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991.
992.
浒苔藻体叶绿素提取方法的比较 总被引:2,自引:0,他引:2
为了确定一种快速准确测定浒苔藻体叶绿素含量的方法,利用分光光度计法比较了两种不同的提取方法及4种提取剂测定叶绿素的效果,并分析了叶绿素在4种提取剂中的稳定性。结果表明:两种提取方法下4种不同提取剂的吸收光谱基本相似,可以用Arnon法的计算公式来计算叶绿素含量。其中,研磨法对浒苔叶绿素的提取效果较浸提法提取速度更快,便于快速测定藻体叶绿素含量。在4种提取剂中,采用95%乙醇提取浒苔叶绿素速度更快,但提取的总量少,稳定性低。 相似文献
993.
Bob Fischer 《Journal of Agricultural and Environmental Ethics》2018,31(3):295-306
Gary Francione is an abolitionist: he maintains that we ought to abolish the institutions and practices that support the exploitation of animals. He also believes that veganism is the “moral baseline”—that is, he thinks it’s morally required of nearly everyone in the developed world, and many beyond it. Luis Cordeiro-Rodrigues claims that abolitionism is guilty of racism, albeit “racism without racists.” I contend that his arguments for this conclusion aren’t successful. 相似文献
994.
Nicolas Nantel-Fortier Ann Letellier Virginie Lachapelle Philippe Fravalo Yvan L’Homme Julie Brassard 《Food and environmental virology》2016,8(4):296-304
Viral contamination along the production chain is a significant concern in both food safety and livestock health. Pigs have been reported to act as a reservoir for zoonotic viruses, sometimes emerging ones, and epidemiological studies have shown direct links between the consumption of uncooked pork offal and cases of hepatitis caused by the hepatitis E virus (HEV) genotype 3 in humans. The presence of HEV in swine herds has been reported, but its dissemination in pork production environments is still unknown. To investigate viral contamination sources in the swine industry, 452 environment and fecal samples, including samples from livestock transportation vehicles, were collected over a period of 11 months from ten farms and one slaughterhouse that together represent a single production network. Hepatitis E virus RNA was detected by nested RT-PCR in 32 samples from both inside and outside farm buildings, on trucks, and, mostly, from fomites collected in the slaughterhouse yard, such as on a utility vehicle. Phylogenetic analysis showed a wide diversity of HEV genotype 3 strains, similar to human and swine strains previously found. According to the results of this study, the movements of trucks and utility vehicles might play an important role in HEV dissemination on a slaughterhouse site and throughout an entire network. 相似文献
995.
Faith E. Bartz Domonique Watson Hodge Norma Heredia Anna Fabiszewski de Aceituno Luisa Solís Lee-Ann Jaykus Santos Garcia Juan S. Leon 《Food and environmental virology》2016,8(3):221-226
Somatic coliphages were quantified in 459 produce and environmental samples from 11 farms in Northern Mexico to compare amounts of somatic coliphages among different types of fresh produce and environmental samples across the production steps on farms. Rinsates from cantaloupe melons, jalapeño peppers, tomatoes, and the hands of workers, soil, and water were collected during 2011–2012 at four successive steps on each farm, from the field before harvest through the packing facility, and assayed by FastPhage MPN Quanti-tray method. Cantaloupe farm samples contained more coliphages than jalapeño or tomato (p range <0.01–0.03). Across production steps, jalapeños had higher coliphage percentages before harvest than during packing (p = 0.03), while tomatoes had higher coliphage concentrations at packing than all preceding production steps (p range <0.01–0.02). These findings support the use of targeted produce-specific interventions at multiple points in the process of growing and packing produce to reduce the risk of enteric virus contamination and improve food safety during fruit and vegetable production. 相似文献
996.
This study characterizes the persistence of human norovirus in Eastern oysters (Crassostrea virginica) held at different seawater temperatures. Oysters were contaminated with human norovirus GI.1 (Norwalk strain 8FIIa) by exposing them to virus-contaminated water at 15 °C, and subsequently holding them at 7, 15, and 25 °C for up to 6 weeks. Viral RNA was extracted from oyster tissue and hemocytes and quantitated by RT-qPCR. Norovirus was detected in hemocytes and oysters held at 7 and 15 °C for 6 weeks and in hemocytes and oysters held at 25 °C for up to 2 and 4 weeks, respectively. Results confirm that NoV is quite persistent within oysters and demonstrate that cooler water temperatures extend norovirus clearance times. This study suggests a need for substantial relay times to remove norovirus from contaminated shellfish and suggests that regulatory authorities should consider the effects of water temperature after a suspected episodic norovirus-contamination event. 相似文献
997.
998.
Baculoviruses are the ingenious insect pathogens. Outside the host, baculovirus occlusion bodies (OB) provide stability to occlusion-derived viruses (ODV) embedded within. The OB is an organized structure, chiefly composed of proteins namely polyhedrin, polyhedron envelope protein (PEP) and P10. Currently, the structural organization of OB is poorly understood and the role of OB proteins in conferring the stability to ODV is unknown. Here we have shown that the assembly of polyhedrin unit cells into an OB is a rapid process; the PEP forms in multiple layers; the PEP layers predominantly contribute to ODV viability. Full-grown OBs (n = 36) were found to be 4.0 ± 1.0 µm in diameter and possessed a peculiar geometry of a truncated rhombic dodecahedron. The atomic force microscopy (AFM) study on the structure of OBs at different stages of growth in insect cells revealed polyhedrin assembly and thickness of PEP layers. The thickness of PEP layers at 53 h post-transfection (hpt) ranged from 56 to 80 nm. Mature PEP layers filled up approximately one third of the OB volume. The size of ODV nucleocapsid was found to be 433 ± 10 nm in length. The zeta potential and particle size distribution study of viruses revealed the protective role of PEP layers. The presence of a multilayered PEP confers a viable advantage to the baculoviruses compared to single-layered PEP. Thus, these findings may help in developing PEP layer-based biopolymers for protein-based nanodevices, nanoelectrodes and more stable biopesticides. 相似文献
999.
Assessing agricultural systems vulnerability to climate change to inform adaptation planning: an application in Khorezm,Uzbekistan 总被引:1,自引:0,他引:1
Mariya Aleksandrova Animesh K. Gain Carlo Giupponi 《Mitigation and Adaptation Strategies for Global Change》2016,21(8):1263-1287
Agriculture is one of the most vulnerable sectors to climate change. The current vulnerability assessments through traditional fragmented sectoral methods are insufficient to capture the effects on complex agricultural systems. Therefore, the traditional methods need to be replaced by integrated approaches. The objective of this study is to propose a holistic vulnerability assessment method for agricultural systems. By aggregating both agro-ecological and socio-economic information, we develop an agricultural systems vulnerability index (ASVI) which allows for (i) a classification of geographical units according to their vulnerability level, (ii) an identification of key determinants of vulnerability for each unit and (iii) an assessment of adaptation policy scenarios considering their effects on the sustainability of the analysed systems. The proposed method is applied in the Khorezm region of Uzbekistan—a representative irrigated agricultural region in the lower Amu Darya river basin. A decision support tool is used to facilitate multi-criteria decision analysis, including the computation of the index and performing sensitivity analysis of the results. The assessment for Khorezm reveals significant spatial differences of vulnerability levels due to a variation of contributing factors, e.g. natural resources, water productivity, rural-urban ratio. It reveals also that feasible land and water management policies could reduce the vulnerability in Khorezm, particularly in the districts with the poorest agro-ecological conditions. Overall, the proposed method could support national and local authorities in the identification of sustainable adaptation policies for the agriculture sector. 相似文献
1000.
Zeshan Hyder Nino S. Ripepi Michael E. Karmis 《Mitigation and Adaptation Strategies for Global Change》2016,21(4):515-546
Underground coal gasification (UCG) is an advancing technology that is receiving considerable global attention as an economic and environmentally friendly alternative for exploitation of coal deposits. UCG has the potential to decrease greenhouse gas emissions (GHG) during the development and utilization of coal resources. In this paper, the life cycle of UCG from in situ coal gasification to utilization for electricity generation is analyzed and compared with coal extraction through conventional coal mining and utilization in power plants. Four life cycle assessment models have been developed and analyzed to compare (greenhouse gas) GHG emissions of coal mining, coal gasification and power generation through conventional pulverized coal fired power plants (PCC), supercritical coal fired (SCPC) power plants, integrated gasification combined cycle plants for coal (Coal-IGCC), and combined cycle gas turbine plants for UCG (UCG-CCGT). The analysis shows that UCG is comparable to these latest technologies and in fact, the GHG emissions from UCG are about 28 % less than the conventional PCC plant. When combined with the economic superiority, UCG has a clear advantage over competing technologies. The comparison also shows that there is considerable reduction in the GHG emissions with the development of technology and improvements in generation efficiencies. 相似文献