不同披碱草抗寒性的研究

本文对5个不同品种抗寒性披碱草品种幼苗在零度以上低温下,对组织持水力,叶绿素含量,细胞液外渗量和过氧化物酶活性进行了测定.结果表明:低温使自由水含量降低,束缚水含量相应提高.自由水的丧失量,束缚水的上升量与品种的抗寒性呈反相关.低温处理后,叶绿素含量随品种抗寒性增加而增加;细胞液外渗量都比对照高,且抗寒性弱的外渗量大于抗寒性强的品种;过氧化物酶活性处理比对照的有明显提高,抗寒性强的品种上升幅度小于抗寒性弱的品种.这些品种间表现出的生理特性,可作比较不同抗寒性品种生理生化的依据,可供引种,育种参考.     

茉莉酸甲酯对花生幼苗各器官中碳水化合物含量的影响

本报导用茉莉酸甲酯处理花生幼苗，探讨其对花生幼苗根、茎和叶中碳水化合物含量的影响。茉莉酸甲酯的浓度分别为0ppm、50ppm和100ppm，其中以100ppm的作用最明显。经处理的花生幼苗根、茎和叶的还原为`中溶性糖和淀粉含量都比对照减少，但纤维素和木质素含量却明显提高，其中在茎部尤为明显，两比对照分别增加37％和35％，这对于植物的抗倒伏是很有利的。     

小麦氮磷化肥效应与经济施肥研究

对山东省棕壤、褐土、潮土、砂姜黑土等主要土类的麦田经济施用氮磷化肥进行试验研究。经综合分析,各土类低肥力麦田平均施 N 7.4kg、P_2O_55.0kg、氮磷比1∶0.67最经济;中肥力麦田平均亩施 N8.2kg、P_2O_54.4kg,氮磷比1∶0.53最经济;高肥力麦田平均亩施N9.1kg、P_2O_54.1kg、氮磷比1∶0.45最经济。不同土类上,氮、磷化肥肥效总的趋势是:棕壤>褐土>潮土>砂姜黑土。     

怎样挑选放心豆芽

豆芽是人们喜爱的一种蔬菜。它含有比一般蔬菜更多的蛋白质,大豆蛋白质在发芽过程中分解成氨基酸和肽类,同时破坏了豆类中胰蛋白酶抑制因子,使蛋白质生物利用率提高,与原料豆相比提高了5%～10%。豆类淀粉在发芽后转化为单糖和低聚糖,更易于人体吸收。     

应用热处理茎尖嫁接法脱除苹果病毒的研究

应用热处理茎尖嫁接法在改进的脱毒室脱除苹果病毒。12个苹果品种的220株盆栽苗,经平剪和不平剪2种处理后移人脱毒室,在38℃±1℃下处理21～35天,获脱毒茎尖105个。对其中6个品种的38个脱毒茎尖进行了2种方式的嫁接处理,共成活13株。经温室内杂种楹{孛和田间弗吉尼亚小苹果等检测,证实首红、超红和芋井二系的脱毒苗中不含苹果茎沟槽病毒(SGV)等3种潜隐病毒。     

萧伯纳的《苹果车》评介

<正> 《苹果车》(“The Apple Cart”,1929)是萧伯纳创作的第四十个剧本,也是他的创作生涯后期一出最重要的戏剧。剧名《苹果车》来自英国俗语“弄翻苹果车”(“upset the applecart”),意为“搅乱如意算盘”。在《苹果车》这个“政治狂想剧”里,萧伯     

药剂诱导灰霉病菌产生抗速克灵菌株的研究

将灰霉菌株的菌丝块在含速克灵2、100、1000ppm 的 PSA 培养基上进行抗药性诱导,可产生速克灵抗药性菌株。该菌株与孢子诱导得到的抗性菌株及田间抗性菌株一样,抗性程度很高,最低抑制浓度值大于1000ppm,在无药培养基上连续转移8次,仍保持其抗药性。致病性测定表明,该菌株具有一定的致病性,致病力小于“母株”。     

苹果柱型基因（Co）一个SCAR标记的可靠性分析

以柱型苹果品种、常规栽培品种及二者的杂交分离群体为试材,对在苹果柱型基因（Co）的AFLP标记基础上构建的一个SCAR标记进行分析。结果表明该SCAR标记对苹果柱型性状检测的准确率在90%以上,可用于柱型苹果苗木的鉴定及柱型苹果杂交育种中对群体的早期选择。     

培养基成份对大麦花粉植株高频率再生的影响

在一种基本培养基 FHG 上研究了培养基的多种成份对大麦花粉植株再生频率的影响。诱导培养基中不同的激素配比对愈伤组织诱导数影响很大,在145诱导培养基上,得到一个花药产生16.70块愈伤组织和5.5棵绿苗,分别是对照的2.4倍和3.8倍。在不同的分化培养基上,绿苗分化率以R63培养基为好;培养基中补加 MET 后,能明显的提高绿苗分化率及绿苗产量,最适宜的浓度为0.6mg/L,分别是对照的4.1倍和4.4倍。MET 对大麦花粉植株诱导生根及壮苗也有明显的作用。不同的氨基酸种类对绿苗分化率及绿苗产量作用不同,这种作用具有基因型效应。对 Igri 以730mg/L 的谷氨酰胺绿苗产量最高;谷氨酸次之。     

水果挑选“秘籍“

水果种类繁多,挑起来也有不同的技巧。苹果有许多品种,虽然营养成分不尽相同,但都含有丰富的钾和纤维质。每一品种的成熟季节不同,其口感和外表都不一样。一般选择看起来坚实、颜色鲜明且表皮没有脱水现象的即可。要避免选择有碰伤、发软     

不同基因型棉花下胚轴离体培养胚状体发生的研究

在相同的培养条件下,4个棉花栽培种及其品种间的胚状体发生能力存在明显差异。陆地棉和亚洲棉供试品种的胚状体发生能力明显高于海岛棉与非洲棉。陆地棉栽培品种中,柯字棉系统的胚胎发生能力强,岱字棉系统次之,斯字棉系统最差。胚状体发生能力是一种遗传特性,可以通过杂交转变或选择提高。文中提出了体细胞胚胎发生预决定阈值的概念,并以此解释了不同基因型胚状体发生能力存在差异的现象。     

Heterogeneity in the rise and decline of city-level homicide rates, 1976-2005: A latent trajectory analysis

This study applies latent trajectory methods to the analysis of temporal changes in homicide rates among large US cities across recent decades. Specifically, annual homicide rates for 157 large US cities are analyzed for the 30 years from 1976 to 2005. We address the fundamental questions: Did all of cities experience similar levels and patterns of rise and decline in homicide rates over these three decades? Or is there hidden or unobserved heterogeneity with respect to these temporal patterns, thus leading to the identification of more homogeneous groupings of the cities? And if latent homogeneous groupings surface, is membership due to specific structural characteristics found within those cities? Evidence is found for the existence of four latent homicide rate trajectories. After identifying and classifying the cities into these four groups, multivariate statistical techniques are used to determine which social and economic characteristics are significant predictors of these distinct homicide trends. Criminal justice measures are also included as controls. It is found that larger cities located in the South with higher levels of resource deprivation/concentrated poverty, higher income inequality, higher percentages of the adult male population that are divorced, higher unemployment rates, higher percentages of youth, higher percentages of the population who are Hispanic and higher numbers of police per capita are more likely to be in a higher than a lower homicide trajectory group. Higher percentages of the population enrolled in colleges and universities and locations in states with higher incarceration rates are characteristics of cities associated with membership in a lower homicide trajectory group.     

大学生人际交往能力现状的实证分析

采用自编《大学生人际交往能力调查问卷》,对某高校的380名本科生进行施测。结果显示:大学生人际交往能力的总体水平较好;不同性别、独生子女与非独生子女、不同来源地、不同年级、不同专业的大学生人际交往能力存在显著性差异。具体而言,男性大学生在影响力、开放性、包容度和人际结交能力方面均稍好于女性,但在情绪控制、友谊表达、人际理解能力方面,则女性好于男性;独生子女在人际交往能力的很多方面都优于非独生子女;来自大中城市的学生,人际交往能力要优于来自农村的学生;在人际结交能力、包容度方面,理工类学生要强于文科类学生;人际处理能力、人际理解能力随着年级的升高而逐渐提高。     

朋友关系与儿童分享行为

采用问卷法与访谈法,考察小学一、三、五年级共128名7—11岁儿童在不同朋友关系条件下分享行为的发展特点,并分析了不同朋友关系条件下儿童分享的内部动机。结果发现:(1)一至五年级儿童无论是朋友间还是非朋友间的分享均随年龄的增长呈下降趋势,具体表现为好朋友之间的分享高于非好朋友之间的分享;(2)一至五年级儿童同好朋友的分享行为大多出自个人功利的动机,同不是好朋友的分享行为大多出自遵守规则的动机;(3)同好朋友分享时,小学儿童考虑个人利益的分享动机显著高于非个人利益的分享动机;同不是好朋友分享时,儿童考虑利己与否没有差异。     

How does gun violence affect Americans’ trust in each other?

This article examines how Americans' actual experience of gun victimization affects their trust in others and how this further connects to the widely-discussed association between gun crime and trust at the place level. Analyzing data from the U.S. General Social Survey (GSS), I find that, regardless when it occurred in life, Americans who were victimized by guns trust much less in others than those who had no such experience. In terms of the size of the effect, repeated gun victimization has the strongest effect, followed by adulthood victimization, and then childhood victimization. I also find that individuals who later achieve higher socioeconomic status are better able to recover from the psychological effect of childhood gun victimization, lending support for the experiential theory of trust that people can update their trust according to changing experiences later in life. Finally, combing the GSS data with data from the U.S. Centers for Disease Control and Prevention (CDC), I also show that higher percentages of nonfatal and fatal gun violence victims lead to lower levels of trust both across and within the U.S. census divisions over time. Findings of this study demonstrate that America's gun violence affects not only just those killed, injured, or present during gunfire, but it can also sabotage the social and psychological well-being of all Americans.     

山西生态环境的变迁与晋商的兴起

晋商的兴起与明清山西生态环境的变化有关,但是明代晋商和清代晋商并不一样。一般来说,明初山西生态环境未恶化之前,晋商多出于较富庶的南部地区,是靠手中资本,乘开中纳粮之机,大兴商屯而崛起的。清代的晋商则在山西北部、中部地区生态环境恶化、农业经济一蹶不振之后,兴之于“走西口”和“闯关东”的人流之中。他们是随着关外、口外经济的开发,在不可欠缺的商业发展的需求中,经受历练而走向成功的。     

陨石高温难熔矿物陨硫钙石微量元素化学

报道了5个顽辉石球粒陨石中陨硫钙石的REE，Sc,Se,Br和Zn的INAA数据，结果表明非平衡类型陨中陨硫钙石的REE丰度较平衡陨石中高得多，而且Sc,Se,Br和Zn也有相似的分布。说明了陨硫钙石的早期星云凝聚效应，它们不是简单的蒸发作用残余物，平衡陨石中陨硫钙石的微量元素丰度表明热变质作用导致了矿物微量元素的再分配，这种变质分馏作用反映了元素的挥发性和化学性质差异，陨硫钙石的REE模式说明在变质和火成作用中相对贫化的Eu可能由含Cr硫化物（A，B）矿所携带。     

Cultural capital,teacher bias,and educational success: New evidence from monozygotic twins

In this paper we use new data on Danish monozygotic (MZ) twins to analyze the effect of cultural capital on educational success. We report three main findings. First, cultural capital has a positive direct effect on the likelihood of completing the college-bound track in Danish secondary education. Second, cultural capital leads teachers to form upwardly biased perceptions of children's academic ability, but only when their exposure to children's cultural capital is brief (as in oral and written exams) rather than long (as in grades awarded at the end of the school year). Third, we find that the positive direct effect of cultural capital on educational success is higher for children from high-socioeconomic status (SES) backgrounds than for those from low-SES backgrounds. This result suggests that high-SES children are more likely to be in schooling contexts that enable them to convert cultural capital into educational success.     

殷墟器皿装饰纹样的构成分析

从殷墟出土的器皿中发现，殷王朝人们已经掌握了日用器皿装饰的纹样构成并成功运用了平衡、均齐、协调与节奏的构成法则，创造出了绳纹、云雷纹、夔纹、蟠龙纹、三角纹、焦叶纹、斜云雷乳丁纹、饕餮纹等纹饰样式，依势器皿的造型状态，构成二方或四方连续纹样，装饰在器皿的不同位置。形象概括、简洁、乖巧，有一种朴素的美感，不少青铜器纹饰，层次分明，有单层和多层组合，视觉感极强，表现的素材内容是神话动物，饰于器皿的显著位置，借以玄耀王权尊严和宗族图腾的神圣。