A model of a giant impact between two planetary bodies is widely accepted to account for the Earth–Moon system. Despite the importance of this event for understanding early Earth evolution and the ...inventory of Earth's volatiles critical to life, the timing of the impact is poorly constrained. We explore a data-based, two-stage Pb isotope evolution model in which the timing of the loss of volatile Pb relative to refractory U in the aftermath of the giant impact is faithfully recorded in the Pb isotopes of bulk silicate Earth. Constraining the first stage Pb isotopic evolution permits calculating an age range of 4.426–4.417 Ga for the inflection in the U/Pb ratio related to the giant impact. This model is supported by Pb isotope data for angrite meteorites that we use to demonstrate volatility-driven, planetary-scale Pb loss was an efficient process during the early Solar System. The revised age is ∼100 Myr younger than most current estimates for the age of the Moon but fully consistent with recent ages for lunar ferroan anorthosite and the timing of Earth's first crust inferred from the terrestrial zircon record. The estimated loss of ∼98% of terrestrial Pb relative to the Solar System bulk composition by the end of the Moon-forming process implies that the current inventory of Earth's most volatile elements, including water, arrived during post-impact veneering by volatile-rich bodies.
•We use Pb isotopes to constrain the timing of the Moon-forming giant impact.•A two-stage U–Pb model explains the Pb isotopic composition of Earth's mantle.•U/Pb ratio of Earth's mantle increases by devolatization during the giant impact.•The Moon-forming impact formed between 4.426 and 4.417 Ga.•∼98% of terrestrial volatiles are lost during the giant impact.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Maternal depression has consistently demonstrated reliability as a predictor of major depression in children. However, the effect of gender as a potential moderator remains under‐researched. This ...study examined gender differences in depression and hypothesized that maternal depression would be more greatly associated with depression in girls by early adolescence. A representative sample of 7237 participants from the Growing Up in Ireland national longitudinal study of Irish children was examined across two waves when participants were aged 9 and 13. Separate multiple regression analyses were run for girls and boys to ascertain if maternal depression and other key variables predicted child depression by age 13. A third analysis looked at the effect of gender. Maternal depression when the children were aged 9 was found predictive of depressive symptomology by age 13 in girls but not for boys. Additionally, conflict with caregivers, household income, and bullying were significant predictors for both genders. Gender significantly predicted youth depression when the child was female (R² = .13, ƒ2 = .25). These findings indicate that late childhood to early adolescence is a vulnerable period for girls during which they appear more susceptible to developing depressive symptomology than boys, particularly when exposed to maternal depression.
Highlights
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Girls appear more vulnerable than boys to the development of depressive symptomology by early adolescence.
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Exposure to maternal depression appears to account for some of this increased risk.
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Mental health policy aimed at mitigating risk of the development of depression in young adolescent girls should incorporate early intervention strategies that look at the broader familial context, caregiver‐child relations and engage with caregivers where depression is suspected/evident.
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BFBNIB, DOBA, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, SIK, UILJ, UKNU, UL, UM, UPUK
In humans, the neuropeptide oxytocin plays a critical role in social and emotional behavior. The actions of this molecule are dependent on a protein that acts as its receptor, which is encoded by the ...oxytocin receptor gene ( OXTR ). DNA methylation of OXTR , an epigenetic modification, directly influences gene transcription and is variable in humans. However, the impact of this variability on specific social behaviors is unknown. We hypothesized that variability in OXTR methylation impacts social perceptual processes often linked with oxytocin, such as perception of facial emotions. Using an imaging epigenetic approach, we established a relationship between OXTR methylation and neural activity in response to emotional face processing. Specifically, high levels of OXTR methylation were associated with greater amounts of activity in regions associated with face and emotion processing including amygdala, fusiform, and insula. Importantly, we found that these higher levels of OXTR methylation were also associated with decreased functional coupling of amygdala with regions involved in affect appraisal and emotion regulation. These data indicate that the human endogenous oxytocin system is involved in attenuation of the fear response, corroborating research implicating intranasal oxytocin in the same processes. Our findings highlight the importance of including epigenetic mechanisms in the description of the endogenous oxytocin system and further support a central role for oxytocin in social cognition. This approach linking epigenetic variability with neural endophenotypes may broadly explain individual differences in phenotype including susceptibility or resilience to disease.
Significance Although understanding the precise nature of oxytocin’s influence on complex human social behavior has proven difficult, increasing evidence points to an anxiolytic effect. We use an imaging epigenetic approach to further parse oxytocin’s effects by examining a biological marker within the oxytocin system, DNA methylation of the oxytocin receptor gene ( OXTR ). Importantly, this epigenetic modification directly impacts the expression of oxytocin’s receptor, which is critical for the actions of oxytocin to have an effect. We find that higher levels of OXTR methylation are associated with increased neural response and decreased functional coupling within regions supporting social perception and emotion processing. This pattern of activity may be indicative of diminished emotion regulation to negative stimuli and increased risk of pathology.
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BFBNIB, NMLJ, NUK, PNG, SAZU, UL, UM, UPUK
Introduction
With increasing evidence available on the importance of physical activity in the management of Type 2 diabetes, there has been an increase in technology‐based interventions. This review ...provides a systematic and descriptive assessment of the effectiveness of technology to promote physical activity in people with Type 2 diabetes. For this review, technology included mobile phones and text messages, websites, CD‐ROMs and computer‐learning‐based technology, and excluded telephone calls.
Methods
A systematic literature search was conducted to retrieve articles from January 2001 to March 2013 using the following databases: the Cochrane Library, EMBASE, MEDLINE, PsycINFO and PubMed. Articles had to describe an intervention that used technology to promote physical activity in people with Type 2 diabetes. A methodological quality assessment of the studies was conducted and data synthesis was performed.
Results
In total, 15 articles were eligible for review: web‐based (9), mobile phone (3), CD‐ROM (2) and computer based (1). All studies found an increase in physical activity but only nine were significant. The use of a personal coach, logbooks and reinforcement strategies such as phone calls and email counselling were found to be effective components for behaviour change. No studies were ranked as low in terms of methodological quality.
Conclusions
Technology‐based interventions to promote physical activity are effective; using further methods to promote participant adherence is associated with greater benefit. Further research should look into strategies to enhance adherence and sustainability in order to increase the effectiveness of technology‐based physical activity intervention in diabetes care.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Bisphenol A (BPA) is a xenoestrogen that was first synthesized in 1891. Its estrogenic properties were discovered in 1930, and shortly after that chemists identified its usefulness in the production ...of epoxy resins. Since the 1950s BPA has been used as a synthetic monomer in the manufacturing of polycarbonate plastic, polystyrene resins, and dental sealants. Roughly 6.5 billion pounds of BPA are produced each year and it is the major estrogenic compound that leaches into nearby water and food supplies (
vom Saal et al., 2007). BPA has been detected in 95% of human urine samples, which indicates that environmental exposure is widespread (
Calafat et al., 2005). Moreover, BPA affects reproductive tissues and the brain. Thus many studies have focused on the effects of BPA during embryonic development. The most recent FDA update (
Administration January 2010) points to “some concern about the potential effects of Bisphenol A on the brain, behavior, and prostate gland in fetuses, infants, and young children.” In light of this concern, we present an updated review of BPA's action on the brain and behavior. We begin with a discussion of BPA's role as both an endocrine active compound and an agent that alters DNA methylation. Next, we review publications that have reported effects of BPA on brain and behavior. We end with our interpretation of these data and suggestions for future research directions.
► Provide a literature review of Bisphenol A and its action on the brain and behavior. ► Discuss BPA’s mechanisms of action as an endocrine activator and epigenetic modifier. ► Propose a model that incorporates these mechanisms to explain changes in behavior.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Bisphenol A (BPA) is a man-made compound used to make polycarbonate plastics and epoxy resins; public health concerns have been fueled by findings that BPA exposure can reduce sex differences in ...brain and some behaviors. We asked if a low BPA dose, within the range measured in humans, ingested during pregnancy, would affect social behaviors in prepubertal mice. We noted sex differences in social interactions whereby females spent more time sitting side-by-side, while males engaged in more exploring and sitting alone. In addition BPA increased display of nose-to-nose contacts, play solicitations and approaches in both sexes. Interactions between sex and diet were found for self grooming, social interactions while sitting side-by-side and following the other mouse. In all these cases interactions were produced by differences between control and BPA females. We examined brains from embryos during late gestation to determine if gene expression differences might be correlated with some of the sexually dimorphic or BPA affected behaviors we observed. Because BPA treatments ended at birth we took the brains during embryogenesis to increase the probability of discovering BPA mediated effects. We also selected this embryonic age (E18.5) because it coincides with the onset of sexual differentiation of the brain. Interestingly, mRNA for the glutamate transporter, Slc1a1, was enhanced by exposure to BPA in female brains. Also we noted that BPA changed the expression of two of the three DNA methyltransferase genes, Dnmt1 and Dnmt3a. We propose that BPA affects DNA methylation of Sc1a1 during neural development. Sex differences in juvenile social interactions are affected by BPA and in particular this compound modifies behavior in females.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The application of U isotopes in carbonates as a paleo-ocean oxygenation proxy is based on the critical assumption that the calcareous shell-building organisms incorporate U into their shells without ...fractionation relative to the U isotopic composition of ambient seawater. Recent studies claim a small, but resolvable, isotopic offset during abiotic and biogenic aragonite precipitation, whereas no isotope fractionation has been recorded during calcite precipitation. Although aragonite is meta-stable and not preserved over geological timescales (>1 Myr) and U precipitates during diagenesis, the U isotope composition of biogenic aragonite is important because aragonite precipitation is an important U sink to carbonate sediments. In contrast, low-magnesium calcite (LMC) is preserved over geological timescales and may provide a reliable fingerprint of ancient ocean chemistry. Therefore, a more general study is needed that compares U isotope compositions of primary marine biogenic carbonate precipitates.
We report the U isotope compositions of 32 modern samples from geographically distinct localities in the Atlantic Ocean including corals (Scleractinia, Octocorallia), brachiopods (Articulata), molluscs (Tellina Listeri, Codahia Obicularis) and barnacles as well as one fossil mollusc. These samples reflect variable primary minerals, water temperatures, water depths, pH-values of ambient water, and U concentrations. Several seawater samples have also been measured to compare our methods with those of previously published studies.
The analyzed modern corals and brachiopods display U isotopic compositions that are indistinguishable from modern seawater. This suggests that these carbonates have the potential to faithfully record the U isotopic composition of the surrounding seawater in which they form. The analyzed brachiopods are of particular interest as they are composed of the calcium carbonate polymorph LMC that is stable over geological timescales. While this study shows for the first time that LMC phases are robust targets in ancient samples, their low U abundance presents analytical challenges for precise U isotope analyses. We also show that two barnacle shells collected with ambient seawater have U isotopic compositions that are both lighter and heavier than the ambient seawater. The mechanism to explain this offset is not determined, but it demonstrates that at least barnacle shells are not representative of the seawater in which they last lived. Two of three partially fossilized mollusc shells also show resolvable offsets from seawater, likely indicating secondary processes that are known to shift or fractionate U isotopes. Collectively, our new data indicate that: 1) aragonite delivers U with a seawater composition to carbonate sediments, and 2) LMC shells of brachiopods that are stable over geological timescales may be more suitable for reconstructing the U isotope composition of ancient oceans.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
We examine the relation between the quality of corporate governance practices and firm value for Thai firms, which often have complex ownership structures. We develop a comprehensive measure of ...corporate governance and show that, in contrast to conventional measures of corporate governance, our measurement, on average, is positively associated with Tobin’s q. Furthermore, we find that q values are lower for firms that exhibit deviations between cash flow rights and voting rights. We also find that the value benefits of complying with “good” corporate governance practices are nullified in the presence of pyramidal ownership structures, raising doubts on the effectiveness of governance measures when ownership structures are not transparent. We conclude that family control of firms through pyramidal ownership structures can allow firms to seemingly comply with preferred governance practices but also use the control to their advantage.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Oxytocin and its receptor (OXTR) play an important role in a variety of social perceptual and affiliative processes. Individual variability in social information processing likely has a strong ...heritable component, and as such, many investigations have established an association between common genetic variants of OXTR and variability in the social phenotype. However, to date, these investigations have primarily focused only on changes in the sequence of DNA without considering the role of epigenetic factors. DNA methylation is an epigenetic mechanism by which cells control transcription through modification of chromatin structure. DNA methylation of OXTR decreases expression of the gene and high levels of methylation have been associated with autism spectrum disorders (ASD). This link between epigenetic variability and social phenotype allows for the possibility that social processes are under epigenetic control. We hypothesized that the level of DNA methylation of OXTR would predict individual variability in social perception. Using the brain's sensitivity to displays of animacy as a neural endophenotype of social perception, we found significant associations between the degree of OXTR methylation and brain activity evoked by the perception of animacy. Our results suggest that consideration of DNA methylation may substantially improve our ability to explain individual differences in imaging genetic association studies.
Bisphenol A (BPA) is a plasticizer and an endocrine-disrupting chemical. It is present in a variety of products used daily including food containers, paper, and dental sealants and is now widely ...detected in human urine and blood. Exposure to BPA during development may affect brain organization and behavior, perhaps as a consequence of its actions as a steroid hormone agonist/antagonist and/or an epigenetic modifier. Here we show that BPA produces transgenerational alterations in genes and behavior. Female mice received phytoestrogen-free chow with or without BPA before mating and throughout gestation. Plasma levels of BPA in supplemented dams were in a range similar to those measured in humans. Juveniles in the first generation exposed to BPA in utero displayed fewer social interactions as compared with control mice, whereas in later generations (F2 and F4), the effect of BPA was to increase these social interactions. Brains from embryos (embryonic d 18.5) exposed to BPA had lower gene transcript levels for several estrogen receptors, oxytocin, and vasopressin as compared with controls; decreased vasopressin mRNA persisted into the F4 generation, at which time oxytocin was also reduced but only in males. Thus, exposure to a low dose of BPA, only during gestation, has immediate and long-lasting, transgenerational effects on mRNA in brain and social behaviors. Heritable effects of an endocrine-disrupting chemical have implications for complex neurological diseases and highlight the importance of considering gene-environment interactions in the etiology of complex disease.
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