Pedestrian, Crowd, and Evacuation Dynamics

This contribution describes efforts to model the behavior of individual pedestrians and their interactions in crowds, which generate certain kinds of self-organized patterns of motion. Moreover, this article focusses on the dynamics of crowds in panic or evacuation situations, methods to optimize building designs for egress, and factors potentially causing the breakdown of orderly motion.Comment: This is a review paper. For related work see http://www.soms.ethz.c

Chemical and biomechanical characterization of hyperhomocysteinemic bone disease in an animal model

BACKGROUND: Classical homocystinuria is an autosomal recessive disorder caused by cystathionine β-synthase (CBS) deficiency and characterized by distinctive alterations of bone growth and skeletal development. Skeletal changes include a reduction in bone density, making it a potentially attractive model for the study of idiopathic osteoporosis. METHODS: To investigate this aspect of hyperhomocysteinemia, we supplemented developing chicks (n = 8) with 0.6% dl-homocysteine (hCySH) for the first 8 weeks of life in comparison to controls (n = 10), and studied biochemical, biomechanical and morphologic effects of this nutritional intervention. RESULTS: hCySH-fed animals grew faster and had longer tibiae at the end of the study. Plasma levels of hCySH, methionine, cystathionine, and inorganic sulfate were higher, but calcium, phosphate, and other indices of osteoblast metabolism were not different. Radiographs of the lower limbs showed generalized osteopenia and accelerated epiphyseal ossification with distinct metaphyseal and suprametaphyseal lucencies similar to those found in human homocystinurics. Although biomechanical testing of the tibiae, including maximal load to failure and bone stiffness, indicated stronger bone, strength was proportional to the increased length and cortical thickness in the hCySH-supplemented group. Bone ash weights and IR-spectroscopy of cortical bone showed no difference in mineral content, but there were higher Ca(2+)/PO(4)(3- )and lower Ca(2+)/CO(3)(2- )molar ratios than in controls. Mineral crystallization was unchanged. CONCLUSION: In this chick model, hyperhomocysteinemia causes greater radial and longitudinal bone growth, despite normal indices of bone formation. Although there is also evidence for an abnormal matrix and altered bone composition, our finding of normal biomechanical bone strength, once corrected for altered morphometry, suggests that any increase in the risk of long bone fracture in human hyperhomocysteinemic disease is small. We also conclude that the hCySH-supplemented chick is a promising model for study of the connective tissue abnormalities associated with homocystinuria and an important alternative model to the CBS knock-out mouse

Subjective Well-Being, Life Satisfaction and Interpersonal Relationships Associated to Socio-Demographic and Contextual Variables

This study aims associating children’s satisfaction to their interpersonal relationships within their main contexts of interaction (family, friends and school) and their satisfaction regarding their subjective well-being, considering the variables age, gender, type of school (public or private) and city of living (capital or not). There were 2.280 children from 9 to 13 years old (M = 10,99; SD = 0,996), being 1.341 from the capital city (58,8%), most of them from public schools (61%) and 55,5% of the amount were girls. The results showed there is no difference between the average satisfaction data and the interpersonal relationships by age and that children living in country towns are more satisfied with their interpersonal relationships. Children who study in private schools are more satisfied with their family relationships and school environment, while students from public schools are more satisfied with their friendships; besides girls are more satisfied with both their school relationships and friends. The subjective well-being decreased as they become older and boys showed an average subjective well-being significantly higher than girls. Considering the interactions among subjective well-being and the variables evaluated, the children who presented higher average of subjective well-being are those who live in country towns and study in public schools and the ones who live in the capital and study at in private schools

Measuring mental wellbeing among adolescents : a systematic review of instruments

Globally, promoting mental wellbeing among adolescents is of great public health and social significance. However, less is known about advances in measures of mental wellbeing, relevant for use in mental health interventions, which are age-appropriate and acceptable for use among adolescents. Comprehensive assessment includes multiple aspects of mental wellbeing, as well as positive indicators of feeling and functioning. This review used systematic review methods, guided by PRISMA, to identify and assess comprehensive instruments in terms of their content, conceptual relevance for youth, and responsiveness to change. Ryan and Deci’s framework for mental wellbeing, grounded in hedonic and eudaimonic perspectives, was applied to assess the preponderance of feeling and functioning items for each instrument. The review identified 11 instruments that fit specified inclusion criteria. Only four of the scales were developed for adolescents. Though the scales varied in their preponderance of items, all scales encompassed at least one indicator of both feeling and functioning. Findings emphasize the importance of validating adult-developed instruments for youth and ensuring the instrument’s cultural and conceptual relevance within groups of adolescents. As promoting mental wellbeing becomes critical to the field of practice, practitioners need access to relevant and acceptable measures