当孩子顶撞你时······

<正>经常听到有些父母抱怨自己的孩子:你要他做点力所能及的小事,他不理不睬,甚至用白眼回敬你;你耐心给他讲道理,却遭到无理反驳;你批评他的错误行为,他却"砰"的一声摔门而去……我们不禁要问,孩子们为什么要和大人作对?心理学家认为,他们这样做大多是为了引起别人的注意,或是用这种方式来显示自己与大人争论的能力。当然,不能把孩子所有的顶撞统统视为与父母作对,因为当孩     

窃据·盘据·强据·回归·启示

澳门回归之年，回顾澳门被葡萄牙人夺取的始末史，牢记国耻，努力学习、勤奋工作，振兴中华。     

路·房·人·幸福

三十年弹指一挥间,改革开放三十年来团场变化之大,常使人感到太多太多的惊喜和欣慰。改革开放的成果,给人们带来的是梦境般的美好生活。     

2009·4·5—2009·5·13

由科技部、农业部、教育部、中科院、环保部、质检总局等有关部门组成的转基因生物新品种培育重大专项实施组织管理情况联合调研组赴吉林省进行了专题调研。     

芦荟中铬·汞·砷·铅·镉·铜·锌含量的测定

[目的]测定新鲜芦荟中铬、汞、砷、铅、镉、铜和锌元素的含量。[方法]采用具有压力控制系统的MARS5型微波消解系统消解芦荟样品,用双道原子荧光法测定砷、汞,用石墨炉原子吸收法测定铬,用全谱直读电感耦合等离子体原子发射光谱(ICP-AES)测定铜、锌、铅、镉。[结果]各元素在芦荟中的含量均较少。[结论]微波消解法处理芦荟样品,具有快速、简便、节省试剂、消解完全等特点。     

春·季·防·四·病

一、呼吸道传染病常见的如麻疹、风疹、水痘、疱疹性疾病，感冒、咽炎、支气管炎、腮腺炎、猩红热、流行性脑膜炎、白喉、百日咳等等。呼吸道传染病人多通过飞沫传播，且以儿童及青少年为主。预防此类疾病，一是加强体育锻炼，提高机体的防御能力；二是室内保持整洁、通风和一定湿度；三是如有传染病的流行，尽量少带孩子出入人多、空气污浊的公共场所；四是按照规定给孩子进行预防接种，防患于未然。 　　二、消化道疾病如甲型肝炎、溃疡病等。有些消化道疾病虽在夏季多见，但于春季就已开始流行，特别是到春末夏初时节。对于消化道疾病…     

肉·犬·如·何·选种

优良种犬应具备的基本条件：生产性能好，适应性强，繁殖性能好，遗传性稳定。     

想事·议事·办事·记事

在苏北一个普通村子里，人们对于新农村建设，对于村计民生，是怎样想事、议事、办事的？     

和·谐·的·天·空(三)

“谁说女子不如男”，豫剧大师常香玉这家喻户晓的名段唱出了女性的共同心声。如今，在这和谐幸福的时代，她们绽放出了更加灿烂的光彩，忙生产、献爱心……正是有了这些水一般的女性，我们才能够拥有一片更加色彩斑斓的——[编者按]     

穴盘规格和苗龄对塑料大棚菜豆性状及产量的影响

本试验以菜豆品种先行者为试材,采用32孔、50孔两种规格穴盘,设置10、15、20、25 d等4个苗龄段,通过研究不同穴盘规格和苗龄对菜豆性状及产量的影响,筛选出适合菜豆育苗的穴盘规格和适宜的苗龄。结果表明：穴盘育苗的营养面积增大,菜豆产量随之增加,25 d苗龄条件下,32孔穴盘的前期产量和总产量均显著高于50孔穴盘;随着苗龄的增长,菜豆的前期产量和总产量呈增加趋势,其中25 d苗龄的产量显著高于其他苗龄。综合上述各项指标,菜豆育苗阶段,10 d苗龄可选用32孔、50孔穴盘,15 d以上秧苗选用32孔穴盘为宜。     

不同基因型小麦苗期耐低氮性评价及筛选

氮素作为重要的营养元素,限制着小麦的生长发育和经济产量,筛选和培育耐低氮小麦品种是提高氮素利用率、降低生产成本的有效途径。以118份不同基因型小麦为材料,在低氮(0.1 mmol·L^-1)和正常氮(5 mmol·L^-1)条件下苗期水培,测定根干重、茎叶干重、根冠比、植株干重、最大根长、初生根数和二级初生根数等相关指标,采用模糊隶属函数法、主成分分析以及聚类分析法综合评价小麦品种的耐低氮性。结果表明,在低氮胁迫下小麦幼苗的根干重、根冠比和初生根数目显著提高,茎叶干重、植株干重和最大根长不同程度的降低,7个苗期性状指标在两个氮水平下均存在显著性差异。主成分分析提取3个主成分,贡献率分别为 43.575%、22.904%和17.873%,累积贡献率达 84.351%。以耐低氮性综合评价D值进行聚类分析,将118份小麦品种划分为强耐低氮型、耐低氮型、中间型、较敏感型和敏感型5类。筛选出3份耐低氮型小麦（齐大195、金丰7183和天民198）和2份强耐低氮型小麦（山农0917和鲁麦8号）。不同小麦品种的耐低氮机制不同,研究结果为小麦耐低氮品种的选育提供理论依据和材料基础。     

ICP-OES法同时测定果蔬中铅、砷、镉、铬、铜、锡含量

果蔬样品经混酸消化后,控制一定的酸度,定容后应用等离子体发射光谱法(ICP-OES)对果蔬中铅、砷、镉、铬、铜、锡六种有害重金属进行测定,研究了分析测定条件,方法简单快速。测定结果表明,五种元素的加标平均回收率在91.0%~107%之间。其RSD均小于3.5%。按该方法进行处理及测定铅、砷、镉、铬、铜、锡,在选择的测定条件下最低检出限分别为0.0006 mg/kg、0.0003 mg/kg、0.00003 mg/kg、0.00005 mg/kg、0.00003 mg/kg、0.0006 mg/kg。     

Segregation of form, color, movement, and depth: anatomy, physiology, and perception

Anatomical and physiological observations in monkeys indicate that the primate visual system consists of several separate and independent subdivisions that analyze different aspects of the same retinal image: cells in cortical visual areas 1 and 2 and higher visual areas are segregated into three interdigitating subdivisions that differ in their selectivity for color, stereopsis, movement, and orientation. The pathways selective for form and color seem to be derived mainly from the parvocellular geniculate subdivisions, the depth- and movement-selective components from the magnocellular. At lower levels, in the retina and in the geniculate, cells in these two subdivisions differ in their color selectivity, contrast sensitivity, temporal properties, and spatial resolution. These major differences in the properties of cells at lower levels in each of the subdivisions led to the prediction that different visual functions, such as color, depth, movement, and form perception, should exhibit corresponding differences. Human perceptual experiments are remarkably consistent with these predictions. Moreover, perceptual experiments can be designed to ask which subdivisions of the system are responsible for particular visual abilities, such as figure/ground discrimination or perception of depth from perspective or relative movement--functions that might be difficult to deduce from single-cell response properties.     

一串红N、P、K、Ca、Mg、Fe缺素症状研究

以‘展望红’为材料,研究N、P、K、Ca、Mg、Fe缺乏对其生长发育的影响,并总结缺素症状,研究结果表明:N缺乏时植株矮小,叶发黄;P缺乏时叶色暗绿,且影响开花;K缺乏时基部叶枯黄,并易落叶;缺Fe症状较为明显,但能正常开花;Ca、Mg未表现出缺素症状,且各项指标要优于全素处理;N、P显著影响一串红的生长发育,K对开花品质的影响较大。     

Strong, transparent, multifunctional, carbon nanotube sheets

Individual carbon nanotubes are like minute bits of string, and many trillions of these invisible strings must be assembled to make useful macroscopic articles. We demonstrated such assembly at rates above 7 meters per minute by cooperatively rotating carbon nanotubes in vertically oriented nanotube arrays (forests) and made 5-centimeter-wide, meter-long transparent sheets. These self-supporting nanotube sheets are initially formed as a highly anisotropic electronically conducting aerogel that can be densified into strong sheets that are as thin as 50 nanometers. The measured gravimetric strength of orthogonally oriented sheet arrays exceeds that of sheets of high-strength steel. These nanotube sheets have been used in laboratory demonstrations for the microwave bonding of plastics and for making transparent, highly elastomeric electrodes; planar sources of polarized broad-band radiation; conducting appliqués; and flexible organic light-emitting diodes.