Effect of boattail geometry on the acoustics of parallel baffles in ducts

Sound attenuation and total pressure drop of parallel duct baffles incorporating certain boattail geometries were measured in the NASA Ames Research Center 7- by 10-Foot Wind Tunnel. The baseline baffles were 1.56 m long and 20 cm thick, on 45-cm center-to-center spacings, and spanned the test section from floor to ceiling. Four different boattails were evaluated: a short, smooth (nonacoustic) boattail; a longer, smooth boattail; and two boattails with perforated surfaces and sound-absorbent filler. Acoustic measurements showed the acoustic boattails improved the sound attenuation of the baffles at approximately half the rate to be expected from constant-thickness sections of the same length; that is, 1.5 dB/n, where n is the ratio of acoustic treatment length to duct passage width between baffles. The aerodynamic total pressure loss was somewhat sensitive to tail geometry. Lengthening the tails to reduce the diffusion half-angle from 11 to 5 degrees reduced the total pressure loss approximately 9%. Perforating the boattails, which increased the surface roughness, did not have a large effect on the total pressure loss. Aerodynamic results are compared with a published empirical method for predicting baffle total pressure drop

The impact of ADHD on the health and well-being of ADHD children and their siblings

Childhood attention-deficit/hyperactivity disorder (ADHD) has been associated with reduced health and well-being of patients and their families. The authors undertook a large UK survey-based observational study of the burden associated with childhood ADHD. The impact of ADHD on both the patient (N = 476) and their siblings (N = 337) on health-related quality of life (HRQoL) and happiness was quantified using multiple standard measures [e.g. child health utility-9D (CHU-9D), EuroQol-5D-Youth]. In the analysis, careful statistical adjustments were made to ensure a like-for-like comparison of ADHD families with two different control groups. We controlled for carers' ADHD symptoms, their employment and relationship status and siblings' ADHD symptoms. ADHD was associated with a significant deficit in the patient's HRQoL (with a CHU-9D score of around 6 % lower). Children with ADHD also have less sleep and were less happy with their family and their lives overall. No consistent decrement to the HRQoL of the siblings was identified across the models, except that related to their own conduct problems. The siblings do, however, report lower happiness with life overall and with their family, even when controlling for the siblings own ADHD symptoms. We also find evidence of elevated bullying between siblings in families with a child with ADHD. Overall, the current results suggest that the reduction in quality of life caused by ADHD is experienced both by the child with ADHD and their siblings

District variations in educational resources and student outcomes

Abstract Since the 1970s, poorer school districts lacking educational resources have formed coalitions and sued their respective states. Their lawsuits claim that interdistrict variations in educational resources violate state constitutions because they deny poorer school districts an equal educational opportunity. Using data from school districts in Virginia, this research investigates two questions. First, whether a school district's level of educational resources is associated with its socioeconomic characteristics. Second, whether interdistrict variations in student outcomes (achievements, attainments and aspirations) are associated with interdistrict variations in educational resources. Our results indicate that resources are associated with a school district's socioeconomic characteristics and that resources are associated with student outcomes. However, there is evidence of effects of resources on student outcomes only for attainments and aspirations, not for math and reading test scores

Comparisons between adolescent bullies, victims, and bully-victims on perceived popularity, social impact, and social preference

This study investigated the effect of bullying role, i.e., bully, victim, and bully-victim, on three measures of peer status; perceived popularity, social preference, and social impact. In addition to completing peer nominations for these measures of peer status, adolescents (n = 2,721) aged 11 to 16 years from 5 secondary schools completed an online survey that assessed bullying involvement (self- and peer-reported), self-esteem, and behavioral difficulties. Compared to uninvolved adolescents, all bullying roles had a greater social impact. Bullies scored higher than all other roles for perceived popularity, whereas victims and bully-victims were the lowest in social preference. These significant group comparisons remained when controlling for demographic variables, behavioral difficulties, self-esteem and prosocial behavior. Overall, the perceived popularity found for bullies suggests that these adolescents are socially rewarded by peers for their victimization of others. These findings highlight the need to address the whole peer system in raising the social status of those who are victimized, whilst reducing the rewards received by bullies for their behavior.AG and KL were supported to undertake this research by a fellowship from the Department of Psychology, University of Warwick.Published onlin

Dear British criminology: Where has all the race and racism gone?

In this article we use Emirbayer and Desmond’s institutional reflexivity framework to critically examine the production of racial knowledge in British criminology. Identifying weakness, neglect and marginalization in theorizing race and racism, we focus principally on the disciplinary unconscious element of their three-tier framework, identifying and interrogating aspects of criminology’s ‘obligatory problematics’, ‘habits of thought’ and ‘position-taking’ as well as its institutional structure and social relations that combine to render the discipline ‘institutionally white’. We also consider, briefly, aspects of criminology’s relationship to race, racism and whiteness in the USA. The final part of the article makes the case for British criminology to engage in telling and narrating racisms, urging it to understand the complexities of race in our subject matter, avoid its reduction to class and inequality, and to pay particular attention to reflexivity, history, sociology and language, turning to face race with postcolonial tools and resolve

INDIRECT EFFECTS IN THE PEER VICTIMIZATION-ACADEMIC ACHIEVEMENT RELATION: THE ROLE OF ACADEMIC SELF-CONCEPT AND GENDER

Peer victimization is a concern because victimized youth are more likely to have social, emotional, and academic difficulties. The current study examined the link between peer victimization and academic achievement by exploring the indirect effect of academic self-concept on two variables. The sample consisted of 140 middle school students (40% male, 60% female). Using structural equation modeling, a mediation model revealed a significant indirect effect of victimization on academic achievement through academic self-concept; however, when tested for gender differences, the indirect effect was only significant for girls. Interpretation of these results and suggestions for future studies are discussed

The Relationship Between Parenting and Delinquency: A Meta-analysis

This meta-analysis of 161 published and unpublished manuscripts was conducted to determine whether the association between parenting and delinquency exists and what the magnitude of this linkage is. The strongest links were found for parental monitoring, psychological control, and negative aspects of support such as rejection and hostility, accounting for up to 11% of the variance in delinquency. Several effect sizes were moderated by parent and child gender, child age, informant on parenting, and delinquency type, indicating that some parenting behaviors are more important for particular contexts or subsamples. Although both dimensions of warmth and support seem to be important, surprisingly very few studies focused on parenting styles. Furthermore, fewer than 20% of the studies focused on parenting behavior of fathers, despite the fact that the effect of poor support by fathers was larger than poor maternal support, particularly for sons. Implications for theory and parenting are discussed

The effects of single-sex versus coeducational schools on adolescent peer victimization and perpetration

Bullying is a growing public health concern for South Korean adolescents. In our quantitative investigation, we analyze the frequency with which Korean adolescents in single-sex versus coeducational schools are targets of or engage in three peer aggressive behaviors (verbal, relational (social exclusion), and physical (including theft)). We use two nationally representative datasets, the 2011 Trends in International Mathematics and Science Study (TIMSS) and the 2005 Korea Education Longitudinal Study (KELS), and rely on propensity score matching (PSM). For adolescent girls, we find that being in all-girls schools mitigates both their exposure to and engagement in peer victimization. For adolescent boys, we find that boys in all-boys schools have significantly higher odds of experiencing more frequent verbal and physical attacks versus their counterparts in coeducational schools. Our findings strongly suggest that interventions to mitigate peer victimization and aggression in Korea should consider the gendered schooling contexts in which they are implemented