渤海中部营养盐季节变化及限制统计分析

根据2013年7月（夏季）,11月（秋季）和2014年5月（春季）渤海中部海域营养盐数据以及温盐等数据,以浮游植物对营养盐的吸收阈值和化学计量关系为判断标准,对研究海域营养盐分布、限制状况以及季节变化特征进行分析,结果表明：调查海域内各营养盐组分变化均呈现明显季节性特征,表现为夏季低秋季上升春季下降的趋势.夏季受冲淡水影响,海水存在层化现象,溶解无机氮（DIN）、PO₄^3--P和SiO₃^2--Si含量分别为（10.33±7.75）、（0.05±0.03）和（3.94±3.19）μmol/L,DIN/P较高,Si/DIN远低于1,其中表层和10m层存在P和Si限制站位分别达93%、93%和40%、20%,限制状况严重.秋季受底层沉积物扰动再悬浮及营养盐矿化释放等因素影响,各种营养盐含量迅速上升,DIN、PO₄^3--P和SiO₃^2--Si含量为（16.44±6.51）、（0.54±0.20）和（16.94±6.37）μmol/L,分别升高了1.6、10.8和4.3倍,垂向分布差异较小,且仅存在P潜在限制现象.春季由于陆源输入相对较少,同时受浮游植物吸收等因素影响,各营养盐含量急剧下降,DIN、PO₄^3--P和SiO₃^2--Si含量分别为（9.04±8.06）、（0.06±0.04）和（2.47±1.90）μmol/L,分别降低了45%、89%和85%,其中部分站位PO₄^3--P和SiO₃^2--Si含量低于阈值,在表层和10m层海水中存在P和Si限制站位分别达70%、65%和55%、50%,对海域内硅藻作为优势种的浮游植物生长和初级生产力产生影响.     

室温Fenton反应过程H2O2有效利用率的影响因素研究

Fenton反应是H2O2在Fe^2＋催化作用下产生氧自由基并氧化污染物的高效方法。但影响Fenton反应过程H2O2分解及其有效利用率的因素是很多的,其中[Fe^2＋]要求控制在3mmol／L以上。酚类体系H2O2的有效利用率不受H2O2浓度变化的影响,但受初始COD的影响,一般表现为随COD的增加,H2O2有效利用率迅速增加。当初始COD一定时,H2O2浓度在600mg／L和1800mg／L时,一元酚与二元酚体系的H2O2有效利用率均出现了两个峰值,前者的峰值分别为11．83gCOD／gH2O2和12．99gCOD／gH2O2,后者的峰值分别为9．01和11．95gCOD／gH2O2。而醇类体系H2O2的有效利用率受H2O2浓度的影响较大,但与初始COD的关系不明显。当H2O2浓度低于300mg／L时,乙醇比对照体系H2O2的分解率高1-3％,而有效利用率仅为0．6gCOD／gH2O2;随H2O2用量的继续增加,其有效利用率趋于0gCOD／gH2O2。而二元醇体系H2O2有效利用率与其浓度间呈“倒U”型规律,H2O2低于300mg／L时,其有效利用率仅为1．25gCOD／gH2O2;H2O2浓度在300mg／L～900mg／L之间时,其有效利用率可达8．96gCOD／gH2O2;其后随着H2O2的增加,有效利用率迅速下降到与乙醇体系相当。在混合体系中,醇羟基和酚羟基所占比例对H2O2有效利用率也有显著的影响,当乙醇比例小于60％时,H2O2有效利用率稳定在13．0gCOD／gH2O2;随乙醇比例的增加,其对H2O2的分解抑制效应表现出剂量依赖关系,H2O2有效利用率也逐渐下降到近于0gCOD／gH2O2,说明这部分H2O2并没有得以有效地分解用于氧化废水中的COD,这在工程实践中应引起高度的重视。     

氧化沟工艺低氧同步脱氮启动研究

在常温条件下,采用小试Pasveer氧化沟处理低C/N实际污水,通过控制好氧区平均ρ(DO)为0.2～0.4 mg/L,保持好氧区与缺氧区体积比为1∶1,成功实现低氧脱氮过程。其中,模式1先接种好氧污泥并逐渐降低好氧区DO,然后接种缺氧污泥;模式2初始阶段保持低氧环境,并直接接种好氧和缺氧混合污泥。结果显示:两种方式均能成功启动低氧脱氮并保持较高的脱氮率;同时,当C/N值为1.94时,氨氮去除率较高;当C/N值为3.00时,总氮去除率较高,低氧低碳条件下脱氮效果较好。     

泰安市大气臭氧污染特征及敏感性分析

2018年5～7月对泰安市城区站点的臭氧及前体物进行在线监测,并基于特征比值法和光化学模型分析了臭氧及前体物的污染特征及臭氧生成对前体物的敏感性.结果表明,观测期间泰安市正遭受较为严重的臭氧(O₃)污染,臭氧浓度的日变化呈典型的单峰型变化,15:00左右出现最高值,氮氧化物(NO_x)和VOCs的日变化趋势整体呈现夜间高白天低的变化特征.由O₃生成效率(OPE)、VOCs/NO_x和H₂O₂/NO_z特征比值法及基于EKMA曲线的方法均得出观测期间泰安市大气O₃光化学生成偏向于NO_x敏感区及过渡区,削减NO_x和VOCs均对O₃生成具有控制作用.同时基于EKMA曲线的方法还得出在O₃前体物浓度减排时按照丙烯等效浓度(PE)与NO_x浓度比值为8∶3进行VOCs(PE)和NO_x削减可以达到O     

蛤蟆通河流域地下水化学特征及控制因素

为研究蛤蟆通河流域水化学特征及主要离子来源,2017年先后采集地下水样品59组,综合运用数理统计、Piper三线图、Gibbs模型和离子比等方法,分析了蛤蟆通流域地下水的水文地球化学特征,并探讨了蛤蟆通流域的水化学演化规律及主要离子来源.结果表明,该区地下水阳离子以Ca~(2+)为主,占阳离子总量的质量分数为22. 1%～72. 4%,平均为48. 7%;阴离子以HCO_3~-为主,占阴离子总量的质量分数为35. 3%～97. 5%,平均为80%; TDS介于93. 3～521. 1 mg·L~(-1),平均值为219. 1 mg·L~(-1),均为淡水;地下水类型以HCO_3-Ca、HCO_3-Ca·Mg和HCO_3-Ca·Na型水为主;地下水样品均分布在Gibbs模型左中部,说明该流域水化学离子组成受岩石风化作用控制;通过离子来源分析,该区主要离子来源于硅酸盐岩和碳酸盐岩的风化溶解.     

Women and children last: An essay on sex discrimination in disasters

In general, little attention has been given to differential survival between the sexes in disasters. Consideration of physiological differences between males and females would suggest that, all things being equal, morbidity and mortality after disaster, particularly where food shortage is involved, should indicate an excess male mortality. Such statistics as exist in disasters, as in chronic underdevelopment, show that it is females and especially girl children who are at highest risk. The basis of this lies in sex discrimination which is implicit in most social systems.     

Accounting for large-scale factors in the study of understory vegetation using a conditional logistic model

Local-scale and large-scale factors can affect the presence of a species of understory vegetation in the forest. Local-scale factors may be the influence of surrounding trees, while climate and latitude are typically considered large-scale factors. A model for the presence of a species needs to take into account both scales. A conditional logistic model is proposed for those studies where only the local-scale factors are of interest and that avoids estimating the large-scale parameters. Conditioning is carried out by the number of quadrats in the plot where the vegetation is found. As the latter is a sufficient statistic for the large-scale factors, a model free from these parameters is obtained. Data gathered in the permanent sample plots of the 1985–1986 National Forest Inventory of Finland is used for illustration, where the local-scale factor of interest is the influence of the trees, quantified by an index based on the size and location of the trees. The model fitted to Vaccinium vitis-idaea showed a significant and positive influence of Scots pine on the presence of this species, while for Calamagrostis arundinacea, a decrease in the odds ratio was observed due to the influence of Norway spruce.     

Sex ratios,mating behavior and sexual size dimorphism of the northern water snake,Nerodia sipedon

Competition among males to mate is generally associated with male-biased size dimorphism. In this study we examine mating behavior in the northern water snake (Nerodia sipedon), a species in which males are much smaller than females despite substantial competition among males to mate. Competition among males was a consequence of a male-biased operational sex ratio due to slightly higher female mortality from a birth sex ratio of 1 : 1, and, in 1 year, more synchronous and longer mating activity by males. Approximately one-third of both males and females appeared not to mate in a given year. Larger males were generally more likely to attempt mating, but size did not explain the variance in the number of aggregations in which individual males participated. Within aggregations, males that were successful at achieving intromission were larger than unsuccessful males in 1 of 2 years. Variation in condition (mass relative to length) and relative tail length were not generally useful predictors of either mating effort or success in males. Because large size was often advantageous to males, sexual size dimorphism appeared not to be a consequence of sexual selection favoring smaller males. Because sexual dimorphism was evident at birth, and both males and females matured sexually at about 4 years, sexual dimorphism was not simply a consequence of one sex growing at the maximum rate for longer. Female fecundity increased with size, and sex differences in size-fecundity relations may underly the pattern of sexual size dimorphism. However, because multiple mating by females is common, sperm competition is likely to be important in determining male reproductive success. Therefore, allocation of energy to sperm rather than growth may also prove to be an important influence on male growth rates and sexual size dimorphism.     

Group histories and offspring sex ratios in ringtailed lemurs (Lemur catta)

Birth sex ratios were examined for ringtailed lemurs (Lemur catta) at the Duke University Primate Center. This population provides a long-term database of births under a variety of demographic and management conditions, including two semi-freeranging groups between which males transfer freely and females defend stable territorial boundaries. We examined three hypotheses usually considered in studies of primate sex ratio bias. The Trivers-Willard hypothesis predicts that dominant females produce males, local resource competition at the population level (LRC-population) predicts that the dispersing sex (males) will be overproduced in dense populations, and local resource competition among individuals (LRC-individual) predicts that dominant females overproduce the philopatric sex (females). We also examined a fourth hypothesis, local resource enhancement (LRE), which is usually subsumed under LRC-individual in studies of primate sex ratio evolution. LRE predicts that under certain conditions, females will produce the sex that provides later cooperative benefits, such as alliance support for within- or between-group competition. Our data provide support for LRE: females overproduce daughters given prospects of new group formation, either through group fission or threatened expulsion of young mothers. Behavioral data from Duke and also wild populations show that daughters serve mothers as important allies in this context and LRE effects also have been documented in other mammals that experience similar group histories. Nonsignificant trends in the data supported the LRC-population hypothesis, and we suggest that LRC interacts with LRE to explain offspring sex ratios in ringtailed lemurs. Received: 27 August 1999 / Received in revised form: 6 March 2000 / Accepted: 18 March 2000     

Metal Extraction from Road Sediment using Different Strength Reagents: Impact on Anthropogenic Contaminant Signals

Washoff of road deposited sediment into storm drainsystems is one of the major contributors to nonpoint sourcepollution in urban fluvial networks. These sediments contain avariety of potentially toxic organic and inorganic contaminants.Road sediment from 13 locations in an urban (non-industrialized)drainage basin, and soil from 10 background (control) locationswere collected to assess total and labile fractions of Al, Co,Cu, Fe, Mn, Ni, Pb and Zn. Four digestions, of varying strength,were used to assess contaminant levels, these included: a totalfour-acid digestion, a microwave-assisted digestion withconcentrated nitric acid (USEPA Method 3051), a 0.5 M `cold' HCl,and a 0.05 M EDTA (pH 7). Road sediment data indicate that Al,Co, Fe, Mn and Ni were primarily lithogenic in origin, while Cu,Pb and Zn showed very significant anthropogenic signals, mostprobably from vehicle-related sources. Median Pb concentrationenrichment ratios for the EDTA extraction were about 42,indicating an extreme anthropogenic signal. The weak extractants(HCl and EDTA) are considered in this study to be superior intheir ability to characterize the degree of anthropogeniccontamination and should be utilized more widely in environmentalcontaminant studies.