Early life experiences: meaningful differences within and between families

Previous research has focused on differences in early life experiences that occur between families and their impact on children's development. However, less is known about the variations in early life experiences that occur within families. Here, 53 British mothers (mean age = 34.46 years; SD = 4.35) of newborn infants (mean age = 1.68 months, SD = 0.96) used a smartphone application (app) to repeatedly rate their wellbeing and support and to report their baby's and their own dietary and sleeping patterns (4 app alerts per week for 3 weeks; 12 assessments in total). We found that the app was a practicable tool for observing early life experiences, and that early life experiences differed on average to a greater extent within, rather than between families (59% versus 41% of the total variance). We also found preliminary evidence for meaningful associations among contemporaneous within-family variations in early life experiences

Mothers’ and fathers’ perceptions of the family context and children’s adjustment: coparenting young twins

Mothers’ and fathers’ perceptions of the quality of coparenting – the way in which they work together in their role as parents – forms the focus of three papers that comprise this thesis. Using a novel sample of ‘intact’ families with young twins, this research extends the existing coparenting literature beyond its typical focus on first-born children, to include more complex families. Participants were families who were part of the Twins, Family and Behaviour (TFaB) Study, a longitudinal, multimethod study of UK families with twins born in 2009/10 conducted by myself and my colleague over a two-year period. Paper 1 examines bidirectional associations between coparenting and the marital relationship during the transition-to-school period. Controlling for cross-sectional associations and temporal stability, parents’ perceptions of higher quality coparenting were associated with their subsequent report of a higher quality marital relationship. Reciprocal associations between the marital relationship and subsequent coparenting, however, were not evidenced. These findings highlight the salience of coparenting for the marital relationship, and suggest that interventions seeking to improve the couples’ marital relationship should pay close attention to their coparenting. Paper 2 focuses on parenting sense of competence (PSOC), examining the role of children’s disruptive behaviour, coparenting, and their interaction. For both mothers and fathers there was a significant interaction between their perceptions of coparenting and children’s disruptive behaviour such that high quality coparenting may protect the PSOC of parents dealing with high levels of children’s disruptive behaviour. These findings imply that practitioners and interventions concerned with promoting PSOC should pay due attention to the quality of coparenting as an important family context. Paper 3 examines family-wide and child-specific effects of coparenting and coercive parenting on the development of children’s disruptive behaviour. Mothers’ perceptions of coparenting interacted with maternal overall coercive parenting such that high quality coparenting intensified the toxicity of maternal coercive parenting for children’s disruptive behaviour. This novel – and unexpected – finding indicates that the influence of high quality coparenting is not necessarily always positive. Coparenting interventions aiming to improve child outcomes would therefore be well-advised to also consider parenting strategies. Further research is encouraged to explore these research questions within samples of socioeconomic diversity and across family types, as well as studies designed to examine twin and non-twin family differences

Mothers’ and fathers’ perceptions of marital relationships and coparenting twins during school transition

Coparenting and the marital relationship are closely related yet distinct family subsystems hypothesized to influence one another. Little is known about these processes with consideration of more than one child in the family, which may have important implications. Here, we specifically focus on families with young twins, enabling us to account for sibling age-difference confounds, as well as due to the greater parenting demands and higher divorce rates in twin families. Using cross-lagged models for both mothers and fathers, we examined bidirectional associations between coparenting and the marital relationship during children’s transition to formal schooling. Parents of twins from 107 ‘intact’ families reported perceptions of coparenting and the marital relationship via telephone interview at Time 1 (Mchild age = 4years 8 months, SDchild age = 4.44 months) and questionnaire at Time 2 (Mchild age = 6 years, SDchild age = 6.12 months). Accounting for within-time associations and temporal stability for both mothers and fathers, coparenting was positively associated with subsequent reports of the marital relationship; there was no evidence of reciprocal associations between the marital relationship and subsequent coparenting. As children transition to primary school, the quality of coparenting may be a driver of the quality of the marital relationship for parents of twins. Those seeking to improve the marital relationship should pay due attention to perceptions of coparenting

A harsh parenting team? Maternal reports of coparenting and coercive parenting interact in association with children’s disruptive behaviour

Background: Parenting and coparenting are both important for children’s adjustment, but their interaction has been little explored. Using a longitudinal design and considering two children per family, we investigated mothers’ and fathers’ perceptions of coparenting as moderators of associations between their coercive parenting and children’s disruptive behaviour. Methods: Mothers and fathers from 106 ‘intact’ families were included from the Twins, Family and Behaviour study (TFaB). At Time 1 (Mchild age=3 years 11 months, SDchild age=4.44 months) parents reported on their coercive parenting and children’s disruptive behaviour via questionnaire; at Time 2 (Mchild age=4 years 8 months, SDchild age=4.44 months) perceptions of coparenting and the marital relationship were collected by telephone interview. Questionnaire-based reports of children’s disruptive behaviour were collected at follow-up (Mchild age=5 years 11 months, SDchild age=5.52 months). Multilevel modelling was used to examine child-specific and family-wide effects. Results: Conservative multilevel models including both maternal and paternal perceptions demonstrated that maternal perceptions of coparenting and overall coercive parenting interacted in their prediction of parent-reported child disruptive behaviour. Specifically, accounting for perceived marital quality, behavioural stability, and fathers’ perceptions, only in the context of perceived higher quality coparenting was there a positive association between mother-reported overall coercive parenting and children’s disruptive behaviour at follow-up. Conclusions: When combined with highly coercive parenting, maternal perceptions of high quality coparenting may be detrimental for children’s adjustment

Using Artificial Selection to Understand Orientation Behavior in Drosophila

Several studies suggest that the fruit fly Drosophila melanogaster can use magnetic fields for orientation1-4; however, the responses to magnetic fields are not consistent across studies and experiments investigating the mechanism of magnetoreception rely on magnetic fields that are at least 10 times stronger than the magnetic field of the Earth5-6. We are attempting to determine whether Drosophila have the ability to detect Earth-strength magnetic fields by running flies through a progressive Y-maze and then selectively breeding the flies based on their choices in the maze. There are two main hypotheses about the mechanism of magnetoreception in animals. The first is based on the use of magnetite, which forms long chains and serves as a magnetic dipole and has been found in organisms such as bats7. The other hypothesis is based on a light-dependent magnetic response utilizing the cryptochromephotoreceptor8. While the predominant hypothesis is that fruit flies use cryptochrome to detect magnetic fields1-6, experimental results have shown that most invertebrates use magnetite or both magnetite and cryptochrome

Dynamical Masses for Low-Mass Pre-Main Sequence Stars: A Preliminary Physical Orbit for HD 98800 B

We report on Keck Interferometer observations of the double-lined binary (B) component of the quadruple pre-main sequence (PMS) system HD 98800. With these interferometric observations combined with astrometric measurements made by the Hubble Space Telescope Fine Guidance Sensors (FGS), and published radial velocity observations we have estimated preliminary visual and physical orbits of the HD 98800 B subsystem. Our orbit model calls for an inclination of 66.8 $\pm$ 3.2 deg, and allows us to infer the masses and luminosities of the individual components. In particular we find component masses of 0.699 $\pm$ 0.064 and 0.582 $\pm$ 0.051 M_{\sun} for the Ba (primary) and Bb (secondary) components respectively. Modeling of the component SEDs finds temperatures and luminosities in agreement with previous studies, and coupled with the component mass estimates allows for comparison with PMS models in the low-mass regime with few empirical constraints. Solar abundance models seem to under-predict the inferred component temperatures and luminosities, while assuming slightly sub-solar abundances bring the models and observations into better agreement. The present preliminary orbit does not yet place significant constraints on existing pre-main sequence stellar models, but prospects for additional observations improving the orbit model and component parameters are very good.Comment: 20 pages, 6 figures, ApJ in press; tables 2 and 3 to be included in ApJ versio

Dynamical Masses for Pre-Main Sequence Stars: A Preliminary Physical Orbit for V773 Tau A

We report on interferometric and radial-velocity observations of the double-lined 51-d period binary (A) component of the quadruple pre-main sequence (PMS) system V773 Tau. With these observations we have estimated preliminary visual and physical orbits of the V773 Tau A subsystem. Among other parameters, our orbit model includes an inclination of 66.0 $\pm$ 2.4 deg, and allows us to infer the component dynamical masses and system distance. In particular we find component masses of 1.54 $\pm$ 0.14 and 1.332 $\pm$ 0.097 M_{\sun} for the Aa (primary) and Ab (secondary) components respectively. Our modeling of the subsystem component spectral energy distributions finds temperatures and luminosities consistent with previous studies, and coupled with the component mass estimates allows for comparison with PMS stellar models in the intermediate-mass range. We compare V773 Tau A component properties with several popular solar-composition models for intermediate-mass PMS stars. All models predict masses consistent to within 2-sigma of the dynamically determined values, though some models predict values that are more consistent than others.Comment: ApJ in press; 25 pages, 6 figures; data tables available in journal versio

KOI-54: The Kepler Discovery of Tidally Excited Pulsations and Brightenings in a Highly Eccentric Binary

Kepler observations of the star HD 187091 (KIC 8112039, hereafter KOI-54) revealed a remarkable light curve exhibiting sharp periodic brightening events every 41.8 days with a superimposed set of oscillations forming a beating pattern in phase with the brightenings. Spectroscopic observations revealed that this is a binary star with a highly eccentric orbit, e = 0.83. We are able to match the Kepler light curve and radial velocities with a nearly face-on (i = 5 degrees.5) binary star model in which the brightening events are caused by tidal distortion and irradiation of nearly identical A stars during their close periastron passage. The two dominant oscillations in the light curve, responsible for the beating pattern, have frequencies that are the 91st and 90th harmonic of the orbital frequency. The power spectrum of the light curve, after removing the binary star brightening component, reveals a large number of pulsations, 30 of which have a signal-to-noise ratio greater than or similar to 7. Nearly all of these pulsations have frequencies that are either integer multiples of the orbital frequency or are tidally split multiples of the orbital frequency. This pattern of frequencies unambiguously establishes the pulsations as resonances between the dynamic tides at periastron and the free oscillation modes of one or both of the stars. KOI-54 is only the fourth star to show such a phenomenon and is by far the richest in terms of excited modes.NASA, Science Mission DirectorateNASA NNX08AR14GEuropean Research Council under the European Community 227224W.M. Keck FoundationMcDonald Observator