浅谈我国饲料企业的设备管理

<正>目前,国内外对现代企业设备管理的研究很多,成熟的理论和丰富的经验也不少。但当前我国饲料企业设备管理的实际情况与其他如电子、机械等行业大有不同,再先进的设备管理模式也不一定能很好地适合饲料企业的实际。本文在分析当前我国饲料企业设     

大蒜素对断奶仔猪血清生化指标及生长相关激素的影响

为了研究大蒜素(allicin)对断奶仔猪血清生化指标和生长相关激素的影响,试验选择21日龄体重5.6kg左右的断奶仔猪(杜×长×大)24头,随机分为3个处理,每个处理4个重复,每个重复2头,处理1饲喂基础日粮(对照组),处理2饲喂基础日粮+0.01%大蒜素(试验组),处理3饲喂基础日粮+0.07%抗生素(抗生素组),试验期21d,测定了仔猪血清生化指标、生长相关激素的变化。结果表明:大蒜素能改善断奶仔猪血清生化指标和生长相关激素水平。大蒜素组血清LDL(低密度脂蛋白)、CHO(总胆固醇)和GLU(葡萄糖)含量在断奶后第7d比对照组高23.9%、38.1%(P<0.05)、11.4%;第14d高14.7%(P<0.05)、15.6%、12.0%。断奶后SUN(血清尿素氮)含量升高,大蒜素组和抗生素组低于对照组;各处理血清ALP(碱性磷酸酶)活性有升高的趋势。大蒜素组FT3、IGF-1含量及FT3/FT4显著高于对照组(P<0.05)。整个试验期大蒜素组与抗生素组各项指标差异不显著。     

基于PCA-RBF神经网络的烟田土壤水分预测

为建立烟田土壤水分预测模型以利于烟区种植的规划和管理,该文提出了基于主元分析（PCA）与径向基函数（RBF）神经网络模型的烟田土壤水分预测方法。首先,利用PCA消除原始输入层数据的相关性,以解决神经网络建模时输入变量过多、网络规模过大导致效率下降的问题;然后,以主元模型结果为输入建立土壤水分RBF神经网络预测模型。实例研究表明,烟田土壤水分PCA-RBF神经网络预测模型具有较好的预测效果,平均预测精度达到96.02%,与全要素误差反向传播（BP）神经网络和RBF神经网络相比,平均预测精度分别提高5.20%和6.06%,完全符合实际烟区种植规划的需求,为研究其他类型的土壤水分预测提供了参考。     

以聚丁二酸丁二醇酯为碳源去除含盐水体硝酸盐及其动力学模型

以固体碳源反硝化工艺应用于闭合循环养殖废水的脱氮提供理论和技术参数为目的,研究了以一种非水溶性可生物降解多聚物材料（BDPs）聚丁二酸丁二醇酯（PBS）作为反硝化碳源和生物膜载体的填料床反应器对含盐水体硝酸盐的去除效果及动力学特征。结果表明：水力停留时间对NO3--N去除效果影响较大,NO3--N去除率随水力停留时间延长而提高。在温度为(29±1)℃,进水NO3--N质量浓度为25～236 mg/L的条件下,进水NO3--N负荷低于0.32 kg/(m3·d)时,NO3--N体积去除负荷随进水NO3--N负荷的增加呈线性上升;进水NO3--N负荷为0.32 kg/(m3·d)时达到最大NO3--N体积去除负荷为0.21 kg/(m3·d);进一步提高进水NO3--N负荷则NO3--N体积去除负荷开始下降且出水中出现NO2--N积累。动力学研究结果表明以PBS为碳源和生物膜载体的反硝化速率遵循一级反应动力学。用Eckenfelder模型拟合,求出反应速度常数K值和常数n值且相关性良好。采用该动力学模型参数可以预测出水NO3--N浓度并用于实际闭合循环养殖系统的工程设计和优化运行。     

Aging promotes todorokite formation from layered manganese oxide at near-surface conditions

Purpose

Todorokite is one common manganese oxide in soils and sediments and is commonly formed from layered Na-buserite. Aging processes can alter the physicochemical properties of freshly formed Na-buserite in natural environments. However, it is not clear whether and how aging affects the formation of todorokites. In the present paper, Na-buserite with aging treatment was employed to prepare todorokite at atmospheric pressure to investigate the effects of aging treatment of Na-buserite on the formation of todorokite.

Materials and methods

Four aged Na-buserite samples, which are produced through oxidation of Mn²⁺ in concentrated NaOH medium by O₂ with aging for 3, 6, 9, and 12 months, were employed to investigate the effects of aging processes on the transformation from Na-buserite to todorokite by Mg²⁺-templating reaction at atmospheric pressure. The manganese oxides were examined using X-ray diffraction (XRD), elemental analysis, determinations of the average manganese oxidation number, infrared spectroscopy (IR), and transmission electron microscopy (TEM).

Results and discussion

The XRD, IR, and elemental analyses indicate that aging treatment can alter the substructure of the freshly synthesized Na-buserite. During the aging process, some of the Mn(III) may migrate into the interlayer region or disproportionate to form Mn²⁺ and Mn⁴⁺ from the layer of Na-buserite and the concomitant formation of layer vacancies. The interlayer Mn³⁺ or Mn²⁺ occupied above or below the layer vacancy sites and become corner-sharing octahedral. XRD analyses and TEM clearly show that the transformation from Na-buserite to todorokite was promoted by aging treatments. The alterations of substructure of aged Na-buserites can promote the rearrangement of manganese to construct a tunnel structure during the transformation from layered manganese oxides to tunnel-structure todorokite at atmospheric pressure.

Conclusions

The transformation from Na-buserite to todorokite was promoted by aging treatments at atmospheric pressure, and it is more suitable to explore the origination of natural todorokite in Earth surface environments using aged layered manganese oxides.     

细胞穿膜肽pep-1与vMIP-Ⅱ的融合表达与纯化

细胞穿膜肽是一类能携带大分子物质进入细胞的短肽,其穿膜能力不依赖经典的胞吞作用。本研究构建了含有细胞穿膜肽pep-1和病毒巨噬细胞炎症蛋白-Ⅱ（viral macrophage inflammatory protein-Ⅱ,vMIP-Ⅱ）的融合表达质粒pET15b-pep-1-vMIP-Ⅱ,并将其转化大肠杆菌BL21（DE3）plysS中经IPTG诱导表达,经SDS-PAGE和Western-blot鉴定出可溶性的融合蛋白pep-1-vMIP-Ⅱ。通过对IPTG浓度、温度等诱导表达条件进行优化,确定在IPTG浓度为0.2mmol/L、28℃下诱导7h可溶性蛋白的表达量相对较高,经Ni-NTA亲和层析,超滤除盐纯化获得高纯度的融合蛋白pep-1-vMIP-Ⅱ,将该蛋白作用于Hela细胞,激光共聚焦显微镜观察结果显示该融合蛋白能够携带目的基因穿透细胞膜。本文结果将为进一步研究vMIP-Ⅱ的功能和细胞穿膜肽技术的应用奠定基础。     

Future habitat loss and the conservation of plant biodiversity

Rapid land-use and climate changes are projected to cause broad-scale global land-cover transformation that will increase species extinction rates. We assessed the exposure of globally threatened plant biodiversity to future habitat loss over the first half of this century by testing country-level associations between threatened plant species richness and future habitat loss owing to land-use and climate changes, separately. In countries overlapping Biodiversity Hotspots, plant species endangerment increases with climate change-driven habitat loss. This association suggests that many currently threatened plant species will become extinct owing to anthropogenic climate change in the absence of potentially mitigating factors such as natural and assisted range shift, and physiological and genetic adaptations. Countries rich in threatened species, which are also projected to have relatively high total future habitat loss, are concentrated around the equator. Because poverty and poor governance can compromise conservation, we considered the economic condition and quality of governance with the degree of plant species endangerment and future habitat loss to prioritize countries based on conservation need. We identified Angola, Cuba, Democratic Republic of Congo, Ethiopia, Kenya, Laos, Madagascar, Myanmar, Nepal, Tajikistan, and Tanzania as the countries in greatest need of conservation assistance. For conservation endeavors to be effective, the conservation capacity of these high-need countries needs to be improved by assisting political stability and economic sustainability. We make policy recommendations that aim to mitigate climate change, promote plant species conservation, and improve the economic conditions and quality of governance in countries with high conservation need.     

High levels of spatial heterogeneity in the biodiversity of soil prokaryotes on Signy Island, Antarctica

In a previous study, soil bacterial diversity at environmentally distinct locations on Signy Island was examined using denaturing gradient gel electrophoresis (DGGE) profiling, and a range of chemical variables in soils was determined in order to describe variations between them. The dominant bacterial communities of all locations were found to be significantly different, although higher levels of similarity were observed between locations with similar physico-chemical characteristics, such as at penguin rookeries, seal wallows and vegetated soils. Extending this study, here soil prokaryote biodiversity was compared between 15 distinct locations in order to elucidate any interaction between four general habitat types on Signy Island (South Orkney Islands, maritime Antarctic) and any influence of previous human impacts at these sites. Specific sites were selected to represent the range of different soil environments present and to cover a range of environmental factors present in the maritime Antarctic which are known to influence bacterial community composition in soils elsewhere. A diverse prokaryote community is described, again with the majority of excised and sequenced bands belonging to the Bacteroidetes. Although DGGE profiling identified significant differences in prokaryotic biodiversity between all sampling sites, aggregations of banding patterns were also apparent across the different soil environments examined. Correlations between specific DGGE profiles and 10 selected soil parameters suggested that much of this variation could be explained by differences in the levels of environmental disturbance and soil pH. In particular, a greater proportion of variation in soil bacterial diversity was explained by differences in soil properties at human-disturbed locations than at undisturbed locations, with higher explanatory values by edaphic factors in the former and soil metal content in the later. In general, our data indicate that small-scale variation is an important factor in understanding patterns of prokaryotic distributions in soil habitats in the maritime Antarctic environment.     

南美白对虾混养高产养殖技术

由于池塘老化和养殖病害等因素影响,对虾养殖生产和发展受到了严重制约.作者在南美白对虾(P.vannamei)养殖生产中,通过投放一定数量的卵圆鲳鲹(Trachinotus ovatus)、锯缘青蟹[Scylla serrata(Forskal)],采取鱼、虾、蟹混养的养殖技术方法,有效的改善养殖生态环境,防止了养殖病害的发生和病害的蔓延,养殖效果得到明显提高,并在2007年的养殖生产试验中取得成功,平均产量达11062.0元/667 m2,盈利达6308.5元/667m2,取得了良好的经济效益.     

远郊校区图书馆多维阅览服务模式构建

上海海洋大学为远郊校区办学,面对新环境的挑战,图书馆尝试建构新的阅览服务模式,采取多维阅览服务方式,即:拓展物理空间、网络空间和人文空间的阅览服务举措,进而提升阅览服务水平,从而更好地为教学、科研服务。