黄土丘陵区柳枝稷光合生理生态特性的初步研究

研究了黄土丘陵区引种草种柳枝稷 ( Panicum virgatum)的光合生理生态特性 ,比较了不同叶位叶片光合速率 ( Pn)、蒸腾速率 ( Tr)、水分利用效率 ( WUE)的日变化以及环境因子的作用。结果表明 ,柳枝稷叶片 Pn日变化曲线为双峰型 ,中午“光合降低”主要是由于叶温过高导致呼吸高引起的净光合速率降低。叶龄增大 ,叶片 Pn日变化相对较平缓 ,其中壮龄叶Pn日变化最为平缓。幼龄叶 Tr的日变化为双峰型 ,随叶龄增大 (叶位下降 )而成为单峰型。WUE的日变化可划分为上午的降低和下午的波动 2个阶段 ,最上充分展开叶 (旗叶 )的WUE始终最高。

温室蔬菜栽培对土壤DTPA浸提态铁锰铜锌含量的影响

对沈阳市大民屯镇蔬菜生产基地温室番茄栽培条件下0~30 cm土层土壤DTPA浸提态微量元素含量的调查表明,温室土壤DTPA浸提态Mn、Cu、Zn含量高于相邻的露地菜田,0~20 cm土层DTPA-Fe含量低于露地土壤。与露地菜田相比,高量施肥条件下温室土壤DTPA-Zn富集是微量元素变化的一个主要特征,11年和5年温室土壤0~20 cm土层DTPA-Zn平均含量分别是露地菜田的4.0和4.8倍。温室栽培条件下高量施用有机肥、土壤pH降低及土壤Eh变化是引起土壤DTPA浸提态微量元素变化的主要因素。

Nanoelectrocatalyst based on high-density Au/Pt hybrid nanoparticles supported on a silica nanosphere

A high-efficiency nanoelectrocatalyst based on high-density Au/Pt hybrid nanoparticles supported on a silica nanosphere (Au-Pt/SiO2) has been prepared by a facile wet chemical method. Scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy are employed to characterize the obtained Au-Pt/SiO2. It was found that each hybrid nanosphere is composed of high-density small Au/Pt hybrid nanoparticles with rough surfaces. These small Au/Pt hybrid nanoparticles interconnect and form a porous nanostructure, which provides highly accessible activity sites, as required for high electrocatalytic activity. We suggest that the particular morphology of the AuPt/SiO2 may be the reason for the high catalytic activity. Thus, this hybrid nanomaterial may find a potential application in fuel cells.

Voltammetric behavior of tetracine on glassy garbon electrode and its application

The anodic voltammetric behavior of anaesthetic tetracine and its application were studied. In 0.1 mol/L HClO4 solution, the potential of anodic peak for tetracine is 1.04 V(vs. Ag/AgCl) at a glassy carbon electrode. A linear relationship between the peak height and the concentration of tetracine in the range of 5 x 10(-4) similar to 1 x 10(-1) g/L was obtained. The peak current decreases with the decreasing acidity of the solution. the mehtod has been used for the direct determination of tetracine in injections. The average recoveries of tetracine in urine samples were 98.5%. The mechanism of the electrode reaction was also discussed.

丁卡因在玻碳电极上的伏安行为及测定

对丁卡因在玻碳电极上的伏安行为进行了研究,发现在0.1mol/L高氯酸溶液中,于1.04V(vs.Ag/AgCl)左右产生一个与丁卡因呈良好线性关系的阳极氧化伏安峰,大多数金属离子和20多种有机生化物质不干扰测定.方法用于注射针剂和加标尿样中丁卡因的测定,结果满意,对电极反应也进行了初步探讨.

地球流体力学若干基础问题的研究

地球流体动力学是研究发生在大气、海洋和地球内部以及其它星球上从微观尺度到天气尺度的运动和物理现象。水是地球流体动力学的主要研究对象之一，研究水的微观统计性质和水波方程的一些力学性质，对我们进一步研究海洋运动及其物理性质有着重要意义。本文主要开展了一列三个基础问题的研究。1.非平衡态统计流体力学。我们通过提出水的微观简化模型，从刘维方程出发。推导出分布函数动力学方程，并求得扰动解，此外，我们还计算了水的粘性系数，得到相当满意的结果。2.水波方程的正则化形式。我们从理想的波动方程出发，确定海波速度场和表面高度是一对正则变量，并得到水波方程的正则形式，这为以后用经典力学方法来处理海波运动很有启发。3.不可压缩粘性流性运动的变分原理。我们应用广义变分原理，证明了波浪谱函数对应着最大功率消耗原理而不是以前认为的最小功率消耗原理。

高原鼠兔与达乌尔鼠兔食物资源维生态位的研究

作者于１９９３年在青海省刚察县年诺索玛地区发现高原鼠兔（Ｏｃｈｏｌｏｎａｃｕｒｚｏｎｉａｅ）和达乌尔鼠兔（Ｏ．ｄａｕｒｉｃａ）在布哈河谷二阶地同域且重叠分布之现象，并从这两种鼠兔的食物资源利用出发，研究了其生态位关系问题。在食物资源维上的生态位宽度（ＰＳ）．高原鼠兔为０．４７４４．达乌尔鼠兔为０．４９６４，即它们具有相近似的生态位宽度。这两种动物的生态位在食物资源谱维上的重叠值（ＦＴ）为０．８０９１．表明它们在对食物资源的利用方面存在着激烈的竞争。

贵阳市表层土壤中镍的基线及污染研究

以贵州省贵阳市8 046 km2 为研究区域, 将土壤中镍的空间分布规律与环境地球化学机理研究相结合, 建立镍的区域土壤环境地球化学基线, 并进行污染分析. 通过对332 个样品的分析, 得到以下结论: 贵阳市表层土壤中镍的基线值为1710 mg/ kg , 大于5710 mg/ kg 的样品可能遭受人为污染. 地质累积指数分析结果显示贵阳市1912 %的表层土壤未受镍的污染, 6317 %的表层土壤在无污染到中度污染之间, 1618 % 的中度污染, 只有013 %的表层土壤介于中度污染到强污染之间. 污染程度指数分析则显示贵阳市64 %的表层土壤未受到镍的污染, 镍的污染程度最大为1156 , 总污染程度小于0 , 即总体未受到污染.

Free Indexation: Combinatorial Analysis and a Compositional Algorithm

In the principles-and-parameters model of language, the principle known as "free indexation'' plays an important part in determining the referential properties of elements such as anaphors and pronominals. This paper addresses two issues. (1) We investigate the combinatorics of free indexation. In particular, we show that free indexation must produce an exponential number of referentially distinct structures. (2) We introduce a compositional free indexation algorithm. We prove that the algorithm is "optimal.'' More precisely, by relating the compositional structure of the formulation to the combinatorial analysis, we show that the algorithm enumerates precisely all possible indexings, without duplicates.

Estudo do comportamento no âmbito da radioprotecção de uma população trabalhadora na área da medicina dentária

Monografia apresentada à Universidade Fernando Pessoa como parte dos requisitos para obtenção do grau de Licenciada em Medicina Dentária

The United Methodist Church at 40: What Can We Hope For?

The necessity we face for the future of Methodism is the re-invention of traditions. To re-invent traditions is to re-visit the past with all of its richness; to discern what in our tradition is most central to Christian faith; to analyze those parts of our past that continue to give life; to discern and build upon what is of value in the newly emerging tradition; and to reflect on those aspects of the neglected and rejected past that challenge our present perspectives and practices. To re-invent traditions is to develop new perspectives and practices from the building blocks of the past and from the fresh movements of the Spirit in the present. To do so is to recognize that Christianity in general, and Methodism in particular, is marked by traditions that have continually been passed on, critiqued, eliminated, created, and re-invented for the sake of a living Christian witness. What we can hope for is that God is there in the future already, pulling us toward God’s own New Creation.

Novel coatings for hard tissue implants

A novel deposition process named CoBlastTM, based on grit blasting technology, has been used to deposit hydroxyapatite (HA) onto titanium (Ti) metal using a dopant/abrasive regime. The various powders (HA powder, apatitic abrasives) and the treated substrates were characterised for chemical composition, coating coverage, crystallinity and topography including surface roughness. The surface roughness of the HA surfaces could be altered using apatitic abrasives of different particle sizes. Compared to the standard plasma spraying process, the CoBlast surface produced excellent coating adhesion, lower dissolution, higher levels of mechanical and chemical stability in stimulated body fluid (SBF). Enhanced viability of osteoblastic cells was also observed on the CoBlast HA surfaces compared to the microblast and untreated Ti as well as the plasma HA coating. CoBlast offers an alternative to the traditional methods of coating HA implants with added versatility. Apatites substituted with antimicrobial metals can also be deposited to add functionality to HA coatings without cytotoxicty. The potential use of these coatings as an infection preventing strategy for application on hard tissue implants was assessed in vitro and also in vivo. Surface physicochemical properties and morphology were determined in addition to surface cytocompatibility assessments using a MG-63 osteoblast cell line. The antibacterial potential of the immobilised metal ion on the surface and the eluted ion to a lesser extent, contributed to the anticolonising behaviour of the surfaces against a standard bacteria strain (S. aureus) as well as a number of clinically relevant strains (MRSA, MSSA and S. epidermis). The results revealed that the surfaces coated with silver substituted apatites (AgA) outperformed the other apatites examined (apatites loaded with Zn, Sr and both Ag and Sr ions). Assessment of bacterial adherence on coated K-wires following subcutaneous implantation in a nude mouse infection model (S. aureus) for two days demonstrated that the 12% wt surface outperformed the 5% wt AgA coating. Lower inflammatory responses were activated with the insertion of the Ag loaded K-wires with a localised infection at the implantation site noted over the two day study period. These results indicated that the AgA coating on the surface of orthopaedic implants demonstrate good biocompatibility whilst inhibiting bacterial adhesion and colonising of the implant surface.

Observations of spatial flow patterns at the coral colony scale on a shallow reef flat

Although small-scale spatial flow variability can affect both larger-scale circulation patterns and biological processes on coral reefs, there are few direct measurements of spatial flow patterns across horizontal scales <100 m. Here flow patterns on a shallow reef flat were measured at scales from a single colony to several adjacent colonies using an array of acoustic Doppler velocimeters on a diver-operated traverse. We observed recirculation zones immediately behind colonies, reduced currents and elevated dissipation rates in turbulent wakes up to 2 colony diameters downstream and enhanced Reynolds stresses in shear layers around wake peripheries. Flow acceleration zones were observed above and between colonies. Coherent flow structures varied with incident flow speeds; recirculation zones were stronger and wakes were more turbulent in faster flows. Low-frequency (<0.03 Hz) flow variations, for which water excursions were large compared with the colony diameters (Keulegan-Carpenter number, KC >1), had similarspatial patterns to wakes, while higher-frequency variations (0.05-0.1 Hz, KC<1) had no observable spatial structure. On the reef flat, both drag and inertial forces exerted by coral colonies could have significant effects on flow, but within different frequency ranges; drag dominates for low-frequency flow variations and inertial forces dominate for higher frequency variations, including the wave band. Our scaling analyses suggest that spatial flow patterns at colony and patch scales could have important implications or both physical and biological processes at larger reef scales through their effects on forces exerted on the flow, turbulent mixing, and dispersion. © 2013. American Geophysical Union. All Rights Reserved.