广州城市流浪乞讨者的空间管治与日常生活实践

以广州流浪乞讨者为研究对象,通过深度访谈等质性研究方法,解读针对流浪乞讨者的空间管治政策与手段,分析流浪乞讨者的日常生活实践与生境协商。研究发现：在地方城市政策对流动性与公共秩序限制的双重压力下,在流浪乞讨者的日常生活实践中,不仅有针对管治行动者而刻意为之的特殊营建,亦有基于程式化生活流程对自我身份认同的重塑与真情实感的展演。地方政府基于空间目标的救助与真实存在的日常生活实践存在着一种张力。研究关注了城市边缘群体日常生活对地理意义的主动塑造过程,对全面理解并规范管理中国城市流浪乞讨现象具有借鉴意义。     

Nutrient flux into an intense deep chlorophyll layer in a mode-water eddy

An intense deep chlorophyll layer in the Sargasso Sea was reported near the center of an anticyclonic mode-water eddy by McGillicuddy et al. [2007. Eddy–wind interactions stimulate extraordinary mid-ocean plankton blooms, Science, accepted]. The high chlorophyll was associated with anomalously high concentrations of diatoms and with a maximum in the vertical profile of ¹⁴C primary productivity. Here we report tracer measurements of the vertical advection and turbulent diffusion of deep-water nutrients into this chlorophyll layer. Tracer released in the chlorophyll layer revealed upward motion relative to isopycnal surfaces of about 0.4 m/d, due to solar heating and mixing. The density surfaces themselves shoaled by about 0.1 m/d. The upward flux of dissolved inorganic nitrogen, averaged over 36 days, was approximately 0.6 mmol/m²/d due to both upwelling and mixing. This flux is about 40% of the basin wide, annually averaged, nitrogen flux required to drive the annual new production in the Sargasso Sea, estimated from the oxygen cycle in the euphotic zone, the oxygen demand below the euphotic zone, and from the ³He excess in the mixed layer. The observed upwelling of the fluid was consistent with theoretical models [Dewar, W.K., Flierl, G.R., 1987. Some effects of wind on rings. Journal of Physical Oceanography 17, 1653–1667; Martin, A.P., Richards, K.J., 2001. Mechanisms for vertical nutrient transport within a North Atlantic mesoscale eddy. Deep-Sea Research II 48, 757–773] in which eddy surface currents cause spatial variations in surface stress. The diapycnal diffusivity at the base of the euphotic zone was 3.5±0.5×10⁻⁵ m²/s. Diapycnal mixing was probably enhanced over more typical values by the series of storms passing over the eddy during the experiment and may have been enhanced further by the trapping of near-inertial waves generated within the eddy.     

船体可靠性评估

为了研究不同结构船体的寿命和使用时可靠度的关系,提出了一种基于试验的可靠度估计方法.针对不同结构船体寿命服从Weibull分布,在无失效数据情形下、置信度至少为γ和寿命为t时,根据船体寿命试验数据,给出了可靠度的单侧置信下限.该方法是在Weibull分布形状参数下限已知的情况下,能将所有的无失效寿命数据进行累加,大大提高了可靠性分析的精度.最后,对钢结构、钛合金结构、铝合金结构的船体,在寿命为t月、置信度至少为γ时,计算了3种结构船体的可靠度单侧置信下限.结果表明该方法易于计算,便于工程应用.     

干湿循环下原状黄土抗压强度试验研究

黄土是干旱、半干旱条件下形成的,具有特殊结构的土,季节性的降雨和蒸发作用必将引起其力学性质和结构改变,从而造成其强度降低和变形增大的问题。通过单轴抗压强度试验探讨了黄土抗压强度与含水率、干湿循环次数的变化规律,借助SEM图像定性和定量分析了其强度变化的微观机制。试验结果表明：黄土单轴抗压强度随含水率的减小表现为非线性的增大;随干湿循环次数的增加而减小,经历多次干湿循环后趋于稳定;含水率增大和干湿循环次数的增加不仅仅会使得粗颗粒的接触方式改变与胶体物质和腐殖质数量减少,还会使得土体孔隙直径增大,大、中孔隙所占百分比之和明显增多,进而从微观结构阐述了土体宏观强度的变化规律。     

基于裂缝混凝土的修正氯离子迁移模型研究

通过研究裂缝混凝土内的氯离子运移,建立了混凝土内考虑扩散、结合和电迁移场作用以及裂缝影响的氯离子迁移耦合模型。预测混凝土寿命。模型从已有试验数据中得到了较好验证。在南通盐渍土环境,运用Comsol Multiphysics软件计算混凝土内氯离子随时间和空间的分布;随裂缝宽度、深度及保护层厚度变化的混凝土使用年限变化规律。研究表明：混凝土内氯离子浓度,随时间增加而增加,增速减小;随离子侵入混凝土深度增加而减小,减速趋缓。氯离子从裂缝运移到混凝土孔隙,浓度突降。混凝土使用年限,随保护层厚度增加呈近似线性增加;随裂缝深度增加而减小;随裂缝宽度增加呈指数型函数关系。     

Roles of Biogeochemical Processes in the Oceanic Carbon Cycle Described with a Simple Coupled Physical-Biogeochemical Model

To evaluate the contribution of biogeochemical processes to the oceanic carbon cycle and to calculate the ratio of calcium carbonate to organic carbon downward export, we have incorporated biological and alkalinity pumps in the yoked high-latitude exchange/interior diffusion-advection (YOLDA) model. The biogeochemical processes are represented by four parameters. The values of the parameters are tuned so that the model can reproduce the observed phosphate and alkalinity distributions in each oceanic region. The sensitivity of the model to the biogeochemical parameters shows that biological production rates in the euphotic zone and decomposition depths of particulate matters significantly influence horizontal and vertical distributions of biogeochemical substances. The modeled vertical fluxes of particulate organic phosphorus and calcium carbonate are converted to vertical carbon fluxes by the biological pump and the alkalinity pump, respectively. The downward carbon flux from the surface layer to the deep layer in the entire region is estimated to be 3.36 PgC/yr, which consists of 2.93 PgC/yr from the biological pump and 0.43 PgC/yr from the alkalinity pump, which is consistent with previous studies. The modeled rain ratio is higher with depth and higher in the Pacific and Indian Oceans than in the Atlantic Ocean. The global rain ratio at the surface layer is calculated to be 0.14 to 0.15. This value lies between the lower and higher ends of the previous estimates, which range widely from 0.05 to 0.25. This study indicates that the rain ratio is unlikely to be higher than 0.15, at least in the surface waters.     

日照近海金乌贼生物学的初步研究

为给金乌贼渔业的可持续发展提供依据,通过形态学观察及生物学测定,初步研究了山东日照岚山头近海金乌贼Sepia esculentaHoyle,1885的外部形态特征和生物学特性(胴长与体重组成、生长参数相关关系等),并结合相关资料,对其生活史进行了讨论。研究结果表明:金乌贼胴长(ML)与体重(TW)之间的关系为:TW幼体=6.0×10-4ML2.762 6,TW♀=6.0×10-4ML2.767 1,TW♂=12.0×10-4ML2.585 6;金乌贼为异速生长型,其生长迅速、个体生长差异较大;5~6月为金乌贼繁殖季节,成体交配产卵后死亡,属1年生头足类。     

人工诱导栉孔扇贝雌核发育胚胎的SNP标记分析

利用紫外线照射灭活的同源精子,激活栉孔扇贝(Chlamys farreri)卵子分裂,获得雌核发育胚胎,流式细胞仪检测胚胎细胞平均单倍体率为82.5%。对获得的胚胎进行全基因组扩增,获得足量的基因分型模板,利用高分辨率溶解曲线(HRM)技术对其进行96个单核苷酸多态性(SNP)位点分型。结果显示,诱导雌核发育胚胎的位点检出率为96.27%,其中99.06%的位点分型结果与相应雌性亲本相符;单个胚胎中只表现一种等位形式的位点占91.67%~96.88%,平均为94.81%,较雌性亲本的纯合位点比例(64.25%)明显提高。本研究利用灭活同源精子诱导获得栉孔扇贝雌核发育胚胎,并利用单个胚胎的全基因组扩增产物进行基因位点分析,为扇贝人工诱导雌核发育个体的早期多基因位点检测和评价提供参考。     

1998年季风爆发期南海大气边界层的日变化

在南海尚未有关于海洋大气边界层结构日变化方面的研究.研究海洋大气边界层,有利于我们更好地研究海洋表层结构变化影响机制,对发生在海洋大气边界层上的过程进行预测预报.因此了解南海海洋大气边界层的结构特征,对于我们进一步了解南海天气尺度海气相互作用有非常重要的意义.通过对1998年在南海南部(6°15′N,110°E)和南海北部(20°29′39″N,116°57′48″E)的南海季风试验中定点科考船释放一天四次的探空观测资料分析得出,季风爆发前海洋大气边界层存在规则的日变化,在中午达到深厚.季风爆发后南海北部大气边界层日变化消失,南海南部依然明显.分析表明对其日变化起重要影响的是短波辐射;潜热输送对大气边界层高度日变化影响不大.与大气边界层厚度日变化相对应,南海南部边界层内水汽日变化明显,而南海北部较不明显.     

Tantulocarida (Crustacea: Maxillopoda): A New Taxon from the Temporary Meiobenthos1

Abstract. Two new genera of Tantulocarida are described from the Ligurian deep sea (Western Mediterranean) off Corsica. Xenalytus scotophilia is referred to the Microdajidae and differs from Microdajus GREVE in thoracopodal segmentation as well as in the presence of coupling spines on thoracopod 6 and longitudinal lamellae on the cephalic shield. Aphotocentor styx is placed in the Deoterthridae and holds an intermediate position between Deoterthron BRADFORD & HEWITT and Boreotantulus HI/YS & BOXSHALL. Some aspects of cephalon internal structure are described for the first time and give a possible explanation for the mechanism of stylet protrusion. The external structures of the oral disc are described using SEM. The discovery of well-developed muscles in the trunk and thoracopods is discussed in the light of the benthic phase the tantulus passes through. The boundary between the thorax and abdomen in the tantulus is reinterpreted, corroborating the 5–7-5 bodyplan of the hypothetical urmaxillopodan as found in the Upper Cambrian Skaracarida and possibly also Dala peilertae MOLLER. Some aspects related to dispersal, infection, and feeding are reinterpreted or approached from a different perspective. SEM of Microdajus langi GREVE gives evidence that the tantuli hatch via a conspicuous slit located at the posterior end of the female trunk sac. A worldwide key to the tantulocaridan families and genera is given, and distributional records are compiled. It is suggested that Tantulocarida might be common representatives of the temporary meiobenthos and that their present species number represents only the tip of the iceberg.