Occurrence of the Dinoflagellate Gymnodinium Catenatum (Graham) Along the Mediterranean Coast of Alexandria (Egypt)

A monitoring programme during 4 years (1993-1996) was established in four eutrophic marine basins along the Mediterranean coast of Alexandria (Egypt) to follow the occurrence of a newly recorded dinoflagellate Gymnodinium catenatum and ambient environmental conditions. the species achieved its massive occurrence in warm seasons at low salinity, density stratified water column and different nutrient concentrations. A simple statistical approach showed temperature and phosphate to effect its distribution. Apparently no cases of toxic effect have accompanied the occurrence of G. catenatum. the regular occurrence of the species during the 4 year survey mean the existence of its benthic resting cysts, which certainly have important implications for its distribution dynamics.     

Land use change and population growth in the Morobe Province of Papua New Guinea between 1975 and 2000

The relation between human population growth and land use change is much debated. Here we present a case study from Papua New Guinea where the population has increased from 2.3 million in 1975 to 5.2 million in 2000. Since 85% of the population relies on subsistence agriculture, population growth affects agricultural land use. We assessed land use change in the Morobe province (33,933 km2) using topographic maps of 1975 and Landsat TM images of 1990 and 2000. Between 1975 and 2000, agricultural land use increased by 58% and population grew by 99%. Most new agricultural land was taken from primary forest and the forest area decreased from 9.8 ha person(-1) in 1975 to 4.4 ha person(-1) in 2000. Total population change and total land use change were strongly correlated. Most of the agricultural land use change occurred on Inceptisols in areas with high rainfall (>2500 mm year(-1)) on moderate to very steep slopes (10-56%). Agricultural land use changes in logged-over areas were in the vicinity of populated places (villages), and in close proximity to road access. There was considerable variation between the districts but districts with higher population growth also had larger increases in agricultural areas. It is concluded that in the absence of improved farming systems the current trend of increased agriculture with rapid population growth is likely to continue.     

农业废弃物对土壤中N_2O、CO_2释放和土壤氮素转化及pH的影响

用一种丹麦农业土壤作为供试材料，在室内培养条件下探讨了施用４种常见农业废弃物（猪粪泥浆、牛粪泥浆、黑麦秸秆、小麦秸秆）对土壤中Ｎ_２Ｏ、ＣＯ_２释放和土壤氮素转化及ｐＨ的影响。试验结果表明，施用４种农业废物均会明显增加Ｎ_２Ｏ、ＣＯ_２释放量。培养２周后，土壤中Ｎ_２Ｏ的释放量分别为：猪粪＞牛粪＞黑麦秸秆＞小麦秸秆；ＣＯ_２的释放量为：黑麦秸秆＞小麦秸秆＞牛粪＞猪粪。施用４种农业废物均会显著促进ＮＯ_３－Ｎ的转化和ＮＨ_４－Ｎ、ＮＯ_２－Ｎ的累积。施用４种废物均会改变土壤ｐＨ，其中施用秸秆的２个处理中ｐＨ显著降低，但施用牲畜粪便的２个处理中ｐＨ则稍微升高。     

Exploring the impact of new particle formation events on PM2.5 pollution during winter in the Yangtze River Delta, China

New particle formation（NPF） events are an increasingly interesting topic in air quality and climate science. In this study, the particle number size distributions, and the frequency of NPF events over Hefei were investigated from November 2018 to February 2019. The proportions of the nucleation mode, Aitken mode, and accumulation mode were 24.59%,53.10%, and 22.30%, respectively, which indicates the presence of abundant ultrafine particles in Hefei. Forty-six NPF events occurred during the obser...     

复杂地质条件下某高层建筑基础方案比选

某高层建筑位于内蒙古赤峰市,地下1层,地上11层。本文通过对该高层建筑的工程地质勘察资料进行分析,结合本工程所属的地质条件、本地区常用的施工方法,预估本工程可能采用的基础方案,进行分析比较,最终对基础方案进行评价和优选。     

黄土地区灰渣库地质灾害危险性评估

以河南黄土地区某灰渣库为例,介绍了地质灾害危险性评估的主要内容和方法.评估区地质灾害类型为崩塌、滑坡、水库塌岸、泥石流、黄土湿陷及黄土陷穴.对地质灾害的危险性及建设场地的适宜性进行了评估,并提出了相应的地质灾害防治措施.     

简青霉降解秸秆条件最优化和诱导剂的作用

实验中采用简青霉对稻草秸秆进行降解作用,通过正交实验的极差、三因素三水平作用趋势图和降解选择性分析,对影响简青霉降解稻草秸秆的3种因素进行了优化,得到培养温度40℃、含水率80%、培养pH为8是降解的最佳固态发酵培养条件。并研究了碱木质素对简青霉分泌木质素降解酶的诱导作用,不同浓度的碱木质素对简青霉产酶的诱导作用不同,且对不同酶的诱导效果也不同,最后得到较低浓度0.5和1 g/L是诱导的适宜浓度。对比较适浓度的碱木质素和常用的诱导剂愈创木酚、吐温80的诱导作用,发现在同样的培养条件下,碱木质素的诱导效果比愈创木酚和吐温80效果都好。     

太湖水-沉积物界面磷、pH及碱性磷酸酶的时空特征及相关性

于2011年3、6和9月通过对太湖不同营养化湖区的5个标准采样位点进行采样分析,探讨了界面沉积物间隙水和上覆水中磷含量、pH及碱性磷酸酶活性的时空分布特征及相关性。结果表明,上覆水及沉积物间隙水中的总磷（TP）、可溶性正磷酸盐（SAP）、pH及碱性磷酸酶（ALP）活性均表现出明显的空间异质性和季节变化趋势。间隙水总磷（PW-TP）、间隙水可溶性正磷酸盐（PW-SAP）高于上覆水,分别最高高出0．082、0．042mg·L-1;上覆水pH值高于间隙水pH值,最高高出O．35个单位;间隙水中碱性磷酸酶（PW-ALP）活性高于上覆水中碱性磷酸酶（W-ALP）活性,最高高出13．244μg·mL·h-1。TP、SAP、pH及ALP活性在3、6、9月份中均以16#样品最高,其中6月份16#样品PW-TP、PW-SAP、上覆水pH及PW-ALP活性分别O．527、0．132、7．46和61．090μg·mL·h-1。参数相关性分析结果表明,W-TP与W-SAP、W-pH显著相关。W-SAP与PW-TP、PW-SAP、W-ALP、PW-ALP均显著相关。PW-TP与PW-pH显著相关性,与PW-ALP活性存在一定的相关性,但不显著。PW-SAP与PW-ALP显著相关。     

Biological removal of selenate in saline wastewater by activated sludge under alternating anoxic/oxic conditions

Removal of selenate in saline wastewater by activated sludge was examined. Sequencing batch reactor was operated under alternating anoxic/oxic conditions. Above 97% removal of soluble selenium (Se) was achieved continuously. Major Se removal mechanism varied depending on the length of aeration period. Various Se-reducing bacteria likely contributed to coordinately to Se removal. Selenium (Se)-containing industrial wastewater is often coupled with notable salinity. However, limited studies have examined biological treatment of Se-containing wastewater under high salinity conditions. In this study, a sequencing batch reactor (SBR) inoculated with activated sludge was applied to treat selenate in synthetic saline wastewater (3% w/v NaCl) supplemented with lactate as the carbon source. Start-up of the SBR was performed with addition of 1–5 mM of selenate under oxygen-limiting conditions, which succeeded in removing more than 99% of the soluble Se. Then, the treatment of 1 mM Se with cycle duration of 3 days was carried out under alternating anoxic/oxic conditions by adding aeration period after oxygen-limiting period. Although the SBR maintained soluble Se removal of above 97%, considerable amount of solid Se remained in the effluent as suspended solids and total Se removal fluctuated between about 40 and 80%. Surprisingly, the mass balance calculation found a considerable decrease of Se accumulated in the SBR when the aeration period was prolonged to 7 h, indicating very efficient Se biovolatilization. Furthermore, microbial community analysis suggested that various Se-reducing bacteria coordinately contributed to the removal of Se in the SBR and main contributors varied depending on the operational conditions. This study will offer implications for practical biological treatment of selenium in saline wastewater.     

电石公路运输事故特征与安全条件的研究

基于电石生产销售实际以及公路运输特征,笔者系统研究了电石公路运输应该具备的道路条件、人员条件、车辆条件、包装条件、仓储条件、自然条件、装卸条件、承运与交付条件;提出了电石道路运输耐压力、耐冲击、耐震动、耐水、耐低气压的实验设计;分析了电石公路运输事故的主要原因并结合电石公路运输事故中典型的火灾事故的特征;给出了电石火灾的水泥罐车灭火方法以及电石运输事故的紧急救援预案。