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971.
广东南岭国家森林公园旅游形象定位 总被引:2,自引:0,他引:2
本文通过对广东南岭国家森林公园基本情况的介绍,论述了旅游形象定位对于该森林公园的重要意义:从该森林公园的旅游形象基础、旅游环境、旅游资源特色、旅游市场感应等几个方面进行全面分析和系统综合.提出了合理的旅游形象定位和形象推广措施。 相似文献
972.
基于知识仓库的虚拟产品开发技术整合社会资源,利用web技术在不实际生产产品实物的情况下,利用模块化思想采用网络化并行设计,在产品设计初期就考虑到后续工艺和加工需求以及用户可能的附加要求,可缩短新产品开发周期。本文基于知识仓库,针对虚拟产品开发技术,分析虚拟产品技术的国内外研究现状,阐述虚拟产品开发技术的原理以及相关技术,构造虚拟产品开发的设计流程,并且基于Delphi8.0网络环境下构建基于知识的虚拟产品创新设计制造个人工作空间子系统。 相似文献
973.
974.
Agrobacterium tumefaciens‐mediated transformation (ATMT) is being increasingly recognized as an effective insertional mutagenesis tool in studies of filamentous fungi for gene discovery and functional analysis. We developed and optimized ATMT for 2 Colletotrichum species, Colletotrichum gloeosporioides and Colletotrichum acutatum, the causative agents of Colletotrichum leaf disease in rubber trees in Southern China. A. tumefaciens strain AGL‐1 carrying an ILV1 gene and a green fluorescent protein gene were used to transform the conidia of these 2 Colletotrichum species. The transformation efficiency was correlated with the co‐cultivation duration and bacterial cell concentrations, which reached 300–400 transformants per 1 × 106 conidia after optimization. Southern blot analysis indicated that about 60.0% of the C. gloeosporioides transformants and 46.2% of the C. acutatum transformants had a single copy of T‐DNA in their genomes. Fungal genomic DNA segments flanking the T‐DNA were identified in the transformants through thermal asymmetrical interlaced polymerase chain reaction followed by sequencing. The flanking sequences from 4 C. acutatum and 7 C. gloeosporioides transformants showed moderate or weak homology to the NCBI database entries. Some sequences matching those reported virulence‐related genes. The results suggest that the T‐DNA inserted mutants banks constructed are useful for the discovery of new or important genes and to elucidate their function in the 2 Colletotrichum species. 相似文献
975.
信阳市平桥区中小型水库82座,养鱼面积3万多亩。近年来,随着养殖水平的不断提高,中小型水库精养半精养技术得到普遍推广,由于放养密度增大,养殖环境受到污染,每年都出现大批死鱼现象,给养殖户带来了极大的经济损失。笔者多年来对中小型水库的疫情进行监控,死鱼的主要原因是中华 相似文献
976.
Weihai H. Xu Gan Zhang Onyx W. H. Wai Shichun C. Zou Xiangdong D. Li 《Journal of Soils and Sediments》2009,9(4):364-373
Background, aim, and scope Bed sediments are the major sink for many contaminants in aquatic environments. With increasing knowledge of and research
on the environmental occurrence of antibiotics, there has been growing interest in their behaviour and fate in aquatic environments.
However, there is little information about the behaviour of antibiotics in a dynamic water/sediment environment, such as river
and coastal marine water. Therefore, the aims of the present study were: (1) to study the transport and distribution of four
common antibiotics between water and sediment in both dynamic and quiescent water/sediment systems and (2) to understand the
persistence and possible degradation of the four antibiotics in the two different systems.
Materials and methods A lid-driven elongated annular flume, designed to reduce the centrifugal effect, was used to simulate a dynamic water environment.
In addition, a quiescent water/sediment experiment was conducted for comparison with the dynamic water system. The seawater
and sediment, used in both experiments of flowing and quiescent water/sediment systems, were collected from Victoria Harbour,
a dynamic coastal environment in an urban setting. The four antibiotics selected in this study were ofloxacin (OFL), roxithromycin
(RTM), erythromycin (ETM), and sulfamethoxazole (SMZ), the most commonly used antibiotics in South China.
Results and discussion Antibiotics in an overlying solution decreased very quickly in the flume system due to the sorption to suspended particles
and surface sediment. There were significant differences in the adsorption of the four antibiotics in sediment. OFL showed
a high tendency to be adsorbed by sediment with a high K
d value (2980 L/Kg), while the low K
d values of SMZ indicated that there was a large quantity in water. The four antibiotics reached a depth of 20–30 mm in the
sediment over a period of 60 days in the flume system. However, the compounds were only found in surface sediment (above 10 mm)
in the quiescent system, indicating the influence of the dynamic flume system on the distribution of antibiotics in sediment.
OFL showed a moderate persistence in the dynamic flume system, while other three antibiotics had less persistence in sediment.
However, all of the four compounds showed moderate persistence in the quiescent system.
Recommendations and perspectives The study showed the rapid diffusive transfer of antibiotics from water to sediment in the dynamic flume system. The four
antibiotics exhibited larger differences in their adsorption to sediment in both dynamic and quiescent systems due to their
different K
d values. The high sorption of antibiotics to marine sediment may reduce their availability to benthic invertebrates. 相似文献
977.
We analysed the metabolic rate of large individuals (LIs) and small individuals (SIs) (based on body weight) of 80‐day‐old specimens of Portunus trituberculatus injected with 40 mg/kg florfenicol (FLR). The results showed that FLR contents in the gills and hepatopancreas were higher in the SIs than in the LIs. The activities of erythromycin N‐demethylase and 7‐ethoxyresorufin‐O‐deethylase related to cytochrome oxidase P450 (CYP) were induced after FLR injection and showed a size‐dependent pattern; however, no significant difference in aminopyrine N‐demethylase activity was found between the LIs and SIs. The activity of the phase II enzyme glutathione S‐transferase (GST) increased in the hepatopancreas after FLR injection, and it was higher in the SIs than the LIs. Moreover, induction of CYP2, CYP3, GST, ABCB and ABCG was observed in the first 24 hr after FLR injection. FLR caused more biomolecular damage in the SIs than the LIs, displaying an obvious body weight‐ and time‐dependent pattern. In summary, the SIs exhibited faster FLR uptake and slower depuration in this species, and FLR caused more biomolecular damage to the SIs. 相似文献
978.
In this study,hypoxia inducible factor-1α(HIF-1α) gene was cloned from yak spleen by RT-PCR,and it was divided into two sections for amplification.The sequence and protein structure were analyzed using related bioinformatics tools.The length of the coding region was 2 472 bp,which encoded 823 amino acids.Its molecule mass was 92.13 ku,and PI was 5.09.It displayed as a hydrophilic protein,whose secondary structure was mainly composed of random coil and α-helix.It had 69 phosphorylation sites and 4 N-glycosylation sites.Phylogenetic tree displayed that Maiwa yak,Bos grunniens,Bos mutus and Bos taurus gathered into one cluster.Maiwa yak HIF-1α gene was successfully cloned in this study,it provided a viable reference for further study of genetic characteristics of HIF-1α. 相似文献
979.
980.