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401.
Jason D. Pless J. Benjamin Chwirka James L. Krumhansl 《Environmental Chemistry Letters》2007,5(2):85-89
The objective of this document is to report on the early success for sequestering 129I. Sorption coefficients (K
d) for I− and IO3
− onto delafossites, spinels and layered metal hydroxides were measured and compared for their applicability to sequester 129I. The studies were performed using a dilute fluid composition representative of groundwater indigenous to the Yucca mountain
area. Delafossites generally exhibited relatively poor sorption coefficients (<35 mL/g). In contrast, the composition of the
layered hydroxides significantly affects their ability to sorb I. Cu/Al and Cu/Cr layered hydroxide samples exhibit K
d’s greater than 1000 mL/g for both I− and IO3
−. 相似文献
402.
湿地生态系统固碳潜力研究进展 总被引:13,自引:0,他引:13
固碳是湿地生态系统一项重要的服务功能。文章通过对各种类型湿地的固碳量及其潜力进行分析,发现湿地的固碳潜力要高于其他类型的生态系统,维持和恢复湿地的固碳潜力对全球碳循环具有重要的意义。如果湿地遭到破坏或转为他用,其固碳能力就会随之下降,所以保护湿地是保证湿地固碳潜力优先考虑的管理措施。此外通过对泥炭湿地、沿海湿地、森林湿地和人工湿地的恢复措施及效果的分析,发现恢复和创造湿地可以恢复并增强湿地生态系统的固碳潜力,但针对湿地碳库的固碳措施需要进一步的探索和实践。 相似文献
403.
Insect societies are sometimes exploited by workers who reproduce selfishly rather than help to rear the queens offspring. This causes a conflict-of-interest with the mother queen and, frequently, with the non-reproductive workers as well. One mechanism that can reduce conflict is policing, whereby either the queen or other workers aggress egg-laying workers or destroy worker-laid eggs. Here we present the first direct observations of queen and worker policing in natural, unmanipulated colonies of a social insect, the tree wasp Dolichovespula sylvestris. Worker reproduction was common, with workers producing 50% of all male eggs. However, most worker-laid eggs, 91%, were policed within 1 day, whereas most queen-laid eggs, 96%, remained unharmed. The workers were responsible for 51% of all policing events and the queen for 49%. The workers and mother queen also commonly aggressed ovipositing workers, and successfully prevented them from depositing eggs in 14% and 6% of all attempted ovipositions. Hence, both queen policing and worker policing occur and policing acts via two distinct mechanisms: selective destruction of worker-laid eggs and aggression of ovipositing workers. At a general level, our study shows that both centralized and decentralized control can act together to suppress conflict within social groups.Communicated by R. Page 相似文献
404.
持久性有机污染物在土壤中的老化行为研究进展 总被引:3,自引:0,他引:3
介绍了持久性有机污染物在土壤中的老化行为对生物可用性的影响,并介绍了老化行为的机理和影响封锁行为的因素。据此,提出了几种可以促进土壤生物修复的方法。 相似文献
405.
Summary A number of aposematic butterfly and moth species sequester toxic substances from their host plants. Some of these insects can detect the toxic compounds during food assessment. Some pipevine swallowtails use aristolochic acids among the host finding cues during oviposition and larval feeding and accumulate the toxins in the body tissues throughout all life stages. Likewise, a danaine butterfly,Idea leuconoe, which sequesters high concentrations of pyrrolizidine alkaloids in the body, lays eggs in response to the specific alkaloid components contained in the apocynad host. Insect species sharing the same poisonous host plants may differ in the degree of sequestration of toxins. Two closely ralated aposematic geometrid moth species,Arichanna gaschkevitchii andA. melanaria, sequester a series of highly toxic diterpenoids (grayanotoxins) in different degrees, while a cryptic geometrid species,Biston robstus, does not sequester the toxins, illustrating the diversity in adaptation mechanisms even within the same subfamily. By contrast, a number of lepidopteran species store the same compounds though feeding upon taxonomically diverse plant species. A bitter cyanoglycoside, sarmentosin, was characterised from several moth species in the Geometridae, Zygaenidae and Yponomeutidae, and from the apollo butterflies,Parnassius spp. (Papilionidae), although each species feeds on different groups of plants.Interspecific similarities and differences in life history and ecology are discussed in relation to variable characteristics of sequestration of plant compounds among these lepidopteran insects. 相似文献
406.
Hu Y Li JH Zhu YG Huang YZ Hu HQ Christie P 《Environmental geochemistry and health》2005,27(2):169-176
A pot experiment was carried out in a greenhouse to investigate the sequestration of As in iron plaques on root surface of
three rice (Oryza sativa L.) cultivars. Phosphate (P) fertilization increased both plant biomass and tissue P concentrations significantly, indicating
that the soils used in this study was highly P-deficient. Results from this study confirmed that low P supply improved the
formation of iron plaque on rice roots. As a consequence, arsenic (As) concentrations in DCB-extracts with no P addition were
significantly higher than those with P fertilization. Arsenic was highly sequestrated in iron plaque; arsenic concentration
in iron was up to nearly 120 mg kg−1, while arsenic concentrations in roots were just several mg kg−1. Both arsenic and phosphate concentrations in iron plaque were highly positively correlated with the amounts of iron plaque
(DCB-extractable Fe). Contrary to normal understanding that increasing P supply could reduced As accumulation in plants, results
from the present study showed that P fertilization did not inhibit the As uptake by plants (As accumulation in aboveground),
which was probably due to the fact that iron plaque formation was improved under low P conditions, thus leading to more As
sequestration in the iron plaque. Thus results obtained in this study indicated that the iron plaque may inhibit the transfer
of As from roots to shoots, and thus alter the P–As interaction in plant As uptake processes. 相似文献
407.
垃圾堆肥高效纤维素分解菌的筛选与培育技术 总被引:2,自引:0,他引:2
从堆肥、马粪、果园土、污泥等20个样品中,分离筛选出3株对滤纸分解旺盛的纤维素分解菌:C1、C2、C3,并外购康氏木霉、白腐菌、变色栓菌一起作为出发株,经紫外诱变处理后,在含葡萄糖的产酶培养基平板上筛选到能形成较大透明圈的突变株,并进行CMC酶活、微晶纤维素酶活及天然粗纤维分解能力测定。实验结果证明白腐菌经紫外线照射60s诱变而得的C16不仅透明圈大,CMC酶活高(60.08U/mL)是出发株的2倍,而且其对天然粗纤维分解能力强,10d分解率达35%。 相似文献
408.
二氧化硫对环境及人类的危害越来越严重,对其的治理是保护大气环境的重要方面。本文阐述了二氧化硫的污染现状以及治理二氧化硫烟气的主要方法,为烟气脱硫方法的选择提供参考。最后用综合治理二氧化硫污染的实例,说明了环境治理中要尽量采用“绿色技术”,变废为宝,体现环境保护的新思维,实现循环经济的发展要求。 相似文献
409.
王自法 《防灾技术高等专科学校学报》2006,8(1):6-10
本文从简要回顾国内外著名大学的历史出发,给出了学校发展的最终定位.在这个大目标下,文章从分期目标、思路、方法、计划以及存在的问题等几方面着手,讨论了学校学科发展的各阶段主要目标、学校发展的思路以及理念、推动和促进学校发展的几种方法、实现这些理念与实践这些方法的计划以及可能存在的问题.文章最后对这些设想作一个简要总结,指出实现学校发展的最终目标是一个艰辛而漫长、是一个需要几代人持之以恒共同努力的自然结果。 相似文献
410.
Carbon Sequestration by Carbonization of Biomass and Forestation: Three Case Studies 总被引:3,自引:0,他引:3
Makoto Ogawa Yasuyuki Okimori Fumio Takahashi 《Mitigation and Adaptation Strategies for Global Change》2006,11(2):421-436
We proposed the carbon sink project called “Carbon Sequestration by Forestation and Carbonization (CFC),” which involves biomass
utilization and land conservation by incorporating the products of biomass carbonization into the agents for soil improvement,
water purification, etc. Our purpose was to demonstrate the potential of the CFC scheme for carbon sequestration, particularly
carbon storage in soil. Case studies were conducted in both developing and developed countries. 1. In southern Sumatra, Indonesia,
88,369 Mg-C year−1 of wood residue from a plantation forest and excess bark from a pulp mill would be converted into 15,571 Mg-C year−1 of the net carbon sink by biochar for soil improvement. The fixed carbon recovery of the system is 21.0%. 2. In a semiarid
region in western Australia, the carbonization of wood residue was incorporated with multipurpose projects of a mallee eucalyptus
plantation that involved the function of salinity prevention. During the project period of 35 years, the total carbon sink
would reach 1,035,450 Mg-C with 14.0% by aboveground biomass, 33.1% by belowground biomass and 52.8% by biochar in soil. 3.
In southern Kyushu, Japan, the study was focused on the effective use of surplus heat from a garbage incinerator for carbonizing
woody materials. Sawdust of 936.0 Mg-C year−1 would be converted into the net carbon sink of 298.5 Mg-C year−1 by carbonization, with the fixed carbon recovery of the system being 31.9%. Consequently, the CFC project could encourage
the creation of a carbon sink in soil. However, we recognize that the quality standard of biochar, the stability of biochar
in soil, and the methods for monitoring biochar utilization must be clarified before incorporating biochar carbon into the
carbon credit system.
Throughout this article (except for diagrams and in citation details) carbonized biomass is, with the authors'agreement, called
‘biochar’ in lieu of the commonly used but misleading word ‘charcoal’ (Editor). 相似文献