离体培养条件下12个白榆优良无性系氯化钠盐分抗性筛选的研究

以12个优良白榆无性系为材料,采用培养基中加入不同盐分的方法,对0.3%、0.4%、0.5%、0.6%、0.7%、0.8%氯化钠梯度条件下的白榆无性系离体培养植株生长量进行了测定,排除了外界环境条件变化对白榆无性系耐盐能力的影响,并通过隶属函数法,对12个白榆无性系的耐盐能力进行了分析与评价。结果表明,58号、30号、50号3个白榆无性系的抗性较强。通过主成分分析,将12个白榆无性系分为3类,也得出类似结论,同时还对分类依据与应用状况进行系统分析与说明,为白榆耐盐性评价系统提供较为可靠的评价方法。     

层次分析法在干旱区园林树木评选中的应用

经过对新疆昌吉试验区的２８种榆属树木抗寒性、抗旱性、生态学特性系统的调查,并参考有关献,利用树木抗逆性指标、形态指标、生长指标,构建了榆属资源多级递阶结构模型,结合旱生榆属树木特点,提出了８种适合北疆平原园林绿化最佳榆属树木。     

英语与英美文化

英语作为英美文化信息的载体和表现形式，深深地烙上了英美独有的文化印记。本文试图阐述英语作为英美文化的一面镜子，镜像折射了英美的自然生态环境、历史，以及英美的社会问题、人们的价值观念、形形色色的社会心态、各自的文化特异现象等。     

美国英语发展的政治痕迹初探

语言发展是社会变迁的结果。美国英语作为一种标准英语，是在17世纪英国英语基础上发展起来的，但决不是英国英语的简单移植。美国英语的发展有其政治渊源，与美国独立运动、综合国力息息相关，同时美国的政治体制和政治活动为美国英语创造了独特的政治语境和发展空间。     

Catastrophic flooding origin of shelf valley systems in the English Channel

Megaflood events involving sudden discharges of exceptionally large volumes of water are rare, but can significantly affect landscape evolution, continental-scale drainage patterns and climate change. It has been proposed that a significant flood event eroded a network of large ancient valleys on the floor of the English Channel-the narrow seaway between England and France. This hypothesis has remained untested through lack of direct evidence, and alternative non-catastrophist ideas have been entertained for valley formation. Here we analyse a new regional bathymetric map of part of the English Channel derived from high-resolution sonar data, which shows the morphology of the valley in unprecedented detail. We observe a large bedrock-floored valley that contains a distinct assemblage of landforms, including streamlined islands and longitudinal erosional grooves, which are indicative of large-scale subaerial erosion by high-magnitude water discharges. Our observations support the megaflood model, in which breaching of a rock dam at the Dover Strait instigated catastrophic drainage of a large pro-glacial lake in the southern North Sea basin. We suggest that megaflooding provides an explanation for the permanent isolation of Britain from mainland Europe during interglacial high-sea-level stands, and consequently for patterns of early human colonisation of Britain together with the large-scale reorganization of palaeodrainage in northwest Europe.     

英语“贵族”词汇分析

英国英语中存在许多与贵族有关联的词汇,这是英国特有的贵族体制的反映。在英国贵族概念有广义和狭义之分,贵族勋位与贵族称谓有其独特的表达方式。     

A molecular clone of HTLV-III with biological activity

Acquired immune deficiency syndrome (AIDS) is an epidemic immunosuppressive disease characteristically associated with a depletion of T lymphocytes of the helper/inducer phenotype. Numerous converging lines of research have implicated a human T-cell lymphotropic retrovirus, HTLV-III, in the pathogenesis of AIDS. Recently, several distinct forms of the HTLV-III genome were molecularly cloned in phage and extensively characterized. In the present study, a clone containing full-length HTLV-III proviral DNA was inserted into a plasmid and used to transfect cord blood T cells from normal newborn humans. We demonstrate that this molecular clone is infectious in vitro and causes marked cytopathic effects on T-cell cultures. This is the first direct evidence that the HTLV-III genome, rather than a minor component of the virus complex, is cytopathic for T cells. Using this biologically competent clone and mutants derived from it, it should now be possible to localize the subgenomic regions that contribute to the biological effects of HTLV-III.     

汉诗和英诗的节奏比较

节奏在汉语诗歌和英语诗歌的音节、词汇、韵律等多方面存在很大的差异,从“节奏”这一角度来探讨汉语诗歌和英语诗歌的差异,以及英诗节奏对现代汉语格律诗歌的影响,对更准确地理解和欣赏汉诗和英诗会有助益。     

Cattle movements and bovine tuberculosis in Great Britain

For 20 years, bovine tuberculosis (BTB) has been spreading in Great Britain (England, Wales and Scotland) and is now endemic in the southwest and parts of central England and in southwest Wales, and occurs sporadically elsewhere. Although its transmission pathways remain poorly understood, the disease's distribution was previously modelled statistically by using environmental variables and measures of their seasonality. Movements of infected animals have long been considered a critical factor in the spread of livestock diseases, as reflected in strict import/export regulations, the extensive movement restrictions imposed during the 2001 foot-and-mouth disease outbreak, the tracing procedures after a new case of BTB has been confirmed and the Government's recently published strategic framework for the sustainable control on BTB. Since January 2001 it has been mandatory for stock-keepers in Great Britain to notify the British Cattle Movement Service of all cattle births, movements and deaths. Here we show that movements as recorded in the Cattle Tracing System data archive, and particularly those from areas where BTB is reported, consistently outperform environmental, topographic and other anthropogenic variables as the main predictor of disease occurrence. Simulation distribution models for 2002 and 2003, incorporating all predictor categories, are presented and used to project distributions for 2004 and 2005.     

英汉旅游篇章中词汇认知图式的文化对比分析

以辽宁旅游篇章(LTT)的英译文本与英美两国的旅游篇章(BTT/ATT)随机采样为主要样本,从英汉词汇层所反映的文化差异探讨了英汉旅游篇章的词汇认知图式和文化积淀等方面的差异,以期通过一种新的视角,在理论和实践两个方面为中国旅游文化的英译文本提供有价值的参考。     

浑善达克沙地中部榆树疏林景观格局

 通过野外调查及3S技术,分析了浑善达克沙地中部榆树疏林景观的景观数量、景观面积及形状复杂性等景观格局特征.结果发现,疏林景观斑块数量高达100606个,但是77%的疏林斑块面积不到0.5hm²,表现为景观斑块数量多、面积小,斑块形状复杂,斑块破碎化比较严重,急需保护.在进行浑善达克沙地生态恢复时,首先考虑的应当是保护榆树疏林斑块的完整性,坚持景观斑块连片保护,提高保护效果.     

中英教学的比较与思考

笔者结合自己在宁波诺丁汉大学的求学经历,对中英两国的教学进行了调查与研究,希望通过对两国教学方法、教材选择、教师形象等几方面的探讨,能为未来的英语教学提供启示。     

英国英语和美国英语在词汇上的差异

随着历史的发展和经济文化的进步,英国英语与美国英语在语音、语法、词汇上产生了较多的差异,其中两者在词汇上的差异最为明显,它主要体现在同词异义、同义异词、拼写和特有词等四个方面。     

Cloning of the breakpoint of an X;21 translocation associated with Duchenne muscular dystrophy

Duchenne muscular dystrophy (DMD) is an X-linked recessive disorder which affects approximately 1 in 3,300 males, making it the most common of the neuromuscular dystrophies. The biochemical basis of the disease is unknown and as yet no effective treatment is available. A small number of females are also affected with the disease, and these have been found to carry X; autosome translocations involving variable autosomal sites but always with a breakpoint within band Xp21 of the X chromosome (implicated by other kinds of genetic evidence as the site of the DMD lesion). In these female patients the normal X chromosome is preferentially inactivated, which it is assumed silences their one normal DMD gene, leading to expression of the disease. In one such affected female the autosomal breakpoint lies in the middle of the short arm of chromosome 21, within a cluster of ribosomal RNA genes. Here we have used rRNA sequences as probes to clone the region spanning the translocation breakpoint. A sequence derived from the X-chromosomal portion of the clone detects a restriction fragment length polymorphism (RFLP) which is closely linked to the DMD gene and uncovers chromosomal deletions in some male DMD patients.     

Field sports and conservation in the United Kingdom

Many natural habitats exist on privately owned land outside protected areas, but few governments can afford to enforce or subsidize conservation of this biodiversity. Even in some developed countries, conservation subsidy schemes have only achieved limited success. Fortunately, some landowners may be willing to accept management costs in return for other benefits, although this remains controversial when it involves the killing of charismatic species. For example, participants in British field sports, such as fox hunting and game-bird shooting, may voluntarily conserve important habitats that are required by quarry species. Here we report results from a multidisciplinary study that addressed this issue by focusing on three sites across central England. We found that landowners participating in field sports maintained the most established woodland and planted more new woodland and hedgerows than those who did not, despite the equal availability of subsidies. Therefore, voluntary habitat management appears to be important for biodiversity conservation in Britain. Current debates on the future of field sports in Britain, and similar activities globally, may benefit from considering their utility as incentives to conserve additional habitat on private land.     

饭店英语教学初探

饭店英语显然是一种特殊用途英语（ESP）,要想教好这种特殊用途英语就必须知道特殊用途英语与普通英语有何异同。笔者认为,实际上英语就是英语没有这那之分无论是饭店英语,求职英语,还是医学英语,他们的语法结构没有什么不同,如果说有区别就在于某种特殊学科领域的词汇,术语多一些而已。所以基于这一理念,我们就找到了饭店英语教学的核心所在。     

Fibrils from brains of cows with new cattle disease contain scrapie-associated protein

During the past two years, more than 1,000 cases of a neurological disorder of cattle, bovine spongiform encephalopathy (BSE), have been confirmed from farms throughout Great Britain. The neurological signs and brain pathology of BSE resemble those produced in other species by the pathogens of scrapie and related disorders. The discovery of fibrils similar to scrapie-associated fibrils in detergent extracts o BSE-affected brain supported the clinical and pathological diagnosis of the disease, but has been controversial. Scrapie-associated fibrils are found in brain extracts of all species affected by scrapie and diseases caused by related pathogens. They are pathological aggregates of a neuronal membrane protein termed PrP and a protease-resistant form of PrP is a molecular marker of scrapie-associated fibrils. In this report, we show the major protein of BSE fibrils is the bovine homologue of PrP as judged by its size, protease resistance, immunoreactivity, lectin binding and partial N-terminal protein sequence. This confirms that BSE is a scrapie-like disease.