含量明显高于对照组,SOD含量显著低于对照组,病理学切片显示,试验组动物肝脏脂肪细胞增多,并出现少量纤维化。结果表明,小剂量四氯化碳结合乙醇可用于制备小鼠慢性肝损伤模型。     

Seasonal modulation of microbially mediated carbon fluxes in the northern Adriatic Sea — a model study

A model study of the seasonal changes in the food web structure of the northern Adriatic Sea is presented. A 1–D ecosystem coupled model (POM/ERSEM) forced with climatological functions has been applied at two different station locations in the northern Adriatic Sea, one under the direct influence of the Po river inflow and one representing a more open sea situation. The ability of the model to reproduce the main physical and biogeochemical patterns allows us to study the underlying carbon fluxes, which determine these features. Analysis of the seasonal carbon-transfer pathways among the main trophic levels shows a possible seasonal modulation at both stations, but a different food web development. It seems that the prevailing path could be related to the seasonal variability of the water column (nutrient input and/or vertical stratification). Moreover, results from this numerical experiment suggest that the northern Adriatic shallow coastal area has a predominantly multivorous food web and has significant microbial recycling, even if this latter pattern is not so evident as in open sea areas.     

碳纤维人工食管用于牛羊的实验研究

选用碳纤维作为食管代替物,对各切除颈段固有食管3～4cm的8例绵羊和2例犊牛行食管植入吻合术。植入的碳纤维人工食管长度为3～4.5cm,管径为1～2cm,管壁厚为0.1～0.15cm。人工食管与食管断端采用作者改进的高桥氏二层重叠缝合方法吻合。术后除2例绵羊因人工食管渗漏子第4d死亡外,其余吻合手术均获成功。绵羊术后4～5d采食咀嚼碎青草自如,但咽下较缓慢,有时反复2～3次方能咽下;术后5～20d,采食及吞咽恢复至正常状态;20d后又复出现吞咽缓慢。犊牛术后饮奶咽下顺利,到20d后偶有反复吞咽和奶汁由鼻孔中返流现象,经3～5d恢复正常。经X线透视或钡剂食管造影检查,术后7～14d,钡液顺利通过食管和人工食管,显示人工食管部较正常食管稍细,术后22～26d,人工食管脱落,脱落部食管狭窄,其前方食管呈纺锤状扩张。动物全身及血液,生化指标观察均无明显改变。病理学观察,术后15d可见在食管两断端由新生肉芽组织形成纤维膜管以包裹人工食管,在新生肉芽组织纤维膜管内面,靠近食管吻合口边缘,已长出灰白色薄层粘膜;术后22～25d,人工食管脱落于瘤胃或网胃中,食管缺损段已由新生的食管组织连接在一起,新生食管外周形成纤维膜包裹,管腔内面被覆有较完整的薄层粘膜;术后35～40d。见新生食管内面粘膜层覆盖完整,管壁稍增厚,内腔稍