Global General Relativistic Magnetohydrodynamic Simulations of Accretion Tori

This paper presents an initial survey of the properties of accretion flows in the Kerr metric from three-dimensional, general relativistic magnetohydrodynamic simulations of accretion tori. We consider three fiducial models of tori around rotating, both prograde and retrograde, and nonrotating black holes; these three fiducial models are also contrasted with axisymmetric simulations and a pseudo-Newtonian simulation with equivalent initial conditions to delineate the limitations of these approximations.Comment: Submitted to ApJ. 30 pages, 21 figures. Animations and high-resolution version of figures available at http://www.astro.virginia.edu/~jd5

The interaction of a giant planet with a disc with MHD turbulence I: The initial turbulent disc models

This is the first of a series of papers aimed at developing and interpreting simulations of protoplanets interacting with turbulent accretion discs. Here we study the disc models prior to the introduction of a protoplanet.We study models in which a Keplerian domain is unstable to the magnetorotational instability (MRI). Various models with B-fields having zero net flux are considered.We relate the properties of the models to classical viscous disc theory.All models attain a turbulent state with volume averaged stress parameter alpha ~ 0.005. At any particular time the vertically and azimuthally averaged value exhibited large fluctuations in radius. Time averaging over periods exceeding 3 orbital periods at the outer boundary of the disc resulted in a smoother quantity with radial variations within a factor of two or so. The vertically and azimuthally averaged radial velocity showed much larger spatial and temporal fluctuations, requiring additional time averaging for 7-8 orbital periods at the outer boundary to limit them. Comparison with the value derived from the averaged stress using viscous disc theory yielded schematic agreement for feasible averaging times but with some indication that the effects of residual fluctuations remained. The behaviour described above must be borne in mind when considering laminar disc simulations with anomalous Navier--Stokes viscosity. This is because the operation of a viscosity as in classical viscous disc theory with anomalous viscosity coefficient cannot apply to a turbulent disc undergoing rapid changes due to external perturbation. The classical theory can only be used to describe the time averaged behaviour of the parts of the disc that are in a statistically steady condition for long enough for appropriate averaging to be carried out.Comment: 10 pages, 23 figures, accepted for publication in MNRAS. A gzipped postscript version including high resolution figures is available at http://www.maths.qmul.ac.uk/~rp

Outcomes following childhood head injury : a population study

Objectives: To identify outcomes following head injury (HI) amongst a population of children admitted to one hospital centre and compare outcomes between different severity groups. Methods:A postal follow-up of children admitted with HI to one NHS Trust, between 1992-1998, was carried out. Children were aged 5-15 years at injury (mean 9.8), followed-up at a mean of 2.2 years post-injury. Parents of 526 injured children (419 mild, 58 moderate, 49 severe) and 45 controls completed questionnaires. Outcomes were assessed using the King’s Outcome Scale for Childhood Head Injury (KOSCHI). Results:Frequent behavioural, emotional, memory and attentional problems were reported by one third of the severe group, one quarter of the moderate, and 10-18% of the mild. Personality change since HI was reported for 148 children (28%) (21% mild HI, 46% moderate, 69% severe). There was a significant relationship between injury severity and KOSCHI outcomes. Following the HI, 252(48%) had moderate disability (43% mild HI, 64% moderate, 69% severe), 270(51%) made a good recovery (57% mild HI, 36% moderate, 22% severe). There was a significant association between social deprivation and poor outcome (p=0.002). Only 30%(158) of children received hospital follow-up after the HI. All children with severe disability received appropriate follow-up, but 64% of children with moderate disability received none. No evidence was found to suggest a threshold of injury severity below which the risk of late sequelae could be safely discounted. Conclusions:Children admitted with mild HI may be at risk of poor outcomes, but often do not receive routine hospital follow-up. A postal questionnaire combined with the KOSCHI to assess outcomes after HI may be used to identify children who would benefit from clinical assessment. Further research is needed to identify factors which place children with mild HI at risk of late morbidity

Return to school after brain injury

Objective: To examine return to school and classroom performance following traumatic brain injury (TBI) Design: Cross-sectional Setting: Community Subjects: 67 school-age children with TBI (35 mild, 13 moderate, 19 severe), and 14 uninjured matched controls. Interventions: Parents and children were interviewed and children assessed at a mean of two years post injury. Teachers reported on academic performance and educational needs. Main measures: Classroom performance, Children’s Memory Scale (CMS), WISC-III, WORD. Results: One third of teachers were unaware of the TBI. On return to school, special arrangements were made for 18 children (27%). Special educational needs were identified for 16 (24%), but only six children (9%) received specialist help. Two-thirds of children with TBI had difficulties with school-work, half had attention/concentration problems and 26 (39%) had memory problems. Compared to other pupils in the class, one third of children with TBI were performing below average. On the CMS, one third of the severe group were impaired/borderline for immediate and delayed recall of verbal material, and over one quarter were impaired/borderline for general memory. Children in the severe group had a mean full-scale IQ significantly lower than controls. Half the TBI group had a reading age ≥1 year below their chronological age, one third were reading ≥2 years below chronological age. Conclusions: Schools rely on parents to inform them about a TBI, and rarely receive information on possible long-term sequelae. At hospital discharge, health professionals should provide schools with information about TBI and possible long-term impairments, so that children returning to school receive appropriate support

Parental stress and burden following traumatic brain injury amongst children and adolescents

Primary objectives: to assess parental stress following paediatric traumatic brain injury (TBI) and examine the relationship between self-reported problems and parental stress and general health. Research design: controlled interview study Methods and procedures: Parents of ninety-seven children admitted with a TBI (49 mild, 19 moderate, 29 severe) were identified from a case register of all paediatric admissions from 1992-1998. Parents of 31 uninjured children acted as controls. Structured interviews were carried out with families, and parents assessed on the Parenting Stress Index (PSI/SF) and General Health Questionnaire (GHQ-12) at recruitment, and repeated 12 months later. Main outcomes and results: regardless of injury severity, parents of injured children suffered greater stress than control parents as measured by the PSI/SF (p = 0.001). There was a highly significant relationship between number of problems reported and level of parental stress (p = 0.001). Financial burden was related to severity of TBI. Conclusions: improved information, follow-up, and support is likely to reduce parental stress and family burden

Children's brain injury : a postal follow-up of 525 children from one health region in the UK

Primary objectives: to follow-up a population of children admitted to one Hospital Trust with traumatic brain injury (TBI), and compare outcomes following mild TBI with outcomes following moderate or severe TBI. Research design: population-based postal questionnaire survey. Methods and procedures: questionnaires were mailed to parents of all 974 surviving children on a register of paediatric TBI admissions, 525 completed questionnaires were returned (56.2%). Most children (419) had suffered mild TBI, 57 moderate, and 49 severe. Main outcomes and results: Thirty percent of parents received no information on post-injury symptoms, and clinical follow-up was limited. Statistically significant differences were observed between mild and moderate/severe groups for cognitive, social, emotional, and mobility problems. Nevertheless, approximately 20% of the mild group suffered from poor concentration, personality change, and educational problems post-injury. Few schools (20%) made special provision for children returning after injury. Conclusions: children can have long lasting and wide ranging sequelae following TBI. Information should be routinely given to parents and schools after brain injury

Parental instruction in Relation to Sunday-School Teaching

On no subject do the Scriptures more clearly or more earnestly teach the duty of parents than in reference to the religious education and salvation of their children. The relations of children to the Church are also clearly indicated in them.https://place.asburyseminary.edu/ecommonsatsdigitalresources/1174/thumbnail.jp

Prominent Doctrines and Peculiar Usages of the Methodist Episcopal Church Stated and Defended with Scripture Proofs and Illustrations

Our main doctrines, which include all the rest, are repentance, faith, and holiness. The first of these we account, as it were, the porch of religion; the next, the door; the third, religion itself. - John Wesleyhttps://place.asburyseminary.edu/ecommonsatsdigitalresources/1321/thumbnail.jp