大兴安岭舟形藻科(硅藻门)中国新记录植物

在大兴安岭沼泽硅藻生物多样性的研究过程中,对采自大兴安岭的600余号标本进行了详细的观察,共观察到舟形藻科中国新记录植物10个分类单位,隶属于4个属,其中类缝藻属1种:粗脉肋缝藻;长篦藻属3种:大长篦藻、细尖长篦藻、双型长篦藻;舟形藻属1种:乌普萨拉舟形藻;辐节藻属5种:两头辐节藻、河生辐节藻、细长辐节藻、豆形辐节藻、地中海辐节藻。本文对这些种类的分类学特征及生态分布特点进行了详细的描述。     

中国多辐藻属(Myriactula)三个新记录种

报道中国产粘膜藻科(Leathesiaceae)多辐藻属(Myriactula)三个新记录种:阿拉伯多辐藻(Myriactula arabica)、粗丝多辐藻(M.clavata)和马尾多辐藻(M.sargassi)。     

双菱藻科（硅藻门）——四个中国新纪录种

本文报道了采自新疆及云南地区的双菱藻科（硅藻门）中国新纪录植物4种,分别为耳蜗波缘藻Cymato—pleura cochlea Brun、维苏双菱藻Surirella visurgis Hustedt、盾状马鞍藻Campylodiscus clypeus Ehrenberg和莱温德马鞍藻Campylodiscus levanderi Hustedt。通过光镜（LM）和扫描电镜（SEM）观察,对其分类学特征进行了详细的描述,并介绍了他们的生境特征等。     

武汉东湖隐藻门植物的分类学研究

隐藻门植物在各种淡水水体中很常见,其中卵形隐藻、啮蚀隐藻在国内被多次报道过。但是由于缺乏分类学的资料,国内关于隐藻门植物的报告并不完全准确,其类群也常常被忽视。我们在2009年6月到2010年3月间,不定期从武汉东湖的各个区域采集水样,共鉴定隐藻门植物4属8种：卵形隐藻、啮蚀隐藻、蛋白核隐藻、四蛋白核隐藻、马索隐藻、反曲弯隐藻、犀角织隐藻、具尾逗隐藻。其中四蛋白核隐藻和犀角织隐藻为中国新记录。作为具尾逗隐藻的异名,尖尾蓝隐藻此前也曾在国内被报道。     

鄂西地区裸藻的新种类

本文报道的是1981年5—6月在鄂西地区(包括五峰、宜都、宜昌、当阳、兴山及神农架林区)采集到的裸藻门植物5个新种,7个新变种和3个新变型。       

淡水刚毛藻目三个中国新记录种

刚毛藻目（Ｃｌａｄｏｐｈｏｒａｌｅｓ）属绿藻门,细胞多核管状,植物体为分枝或不分枝丝状体。刚毛藻目植物广泛分布于各种淡水、咸水、海水中,世界各地甚至于南极和北极都有它们的踪迹。就目前所知,海产种类比淡水多。有些刚毛藻目植物着生在乌龟、螺助等的贝壳上,极具观赏价值,如绿毛龟等。我国对此目的研究仅见建国前的一些零星报道,至今尚无专门的研究。到目前为止,中外藻类学家报道的我国淡水刚毛藻目的名录为６属３１种１１变种２变型,其中有新属１个、新种７个、新变种３个、新变型２个。主要的研究者有饶钦止、李良庆、王…     

武陵山区缘蝽科新种记述(半翅目:异翅亚目)

本文报道武陵山区缘蝽科6新种:细足赧缘蝽Ochrochira stenopoda sp.nov,武陵黑缘蝽H-ygia(Colpura)wulingana sp.nov,雅翅同缘蝽 Homoecerus(Anacanthoris)viridulus sp.nov,钩曼缘蝽Manocoreus grypidus sp.nov,四川锤缘蝽 Marcius sichuananus sp.nov.,黑刺锤缘蝽 Marcius ni-grospinosussp.nov.。     

团藻目新资料

本文报道湖北省武汉市团藻目7个属的5个新种,2个新变种,2个中国新记录。     

The Wald Statistic in Proportional Hazards Hypothesis Testing

In survivorship modelling using the proportional hazards model of Cox (1972, Journal of the Royal Statistical Society, Series B, 34, 187–220), it is often desired to test a subset of the vector of unknown regression parameters β in the expression for the hazard rate at time t. The likelihood ratio test statistic is well behaved in most situations but may be expensive to calculate. The Wald (1943, Transactions of the American Mathematical Society 54, 426–482) test statistic is easier to calculate, but has some drawbacks. In testing a single parameter in a binomial logit model, Hauck and Donner (1977, Journal of the American Statistical Association 72, 851–853) show that the Wald statistic decreases to zero the further the parameter estimate is from the null and that the asymptotic power of the test decreases to the significance level. The Wald statistic is extensively used in statistical software packages for survivorship modelling and it is therefore important to understand its behavior. The present work examines empirically the behavior of the Wald statistic under various departures from the null hypothesis and under the presence of Type I censoring and covariates in the model. It is shown via examples that the Wald statistic's behavior is not as aberrant as found for the logistic model. For the single parameter case, the asymptotic non-null distribution of the Wald statistic is examined.     

An online updating approach for testing the proportional hazards assumption with streams of survival data

The Cox model—which remains the first choice for analyzing time-to-event data, even for large data sets—relies on the proportional hazards (PH) assumption. When survival data arrive sequentially in chunks, a fast and minimally storage intensive approach to test the PH assumption is desirable. We propose an online updating approach that updates the standard test statistic as each new block of data becomes available and greatly lightens the computational burden. Under the null hypothesis of PH, the proposed statistic is shown to have the same asymptotic distribution as the standard version computed on an entire data stream with the data blocks pooled into one data set. In simulation studies, the test and its variant based on most recent data blocks maintain their sizes when the PH assumption holds and have substantial power to detect different violations of the PH assumption. We also show in simulation that our approach can be used successfully with “big data” that exceed a single computer's computational resources. The approach is illustrated with the survival analysis of patients with lymphoma cancer from the Surveillance, Epidemiology, and End Results Program. The proposed test promptly identified deviation from the PH assumption, which was not captured by the test based on the entire data.     

Translational regulation in growing clonal human astrocytoma cells in culture

The in vivo and in vitro protein synthesis by polysomes prepared from Cox astrocytoma cells grown in the presence of 100 mM ethanol were examined during transition from exponential to stationary growth phase. A sharp decline of translational activities of Cox poly (A)+messenger RNAs (mRNAs) occurred during this transition. This decline was accentuated when cells were grown in the presence of ethanol. The observed decline in mRNA translational activity was investigated in vitro in a micrococcal nuclease treated, mRNA depleted postmitochondrial supernatant (PMS) fraction containing [³⁵S]methionine. The formation of the³⁵S-labeled 40S ternary complex in the absence of mRNA and of the³⁵S-labeled 80S initiation complex in the presence of Cox or brain poly (A)+mRNAs were reduced substantially when the source of PMS was from stationary phase or ethanol exposed cells. The sedimentation of peaks containing 40S ternary and 80S initiation complexes following sucrose density gradient analysis showed marked reductions in [³⁵S] methionine labeling during the transition to stationary phase and also following ethanol exposure. The reduced formation of initiation complexes suggests possible functional modifications of eukaryotic initiation factor-2 (eIF-2) present in the PMS fraction and of mRNAs under these conditions. Data suggest that cells initiate adaptive or protective mechanisms by reducing the rate of the initiation reaction following environmental alterations produced by ethanol.     

Sex‐ and age‐biased mortality in wild Grey Partridge Perdix perdix populations

Differing reproductive effort, individual qualities and local environmental conditions can lead to uneven mortality risk among individuals within populations and may result in survival differences according to age and sex. Identification of factors contributing to unequal operational sex ratios has been important for understanding population dynamics and conservation management. In this study, sex‐ and age‐specific mortality was estimated in three wild Grey Partridge populations from analysis of year‐round radiotracking data from 168 individuals. Survival days were counted in three periods defined individually for each bird: the pairing period (covey break‐up to laying of the first egg); the nesting period (between clutch initiation date and failure of the last nesting attempt, or the date when chicks were 14 days old); and the covey period (the end of the nesting period or joining a group until covey break‐up). Predation was the main cause of mortality. A significant effect of age on survival was found during the pairing period, when older individuals paired off faster and survived better. The highest mortality risk overall was found during the nesting period. Furthermore, significantly higher mortality of females was recorded during the nesting period, suggesting that greater investments in reproduction, behaviour at the nest or the quality of nesting habitats can decrease survival of females and cause a male‐skewed sex ratio. No significant effect of age or sex was found during the covey period, or for the year as a whole, but there was a significant difference in annual mortality rates between the three study populations. Our results confirm age‐ and sex‐specific variation of adult mortality in a ground‐nesting bird with biparental care during the annual cycle, documenting differing sensitivities of various population cohorts to predation.     

用Cox B3 cDNA探针检测不同病毒感染Hela细胞及小鼠心肌炎组织细胞中的肠道病毒RNA

本文用生物素标记柯萨奇B3病毒(Cox B3)cDNA(530bp)制备探针,检测不同病毒(Cox A9,Cox B1—B6,Polio1,ECHO1,AD3,HSV-1,HSV-2,VV)感染的Hela细胞,结果表明该探针只与肠道病毒核酸杂交而不与非肠道病毒核酸杂交,且可检测出Cox B3感染Hela细胞后3小时细胞病变阴性(CPE~-)细胞内的肠道病毒核酸,表明该探针具有良好的特异性和敏感性.同时用Cox B1感染BalB/c小鼠,建立小鼠心肌炎模型,取心肌组织与该探针进行原位杂交,成功地检测出心肌组织中的肠道病毒核酸.这对于用该探针检测人类病毒性心肌炎组织中的肠道病毒核酸,对病毒性心肌炎进行特异的早期诊断积累了经验.     

Oligomerization of Heme o Synthase in Cytochrome Oxidase Biogenesis Is Mediated by Cytochrome Oxidase Assembly Factor Coa2

The synthesis of the heme a cofactor used in cytochrome c oxidase (CcO) is dependent on the sequential action of heme o synthase (Cox10) and heme a synthase (Cox15). The active state of Cox10 appears to be a homo-oligomeric complex, and formation of this complex is dependent on the newly synthesized CcO subunit Cox1 and the presence of an early Cox1 assembly intermediate. Cox10 multimerization is triggered by progression of Cox1 from the early assembly intermediate to downstream intermediates. The CcO assembly factor Coa2 appears important in coupling the presence of newly synthesized Cox1 to Cox10 oligomerization. Cells lacking Coa2 are impaired in Cox10 complex formation as well as the formation of a high mass Cox15 complex. Increasing Cox1 synthesis in coa2Δ cells restores respiratory function if Cox10 protein levels are elevated. The C-terminal segment of Cox1 is important in triggering Cox10 oligomerization. Expression of the C-terminal 54 residues of Cox1 appended to a heterologous matrix protein leads to efficient Cox10 complex formation in coa2Δ cells, but it fails to induce Cox15 complex formation. The state of Cox10 was evaluated in mutants, which predispose human patients to CcO deficiency and the neurological disorder Leigh syndrome. The presence of the D336V mutation in the yeast Cox10 backbone results in a catalytically inactive enzyme that is fully competent to oligomerize. Thus, Cox10 oligomerization and catalytic activation are separate processes and can be uncoupled.     

Survival model predictive accuracy and ROC curves

The predictive accuracy of a survival model can be summarized using extensions of the proportion of variation explained by the model, or R2, commonly used for continuous response models, or using extensions of sensitivity and specificity, which are commonly used for binary response models. In this article we propose new time-dependent accuracy summaries based on time-specific versions of sensitivity and specificity calculated over risk sets. We connect the accuracy summaries to a previously proposed global concordance measure, which is a variant of Kendall's tau. In addition, we show how standard Cox regression output can be used to obtain estimates of time-dependent sensitivity and specificity, and time-dependent receiver operating characteristic (ROC) curves. Semiparametric estimation methods appropriate for both proportional and nonproportional hazards data are introduced, evaluated in simulations, and illustrated using two familiar survival data sets.