中日美三国文化思维方式的异同

中日美三国人民的思维方式、文化内涵有同有异。在对外交往中,东西方文化的碰撞是不可避免的。全面了解中日美三国文化的差异,尤其是思维方式的不同,对于我们有效避免在相互交际中可能发生的冲突与碰撞大有裨益。     

Risk assessment and comparisons: an introduction

Risk assessment is presented as a way of examining risks so that they may be better avoided, reduced, or otherwise managed. Risk implies uncertainty, so that risk assessment is largely concerned with uncertainty and hence with a concept of probability that is hard to grasp. The results of even the simplest risk assessments need to be compared with similar assessments of commonplace situations to give them some meaning. We compare and contrast some risk estimates to display their similarities and differences.     

狭果秤锤树种群年龄结构和空间分布格局研究

对江西永修狭果秤锤树种群径级结构和空间分布格局进行调查和分析,结果表明:该地狭果秤锤树种群年龄结构总体呈现"反J"型趋势,即是增长型;群落个体的存活曲线大致为DeeveyⅠ型,即凸型曲线,表明该种群中的年幼个体比成年个体更容易存活;但静态生命表显示,从年幼个体到老年个体的死亡率变化规律不明显,可能存在未知的的生物学因素导致该现象出现。对于种群密度大的样地,空间分布格局特征不明显,而对于受人类活动影响大、种群密度小的样地,则明显呈现集群分布特征。从年龄结构和空间分布特点来看,研究地的狭果秤锤树种群生存状况受人类活动影响大,除该物种本身的生物学因素外,人类活动是制约种群发展的重要因素,减少人类活动对其影响是保护该物种的重要措施之一。     

大学生的学习成绩与智力、人格特征的关系

采用问卷法对160名北京本科一年级的学生进行调查,对大学生的学习成绩与智力、人格特征的关系进行讨论。学习成绩用高考成绩表示。问卷包括团体IQ测验量表和青年人格问卷(CPI),分别对智力和人格特征进行测量。结果表明,大学生的学习成绩不仅跟智力有关,而且还跟人格特征有着紧密的相关。因此,我们不仅要重视学生智力的培养,也要要关注学生健康人格的培养。     

小麦转基因方法的回顾、比较与展望

十多年来,对小麦转基因技术的研究有了长足的进展.以原生质体为受体的基因转导最先受到瞩目,但由于原生质体培养和再生困难而缺乏实用性.基因枪法是小麦转基因最常用的方法,其转基因体系已基本建立.农杆菌介导的小麦基因转化获得了突破,并将以其诸多优点代替基因枪法成为今后研究的热点.花粉管通道法取得了实用性成果,以其简便易行被更多的育种家所接受.笔者回顾了20世纪80年代以来用于小麦的各种遗传转化方法,对其优缺点作一比较,并对各种方法的前景进行了展望.     

台湾中部暖温带阔叶林年轮特征、生长与树龄结构

台湾目前对于阔叶树种的生长轮少有研究,尤其对于天然阔叶林的生长趋势与模型的相关研究更是缺乏,许多资料仍相当不足,有鉴于此,本研究将针对台湾中部地区的典型暖温带阔叶林进行生长轮的研究与探讨。神木溪保护林于2003年已设置完成18个长期观察的森林动态样区,本研究采用第13~18共6个样区内所有胸径大于6 cm之阔叶树,依据林分特征调查结果,钻取大于6 cm胸径林木,钻取高度约在胸径位置,共取得22科33属39种合计448支树芯。年轮分析运用实体显微镜配合CCD拍摄,目视各树种内年轮的变异,并加以分类,作为年轮目视判视与计数年轮的依据,并用Velmax系统量测年轮宽度,应用树冠级模式(CCM)、定期生长量模式(PAI)及混合模式(Mixed)建立各冠层生长趋势,并解析各树种树龄结构,以提供台湾最大面积、分布最广之楠槠及栎林带林分经营之参考。年轮特征上,属于散孔材树种占79%;半环孔材树种占18%;环孔材树种占3%。生长趋势上,所有树种的平均生长速率统计结果为3.53 mm/a。冠层产生垂直层次分化作用明显,显示出其生长的趋势,上主冠层直径增长情形最快,平均生长率为4.47 mm/a;主冠层其次,平均生长率为2.95 mm/a;底冠层速率最慢,平均生长率为2.92 mm/a。PAI模式显示大部分树种的生长趋势是呈现年轮宽度随树龄增加而增加或线性常数的情形。树龄估算以树冠级模式、PAI模式和混合模式3种模式估算,全部平均年龄分别为55、60、59年。混合模式的利用可以降低单独使用树冠级模式或PAI模式的误差率。树龄结构上,依树冠级模式、PAI模式及混合模式龄级分布结果,本样区充满耐阴性树种前生苗与灌木,逐渐形成典型的复层林。树龄出现2种分群,第1种大多为耐阴性树种的小苗,树木建立时间为20世纪后期;第2种在1900年左右形成了1个独立的单峰。年轮不明显区别造成类型分类的困难,轮宽不规则也无法明确定年,PAI模式需要大量的各龄阶树芯数据建立回归模式,所得到的模型才具有足够之代表性,混合模式虽解决了部分树龄推估的误差,但仍有其他问题,因此日后应更进一步进行探讨与分析,方能对森林生态系之永续经营与发展产生一定程度的帮助。本研究提供暖温带阔叶林林分径向生长与树龄结构信息,以供森林收获采伐和森林永续经营参考。      

高产优质杂交水稻粤优938叶龄模式及其应用

通过粤优 938的播期、栽插密度试验 ,对其生育模式进行了观察和研究。结果表明 ,粤优938主茎叶龄数与伸长节间数、幼穗分化进程、分蘖动态及穗数、穗粒数及粒重有一定的关系 ,根据这一模式特点在生产上应掌握 :粤优 938播量 1 1 2 .5kg/hm2 ,播期 4月底至 5月初 ,栽插规格 1 6.5cm× 2 3.1cm为宜 ,基本苗控制在 90～ 1 0 5万 /hm2 ,当大田总基本苗数达到 2 5 0～30 0万 /hm2 晒田。     

Mid-atlantic ridge: age and spreading rates

Fission-track dating of basaltic glass from the Mid-Atlantic Ridge gives results which are consistent with the proposal of ocean-floor spreading. Solidification ages from ~10,000 years to ~300,000 years were measured. Correlation is also possible between the magnetic anomaly patterns over the Crest Mountains at 45 degrees N and the geochronology of the outcropping basalts. Renewed volcanic activity well removed from the axis of the Mid-Atlantic Ridge has been demonstrated to have taken place in recent times.     

智慧服务：企业技术创新与图书馆服务的对接

图书馆服务职能的变迁是随着社会责任变化而发展的,智慧服务作为对企业技术创新的响应,是未来图书馆服务理念与技术的一种提升。分析企业创新团队创新行为的动力因素,思考技术创新的培育机制,可以探究出图书馆智慧服务的形态,服务企业技术创新应该是一种建立在智慧基础上的创造性的知识创新引导服务。     

Transmission between pairs of hippocampal slice neurons: quantal levels, oscillations, and LTP

Long-term potentiation (LTP) of synaptic transmission after coincident pre- and postsynaptic activity is considered a cellular model of changes underlying learning and memory. In intact tissue, LTP has been observed only between populations of neurons, making analysis of mechanisms difficult. Transmission between individual pre- and postsynaptic hippocampal cells was studied, suggesting quantal amplitude distributions with little variability in quantal size. LTP between such pairs is manifested by large, persistent, and synapse-specific potentiation with a shift in amplitude distribution that suggests presynaptic changes. Oscillations in amplitude of transmission, apparently of presynaptic origin, are common and can be triggered by LTP.     

Toxicity in sponges and holothurians: a geographic pattern

Toxicity in sponges and holothurians is inversely related to latitude and may reach 100 percent for holothurians in high-diversity coral reefs. Evidence from approximately 700 experiments and from underwater observations suggests that predation by fish has resulted in natural selection for noxious and toxic chemical compounds in species within these taxa.     

Stable high-order molecular sandwiches: hydrocarbon polyanion pairs with multiple lithium ions inside and out

Stable ten-component sandwich compounds have been characterized in which four lithium ions reside between two tetraanions derived from corannulene or its alkyl-substituted derivatives and four additional lithium ions decorate the exterior. In tetrahydrofuran solution, the four lithium ions inside the sandwich can exchange environments with the four external lithium atoms, but the two tetraanion decks of the sandwich never separate from one another on the time scale of nuclear magnetic resonance. Theoretical calculations point to a "stacked bowl" conformation and a low energy barrier for synchronous double inversion of the tetraanion bowls in the solvated sandwich compounds.     

Oxygen-18 studies of recent planktonic Foraminifera: comparisons of phenotypes and of test parts

Oxygen isotopic comparisons of phenotypes of Recent Planktonic Foraminifera with both normal and diminutive final chambers are compatible with a model in which the latter develop as a response to environmental stress. Isotopic evidence shows that Spheroidinella dehiscens is probably not a late-stage, aberrant form of Globogerinoides sacculifer.     

Following-response initiation in ducklings: age and sensory stimulation

On the basis of visual stimulation alone, younger ducklings are much less apt than older ducklings to follow a moving model. When the model emits both visual and auditory stimulation, the following-response of the ducklings is greatly enhanced at all ages.     

Magma generation on Mars: amounts, rates, and comparisons with Earth, moon, and venus

Total extrusive and intrusive magma generated on Mars over the last approximately 3.8 billion years is estimated at 654 x 10(6) cubic kilometers, or 0.17 cubic kilometers per year (km(3)/yr), substantially less than rates for Earth (26 to 34 km(3)/yr) and Venus (less than 20 km(3)/yr) but much more than for the Moon (0.025 km(3)/yr). When scaled to Earth's mass the martian rate is much smaller than that for Earth or Venus and slightly smaller than for the Moon.     

Alteration of lunar optical properties: age and composition effects

A model for lunar surface processes is presented which explains the main albedo and color contrasts and the temporal changes in these optical properties. Evidence from Apollo 11 and Apollo 12 samples and telescopic spectral reflectivity measurements indicates that the maria are similar in mineralogy on a regional scale and that the highlands are consistent with an anorthositic-gabbro composition. Bright craters and rays in both regions expose materials that are relatively crystalline compared with their backgrounds, which are richer in dark glass. With age, bright craters and rays in the maria darken in place by meteorite impact-induced vitrification and mixing with the surrounding material. Highland bright craters and rays may, however, darken primarily through regional contamination by iron- and titanium-rich mare material.