Effect of number and position of siblings on child and adult outcomes

This paper develops a theoretical model of the effects of family size and birth order on educational attainment and earnings. The parental utility maximization model allows the development of closed-form expressions for the within-family ratios of schooling and earnings. A reduced form demand function for each child's schooling and earnings also can be obtained. Each of these functions depends on the exogenous variables of the price of education divided by the price of parental consumption, parental income, the child's endowment, and the parameters of the utility and the production function. Application of this model to empirical data from the Twin and Adult Offspring Sample confirmed both birth order and family size effects for schooling even when parental age, income, education, and father's religion were controlled. The effects were larger for daughters than sons. The difference in educational attainment between 1st and 5th-born was 0.7 years for males and 1.4 years for females. Family size further reduces parental contribution to college education and encourages working, loans, and scholarships. The earnings data do not display birth order effects once family background and sibship size are controlled.     

Effect of number, order, and spacing of siblings on child and adult outcomes: an overview of current research

The impact of the number, order, and spacing of siblings on child and adult outcomes has been the topic of research by scholars in 4 separate fields (human biology, psychology, sociology, and economics), and the barriers to communication between academic disciplines are strong. Also most researchers have had to work with data sets gathered for other purposes. This has resulted in a relative inadequacy of research. Social scientists have 3 theories concerning the relationship between the number, order, and spacing of siblings and child and adult outcomes: that an increase in the number of siblings or a decrease in the spacing between them dilutes the time and material resources that parents can give to each child and that these resource dilutions hinder the outcome for each child; that account must be taken not only of parental resources but also of the resources given to each child by his/her siblings; and that there is no causal relationship between number, order and spacing of siblings and child outcomes and that any apparent relationships are spurious. In light of these theories, the question arises as to how should the sibling variables be measured. The most important aspect of sibling number is that it is a variable over time. Yet, the proper measurement of sibling number has an additional complication. According to all existing theories, the ages of the other siblings are relevant for the outcome for the given child. All of the relevant information is now available only when it is possible to construct a matrix in which the rows present the age of the given child and the columns the age grouping of the siblings for whom a count of sibling number will be made. Many such matrices could be developed, some much more elaborate than others. For illustrative purposes, Table 1 presents the matrix of the number of siblings for a child who is the first-born among 5 children, all of whom are spaced exactly 3 years apart and all of whom are financially dependent only up to exact age 21. Table 2 presents the matrix for the last-born child among 5 children with characteristics identical to those in Table 1. It can be inferred from these tables that the oldest child in the family, as compared to the youngest child, probably will suffer from a diminution of parental resources, most likely financial resources, in adolescence. The youngest will suffer from a reduction of parental resources, probably time resources, in infancy and early childhood. Research concerned with the consequences of the number and spacing of children should be based on data sets for which some version of this matrix can be constructed.     

Skin test reactivity and number of siblings.

OBJECTIVE--To investigate the relation between skin test reactivity in children and number of siblings. DESIGN--Cross sectional survey among schoolchildren aged 9-11 years. Skin prick tests in the children and self completion of written questionnaire by their parents. SUBJECTS--5030 children in Munich and 2623 children in Leipzig and Halle, Germany. MAIN OUTCOME MEASURES--Atopic status assessed by skin prick tests. RESULTS--After possible confounders were controlled for, the prevalence of atopic sensitisation decreased linearly with increasing number of siblings (odds ratio = 0.96 for one sibling, 0.67 for five or more siblings; P = 0.005). In atopic children the severity of the skin test reaction as assessed by the weal size was not associated with the number of siblings. CONCLUSIONS--Factors directly or indirectly related to the number of siblings may decrease the susceptibility of children to become atopic. Thus, declining family size may in part contribute to the increased prevalence of atopic diseases reported in Western countries over the past few decades.     

Genetics of obesity in adult adoptees and their biological siblings.

An adoption study of genetic effects on obesity in adulthood was carried out in which adoptees separated from their natural parents very early in life were compared with their biological full and half siblings reared by their natural parents. The adoptees represented four groups who by sampling from a larger population were categorised as either thin, medium weight, overweight, or obese. Weight and height were obtained for 115 full siblings of 57 adoptees and for 850 half siblings of 341 adoptees. In full siblings body mass index (kg/m2) significantly increased with weight of the adoptees. Body mass index of the half siblings showed a steady but weaker increase across the four weight groups of adoptees. There were no significant interactions with sex of the adoptees, sex of the siblings, or (for the half siblings) sex of the common parent. In contrast with the findings in half siblings and (previously) the natural parents there was a striking, significant increase in body mass index between full siblings of overweight and obese adoptees. The degree of fatness in adults living in the same environment appears to be influenced by genetic factors independent of sex, which may include polygenic as well as major gene effects on obesity.     

Breastfeeding and child disability: A comparison of siblings from the United States

Little is known about whether breastfeeding may prevent disabilities throughout childhood. We evaluate the effects of breastfeeding on child disability using data from the National Survey of Family Growth merged to the National Health Interview Survey for a large nationally representative sample of children aged 1–18 years from the U.S. including over 3000 siblings who are discordant on breastfeeding status/duration. We focus on a mother fixed effect model that compares siblings in order to account for family-level unobservable confounders and employ multiple specifications including a dynamic model that accounts for disability status of the prior child. Breastfeeding the child for a longer duration is associated with a lower risk of child disability, by about 0.2 percentage-points per month of breastfeeding. This effect is only observed on the intensive margin among breastfed children, as any breastfeeding has no effect on the extensive margin. We conclude that very short breastfeeding durations are unlikely to have an effect on reducing disability risk.     

Correlation between number and position of floral organs in Arabidopsis

Background and Aims

The study of variation in number, position and type of floral organs may serve as a key to understanding the mechanisms underlying their variation, and will make it possible to improve the analysis of gene function in model plant species by means of a more accurate characterization of mutant phenotypes. The present analysis was carried out in order to understand the correlation between number and position of floral organs in Arabidopsis thaliana.

Methods

An analysis of number and position of organs in flowers of wild type as well as in a series of mutations with floral organ position alterations was carried out, using light and electron microscopy. Variation common to different genotypes was analysed by means of individual diagrams, upon which generalized diagrams depicting variation in number and position of organs, were built by superimposition.

Key Results and Conclusions

It is shown that in the Arabidopsis flower a correlation exists between positions of petals and sepals, as well as between positions of stamens and carpels, whereas the position of carpels does not seem to depend on number and position of petals and stamens. This suggests that the position of organs in the basal (sepals) and apical (carpels) parts of the flower are determined before that in the intermediate zone. This assumption is consistent with the results of mathematical modelling and is supposed to be the consequence of stem-cell activity in the flower.     

The relationship between early-life conditions in the home country and adult outcomes among child immigrants in the United States

We examine the impact of health and economic conditions at birth on the adult outcomes of child immigrants using the Children of Immigrants Longitudinal Study. Our sample consists of children from 39 countries who were brought to the United States before the age of 13. We estimate immigrant outcomes as a function of the infant mortality rate (IMR) and GDP per capita of their home country in the year of birth, controlling for birth-year, year-of-arrival and country-of-birth fixed effects, as well as demographic characteristics. IMR has a significant negative impact on English reading ability and GPA in middle school. IMR significantly decreases first job prestige, years of schooling, working hours and log earnings. Some of these effects appear to be working through the lower middle school GPA. IMR does not influence self-rated health or labor market participation in adulthood, and there is no statistically significant relationship between GDP per capita and adult outcomes. Detrimental effects of IMR are significantly lower for children who arrived younger and whose parents have high school degree or above. Our estimates are of economic significance: the impact of being born in 1975 versus 1976 in Nicaragua in terms of the impact of IMR on earnings is equal to the gender effect on earnings. Our results cannot be explained by selection on observables: the pre-migration characteristics of children and parents are not associated significantly with the health and economic conditions at birth. Also, several tests show that our results cannot be explained by potential selection on unobservables.     

Influence of age and position on the CT number of adipose tissues in pigs

The location of adipose tissue depots is important in determining their significance. Research into the physical and chemical differences between these depots is therefore of interest. Using image analysis, this paper examines the influence of location on the linear attenuation coefficient of adipose tissue for X-rays, in computed tomography (as indicated by CT number) at three time points. Nine pigs were CT scanned on three separate occasions approximately 1 month apart. The mean CT number was -78, -100, and -104 for visceral adipose tissue (VAT) from the first to the final scan, respectively. The corresponding CT numbers for subcutaneous adipose tissue (SAT) were -80, -101, and -106. There was a significant difference between the CT numbers at each location at each scan (P values from 0.025 to <0.001) and between the CT numbers for each location at different times (P < 0.05). In a separate analysis of the final scan session, the mean CT number of adipose tissue at increasing distances from a mathematically defined center of the animal was determined. Regression analysis showed that the CT number of adipose tissue decreases with increasing distance from the animal's center (y = -102.7 - 0.04 x, P < 0.001, where y is the predicted CT number for adipose tissue, from the animal center (x = 0) to the skin (x = 100)). It can thus be expected that the overall mean CT number for adipose tissue can be used as an indicator of the relative quantities of adipose tissue at each location if the mean for each is known.     

Sexual performance of twin ram lambs and the effect of number and sex of contemporary siblings

The objectives of this investigation were to determine the degree of correspondence in the sexual performance of twin male sheep and to compare the sexual performance of ram lambs born co-twin to another male (M-M), co-twin to a female (M-F) and as single (S) offspring. Individual ram lambs (N=117), including 13 M-M twin sets, were exposed to four estrous ewes for 30 min at 7-day intervals over a 4-week period at 8 to 9 months of age.Frequencies of ejaculation (serving capacity) and mounts without ejaculation were recorded. M-M males averaged 2.9 ejaculations and 13.1 mounts per test. Individuals within 9 of the 13 M-M twin sets (69%) differed by an average of 0.5 or fewer ejaculations per test. Although variability within M-M twin sets was very low, variability between the 13 M-M twin sets was also low (coefficient of variation=10.6%). Consequently, frequencies of both ejaculation and mounting (without ejaculation) within the 13 twin sets were not correlated (P=0.50 and P=0.10, respectively). When the progeny of individual sires were compared, mounting frequencies were correlated (P<0.02) but not ejaculation rates (P=0.72). M-M, M-F and S ram lambs did not differ for either ejaculation frequency (P=0.26) or mounts without ejaculation (P=0.98). It was concluded that the sexual performance of related individuals is likely to be very similar and that the number and sex of contemporary siblings does not necessarily influence rates of mounting and ejaculation.     

Co-metabolism of di- and trichlorobenzoates in a 2-chlorobenzoate-degrading bacterial culture: Effect of the position and number of halo-substituents

The degradative properties towards chlorobenzoates by a 2-chlorobenzoate-degrading mixed culture (2MC) were investigated. Although 2MC did not grow on 2,3,5-; 2,3,6- and 2,4,6-trichlorobenzoates, it was able to completely oxidise 2,3,5-trichlorobenzoate and 2,5-dichlorobenzoate. This was degraded through the intermediate formation of 4-chlorocatechol and 3-cis,cis-chloromuconate, suggesting a dioxygenation in 1,2 position. 4-Chlorobenzoate; 3,4- and 2,6-dichlorobenzoate; 2,4,6- and 2,3,6-trichlorobenzoate did not undergo any co-metabolic transformation, the only 2,4-dichlorobenzoate was scarcely transformed into a dichlorinated phenol as end-product. 2MC was constituted of three prominent species: Stenotrophomonas maltophilia, Cupriavidus necator and Flavobacterium sp. Ring-hydroxylating dioxygenase genes (BenA) were retrieved in S. maltophilia and C. necator, indicating the presence of a “modified ortho pathway” in the culture. On the basis of its degradative properties, 2MC could be a good candidate for use in the removal of ortho- and/or meta-chlorobenzoates that are the major end-products of PCB co-metabolism.     

Effects of parental public health insurance eligibility on parent and child health outcomes

Many states expanded their Medicaid programs to low-income adults under the Affordable Care Act (ACA). These expansions increased Medicaid coverage among low-income parents and their children. Whether these improvements in coverage and healthcare use lead to better health outcomes for parents and their children remains unanswered. We used longitudinal data on a large, nationally representative cohort of elementary-aged children from low-income households from 2010 to 2016. Using a difference-in-differences approach in state Medicaid policy decisions, we estimated the effect of the ACA Medicaid expansions on parent and child health. We found that parents’ self-reported health status improved significantly post-expansion in states that expanded Medicaid through the ACA by 4 percentage points (p < 0.05), a 4.7% improvement. We found no significant changes in children’s use of routine doctor visits or parents’ assessment of their children’s health status. We observed modest decreases in children’s body mass index (BMI) of about 2% (p < 0.05), especially for girls.     

Founder myoblasts and fibre number during adult myogenesis in Drosophila

We have examined the mechanisms underlying the setting of myotubes and choice of myotube number in adult Drosophila. We find that the pattern of adult myotubes is prefigured by a pattern of duf-lacZ-expressing myoblasts at appropriate locations. Selective expression of duf-lacZ in single myoblasts emerges from generalized, low-level expression in all adult myoblasts during the third larval instar. The number of founders, thus chosen, corresponds to the number of fibres in a muscle. In contrast to the embryo, the selection of individual adult founder cells during myogenesis does not depend on Notch-mediated lateral inhibition. Our results suggest a general mechanism by which multi-fibre muscles can be patterned.     

Effect of position and lung volume on upper airway geometry

The occurrence of upper airway obstruction during sleep and with anesthesia suggests the possibility that upper airway size might be compromised by the gravitational effects of the supine position. We used an acoustic reflection technique to image airway geometry and made 180 estimates of effective cross-sectional area as a function of distance along the airway in 10 healthy volunteers while they were supine and also while they were seated upright. We calculated z-scores along the airway and found that pharyngeal cross-sectional area was smaller in the supine than in the upright position in 9 of the 10 subjects. For all subjects, pharyngeal cross-sectional area was 23 +/- 8% smaller in the supine than in the upright position (P less than or equal to 0.05), whereas glottic and tracheal areas were not significantly altered. Because changing from the upright to the supine position causes a decrease in functional residual capacity (FRC), six of these subjects were placed in an Emerson cuirass, which was evacuated producing a positive transrespiratory pressure so as to restore end-expiratory lung volume to that seen before the position change. In the supine posture an increase in end-expiratory lung volume did not change the cross-sectional area at any point along the airway. We conclude that pharyngeal cross-sectional area decreases as a result of a change from the upright to the supine position and that the mechanism of this change is independent of the change in FRC.     

Assessment of position of foramen mandibulae in recent adult population

Accurate knowledge about the morphology and topography of foramen mandibulae is of great practical importance in anaesthesia of inferior alveolar nerve. A certain number of skeletotopical relations may be used as valuable orientation points. Because of the controversies about these marking points it has been decided to perform measurements on a large sample of macerated mandibulae that are significant to location and shape of foramen mandibulae (FM) and lingula in relation to the surrounding orientation points. The measurements were taken in antero-posterior and infra-superior directions. In AP direction the distance between PRR and FM was measured; the obtained sample average was 15.03 at variability of Qv 12.18%; ARR-FM distance had the average value of 17.52 at Qv of 50%; the CT-FM distance had the average of 14.81 at Qv of 8.17%. In infra-superior direction the following measurements were made: AM-FM with the average of 21.10 at Qv of 13.98%; IM-IF with the average of 25.19 at Qv of 16.18%; PCO-FM with the average of 44.17 at Qv of 10.48%; and PCR-FM with the average of 42.79 at Qv of 10.87%. Extreme heterogeneity was noticed in the measurements of lingula. In the antero-posterior plane the FM is located in the middle of the CT-PRR distance, i.e., in measurements in which the external oblique line was used as anterior point, FM was located at the juncture of two anterior thirds and the posterior third of ramus mandibulae. In infra-superior direction the lowest FM point was closer to AM than to IM, indicating a somewhat lower position of FM. The mean value of FM depth was 4.31 and the most commonly found shape of the foramen was that of the elongated type (45%). The lingula was prominent, although unevenly, in 51% of study samples.