75 research outputs found
Roughening kinetics of chemical vapor deposited copper films on Si(100)
3 pages, 3 figures.The roughening kinetics of copper films synthesized by low pressure chemical vapor deposition (LPCVD) on Si(100) substrates was investigated by scanning tunneling microscopy (STM). By applying the dynamic scaling theory to the STM images, a steady growth roughness exponent (alfa)=0.81 ± 0.05 and a dynamic growth roughness exponent (beta)=0.62 ± 0.09 were determined. The value of (alfa) is consistent with growth model predictions incorporating surface diffusion. The value of
(beta), while higher than expected from these models, can be related to LPCVD processing conditions favoring growth instabilities.This work was partially supported by the CSICCONICET
cooperation program and by a grant from the
NASA New Jersey Space Grant Consortium.Peer reviewe
Roughening kinetics of chemical vapor deposited copper films on Si(100)
The roughening kinetics of copper films synthesized by low pressure chemical vapor deposition (LPCVD) on Si(100) substrates was investigated by scanning tunneling microscopy (STM). By applying the dynamic scaling theory to the STM images, a steady growth roughness exponent α=0.81±0.05 and a dynamic growth roughness exponent β=0.62±0.09 were determined. The value of a is consistent with growth model predictions incorporating surface diffusion. The value of β, while higher than expected from these models, can be related to LPCVD processing conditions favoring growth instabilities.Instituto de Investigaciones FisicoquÃmicas Teóricas y Aplicada
Unhealthy Gambling Amongst New Zealand Secondary School Students: An Exploration of Risk and Protective Factors
This study sought to determine the prevalence of gambling and unhealthy gambling behaviour and describe risk and protective factors associated with these behaviours amongst a nationally representative sample of New Zealand secondary school students (n = 8,500). Factor analysis and item response theory were used to develop a model to provide a measure of ‘unhealthy gambling’. Logistic regressions and multiple logistic regression models were used to investigate associations between unhealthy gambling behaviour and selected outcomes. Approximately one-quarter (24.2 %) of students had gambled in the last year, and 4.8 % had two or more indicators of unhealthy gambling. Multivariate analyses found that unhealthy gambling was associated with four main factors: more accepting attitudes towards gambling (pp = 0.0061); being worried about and/or trying to cut down on gambling (p p = 0.0009). Unhealthy gambling is a significant health issue for young people in New Zealand. Ethnic and social inequalities were apparent and these disparities need to be addressed
A systematic autopsy survey of human infant bridging veins
In the first years of life, subdural haemorrhage (SDH) within the cranial cavity can occur through accidental and non-accidental mechanisms as well as from birth-related injury. This type of bleeding is the most common finding in victims of abusive head trauma (AHT). Historically, the most frequent cause of SDHs in infancy is suggested to be traumatic damage to bridging veins traversing from the brain to the dural membrane. However, several alternative hypotheses have been suggested for the cause and origin of subdural bleeding. It has also been suggested by some that bridging veins are too large to rupture through the forces associated with AHT. To date, there have been no systematic anatomical studies on infant bridging veins. During 43 neonatal, infant and young child post-mortem examinations, we have mapped the locations and numbers of bridging veins onto a 3D model of the surface of a representative infant brain. We have also recorded the in situ diameter of 79 bridging veins from two neonatal, one infant and two young children at post-mortem examination. Large numbers of veins, both distant from and directly entering the dural venous sinuses, were discovered travelling between the brain and dural membrane, with the mean number of veins per brain being 54.1 and the largest number recorded as 94. The mean diameter of the bridging veins was 0.93Â mm, with measurements ranging from 0.05 to 3.07Â mm. These data demonstrate that some veins are extremely small and subjectively, and they appear to be delicate. Characterisation of infant bridging veins will contribute to the current understanding of potential vascular sources of subdural bleeding and could also be used to further develop computational models of infant head injury
Primary care patients reporting concerns about their gambling frequently have other co-occurring lifestyle and mental health issues
BACKGROUND: Problem gambling often goes undetected by family physicians but may be associated with stress-related medical problems as well as mental disorders and substance abuse. Family physicians are often first in line to identify these problems and to provide a proper referral. The aim of this study was to compare a group of primary care patients who identified concerns with their gambling behavior with the total population of screened patients in relation to co-morbidity of other lifestyle risk factors or mental health issues. METHODS: This is a cross sectional study comparing patients identified as worrying about their gambling behavior with the total screened patient population for co morbidity. The setting was 51 urban and rural New Zealand practices. Participants were consecutive adult patients per practice (N = 2,536) who completed a brief multi-item tool screening primary care patients for lifestyle risk factors and mental health problems (smoking, alcohol and drug misuse, problem gambling, depression, anxiety, abuse, anger). Data analysis used descriptive statistics and non-parametric binomial tests with adjusting for clustering by practitioner using STATA survey analysis. RESULTS: Approximately 3/100 (3%) answered yes to the gambling question. Those worried about gambling more likely to be male OR 1.85 (95% CI 1.1 to 3.1). Increasing age reduced likelihood of gambling concerns – logistic regression for complex survey data OR = 0.99 (CI 95% 0.97 to 0.99) p = 0.04 for each year older. Patients concerned about gambling were significantly more likely (all p < 0.0001) to have concerns about their smoking, use of recreational drugs, and alcohol. Similarly there were more likely to indicate problems with depression, anxiety and anger control. No significant relationship with gambling worries was found for abuse, physical inactivity or weight concerns. Patients expressing concerns about gambling were significantly more likely to want help with smoking, other drug use, depression and anxiety. CONCLUSION: Our questionnaire identifies patients who express a need for help with gambling and other lifestyle and mental health issues. Screening for gambling in primary care has the potential to identify individuals with multiple co-occurring disorders
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