Birth order,family size and educational attainment

This paper investigates the effect of family size and birth order on educational attainment. An instrumental variables approach is used to identify the effect of family size. Instruments for the number of children are twins at last birth and the sex mix of the first two children. The effect of birth order is identified, by examining the relation with years of education for different family sizes separately. No significant effect of family size on educational attainment of the oldest child is found. Birth order has a significant negative effect. Potential mechanisms behind the birth order effects are investigated. The results show that birth order effects are not affected by the average age gap between children. Information on financial transfers shows that earlier born children have a higher probability of receiving money from their parents than later born children, also the amount they receive is higher. These results indicate that the allocation of parental resources is a potential mechanism behind the birth order effects.     

Birth order, family configuration, and verbal achievement

Two samples of National Merit Scholarship participants test in 1962 and the entire population of almost 800,000 participants tested in 1965 were examined. Consistent effects in all 3 groups were observed with respect to both birth order and family size (1st born and those of smaller families scored higher). Control of both socioeconomic variables and maternal age, by analysis of variance as well as by analysis of covariance, failed to alter the relationships. Stepdown analyses suggested that the effects were due to a verbal component and that no differences were attributable to nonverbal factors. Mean test scores were computed for detailed sibship configurations based on birth order, family size, sibling spacing, and sibling sex.     

Birth order and participation in school sports and other extracurricular activities

Argys, L.M., Rees, D.I., Averett S.L., & Witoonchart, B. (2006). Birth order and risky adolescent behavior. Economic Inquiry, 44(2), 215–233 demonstrated that a strong link exists between birth order and adolescent risky behavior. Using data on 10th graders from the National Education Longitudinal Study of 1988, we extend the work of Argys et al. by examining the relationship between birth order and participation in school sports and other extracurricular activities. Our results suggest that having an older sibling is associated with an increased probability that males played baseball and football, were members of the school swim team, and participated in cheerleading. Female 10th graders with older siblings were less likely to engage in a variety of extracurricular activities including school band, community service, and yearbook. These results provide additional evidence that birth order is related to adolescent behavior.     

Birth order and sex of sibling as determinants of mother-infant interaction.

Mother-infant interaction was assessed on 32 first- and second-born siblings when each was 3 months old. Data were colleted during 2 6-hour naturalistic home observations using a modified time-sampling technique. The sample consisted of 4 equal-size subgroups of same and opposite sex sibling pairs. Results suggested that interaction between a mother and her infant varied depending on the birth order and gender of the infant. Mothers spent significantly less time in social, affectionate, and caretaking interaction (except for feeding activities) with their second borns than they had with their firstborns; this difference was greater if the second born was female. Certain patterns of maternal behaviors appeared to be stable from one sibling to the other. Different types of interaction between the mothers and their younger infants were related to attention-seeking behavior in the firstborn male and female siblings.     

Birth order and parental and sibling involvement in sex education. A nationally-representative analysis

This analysis set out to identify associations between birth order and sexual health outcomes, focusing on family involvement in sex education and early sexual experiences. The third National Survey of Sexual Attitudes and Lifestyles is a stratified probability sample survey of 15 162 men and women aged 16–74 in Britain. Logistic regression was conducted to identify odds ratios for the association between birth order and sexual health outcomes. Multiple logistic regression was performed adjusting for socio-demographic factors and sibling number. Middle-born and last-born men had lower odds of reporting ease talking to parents about sex around age 14 and learning about sex from their mothers. Last-born women had lower odds of reporting a parental main source of sex education or having learned about sex from their mother. Findings represent an exploratory analysis in an under-researched area, and provide the basis for further research on the association between birth order and parental involvement in sex education, as well as the role and impact of sex education provided by older siblings.     

Intergenerational correlations in educational attainment: Birth order and family size effects using Canadian data

We exploit the 1986, 1994, and 2001 waves of the Canadian general social surveys in order to estimate intergenerational correlations in education. The use of these specific data is important because of available information on the final educational attainment of survey respondents and both parents, as well as family size and birth order. OLS estimates reveal that: (1) relying exclusively on maternal schooling to capture the effects of parental education results in coefficient estimates that are biased upwards; (2) children born to parents with some post-secondary schooling are more likely to attain similar education levels than children born to parents with lower educational accomplishment; (3) in most specifications coefficient estimates of paternal schooling are greater in magnitude than maternal accomplishment; and finally, (4) coefficient estimates of the number of siblings are consistently negative and significant even after the inclusion of birth order effects, implying that a larger family is correlated with a reduced likelihood of post-secondary education.     

滁菊对淹水胁迫的形态及生理响应

为研究滁菊对淹水胁迫的响应进行本实验.选取滁菊进行淹水处理,观察其外观形态变化,测定了淹水期间滁菊的各项生理指标变化.结果表明：随淹水时间的延长,滁菊叶片逐渐萎蔫发黄、干枯,最后出现植株死亡现象.电导率、可溶性糖含量、脯氨酸含量呈现先上升后下降的趋势且基本高于对照值,叶绿素整体呈现下降趋势且低于对照,变化程度反映了滁菊受淹水胁迫的伤害程度.     

The influence of distractor strength and response order on MCQ responding

Multiple-choice questions (MCQs) play a key role in standardised testing and in-class assessment. Research into the influence of within-item response order on MCQ characteristics has been mixed. While some researchers have shown preferential selection of response options presented earlier in the answer list, others have failed to replicate these results. This paper investigates a possible explanation for these mixed findings by assessing the influence of distractor strength on MCQ response order effects. A real-world assessment was administered to 232 undergraduates in which the response order within items was systematically varied. A generalised multilevel model was then used to show a significant interaction between distractor strength and response position with regard to response behaviour. Furthermore, the effect was found to be independent of student ability. These findings have implications for MCQ test construction, minimising the negative consequences of MCQ test exposure and promoting improved test-taking strategies.     

一阶电路响应中一个值得注意的问题

在一阶电路中，由于含有动态元件，因此当电路换路后，就有一个暂态过程，其响应分为三种情况：零输入响应，规律为f（0＋）e^-1/r；零状态响应，规律为：非状态量为f（∞）＋[fs（0＋）-f（∞）]e^-1/r，状态量为f（∞）（1-e^-1/r）；全响应规律为f（∞）＋｜[fs（0＋）＋fD（0＋）]-f（∞）｜e^-1/r。且全响应=零输入响应＋零状态响应。对状态量是可逆的，但时非状态量是不可逆的。     

甘薯愈伤组织对盐胁迫的生理反应研究

以徐薯18为实验材料,用M S营养液添加不同浓度的NaCl处理甘薯愈伤组织,研究盐胁迫对甘薯愈伤组织可溶性蛋白含量、可溶性糖含量、游离脯氨酸含量、细胞膜透性、超氧化物歧化酶活性、丙二醛含量的影响。结果表明：在盐胁迫下,可溶性蛋白、可溶性糖、丙二醛含量呈先上升后下降的趋势,且都高于对照;游离脯氨酸含量、细胞膜透性呈上升的趋势,且都高于对照;超氧化物歧化酶活性呈下降趋势,且都低于对照。     

镉胁迫对水稻颖果充实和生理活性的影响

通过盆栽试验探讨Cd^2＋胁迫对扬稻6号和粳稻941颖果充实和生理活性的影响,结果表明：Cd^2＋胁迫降低颖果呼吸速率、光合速率以及ATP含量;降低颖壳和果皮叶绿素含量;使颖果灌浆速率减慢,鲜干重增加的速率减缓,灌浆的天数变短,最终成熟颖果干重降低。说明Cd^2＋胁迫降低颖果呼吸活性、能量物质以及其它生理活性,从而降低颖果的代谢活性和发育时间,最终导致贮藏物质的合成和积累量降低。     

抽穗期干旱胁迫对小麦产量及生理特性的影响

为给小麦抗旱栽培提供理论参考,采用盆栽试验,在小麦抽穗期开始进行连续12d的干旱胁迫处理,设置中度干旱(MD,土壤相对含水量为40%~45%)、轻度干旱(LD,土壤相对含水量为55%~60%)及适宜含水量对照(WW,土壤相对含水量为75%~80%)3个水平,研究抽穗期干旱胁迫对小麦生理特性和产量形成的影响。结果表明,抽穗期干旱胁迫初期,剑叶抗氧化酶(超氧化物歧化酶、过氧化物酶、过氧化氢酶)活性均显著增加,轻度干旱处理酶活性均上升了30%左右,中度干旱处理3种酶活性均上升了75%左右。随着胁迫的延长,酶活性开始降低,胁迫程度越重,酶活性降低越快。膜脂过氧化产物丙二醛(MDA)大量积累,积累量随胁迫程度的加重而增加。干旱胁迫显著影响小麦产量的形成,轻度干旱胁迫影响了粒重形成,产量下降了21.57%,中度干旱胁迫影响了每穗粒数和粒重的形成,产量下降了40.56%。     

Sabrina的“大难之日”

前景提要 Casanova带Elena拜访好朋友Georgiana一家,这个温暖的家庭充满了亲切感,而在和Georgiana一家相处的过程中,Elena也了解了Casanova鲜为人知的过去……     

星星诞生记

Like people,stars are born.They will also grow old and die.Their birth places are huge,cold clouds of gas and dust,known as "1)nebulas." The most famous of these is the Orion Nebula.It is just 2)visible with the unaided eye.     

Louisa's Birth

In this column, Rachel Mann shares the story of the birth of her third daughter, Louisa. After a previous pregnancy loss, Mann chose to give birth to her third baby in a hospital with attending care from an obstetrician. In spite of the high-risk medical environment, she was able to have an unmedicated, powerful birth. Mann's careful planning, the support of her husband and doula, and her confidence in her ability to give birth helped make Louisa's birth all that Mann hoped it would be.     

Naomi's Birth

A first-time mother, who is also a nurse, tells the story of her drug-free birth at a free-standing birth center.