青海湖棕头鸥(Larus brunnicephalus)夏秋季活动区研究

2006年4～9月,采用无线电遥测技术对青海湖重要繁殖水鸟棕头鸥(Larus brunnicephalus)在不同繁殖阶段的活动性,以及与人和鸟的关系进行了研究.对6只棕头鸥个体的遥测结果表明,繁殖初期棕头鸥的活动区较大,进入繁殖中期,活动区明显变小;随后繁殖后期的活动区面积有所增加,到了迁徙前期,活动区面积已接近繁殖初期.不同阶段活动区核心面积(50%Fixed Kernel)与活动区变化趋势基本一致.繁殖初期、中期、后期和迁徙前期活动区面积分别为(15.48 km2±4.54 km2)、(1.61 km2±0.41 km2)、(3.53 km2±2.63 km2)和(11.61 km2±9.36 km2).棕头鸥在不同繁殖阶段的日活动区大小有显著差异.繁殖初期,棕头鸥经常活动于鸬鹚岛、蛋岛和布哈河口,它们都是棕头鸥较好的取食地,鸬鹚岛和蛋岛由于有许多游客投喂食物;在繁殖中期,棕头鸥进入孵化阶段,活动区较繁殖前期明显缩小.由于湟鱼返回布哈河口一带产卵繁殖,棕头鸥经常聚集在此地取食;在繁殖后期,棕头鸥需要寻找大量的食物进行育雏,因此活动范围再度扩大;进入迁徙前期,幼鸟已经长大并学会飞翔,其活动区进一步扩大,与繁殖初期较为接近.     

中国近海生物固碳强度与潜力

通过现场调查和数据分析,首次探讨了中国近海浮游植物的固碳强度与潜力以及近海人工养殖大型藻类的固碳能力.结果表明,渤、黄、东海的浮游植物固碳强度约为2.22亿t a-1,固碳量的季节变化从大到小的顺序依次为春季、夏季、秋季、冬季,其中春夏季的固碳量占全年的65.3%.南黄海1999～2005年10～11月间浮游植物固碳强度有较大的年际变化,10～11月份7a间其浮游植物最低固碳量为3.54万t d-1,最高为16.58万t d-1,平均为10.50万t d-1,没有明显的年际变化趋势,磷对浮游植物固碳强度的影响最为明显,次之的影响因素是Chl a和亚硝氮 (NO2-N)的含量.南海的固碳能力约为渤黄东海的2倍,为4.16亿t a-1,其季节变化和渤黄东海不同,南海浮游植物在冬季的固碳能力最强,在夏季最弱.整个中国近海浮游植物年固碳量达6.38亿t,可占全球近海区域浮游植物年固碳量的5.77%.实际外海龙须菜的养殖发现,龙须菜每年固定的碳为8.18 t,养殖密度与方式对其产量和固碳量影响巨大.近几年,我国大型经济藻类养殖产量每年在120～150万t左右,换算为固碳量为36～45万t,平均每年40万t,如果海藻养殖产量每年增加5%,到2010年,我国大型经济藻类养殖的固碳量可达57万t a-1,海藻养殖是海洋增加碳汇有多重价值的重要措施.     

The effect of packing hydrophilization on bacterial attachment and the relationship with the performance of biotrickling filters

Many bioprocesses depend on the effective formation of a biofilm on a solid support. In the present study, three different surface treatments (sandblasting, pure‐O₂ plasma, and He–O₂ plasma treatments) were conducted on polypropylene (PP) Pall rings used as a support in biotrickling filters for air pollution control. The intent was to modify the ring surface and/or electrochemical properties in order to possibly improve cell adhesion, wetting properties, and possibly reduce the start‐up time and increase the performance of the biotrickling filters. The surface treatments were found to generally increase the hydrophilicity and the zeta potential of the surfaces. However, the startup and performance of lab‐scale biotrickling filters packed with treated Pall rings were not significantly different than the control with untreated rings. Cell and colloid deposition experiments conducted in flow cells showed that the treated surfaces and the hydrodynamic conditions were not favorable for cell deposition indicating that there could be significant opportunities for improving packings used in environmental bioprocess applications. Biotechnol. Bioeng. 2009;103: 1060–1067. © 2009 Wiley Periodicals, Inc.     

Dazap2 is required for FGF-mediated posterior neural patterning, independent of Wnt and Cdx function

The organization of the embryonic neural plate requires coordination of multiple signal transduction pathways, including fibroblast growth factors (FGFs), bone morphogenetic proteins (BMPs), and WNTs. Many studies have suggested that a critical component of this process is the patterning of posterior neural tissues by an FGF-caudal signaling cascade. Here, we have identified a novel player, Dazap2, and show that it is required in vivo for posterior neural fate. Loss of Dazap2 in embryos resulted in diminished expression of hoxb9 with a concurrent increase in the anterior marker otx2. Furthermore, we found that Dazap2 is required for FGF dependent posterior patterning; surprisingly, this is independent of Cdx activity. Furthermore, in contrast to FGF activity, Dazap2 induction of hoxb9 is not blocked by loss of canonical Wnt signaling. Functionally, we found that increasing Dazap2 levels alters neural patterning and induces posterior neural markers. This activity overcomes the anteriorizing effects of noggin, and is downstream of FGF receptor activation. Our results strongly suggest that Dazap2 is a novel and essential branch of FGF-induced neural patterning.     

Estimating the capacity for improvement in risk prediction with a marker

Consider a set of baseline predictors X to predict a binaryoutcome D and let Y be a novel marker or predictor. This paperis concerned with evaluating the performance of the augmentedrisk model P(D = 1|Y,X) compared with the baseline model P(D= 1|X). The diagnostic likelihood ratio, DLR_X(y), quantifiesthe change in risk obtained with knowledge of Y = y for a subjectwith baseline risk factors X. The notion is commonly used inclinical medicine to quantify the increment in risk predictiondue to Y. It is contrasted here with the notion of covariate-adjustedeffect of Y in the augmented risk model. We also propose methodsfor making inference about DLR_X(y). Case–control studydesigns are accommodated. The methods provide a mechanism toinvestigate if the predictive information in Y varies with baselinecovariates. In addition, we show that when combined with a baselinerisk model and information about the population distributionof Y given X, covariate-specific predictiveness curves can beestimated. These curves are useful to an individual in decidingif ascertainment of Y is likely to be informative or not forhim. We illustrate with data from 2 studies: one is a studyof the performance of hearing screening tests for infants, andthe other concerns the value of serum creatinine in diagnosingrenal artery stenosis.     

民勤连古城自然保护区群落结构和物种多样性特征分析

通过物种多样性指数、林地承载力以及土壤水分等指标对民勤连古城自然保护区荒漠群落的结构和物种多样性以及影响因子进行了研究。结果表明:(1)群落的优势层片为灌木层,其物种组成和结构比较稳定,受环境变化的影响较小,而草本层为不稳定层片;(2)荒漠群落的物种多样性指数均偏低,生态优势度较高,群落的生态功能主要由优势种群或建群种群实施,在无外界干扰情况下,优势种群或建群种群的稳定性可以揭示群落的稳定性;(3)土壤水分是影响群落结构的主导因子,而降水是土壤水分的主要来源,对群落结构具有显著影响。土壤异质性对群落结构同样具有显著影响,是第二主导因子,其物种多样性指数为黏性土壤>灰棕荒漠土>风沙土;(4)群落物种多样性与其林地承载力无一定规律的相关性,灌木层片中,二者呈对数相关(y=64.787ln(x) 214.04,R2=0.829,P<0.01),能够比较科学地揭示物种多样性与林地承载力之间的关系,而草本层中二者呈幂指数相关(y=0.3198e6.1654x,R2=0.6999,P<0.01),反映了林地承载力受环境因子变化的影响。     

基于随机效应的兴安落叶松材积生长模拟

基于黑龙江省带岭林业局大青川林场80株人工兴安落叶松解析木数据和Logistic生长模型,分别考虑单木效应和样地效应,利用S-PLUS软件中的NLME过程拟合非线性材积生长模型,采用赤池信息准则(AIC)、贝叶斯信息准则(BIC)、对数似然值和似然比检验等模型评价指标对不同模型的精度进行比较.结果表明：当考虑单木效应影响时,b₁、b₂、b₃（分别代表Logistic模型中的渐进、尺度和形状的随机参数）同时作为随机参数时模型拟合效果最好; 当考虑样地效应影响时,b₁作为随机参数时模型拟合效果最好.基于单木效应和样地效应的混合模型的拟合精度高于基本模型（Logistic生长模型）,考虑单木效应影响的混合模型的精度高于考虑样地效应影响的模型.模型检验结果表明,随机效应模型不但能反映单木材积的总体平均变化趋势,还能反映个体之间的差异;随机效应模型通过校正随机参数值能提高模型的预测精度.     

Polo-like kinase 1 is required for localization of Posterior End Mark protein to the centrosome-attracting body and unequal cleavages in ascidian embryos

In ascidian embryos, the posterior-localized maternal factor Posterior End Mark (PEM) is responsible for patterning embryos along the anterior-posterior axis with regard to both cleavage pattern involving unequal cell divisions and gene expression. Although PEM plays important roles in embryogenesis, its mechanism of action is still unclear because PEM has no known functional domain. In the present study, we explored the candidate of PEM partner proteins in Halocynthia roretzi using yeast two-hybrid screening. We isolated a homologue of Polo-like kinase 1 (Plk1), a key regulator of cell division and highly conserved in eukaryotes, as the first potential binding partner of PEM. We biochemically confirmed that interaction occurred between the Plk1 and PEM proteins. Immunostaining showed that Plk1 protein concentrates in the centrosome-attracting body (CAB) at the posterior pole, where PEM protein is also localized. The CAB is a subcellular structure that plays an important role in generating the posterior cleavage pattern. Plk1 localization to the CAB was dependent on the cell cycle phases during unequal cleavage. Inhibition of Plk1 with specific drugs resulted in failure of the nucleus to migrate towards the posterior pole and formation of a microtubule bundle between the CAB and a centrosome, similarly to inhibition of PEM function, suggesting that both proteins are involved in the same process of unequal cleavages. This interrupted nuclear migration was rescued by overexpression of PEM. In Plk1-inhibited embryos, the localization of PEM protein to the CAB was impaired, indicating that Plk1 is required for appropriate localization of PEM.