Patterns of poverty exposure and children\u27s trajectories of externalizing and internalizing behaviors

Using data from the Child Supplement of the National Longitudinal Survey of Youth, we compare trajectories of externalizing and internalizing behaviors among children exposed to five patterns of poverty from birth to age 14: always or never poor – stable patterns; a single transition into or out of poverty, or repeated fluctuations in and out of poverty – changing patterns. We also examine how low maternal education and single parenthood interact with these poverty exposures to compound their adverse effects. Finally, we compare the magnitude of effects associated with the patterns of poverty exposure, as well as their interactions with low maternal education and single parenthood, on trajectories of externalizing and internalizing behaviors to determine if they are significantly different. Results reveal that initial levels and rates of change in children\u27s trajectories of externalizing and internalizing behaviors are similar across the three changing patterns of poverty exposure, leading us to combine them into a single group representing intermittent poverty. Initial disparities between children who are never poor and their counterparts who are always or intermittently poor are constant over time for internalizing behaviors and grow in magnitude for externalizing behaviors. The cumulative negative effect of poverty exposure over time is stronger for externalizing vs. internalizing behaviors. Low maternal education compounds the adverse effects of persistent poverty, an effect that is similar for externalizing and internalizing behaviors

Extrapolating gravitational-wave data from numerical simulations

Two complementary techniques are developed for obtaining the asymptotic form of gravitational-wave data at large radii from numerical simulations, in the form of easily implemented algorithms. It is shown that, without extrapolation, near-field effects produce errors in extracted waveforms that can significantly affect LIGO data analysis. The extrapolation techniques are discussed in the context of Newman--Penrose data applied to extrapolation of waveforms from an equal-mass, nonspinning black-hole binary simulation. The results of the two methods are shown to agree within error estimates. The various benefits and deficiencies of the methods are discussed.Comment: Added missing references; refined data. Version accepted in Phys. Rev.

Mouse skin passage of a Streptococcus pyogenes Tn917 mutant of sagA/pel restores virulence, beta-hemolysis and sagA/pel expression without altering the position or sequence of the transposon

BACKGROUND: Streptolysin S (SLS), the oxygen-stable hemolysin of Streptococcus pyogenes, has recently been shown to be encoded by the sagA/pel gene. Mutants lacking expression of this gene were less virulent in a dermonecrotic mouse infection model. Inactivation of the sagA/pel gene affect the expression of a variety of virulence factors in addition to the hemolysin. Insertion of a Tn917 transposon into the promoter region of the sagA/pel gene of S. pyogenes isolate CS101 eliminated expression of SLS, as well as decreased expression of the streptococcal pyrogenic exotoxin B, streptokinase and M protein. RESULTS: In this study a mouse skin air sac model was utilized to analyze the effect of biological pressures on expression of SLS and other sagA/pel regulated gene products. The insertion delayed the lethal effect of S. pyogenes in a mouse skin infection model. Despite this, bacteria could be cultured from the kidneys 72 hours post infection. These kidney-recovered isolates were β-hemolytic despite the transposon being present in its original location and had equivalent virulence to the wild type isolate when re-injected into naive mice. Northern blot analysis of the kidney-recovered isolates confirmed that transcription of sagA/pel was restored; however the expression of all sagA/pel regulated genes was not restored to wild type levels. CONCLUSIONS: These results show that biological pressure present in the mouse can select for variants with altered expression of key virulence factor genes in S. pyogenes

Suitability of hybrid gravitational waveforms for unequal-mass binaries

This article studies sufficient accuracy criteria of hybrid post-Newtonian (PN) and numerical relativity (NR) waveforms for parameter estimation of strong binary black-hole sources in second- generation ground-based gravitational-wave detectors. We investigate equal-mass non-spinning binaries with a new 33-orbit NR waveform, as well as unequal-mass binaries with mass ratios 2, 3, 4 and 6. For equal masses, the 33-orbit NR waveform allows us to recover previous results and to extend the analysis toward matching at lower frequencies. For unequal masses, the errors between different PN approximants increase with mass ratio. Thus, at 3.5PN, hybrids for higher-mass-ratio systems would require NR waveforms with many more gravitational-wave (GW) cycles to guarantee no adverse impact on parameter estimation. Furthermore, we investigate the potential improvement in hybrid waveforms that can be expected from 4th order post-Newtonian waveforms, and find that knowledge of this 4th post-Newtonian order would significantly improve the accuracy of hybrid waveforms.Comment: 11 pages, 14 figure

Social assistance and trajectories of child mental health problems in Canada: evidence from the National Longitudinal Survey of Children and Youth

Objectives: To examine the link between stability and change in social assistance (SA) use and children’s mental health trajectories to better understand whether social policies targeted at low-income families might be an effective population-based mechanism for preventing mental health problems among children at risk. Methods: The National Longitudinal Survey of Children and Youth (N = 8981) is used to classify children into 5 categories based on their family’s pattern of SA use from age 4–5 to 10–11: always or never on SA, a single transition on or off SA, or fluctuations on and off SA. Latent growth modelling is used to compare trajectories of emotional and behavioural problems among children with different patterns of SA exposure to their counterparts never on SA over this same time period. Results: Child emotional and behavioural problems are exacerbated over time in accordance with patterns of SA use: chronic SA use (behavioural) and moving onto SA (emotional and behavioural). These differential rates of change result in mental health disparities at age 10–11 that were not present at age 4–5. Children exposed to SA when they were age 4–5 but subsequently moved off continue to demonstrate elevated levels of emotional and behavioural problems at age 10–11. Conclusions: Successful social policies and interventions will require understanding the specific mechanisms through which SA undermines child mental health and how programs can be modified to reduce its negative consequences

Concurrent associations among sleep problems, indicators of inadequate sleep, psychopathology, and shared risk factors in a population-based sample of healthy Ontario children

Objectives Examine the contribution of sleep problems and indicators of inadequate sleep to psychopathology among children after accounting for shared risk and comorbid psychopathology. Methods Secondary analyses of cross-sectional data on 4- to 11-year-old (N = 1,550) children without chronic illness or developmental delay or disability. Parents provided information about sleep problems, indicators of inadequate sleep, symptoms of psychopathology, and risk factors for psychopathology. Teachers provided information about indicators of inadequate sleep and symptoms of psychopathology. Results Adjusting for risk factors and comorbid psychopathology, sleeping more than other children was related to parent-rated aggression. Nightmares and trouble sleeping were related to parent-rated anxious/depressed mood. Sleep problems were not related to attention problems. Being overtired was related to parent- and teacher-rated psychopathology. Conclusions Relations among sleep problems, indicators of inadequate sleep, and psychopathology are complex; accounting for potential confounding variables and considering sleep variables separately may clarify these relations. © 2009 The Author. Published by Oxford University Press on behalf of the Society of Pediatric Psychology. All rights reserved

Orbitally excited and hybrid mesons from the lattice

We discuss in general the construction of gauge-invariant non-local meson operators on the lattice. We use such operators to study the $P$- and $D$-wave mesons as well as hybrid mesons in quenched QCD, with quark masses near the strange quark mass. The resulting spectra are compared with experiment for the orbital excitations. For the states produced by gluonic excitations (hybrid mesons) we find evidence of mixing for non-exotic quantum numbers. We give predictions for masses of the spin-exotic hybrid mesons with $J^{PC}=1^{-+},\ 0^{+-}$, and$2^{+-}$.Comment: 31 pages, LATEX, 8 postscript figures. Reference adde

Design Considerations for Ceramic Matrix Composite Vanes for High Pressure Turbine Applications

Issues associated with replacing conventional metallic vanes with Ceramic Matrix Composite (CMC) vanes in the first stage of the High Pressure Turbine (HPT) are explored. CMC materials have higher temperature capability than conventional HPT vanes, and less vane cooling is required. The benefits of less vane coolant are less NOx production and improved vane efficiency. Comparisons between CMC and metal vanes are made at current rotor inlet temperatures and at an vane inlet pressure of 50 atm.. CMC materials have directionally dependent strength characteristics, and vane designs must accommodate these characteristics. The benefits of reduced NOx and improved cycle efficiency obtainable from using CMC vanes. are quantified Results are given for vane shapes made of a two dimensional CMC weave. Stress components due to thermal and pressure loads are shown for all configurations. The effects on stresses of: (1) a rib connecting vane pressure and suction surfaces; (2) variation in wall thickness; and (3) trailing edge region cooling options are discussed. The approach used to obtain vane temperature distributions is discussed. Film cooling and trailing edge ejection were required to avoid excessive vane material temperature gradients. Stresses due to temperature gradients are sometimes compressive in regions where pressure loads result in high tensile stresses

Six-Month Prevalence of Mental Disorders and Service Contacts among Children and Youth in Ontario: Evidence from the 2014 Ontario Child Health Study

© The Author(s) 2019. Objectives: To present the 6-month prevalence and sociodemographic correlates of mental disorders and mental health–related service contacts in a sample of children (4 to 11 years) and youth (12 to 17 years) in Ontario. Methods: The 2014 Ontario Child Health Study is a provincially representative survey of 6537 families with children aged 4 to 17 years in Ontario. DSM-IV-TR mental disorders were assessed using the Mini International Neuropsychiatric Interview for Children and Adolescents (MINI-KID) and included mood (major depressive episode), anxiety (generalized anxiety, separation anxiety, social phobia, specific phobia), and behaviour disorders (attention-deficit/hyperactivity disorder, oppositional-defiant disorder, conduct disorder).The MINI-KID was administered independently to the primary caregiver and youth aged 12 to 17 years in the family’s home. Results: Past 6-month prevalence of any mental disorder ranged from 18.2% to 21.8% depending on age and informant. Behaviour disorders were the most common among children, and anxiety disorders were the most common among youth. Among children and youth with a parent-identified mental disorder, 25.6% of children and 33.7% of youth had contact with a mental health provider. However, 60% had contact with one or more of the providers or service settings assessed, most often through schools. Conclusions: Between 18% and 22% of children and youth in Ontario met criteria for a mental disorder but less than one-third had contact with a mental health provider. These findings provide support for strengthening prevention and early intervention efforts and enhancing service capacity to meet the mental health needs of children and youth in Ontario