1,276 research outputs found
ŠŃŠøŠ¼ŠµŠ½ŠµŠ½ŠøŠµ Š³ŠøŠ±ŃŠøŠ“Š½ŃŃ Š½Š°ŠŗŠ¾ŠæŠøŃŠµŠ»ŠµŠ¹ ŃŠ»ŠµŠŗŃŃŠ¾ŃŠ½ŠµŃŠ³ŠøŠø Š“Š»Ń Š²ŃŃŠ°Š²Š½ŠøŠ²Š°Š½ŠøŃ Š³ŃŠ°ŃŠøŠŗŠ° Š½Š°Š³ŃŃŠ·ŠŗŠø ŠæŃŠµŠ“ŠæŃŠøŃŃŠøŠ¹
In this article, the authors consider the possibility of using a hybrid energy storage system to even out the load profile of the enterprise. Solving the problem of rational use of energy storage taking into account the initial variable load schedule will significantly reduce not only the cost of electricity consumption by the enterprise, but also the costs of its production. Detailed characteristics of batteries with various types of electrolytes and supercapacitors are given. A model of the active scheme of a hybrid electric energy storage system consisting of a lithium-ion battery and a supercapacitor unit with the corresponding characteristics is presented. The model was carried out by using the SimPowerSystems software in MatLab. During the simulation, the temperature and the aging effects and of the batteries were not taken into account. The selfdischarge parameter of the battery was also not presented. As a result of the simulation, discharge characteristics of supercapacitors and batteries were obtained based upon which the expediency of their combined use for leveling load profiles of various types was substantiated. The paper presents the results of the simulation of operating modes of a hybrid energy storage device, combining the advantages of two types of energy storage devices, as well as a diagram of delivered power to the network, corresponding to the specified parameters. The paper provides a mathematical description of the increasing power by hybrid storage system resulting from the combined use of supercapacitors and batteries. The paper presents the dependence of the power increase ratio on the frequency and the pulse current duty ratio, which proves that the maximum possible output power of the hybrid storage system can be several times greater than the power of a single battery having the same parameters
Evo-devo of human adolescence: beyond disease models of early puberty
Despite substantial heritability in pubertal development, much variation remains to be explained, leaving room for the influence of environmental factors to adjust its phenotypic trajectory in the service of fitness goals. Utilizing evolutionary development biology (evo-devo), we examine adolescence as an evolutionary life-history stage in its developmental context. We show that the transition from the preceding stage of juvenility entails adaptive plasticity in response to energy resources, other environmental cues, social needs of adolescence and maturation toward youth and adulthood. Using the evolutionary theory of socialization, we show that familial psychosocial stress fosters a fast life history and reproductive strategy rather than early maturation being just a risk factor for aggression and delinquency. Here we explore implications of an evolutionary-developmental-endocrinological-anthropological framework for theory building, while illuminating new directions for research
ŠŃŠøŠ¼ŠµŠ½ŠµŠ½ŠøŠµ Š³ŠøŠ±ŃŠøŠ“Š½ŃŃ Š½Š°ŠŗŠ¾ŠæŠøŃŠµŠ»ŠµŠ¹ ŃŠ»ŠµŠŗŃŃŠ¾ŃŠ½ŠµŃŠ³ŠøŠø Š“Š»Ń Š²ŃŃŠ°Š²Š½ŠøŠ²Š°Š½ŠøŃ Š³ŃŠ°ŃŠøŠŗŠ° Š½Š°Š³ŃŃŠ·ŠŗŠø ŠæŃŠµŠ“ŠæŃŠøŃŃŠøŠ¹
In this article, the authors consider the possibility of using a hybrid energy storage system to even out the load profile of the enterprise. Solving the problem of rational use of energy storage taking into account the initial variable load schedule will significantly reduce not only the cost of electricity consumption by the enterprise, but also the costs of its production. Detailed characteristics Ā of Ā batteries Ā with Ā various Ā types Ā of Ā electrolytes Ā and Ā supercapacitors Ā are Ā given. A model of the active scheme of a hybrid electric energy storage system consisting of a lithium-ion battery and a supercapacitor unit with the corresponding characteristics is presented. The model was carried out by using the SimPowerSystems software in MatLab. During the simulation, the temperature and the aging effects and of the batteries were not taken into account. The selfdischarge parameter of the battery was also not presented. As a result of the simulation, discharge characteristics of supercapacitors and batteries were obtained based upon which the expediency of their combined use for leveling load profiles of various types was substantiated. The paper presents the results of the simulation of operating modes of a hybrid energy storage device, combining the advantages of two types of energy storage devices, as well as a diagram of delivered power to the network, corresponding to the specified parameters. The paper provides a mathematical description of the increasing power by hybrid storage system resulting from the combined use of supercapacitors and batteries. The paper presents the dependence of the power increase ratio on the frequency and the pulse current duty ratio, which proves that the maximum possible output power of the hybrid storage system can be several times greater than the power of a single battery having the same parameters.Š ŃŃŠ°ŃŃŠµ ŃŠ°ŃŃŠ¼Š°ŃŃŠøŠ²Š°ŠµŃŃŃ Š²Š¾Š·Š¼Š¾Š¶Š½Š¾ŃŃŃ ŠæŃŠøŠ¼ŠµŠ½ŠµŠ½ŠøŃ Š³ŠøŠ±ŃŠøŠ“Š½Š¾Š³Š¾ Š½Š°ŠŗŠ¾ŠæŠøŃŠµŠ»Ń ŃŠ»ŠµŠŗŃŃŠ¾ŃŠ½ŠµŃŠ³ŠøŠø Š“Š»Ń Š²ŃŃŠ°Š²Š½ŠøŠ²Š°Š½ŠøŃ Š³ŃŠ°ŃŠøŠŗŠ° Š½Š°Š³ŃŃŠ·ŠŗŠø ŠæŃŠµŠ“ŠæŃŠøŃŃŠøŃ. Š ŠµŃŠµŠ½ŠøŠµ Š·Š°Š“Š°ŃŠø ŃŠ°ŃŠøŠ¾Š½Š°Š»ŃŠ½Š¾Š³Š¾ ŠøŃŠæŠ¾Š»ŃŠ·Š¾Š²Š°Š½ŠøŃ Š½Š°ŠŗŠ¾ŠæŠøŃŠµŠ»ŠµŠ¹ ŃŠ½ŠµŃŠ³ŠøŠø Ń ŃŃŠµŃŠ¾Š¼ ŠøŃŃ
Š¾Š“Š½Š¾Š³Š¾ ŠæŠµŃŠµŠ¼ŠµŠ½Š½Š¾Š³Š¾ Š³ŃŠ°ŃŠøŠŗŠ° Š½Š°Š³ŃŃŠ·ŠŗŠø ŠæŠ¾Š·Š²Š¾Š»ŠøŃ ŃŃŃŠµŃŃŠ²ŠµŠ½Š½Š¾ ŃŠ½ŠøŠ·ŠøŃŃ Š½Šµ ŃŠ¾Š»ŃŠŗŠ¾ Š·Š°ŃŃŠ°ŃŃ Š½Š° ŠæŠ¾ŃŃŠµŠ±Š»ŠµŠ½ŠøŠµ ŃŠ»ŠµŠŗŃŃŠ¾ŃŠ½ŠµŃŠ³ŠøŠø ŠæŃŠµŠ“ŠæŃŠøŃŃŠøŠµŠ¼, Š½Š¾ Šø Ā Š·Š°ŃŃŠ°ŃŃ Ā ŠæŃŠø Ā ŠµŠµ Ā ŠæŃŠ¾ŠøŠ·Š²Š¾Š“ŃŃŠ²Šµ. Ā ŠŃŠøŠ²Š¾Š“ŃŃŃŃ Ā ŠæŠ¾Š“ŃŠ¾Š±Š½ŃŠµ Ā Ń
Š°ŃŠ°ŠŗŃŠµŃŠøŃŃŠøŠŗŠø Š°ŠŗŠŗŃŠ¼ŃŠ»ŃŃŠ¾ŃŠ½ŃŃ
Š±Š°ŃŠ°ŃŠµŠ¹ Ń ŃŠ°Š·Š»ŠøŃŠ½ŃŠ¼Šø ŃŠøŠæŠ°Š¼Šø ŃŠ»ŠµŠŗŃŃŠ¾Š»ŠøŃŠ¾Š² Šø ŃŃŠæŠµŃŠŗŠ¾Š½Š“ŠµŠ½ŃŠ°ŃŠ¾ŃŠ¾Š². ŠŃŠµŠ“ŃŃŠ°Š²Š»ŠµŠ½Š° Š¼Š¾Š“ŠµŠ»Ń Š°ŠŗŃŠøŠ²Š½Š¾Š¹ ŃŃ
ŠµŠ¼Ń Š³ŠøŠ±ŃŠøŠ“Š½Š¾Š³Š¾ Š½Š°ŠŗŠ¾ŠæŠøŃŠµŠ»Ń ŃŠ»ŠµŠŗŃŃŠ¾ŃŠ½ŠµŃŠ³ŠøŠø, ŃŠ¾ŃŃŠ¾ŃŃŠµŠ³Š¾ ŠøŠ· Š»ŠøŃŠøŠ¹-ŠøŠ¾Š½Š½Š¾Š¹ Š±Š°ŃŠ°ŃŠµŠø Šø Š±Š»Š¾ŠŗŠ° ŃŃŠæŠµŃŠŗŠ¾Š½Š“ŠµŠ½ŃŠ°ŃŠ¾ŃŠ¾Š² Ń ŃŠ¾Š¾ŃŠ²ŠµŃŃŃŠ²ŃŃŃŠøŠ¼Šø Ń
Š°ŃŠ°ŠŗŃŠµŃŠøŃŃŠøŠŗŠ°Š¼Šø. Ā ŠŠ¾Š“ŠµŠ»Ń Ā ŃŠ°Š·ŃŠ°Š±Š¾ŃŠ°Š½Š° Ā Ń Ā ŠæŠ¾Š¼Š¾ŃŃŃ Ā ŠæŠ°ŠŗŠµŃŠ° Ā ŠæŃŠøŠŗŠ»Š°Š“Š½ŃŃ
Ā ŠæŃŠ¾Š³ŃŠ°Š¼Š¼ Ā SimPowerSystems Š² MatLab. ŠŃŠø Š¼Š¾Š“ŠµŠ»ŠøŃŠ¾Š²Š°Š½ŠøŠø Š½Šµ ŃŃŠøŃŃŠ²Š°Š»ŠøŃŃ ŃŠµŠ¼ŠæŠµŃŠ°ŃŃŃŠ½ŃŠ¹ ŃŃŃŠµŠŗŃ Šø ŃŃŃŠµŠŗŃ ŃŃŠ°ŃŠµŠ½ŠøŃ Š°ŠŗŠŗŃŠ¼ŃŠ»ŃŃŠ¾ŃŠ½ŃŃ
Š±Š°ŃŠ°ŃŠµŠ¹, Š° ŃŠ°ŠŗŠ¶Šµ ŠæŠ°ŃŠ°Š¼ŠµŃŃŃ Š¾ŃŠ½Š¾ŃŠøŃŠµŠ»ŃŠ½Š¾ ŃŠ°Š¼Š¾ŃŠ°Š·ŃŃŠ“Š° Š°ŠŗŠŗŃŠ¼ŃŠ»ŃŃŠ¾ŃŠ½Š¾Š¹ Š±Š°ŃŠ°ŃŠµŠø. Š ŃŠµŠ·ŃŠ»ŃŃŠ°ŃŠµ Š¼Š¾Š“ŠµŠ»ŠøŃŠ¾Š²Š°Š½ŠøŃ ŠæŠ¾Š»ŃŃŠµŠ½Ń Ń
Š°ŃŠ°ŠŗŃŠµŃŠøŃŃŠøŠŗŠø ŃŠ°Š·ŃŃŠ“Š° Š±Š»Š¾ŠŗŠ¾Š² ŃŃŠæŠµŃŠŗŠ¾Š½Š“ŠµŠ½ŃŠ°ŃŠ¾ŃŠ¾Š² Šø Š°ŠŗŠŗŃŠ¼ŃŠ»ŃŃŠ¾ŃŠ½ŃŃ
Š±Š°ŃŠ°ŃŠµŠ¹, Š½Š° Š¾ŃŠ½Š¾Š²Š°Š½ŠøŠø ŠŗŠ¾ŃŠ¾ŃŃŃ
Š²ŃŃŠ²Š»ŠµŠ½Š° ŃŠµŠ»ŠµŃŠ¾Š¾Š±ŃŠ°Š·Š½Š¾ŃŃŃ ŠøŃ
ŃŠ¾Š²Š¼ŠµŃŃŠ½Š¾Š³Š¾ ŠøŃŠæŠ¾Š»ŃŠ·Š¾Š²Š°Š½ŠøŃ Š“Š»Ń Š²ŃŃŠ°Š²Š½ŠøŠ²Š°Š½ŠøŃ Š³ŃŠ°ŃŠøŠŗŠ¾Š² Š½Š°Š³ŃŃŠ·ŠŗŠø ŃŠ°Š·Š»ŠøŃŠ½ŃŃ
ŃŠøŠæŠ¾Š². ŠŃŠµŠ“ŃŃŠ°Š²Š»ŠµŠ½Ń ŃŠµŠ·ŃŠ»ŃŃŠ°ŃŃ Š¼Š¾Š“ŠµŠ»ŠøŃŠ¾Š²Š°Š½ŠøŃ ŃŠµŠ¶ŠøŠ¼Š¾Š² ŃŠ°Š±Š¾ŃŃ Š³ŠøŠ±ŃŠøŠ“Š½Š¾Š³Š¾ Š½Š°ŠŗŠ¾ŠæŠøŃŠµŠ»Ń ŃŠ½ŠµŃŠ³ŠøŠø, ŃŠ¾Š²Š¼ŠµŃŠ°ŃŃŠµŠ³Š¾ Š“Š¾ŃŃŠ¾ŠøŠ½ŃŃŠ²Š° Š“Š²ŃŃ
ŃŠøŠæŠ¾Š² Š½Š°ŠŗŠ¾ŠæŠøŃŠµŠ»ŠµŠ¹ ŃŠ½ŠµŃŠ³ŠøŠø, Š° ŃŠ°ŠŗŠ¶Šµ ŠæŠ¾Š»ŃŃŠµŠ½ Š³ŃŠ°ŃŠøŠŗ Š¾ŃŠ“Š°Š²Š°ŠµŠ¼Š¾Š¹ Š² ŃŠµŃŃ Š¼Š¾ŃŠ½Š¾ŃŃŠø, ŃŠ¾Š¾ŃŠ²ŠµŃŃŃŠ²ŃŃŃŠøŠ¹ Š·Š°Š“Š°Š½Š½ŃŠ¼ ŠæŠ°ŃŠ°Š¼ŠµŃŃŠ°Š¼. ŠŃŠøŠ²ŠµŠ“ŠµŠ½Š¾ Š¼Š°ŃŠµŠ¼Š°ŃŠøŃŠµŃŠŗŠ¾Šµ Š¾ŠæŠøŃŠ°Š½ŠøŠµ ŠæŃŠ¾ŃŠµŃŃŠ° ŃŠ²ŠµŠ»ŠøŃŠµŠ½ŠøŃ Š¼Š¾ŃŠ½Š¾ŃŃŠø Š³ŠøŠ±ŃŠøŠ“Š½Š¾Š³Š¾ Š½Š°ŠŗŠ¾ŠæŠøŃŠµŠ»Ń Š² ŃŠµŠ·ŃŠ»ŃŃŠ°ŃŠµ ŃŠ¾Š²Š¼ŠµŃŃŠ½Š¾Š³Š¾ ŠøŃŠæŠ¾Š»ŃŠ·Š¾Š²Š°Š½ŠøŃ Š±Š»Š¾ŠŗŠ¾Š² ŃŃŠæŠµŃŠŗŠ¾Š½Š“ŠµŠ½ŃŠ°ŃŠ¾ŃŠ¾Š² Šø Š°ŠŗŠŗŃŠ¼ŃŠ»ŃŃŠ¾ŃŠ½ŃŃ
Š±Š°ŃŠ°ŃŠµŠ¹. ŠŠ¾ŃŃŃŠ¾ŠµŠ½ Š³ŃŠ°ŃŠøŠŗ Š·Š°Š²ŠøŃŠøŠ¼Š¾ŃŃŠø ŠŗŠ¾ŃŃŃŠøŃŠøŠµŠ½ŃŠ° ŃŠ²ŠµŠ»ŠøŃŠµŠ½ŠøŃ Š¼Š¾ŃŠ½Š¾ŃŃŠø Š¾Ń ŃŠ°ŃŃŠ¾ŃŃ Šø Š²ŠµŠ»ŠøŃŠøŠ½Ń ŠŗŠ¾ŃŃŃŠøŃŠøŠµŠ½ŃŠ° Š·Š°ŠæŠ¾Š»Š½ŠµŠ½ŠøŃ ŠøŠ¼ŠæŃŠ»ŃŃŠ½Š¾Š³Š¾ ŃŠ¾ŠŗŠ°, ŠŗŠ¾ŃŠ¾ŃŃŠ¹ ŠæŠ¾ŠŗŠ°Š·ŃŠ²Š°ŠµŃ, ŃŃŠ¾ Š¼Š°ŠŗŃŠøŠ¼Š°Š»ŃŠ½Š¾ Š²Š¾Š·Š¼Š¾Š¶Š½Š°Ń Š²ŃŃ
Š¾Š“Š½Š°Ń Š¼Š¾ŃŠ½Š¾ŃŃŃ Š³ŠøŠ±ŃŠøŠ“Š½Š¾Š¹ Š½Š°ŠŗŠ¾ŠæŠøŃŠµŠ»ŃŠ½Š¾Š¹ ŃŠøŃŃŠµŠ¼Ń Š¼Š¾Š¶ŠµŃ Š±ŃŃŃ Š² ŃŠ°Š·Ń Š±Š¾Š»ŃŃŠµ Š¼Š¾ŃŠ½Š¾ŃŃŠø Š¾Š“ŠøŠ½Š¾ŃŠ½Š¾Š¹ Š±Š°ŃŠ°ŃŠµŠø Ń ŃŠ°ŠŗŠøŠ¼Šø Š¶Šµ ŠæŠ°ŃŠ°Š¼ŠµŃŃŠ°Š¼Šø
Diverse physical growth trajectories in institutionalized portuguese children below age 3: relation to child, family, and institutional factors
The authors would like to thank the students involved in the data collection and coding, and especially the children, caregivers, and other institutional staff who participated in the study.
Funding from FundaĆ§Ć£o para a CiĆŖncia e Tecnologia.Objective: To identify and analyze diverse longitudinal trajectories of physical growth of institutionalized children and their relation to child, family, and institutional factors.
Methods: 49 institutionalized children were studied for 9 months after admission. Weight, height, and head circumference were measured on 4 occasions, beginning at admission. Data were analyzed using latent class analysis, yielding diverse patterns of growth for each feature, and relations with child characteristics, early family risk factors, and institutional relational care were investigated.
Results: For each growth feature, 4 classes emerged: āāPersistently Low,āā āāImproving,āā āāDeteriorating,āā and āāPersistently High.āā Younger age at admission was a risk factor for impaired physical growth across all domains. Physical characteristics at birth were associated with trajectories across all domains. Lower prenatal risk and better institutional relational care were associated with Improving weight over time.
Conclusions: Discussion highlights the role of childrenās physical features at birth, prenatal risk, and caregiverās cooperation with the child in explaining differential trajectories.This research was supported in part by grant 13/06 from FundaĆ§Ć£o BIAL and by grant PTDC/PSI-PCL/101506/2008 from FundaĆ§Ć£o para a CiĆŖncia e Tecnologia
Differential susceptibility to plasticity: a 'missing link' between gene-culture co-evolution and neuropsychiatric spectrum disorders?
BrĆ¼ne's proposal that erstwhile 'vulnerability' genes need to be reconsidered as 'plasticity' genes, given the potential for certain environments to yield increased positive function in the same domain as potential dysfunction, has implications for psychiatric nosology as well as a more dynamic understanding of the relationship between genes and culture. In addition to validating neuropsychiatric spectrum disorder nosologies by calling for similar methodological shifts in gene-environment-interaction studies, BrĆ¼ne's position elevates the importance of environmental contexts - inclusive of socio-cultural variables - as mechanisms that contribute to clinical presentation. We assert that when models of susceptibility to plasticity and neuropsychiatric spectrum disorders are concomitantly considered, a new line of inquiry emerges into the co-evolution and co-determination of socio-cultural contexts and endophenotypes. This presents potentially unique opportunities, benefits, challenges, and responsibilities for research and practice in psychiatry
Ce-doped Li6Ln(BO3)3 (Ln = Y, Gd) Single crystals fibers grown by micro-pulling down method and luminescence properties
Ce3+-doped borate crystal fibers of Li6Gd(BO 3)3 (LGBO) and Li6Y(BO3)3 (LYBO) compositions are grown by the micro-pulling down (Ī¼-PD) method for potential application in developing new neutron detectors. The ternary equilibrium diagram of Li2O-Gd2O3-B 2O3 is drawn and the preparations of homogeneous mixed LGBO and LYBO powders and growth conditions for single crystal fibers are discussed. Absorption, excitation and X-ray luminescence spectra are investigated. Absolute light yield derived from energy spectra and kinetic decay curves measured under Ī±- and Ī³-scintillations of Ce 3+-doped LGBO and LYBO single crystal fibers is provided. Ā© 2012 Elsevier B.V. All rights reserved
Differential susceptibility in youth: evidence that 5-HTTLPR x positive parenting is associated with positive affect āfor better and worse'
Positive affect has been implicated in the phenomenological experience of various psychiatric disorders, vulnerability to develop psychopathology and overall socio-emotional functioning. However, developmental influences that may contribute to positive affect have been understudied. Here, we studied youths' 5-HTTLPR genotype and rearing environment (degree of positive and supportive parenting) to investigate the differential susceptibility hypothesis (DSH) that youth carrying short alleles of 5-HTTLPR would be more influenced and responsive to supportive and unsupportive parenting, and would exhibit higher and lower positive affect, respectively. Three independent studies tested this geneāenvironment interaction (GxE) in children and adolescents (age range 9ā15 years; total N=1874). In study 1 (N=307; 54% girls), positive/supportive parenting was assessed via parent report, in study 2 (N=197; 58% girls) via coded observations of parentāchild interactions in the laboratory and in study 3 (N=1370; 53% girls) via self report. Results from all the three studies showed that youth homozygous for the functional short allele of 5-HTTLPR were more responsive to parenting as environmental context in a āfor better and worse' manner. Specifically, the genetically susceptible youth (that is, S'S' group) who experienced unsupportive, non-positive parenting exhibited low levels of positive affect, whereas higher levels of positive affect were reported by genetically susceptible youth under supportive and positive parenting conditions. These GxE findings are consistent with the DSH and may inform etiological models and interventions in developmental psychopathology focused on positive emotion, parenting and genetic susceptibility
Differential Genetic Susceptibility to Child Risk at Birth in Predicting Observed Maternal Behavior
This study examined parenting as a function of child medical risks at birth and parental genotype (dopamine D4 receptor; DRD4). Our hypothesis was that the relation between child risks and later maternal sensitivity would depend on the presence/absence of a genetic variant in the mothers, thus revealing a gene by environment interaction (GXE). Risk at birth was defined by combining risk indices of children's gestational age at birth, birth weight, and admission to the neonatal intensive care unit. The DRD4-III 7-repeat allele was chosen as a relevant genotype as it was recently shown to moderate the effect of environmental stress on parental sensitivity. Mothers of 104 twin pairs provided DNA samples and were observed with their children in a laboratory play session when the children were 3.5 years old. Results indicate that higher levels of risk at birth were associated with less sensitive parenting only among mothers carrying the 7-repeat allele, but not among mothers carrying shorter alleles. Moreover, mothers who are carriers of the 7-repeat allele and whose children scored low on the risk index were observed to have the highest levels of sensitivity. These findings provide evidence for the interactive effects of genes and environment (in this study, children born at higher risk) on parenting, and are consistent with a genetic differential susceptibility model of parenting by demonstrating that some parents are inherently more susceptible to environmental influences, both good and bad, than are others
Family composition and age at menarche: findings from the international Health Behaviour in School-Aged Children Study
This research was funded by The University of St Andrews and NHS Health Scotland.Background Early menarche has been associated with father absence, stepfather presence and adverse health consequences in later life. This article assesses the association of different family compositions with the age at menarche. Pathways are explored which may explain any association between family characteristics and pubertal timing. Methods Cross-sectional, international data on the age at menarche, family structure and covariates (age, psychosomatic complaints, media consumption, physical activity) were collected from the 2009ā2010 Health Behaviour in School-aged Children (HBSC) survey. The sample focuses on 15-year old girls comprising 36,175 individuals across 40 countries in Europe and North America (Nā=ā21,075 for age at menarche). The study examined the association of different family characteristics with age at menarche. Regression and path analyses were applied incorporating multilevel techniques to adjust for the nested nature of data within countries. Results Living with mother (Cohenās dā=ā.12), father (dā=ā.08), brothers (dā=ā.04) and sisters (dā=ā.06) are independently associated with later age at menarche. Living in a foster home (dā=āā.16), with āsomeone elseā (dā=āā.11), stepmother (dā=āā.10) or stepfather (dā=āā.06) was associated with earlier menarche. Path models show that up to 89% of these effects can be explained through lifestyle and psychological variables. Conclusions Earlier menarche is reported amongst those with living conditions other than a family consisting of two biological parents. This can partly be explained by girlsā higher Body Mass Index in these families which is a biological determinant of early menarche. Lower physical activity and elevated psychosomatic complaints were also more often found in girls in these family environments.Publisher PDFPeer reviewe
- ā¦