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301.
An important rationale for legally farmed and synthetic wildlife products is that they reduce illegal, wild-sourced trade by supplying markets with sustainable alternatives. For this to work, more established illegal-product consumers must switch to legal alternatives than new legal-product consumers switch to illegal wild products. Despite the widespread debate on the magnitude and direction of switching, studies among actual consumers are lacking. We used an anonymous online survey of 1421 traditional Chinese medicine consumers in China to investigate switching among legal farmed, synthetic, and illegal wild bear bile. We examined the past consumption behavior, applied a discrete choice experiment framed within worsening hypothetical disease scenarios, and used latent class models to investigate groups with shared preferences. Bear bile consumers (86% respondents) were wealthier, more likely to have family who consumed bile, and less knowledgeable about bile treatments than nonconsumers. Consumer preferences were heterogenous, but most consumer preferences switched between bile types as disease worsened. We identified five distinct latent classes within our sample: law-abiding consumers (34% respondents), who prefer legal products and were unlikely to switch; two all-natural consumer groups (53%), who dislike synthetics but may switch between farmed and wild; and two nonconsumer groups (12%), who prefer not to buy bile. People with past experience of bile consumption had different preferences than those without. Willingness to switch to wild products was related to believing they were legal, although the likelihood of switching was mediated by preferences for cheaper products sold in legal, familiar places. We found that consumers of wild bile may switch to legal alternatives, given the availability of a range of products, whereas legal-product consumers may switch to illegal products if the barriers to doing so are small. Understanding preferences that promote or impede switching should be a key consideration when attempting to predict consumer behavior in complex wildlife markets.  相似文献   
302.
经口染毒大鼠检测妊娠动物接触吡草醚原药后引起致畸的可能性,初步评价吡草醚原药致畸危害程度。依据《GB15670-1995农药登记毒理学试验方法》,选用的大鼠按雄、雌2:1比例同笼交配,次日清晨阴道涂片检查雌鼠,发现精子即确定为受孕第0天,设低、中、高三个剂量组(18.56、92.80、464.00 mg·(kg·d)-1)、一个阴性对照组和一个阳性对照组。在雌鼠受孕第6~15天灌胃给予受试物,连续共10天,在妊娠第19.5天,处死孕鼠检查胚胎发育情况。高剂量组和阳性对照组大鼠孕期体重增重值降低,差异有显著性(p0.05);中、高剂量组和阳性对照组大鼠吸收胎率与阴性对照组比较差异有显著性(p0.05);中、高剂量组和阳性对照组胎鼠重量与阴性对照组比较,差异有显著性(p0.01);阳性对照组胎鼠外观畸形明显,与阴性对照组比较差异有显著性(p0.01);各剂量组胎鼠外观畸形与阴性对照组比较,差异均无显著性(p0.05);中、高剂量组组和阳性对照组胎鼠骨骼及内脏畸形例数明显增多,差异有显著性(p0.01)。实验结果表明吡草醚原药中、高剂量组可明显影响雌鼠体重增长及其胚胎的发育。  相似文献   
303.
For many decades, fisheries research has focused on stock assessment and the impact of the fishery effort on resources. Although this knowledge remains necessary, a more integrated analysis of the joint dynamics of resource and operational activities is needed to provide more useful advice for the management of fishery systems. Since 1994 a new approach to fishery science has been carried out for Cameroonian small-scale fisheries, the aim being the incorporation into fishery science of research on fishery management, fishing processes and fishermen's behaviour. This paper presents a more systemic data approach which combines biological parameters and operational factor analyses with the goal of sustainable development. From two years of data collected on the purse seine fishing units operating in the Bay of Biafra (2002 and 2003), a set of three correspondence analyses is applied: (1) to the length frequency distribution of Ethmalosa fimbriata, (2) to the number of visits per fishing ground, and (3) to the species appearance frequency in the landings. These three analyses were plotted per month-year period. The results are presented in the form of an annual exploitation cycle, linking fishing grounds, the main species caught, and corresponding fishing period.  相似文献   
304.
The effects of nitrate on fermentative hydrogen production and soluble metabolites from mixed cultures were investigated by varying nitrate concentrations from 0 to 10 g N/L at 35°C with an initial pH of 7.0. The results showed that the substrate degradation rate, hydrogen production potential, hydrogen yield, and average hydrogen production rate initially increased with increasing nitrate concentrations from 0 to 0.1 g N/L, while they decreased with increasing nitrate concentrations from 0.1 to 10 g N/L. The maximum hydrogen production potential of 305.0 mL, maximum hydrogen yield of 313.1 mL/g glucose, and maximum average hydrogen production rate of 13.3 mL/h were obtained at a nitrate concentration of 0.1 g N/L. The soluble metabolites produced by the mixed cultures contained only ethanol and acetic acid (HAc) without propionic acid (HPr) and butyric acid (HBu). This study used the Modified Logistic model to describe the progress of cumulative hydrogen production in batch tests. A concise model was proposed to describe the effects of nitrate concentration on average hydrogen production rate.  相似文献   
305.
• A model coupling water-heat-salt of unsaturated frozen soil was established. • Future temperature, precipitation, and evaporation increase in freeze–thaw period. • Soil water, heat, and salt transport are closely coupled during freeze–thaw period. • Freeze–thaw cycles and future climate change can exacerbate salinization. The transport mechanisms of water, heat, and salt in unsaturated frozen soil, as well as its response to future climate change are in urgent need of study. In this study, western Jilin Province in north-eastern China was studied to produce a model of coupled water-heat-salt in unsaturated frozen soil using CoupModel. The water, heat, and salt dynamics of unsaturated frozen soil under three representative concentration pathway (RCP) scenarios were simulated to analyze the effects of future climate change on unsaturated frozen soil. The results show that water, heat, and salt migration are tightly coupled, and the soil salt concentration in the surface layer (10 cm) exhibits explosive growth after freezing and thawing. The future (2020–2099) meteorological factors in the study area were predicted using the Statistical Downscaling Model (SDSM). For RCP2.6, RCP4.5, and RCP8.5 scenarios, future temperatures during the freeze–thaw period increased by 2.68°C, 3.18°C, and 4.28°C, respectively; precipitation increased by 30.28 mm, 28.41 mm, and 32.17 mm, respectively; and evaporation increased by 93.57 mm, 106.95 mm, and 130.57 mm, respectively. Climate change will shorten the freeze–thaw period, advance the soil melting time from April to March, and enhance water and salt transport. Compared to the baseline period (1961–2005), future soil salt concentrations at 10 cm increased by 1547.54 mg/L, 1762.86 mg/L, and 1713.66 mg/L under RCP2.6, RCP4.5, and RCP8.5, respectively. The explosive salt accumulation is more obvious. Effective measures should be taken to prevent the salinization of unsaturated frozen soils and address climate change.  相似文献   
306.
Release of elements from municipal solid waste incineration fly ash   总被引:1,自引:0,他引:1  
The element-release behavior of municipal solid waste incineration fly ash was explored through leaching test with continuous set-point pH (pHstat test) and serial single reaction cell (SSRC) tests. First, the relationship between element release and acid neutralizing capacity (ANC) consumption was examined with a pHstat test. Four types of release behaviors were identified which are characteristic for different elements: (1) release curves that were almost linear with ANC consumption (Ca, Zn, and Cd); (2) release that was significantly faster than ANC (Na, K, and Cl); (3) curves that featured a strong increase with ANC consumption, after a transient release, followed by an almost equal decrease (Si and S); and (4) release that is strongly retarded compared with ANC consumption (Cr, Cu, and Pb). In the SSRC system, it the existence of a pH front and a wash-out phenomenon is demonstrated. Combining the results from the SSRC test with the kinetic analysis of the ANC system in the pHstat test, it was inferred that less than one-third of the ANC measured from a batch pH titration plays a neutralization role in a field situation. The methodologies described may provide a powerful set of tools for systematic evaluation of element release from solid wastes.  相似文献   
307.
分别采用UV-Fenton试剂氧化法、次氯酸钙氧化法和二氧化氯氧化法处理模拟聚合物驱废水,考察了各工艺条件对废水降黏效果的影响。实验结果表明:在初始废水pH为7、反应温度为50℃、反应时间为20 min的条件下,UV-Fenton试剂氧化法适宜的H2O2加入量为1 mmol/L,n(H2O2)∶n(Fe2+)=10,处理后废水降黏率达65.7%;次氯酸钙氧化法适宜的次氯酸钙加入量为500 mg/L,处理后废水降黏率达81.7%;二氧化氯氧化法适宜的二氧化氯加入量为100 mg/L,处理后废水降黏率为40.9%。3种氧化法对模拟聚合物驱废水的降黏率大小顺序为:次氯酸钙氧化法>UV-Fenton试剂氧化法>二氧化氯氧化法。  相似文献   
308.
针对某炼油厂二沉池出水回用过程中产生的反渗透浓水高盐、高硬、低COD和可生化性差的特点,采用催化臭氧氧化工艺处理,出水达标排放.实验确定了对臭氧氧化催化效果最好的催化剂,合适的反应条件为:反应时间大于30 min,臭氧质量浓度15-30 mg/L.经催化臭氧氧化处理后,反渗透浓水的COD降低至60 mg/L以下,满足排放要求,同时反渗透浓水可生化性提高.  相似文献   
309.
利用硫铝酸盐水泥作为粘结剂,采用水硬化球团加工工艺,对冶金过程的二次资源进行了成球性能研究。研究结果表明:在70%硫酸渣、20%除尘灰和10%精矿粉原料条件下,添加6.5%的硫铝酸盐水泥和1.2%的复合粘结剂,能够获得粒度组成和强度均较理想的小球作为烧结料。该项成果的特点是带入原料的S iO2大量减少,水硬化球团养护期大幅度缩短,在重钢集团铁业公司取得了良好的生产效果。  相似文献   
310.
湖泊沉积物-水界面微量重金属扩散作用及其水质影响研究   总被引:26,自引:1,他引:25  
通过对云南泸沽湖、洱海沉积物孔隙水微量重金属剖面特征及界面扩散通量的研究,定量评估了微量重金属界面扩散作用对上覆湖水水质的影响,并探讨了春季节性变化规律,结果表明,孔隙水微量重金属浓度面均呈典型的峰形分布,界面氧化还原状况的变化是影响这种分布的主要因素;微量重金属界面扩散通量在夏季明显大于冬季,深水区大于浅水区;这种擅长 用作用对湖水中微量重金属含量的变化影响较大,尤其对深度较小,水体寄宿时间长、  相似文献   
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