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601.
This paper presents the findings of a study on the governance of seed conducted in the framework of a participatory plant breeding (PPB) programme, based on a multi‐year inquiry with a panel of ten Syrian households. The study assessed the interactions between governance regimes regulating the rights to access and control genetic resources at international and national level, compared to the actual ability of the respondent women farmers to access and control the seed of varieties they co‐developed with the PPB programme. The paper argues that gender equal access to seed can “optimally” contribute to enhancing household food security in small scale farming. The paper also argues that to support a gender‐equal access to seed in the respondent households legislation needs to explicitly protect the rights of women farmers to access and share the benefits of genetic material and draw from empirical evidence of the actual access to and control of seed at ground level.  相似文献   
602.
ABSTRACT

Despite increasing evidence of threats to Indigenous food systems, many Indigenous communities are innovating to enhance their resilience while conserving and promoting their traditional food systems, offering important lessons for rural development policy. This community-based case study explores one such Indigenous initiative: Sanjeevini, in Andhra Pradesh, India. Sanjeevini has been effective in designing and implementing creative strategies for seed sovereignty and biocultural conservation. Interviews with key persons associated with Sanjeevini (n?=?8) and participatory field-research in the Araku Valley region, including interviews with small scale farmers (n?=?30), revealed community development strategies emphasising a link between biological and cultural heritage in Indigenous food systems. These include hosting cultural seed festivals, establishing and maintaining community-based seed banks, and facilitating inter-community seed exchanges. Importantly, these strategies take place against a backdrop of community-organising that counteracts the dominant neo-liberal development agenda while resisting deforestation that threatens Indigenous livelihoods. Sanjeevini’s success demonstrates that through the adaptive assertion of self-determination, rural social change is possible. This paper highlights alternative, community-driven articulations of seed sovereignty while underscoring the significance of this community’s own vision in guiding rural innovation and offering promising working models for cultivating rural resilience.  相似文献   
603.
Cost-effective biosorbents made from the byproducts of agriculture, forest, and related industries, such as barley straw, canola meal, and wood sawdust, have significant water adsorption capacity, showing a great potential for selective water removal from bioalcohols to produce fuel grade products. However, there is a challenge that the biosorbents are not stable when they come in contact with aqueous solution. There are organic carbons released from biosorbents to liquid phase, which needs to be addressed before this technology is applied in the industrial purification of bioalcohols. In this work, raw barley straw representing an abundant group of cellulosic materials in the above-mentioned industries was used as a model material. A methodology of chemical and physical treatment was developed to treat barley straw which successfully enhanced the stability and reduced the total organic carbon release from the material into the aqueous solution. In addition, the pre-treated barley straw biosorbent had significantly increased micropores, and the Brunauer--Emmett--Teller surface area favored by water adsorption compared with raw barley straw. It also had higher water uptake and dynamic water adsorption selectivity. The pre-treated barley straw was able to selectively remove water and generate concentrated ethanol.  相似文献   
604.
丁旭  毛康  白雅  张巍 《中国环境科学》2020,40(2):681-687
在国内外研究的基础上,应用固相萃取技术,建立并优化了适用于野外条件的3种常见精神活性物质(甲基苯丙胺、苯丙胺和麻黄碱)的快速前处理方法.比较了污水快速前处理条件(样品pH值和上样流速)对目标物回收率的影响.结果表明,在本文测试条件下,理想的快速前处理参数为使用Oasis HLB柱,在碱性条件、流速为20mL/min的情况下加载样品.与传统方法相比,快速前处理方法所得的目标物浓度稍有降低,但仍很好地反映了生活污水中的目标物浓度水平和变化特征.北京、广东两地的野外验证结果显示,该方法对南北两地生活污水和地表水样品的处理效果都比较稳定.  相似文献   
605.
王洵  张佳佳  袁秋生  胡斌  刘胜 《环境科学》2022,43(7):3623-3634
微生物群落之间通过直接或间接的关系相互作用,在生态过程中发挥重要作用,然而目前对于水库微生物种间互作模式的关注仍然较少.选择江苏省横山水库为研究区域,分别采集表层及深层水样,探究浮游微生物群落结构和分子生态网络对水深变化的响应规律,并辨识不同水深处浮游微生物群落的关键物种.结果发现,表层浮游微生物丰富度及均匀度均高于深层,且不同深度浮游微生物群落结构具有显著差异.水深通过改变环境异质性间接对浮游微生物群落产生影响,其中总有机碳(TOC)、硝酸盐(NO-3)、铵盐(NH+4)和磷酸盐(PO43-)等指标对浮游微生物群落结构影响最为显著.此外,深层浮游微生物分子生态网络的节点数和边数均显著高于表层,且深层浮游微生物群落中关键物种数目和种类均显著高于表层,表明深层浮游微生物群落网络规模更大,但表层浮游微生物群落种间协同合作关系和网络连通性更强.上述结果将为水库微生物群落种间相互作用研究提供科学依据,对预测水库生态系统中微生物的生态规律及全球物质循环影响具有重要意...  相似文献   
606.
不同施工阶段扬尘污染特征研究   总被引:14,自引:5,他引:14  
黄玉虎  田刚  秦建平  李钢  闫宝林 《环境科学》2007,28(12):2885-2888
以北京城近郊区40多个建筑工地为实验工地,以降尘作为施工扬尘监测指标,对不同施工阶段的扬尘污染规律进行了研究,对不同施工阶段自身降尘浓度数据进行频率分布统计.结果表明,挖槽阶段相比结构和装修的施工扬尘污染更加严重;挖槽、装修和结构阶段自身降尘浓度>50 t/(km2·30 d)的概率分别为16%、16%和3%,挖槽和装修阶段比结构阶段更容易发生高强度施工扬尘污染;不同施工阶段都遵循春季施工扬尘污染强度明显大于夏、秋、冬季,以及冬季略大于夏、秋季的规律;不同施工阶段的扬尘污染强弱关系非常明显,扬尘污染强度比值为,挖槽∶结构∶装修等于100∶67∶87.  相似文献   
607.
以赤子爱胜蚓(Eisenia fetida)为受试生物,通过活体与离体实验,研究6:2氟调羧酸(6:2FTCA)在蚯蚓体内的毒理效应和代谢转化机制.结果表明,6:2FTCA对蚯蚓体内丙二醛(MDA)含量和过氧化物酶(POD)活性无显著影响,但能够使过氧化氢酶(CAT)活性提高,使超氧化物歧化酶(SOD)和谷胱甘肽转移酶(GST)活性显著升高,说明6:2FTCA对蚯蚓产生了氧化胁迫效应.6:2FTCA在蚯蚓细胞色素P450(CYP450)和GST酶提取液中的降解动力学均符合一级动力学模型,在CYP450(0.014/h)酶液中的降解速率明显高于GST (0.006/h),其终端全氟羧酸(PFCAs)代谢产物为全氟己酸(PFHxA)、全氟戊酸(PFPeA)和全氟丁酸(PFBA),说明CYP450和GST参与了6:2FTCA在蚯蚓体内的代谢转化,且CYP450贡献大于GST.蚯蚓肠道好氧微生物对6:2FTCA具有显著的降解效果,终端PFCAs降解产物为PFHxA和PFPeA,而肠道厌氧微生物对6:2FTCA无降解作用.  相似文献   
608.
微生物固定化技术与污水处理   总被引:1,自引:0,他引:1  
简要介绍了几种常用微生物固定化方法,重点讨论了微生物固定化技术在污水处理方面的应用,并对未来的发展方向进行了展望。  相似文献   
609.
Methanotrophic based process can be the remedy to offset the wastewater treatment facilities increasing energy requirements due to methanotroph's unique ability to integrate methane assimilation with multiple biotechnological applications like biological nitrogen removal and methanol production. Regardless of the methanotrophic process end product, the challenge to maintain stable microbial growth in the methanotrophs cultivation bioreactor at higher cell densities is one of the major obstacles facing the process upscaling. Therefore, a series of consecutive batch tests were performed to attentively investigate the biomass density influence on type I methanotrophs bacterial growth. In addition, food to microorganisms(F/M), carbon to nitrogen(C/N) and nitrogen to microorganisms(N/M) ratio effect on the microbial activity was studied for the first time. It was clarified that the F/M ratio is the most influencing factor on the microbial growth at higher biomass densities rather than the biomass density increase, whereas C/N and N/M ratio change, while using nitrate as the nitrogen source,does not influence methanotrophs microbial growth. These study results would facilitate the scaling up of methanotrophic based biotechnology by identifying that F/M ratio as the key parameter that influences methanotrophs cultivation at high biomass densities.  相似文献   
610.
A strain saccharomycete STSM-I with high flocculanting activity was isolated from activated sludge with conventional methods.The high production rate and the low cost STSM-I medium was obtained by selecting different kinds of media, carbon source, nitrogen source and inorganic salt ion. The best flocculant-producing conditions were found by changing medium initial pH, culture temperature and ventilation flow. The best flocculating effect was obtained by changing positive ion types, density and concentration of flocculant.  相似文献   
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