大学校园流行语的词语特征

语体具有习得性，这种习得性又具有渐进性、阶段性和终身性。大学阶段语用主体口头语的共体性特征主要表现在词语上，具体体现在小团体专用或创造词语、专业术语通用化、异语(多数是汉语和英语)混合运用、借用方言词语、对旧有词语作新的解释、创造新词语、词语包含了多种修辞格等方面。     

诗歌意象语言的用词特点

从语言学角度分析,与诗歌意象相对应的大多是日常语言中表示具体物象、事象的名词性词语,这些名词性词语用在诗歌中便成为意象词语。诗歌中,担负一组意象语言可以是单个的意象词语,即名词性词语;也可以是一个固定的熟语;还可以是一个以意象词语为主体的非名词性短语或句子等。通过从语言学角度对担负诗歌意象语言主体的意象词语进行语言分析,认为诗歌意象语言具有具象性、隐喻性、民族性等特点。     

解读青少年流行语中的极限语

近年来,青少年言语中流行一种极限性的语义表达,这种极限性主要反映在表达对某种事物或现象的肯定态度和崇尚心理的言语中,尤其是在表称颂的性质形容词、表程度的状语和程度补语的运用三个方面,他们往往通过词义的转移、词语的活用等变异手段,同时配合对这类词语重音的夸大,来表达一种至高至极的极限语义。     

义素分析释义法与词典释义研究——以《现代汉语词典》的释义为例

义素分析释义法是语义研究,并且根据对文词典释义的有效方法。通过比较系统地运用义素分析释义法来对《现代汉语词典》中词语的释义进行分析研究义位进行义素对比分析时所应遵循的区别性、相称性、简化性和对应性等四个原则,或评判其对某些词语释义进行修改的理据,或纠正其在某些词语释义方面尚存在的某些不足之处。这对于语文词典的编纂与修订工作具有一定的指导意义。     

“文化大革命”词语的更新和异化

“文化大革命”(以下简称“文革”)结束十几年后的今天,有些“文革”词语(也包括“文革”前一段极“左”时期产生的词语)随着“文革”的完结而进入语言博物馆,但也还有一部分“文革”词语至今仍程度不同地存在于人们的言语交际中。目前,“文革”词语大都在感情上、词义上或用法上产生了异化,其中相当一部分已被更新,但这一更新和异化的过程是复杂而漫长的。本文旨在探讨这一过程,以引起人们对“文革”词语更新和异化这一问题的关注。一“文革”词语的更新比其消亡要困难得多,一些“文革”词语的消亡往往取决于“文革”词语的更新情况。经过十几年的冲刷,更新了大量的“文革”词语,但也有许多“文     

浅谈日本社会新词

近年来,在日本无论打开收音机、电视机或翻开报纸,都会听到或看到一些脍炙人口、寓意深刻的新词语。这些新词大多出自著名人士之口或来自报刊杂志、小说等。一般以汉字词汇出现的新词,主要是反映并讽刺日本社会和时代的某些消极方面。多数具有较强的思想性。而另一种是以生动的发音和新鲜的表达形式出现,很少有思想性。这些新词一般都比较幽默、夸大、富有娱乐性和感觉性。在一定程度上恰到好处,形象而概括地反映了日     

试析词语模的性能

词语模是当代社会背景下特别活跃、特别引人注目的一种创造新词语的方式。词语模是一种“模块”,具有开放性和能产性;词语模是一种“模式”,具有抽象性、类推性;词语模是一种“模具”,具有定形性、定性性;词语模是一种“模效”行为,具有仿效性、创新性。     

校园流行词语的产生途径及发展趋势

校园流行词语产生途径主要是对外来词的吸收、固有词的改造、方言词的接纳、利用已有语素构造新词等四个方面.校园流行词语的发展趋势是:字母外来词大量增加、双音化趋势明显、外来词多元化倾向突出、仿造词现象普遍、口语性和形象性强.     

英语双关语的语义特征探微

英语双关语运用词语或短语多义性来暗示两层或两层以上的意义及不同的语义关联，或运用词语的同音异义或近音异义性进行多层次的语义暗示，体现了英语语言的诙谐与幽默，承栽着与其它修辞手段不一样的语义特征。其语义特征主要有双重性、审美性和游戏性。     

说“得”字句的补语

“得”字句补语位置上的词语大多是动词性词语、形容词性词语和主谓短语,但也有表程度或情状的副词性词语,在某些特殊的语境中还有名词性词语。从语义和语用的角度来看,“得”字句补语在语义上大多由两个动核结构组成,补语表示动作发生或性状变化后所引出的情状,这种情状有一定的语义指向;补语在语用上属于述题中的一个重要组成部分,是传达新信息的关键,即焦点。     

Evolutionary speed limits inferred from the fossil record.

The dynamics of extinction and diversification determine the long-term effects of extinction episodes. If rapid bursts of extinction are offset by equally rapid bursts of diversification, their biodiversity consequences will be transient. But if diversification rates cannot accelerate rapidly enough, pulses of extinction will lead to long-lasting depletion of biodiversity. Here I use spectral analysis of the fossil record to test whether diversification rates can accelerate as much as extinction rates, over both short and long spans of geological time. I show that although the long-wavelength variability of diversification rates equals or exceeds that of extinctions, diversification rates are markedly less variable than extinction rates at wavelengths shorter than roughly 25 million years. This implies that there are intrinsic speed limits that constrain how rapidly diversification rates can accelerate in response to pulses of extinction.     

Extinction and climate change

Arising from F. He & S. P. Hubbell 473, 368-371 (2011). Statistical relationships between habitat area and the number of species observed (species-area relationships, SARs) are sometimes used to assess extinction risks following habitat destruction or loss of climatic suitability. He and Hubbell argue that the numbers of species confined to-rather than observed in-different areas (endemics-area relationships, EARs) should be used instead of SARs, and that SAR-based extinction estimates in the literature are too high. We suggest that He and Hubbell's SAR estimates are biased, that the empirical data they use are not appropriate to calculate extinction risks, and that their statements about extinction risks from climate change do not take into account non-SAR-based estimates or recent observations. Species have already responded to climate change in a manner consistent with high future extinction risks.     

生物的辐射演化和绝灭事件

任何生物在其绝灭之前都会程度不同地发生辐射演化,这种辐射演化是由多种因素引起的。辐射演化的结果不仅使生物增强了对环境的适应能力,也增加了对环境的专属性和依赖性,进而也增大了其绝灭的可能性。地质历史时期生物发展的历史,充分体现了生物辐射演化和绝灭事件之间的密切联系。     

金属双纳米棒表面等离子体耦合共振特性研究

本文利用离散偶极子近似法,研究金纳米棒双体结构之间的表面等离子体耦合共振特性,发现当金属双纳米棒之间的排列方式和间距改变时,其表面等离子体共振消光峰发生红移或者蓝移,适当间距的金纳米棒双体结构可以产生更强的局域表面增强电场. 本文对于金纳米棒双体结构的计算结果对于金纳米棒在生物传感方面应用具有一定的参考价值.     

Species-area relationships always overestimate extinction rates from habitat loss

Extinction from habitat loss is the signature conservation problem of the twenty-first century. Despite its importance, estimating extinction rates is still highly uncertain because no proven direct methods or reliable data exist for verifying extinctions. The most widely used indirect method is to estimate extinction rates by reversing the species-area accumulation curve, extrapolating backwards to smaller areas to calculate expected species loss. Estimates of extinction rates based on this method are almost always much higher than those actually observed. This discrepancy gave rise to the concept of an 'extinction debt', referring to species 'committed to extinction' owing to habitat loss and reduced population size but not yet extinct during a non-equilibrium period. Here we show that the extinction debt as currently defined is largely a sampling artefact due to an unrecognized difference between the underlying sampling problems when constructing a species-area relationship (SAR) and when extrapolating species extinction from habitat loss. The key mathematical result is that the area required to remove the last individual of a species (extinction) is larger, almost always much larger, than the sample area needed to encounter the first individual of a species, irrespective of species distribution and spatial scale. We illustrate these results with data from a global network of large, mapped forest plots and ranges of passerine bird species in the continental USA; and we show that overestimation can be greater than 160%. Although we conclude that extinctions caused by habitat loss require greater loss of habitat than previously thought, our results must not lead to complacency about extinction due to habitat loss, which is a real and growing threat.     

Parallel extinction risk and global distribution of languages and species

There are global threats to biodiversity with current extinction rates well above background levels. Although less well publicized, numerous human languages have also become extinct, and others are threatened with extinction. However, estimates of the number of threatened languages vary considerably owing to the wide range of criteria used. For example, languages have been classified as threatened if the number of speakers is less than 100, 500, 1,000, 10,000, 20,000 or 100,000 (ref. 3). Here I show, by applying internationally agreed criteria for classifying species extinction risk, that languages are more threatened than birds or mammals. Rare languages are more likely to show evidence of decline than commoner ones. Areas with high language diversity also have high bird and mammal diversity and all three show similar relationships to area, latitude, area of forest and, for languages and birds, maximum altitude. The time of human settlement has little effect on current language diversity. Although similar factors explain the diversity of languages and biodiversity, the factors explaining extinction risk for birds and mammals (high altitude, high human densities and insularity) do not explain the numbers of endangered languages.     

Extinction pattern of reef ecosystems in latest Permian

Studies of two Permian-Triassic boundary (PTB) sections on top of a Changhsingian reef in Ziyun, Guizhou Province, southwestern China indicate that the end-Permian mass extinction of reef ecosystems occurred in two steps. The first step is the extinction of all stenotropic organisms such as calcisponges and fusulinids in the latest Permian (in the Clarkina yini conodont zone). The biota after the first extinction is simple, comprising eurytropic organisms including microgastropods, ostracods, and some small burrowing organisms, or only algal mats. At the beginning of the Early Triassic (i.e. the beginning of the Hindeodus parvus zone), the environments became anoxic, and the microgastropod dominated biota or algal mats disappeared, which constituted the second episode of the mass extinction. The biota after the second extinction comprises small spherical microproblematica, some kinds of specialized organisms tolerant of anoxic or oxygen-poor conditions. As the environments became oxygenated, the specialized biota was replaced by a microgastropod-dominated simple biota. When the environmental conditions improved further, the simple biota was replaced by a diverse biota with normal-sized ammonoids, bivalves, and gastropods, representing restoration of normal oceanic condi- tions. Comparison with PTB sections in Dolomites, Italy and Meishan, Zhejiang Province shows that non-reef ecosystems had a similar first episode of mass extinction in the latest Permian. In the case that oceanic anoxia happened, non-reef ecosystems had a second extinction episode similar to that of reef ecosystems.     

Opposite effects of fear conditioning and extinction on dendritic spine remodelling

It is generally believed that fear extinction is a form of new learning that inhibits rather than erases previously acquired fear memories. Although this view has gained much support from behavioural and electrophysiological studies, the hypothesis that extinction causes the partial erasure of fear memories remains viable. Using transcranial two-photon microscopy, we investigated how neural circuits are modified by fear learning and extinction by examining the formation and elimination of postsynaptic dendritic spines of layer-V pyramidal neurons in the mouse frontal association cortex. Here we show that fear conditioning by pairing an auditory cue with a footshock increases the rate of spine elimination. By contrast, fear extinction by repeated presentation of the same auditory cue without a footshock increases the rate of spine formation. The degrees of spine remodelling induced by fear conditioning and extinction strongly correlate with the expression and extinction of conditioned fear responses, respectively. Notably, spine elimination and formation induced by fear conditioning and extinction occur on the same dendritic branches in a cue- and location-specific manner: cue-specific extinction causes formation of dendritic spines within a distance of two micrometres from spines that were eliminated after fear conditioning. Furthermore, reconditioning preferentially induces elimination of dendritic spines that were formed after extinction. Thus, within vastly complex neuronal networks, fear conditioning, extinction and reconditioning lead to opposing changes at the level of individual synapses. These findings also suggest that fear memory traces are partially erased after extinction.     

Neurons in medial prefrontal cortex signal memory for fear extinction

Conditioned fear responses to a tone previously paired with a shock diminish if the tone is repeatedly presented without the shock, a process known as extinction. Since Pavlov it has been hypothesized that extinction does not erase conditioning, but forms a new memory. Destruction of the ventral medial prefrontal cortex, which consists of infralimbic and prelimbic cortices, blocks recall of fear extinction, indicating that medial prefrontal cortex might store long-term extinction memory. Here we show that infralimbic neurons recorded during fear conditioning and extinction fire to the tone only when rats are recalling extinction on the following day. Rats that froze the least showed the greatest increase in infralimbic tone responses. We also show that conditioned tones paired with brief electrical stimulation of infralimbic cortex elicit low freezing in rats that had not been extinguished. Thus, stimulation resembling extinction-induced infralimbic tone responses is able to simulate extinction memory. We suggest that consolidation of extinction learning potentiates infralimbic activity, which inhibits fear during subsequent encounters with fear stimuli.     

The endogenous cannabinoid system controls extinction of aversive memories

Acquisition and storage of aversive memories is one of the basic principles of central nervous systems throughout the animal kingdom. In the absence of reinforcement, the resulting behavioural response will gradually diminish to be finally extinct. Despite the importance of extinction, its cellular mechanisms are largely unknown. The cannabinoid receptor 1 (CB1) and endocannabinoids are present in memory-related brain areas and modulate memory. Here we show that the endogenous cannabinoid system has a central function in extinction of aversive memories. CB1-deficient mice showed strongly impaired short-term and long-term extinction in auditory fear-conditioning tests, with unaffected memory acquisition and consolidation. Treatment of wild-type mice with the CB1 antagonist SR141716A mimicked the phenotype of CB1-deficient mice, revealing that CB1 is required at the moment of memory extinction. Consistently, tone presentation during extinction trials resulted in elevated levels of endocannabinoids in the basolateral amygdala complex, a region known to control extinction of aversive memories. In the basolateral amygdala, endocannabinoids and CB1 were crucially involved in long-term depression of GABA (gamma-aminobutyric acid)-mediated inhibitory currents. We propose that endocannabinoids facilitate extinction of aversive memories through their selective inhibitory effects on local inhibitory networks in the amygdala.