An Alternative Approach to the Calculation and Analysis of Connectivity in the World City Network

Empirical research on world cities often draws on Taylor's (2001) notion of an 'interlocking network model', in which office networks of globalized service firms are assumed to shape the spatialities of urban networks. In spite of its many merits, this approach is limited because the resultant adjacency matrices are not really fit for network-analytic calculations. We therefore propose a fresh analytical approach using a primary linkage algorithm that produces a one-mode directed graph based on Taylor's two-mode city/firm network data. The procedure has the advantage of creating less dense networks when compared to the interlocking network model, while nonetheless retaining the network structure apparent in the initial dataset. We randomize the empirical network with a bootstrapping simulation approach, and compare the simulated parameters of this null-model with our empirical network parameter (i.e. betweenness centrality). We find that our approach produces results that are comparable to those of the standard interlocking network model. However, because our approach is based on an actual graph representation and network analysis, we are able to assess cities' position in the network at large. For instance, we find that cities such as Tokyo, Sydney, Melbourne, Almaty and Karachi hold more strategic and valuable positions than suggested in the interlocking networks as they play a bridging role in connecting cities across regions. In general, we argue that our graph representation allows for further and deeper analysis of the original data, further extending world city network research into a theory-based empirical research approach.Comment: 18 pages, 9 figures, 2 table

Hopane biomarkers traced from bedrock to recent sediments and ice at the Haughton Impact Structure, Devon Island: Implications for the search for biomarkers on Mars

Hopanoid biomarkers have been traced from bedrock to ice in the Haughton Impact Structure, suggesting that they represent a promising strategy in the search for life in ice deposits on Mars and other icy bodies

Comment on "Drip Paintings and Fractal Analysis", arXiv:0710.4917v2, by K. Jones-Smith, H. Mathur and L.M. Krauss

In a recent manuscript (arXiv:0710.4917v2), Jones-Smith et al. attempt to use the well-established box-counting technique for fractal analysis to "demonstrate conclusively that fractal criteria are not useful for authentication". Here, in response to what we view to be an extremely simplistic misrepresentation of our earlier work by Jones-Smith et al., we reiterate our position regarding the potential of fractal analysis for artwork authentication. We also point out some of the flaws in the analysis presented in by Jones-Smith et al.Comment: Comment on arXiv:0710.4917v2 [cond-mat.stat-mech

Benchmark full configuration-interaction calculations on HF and NH2

Full configuration-interaction (FCI) calculations are performed at selected geometries for the 1-sigma(+) state of HF and the 2-B(1) and 2-A(1) states of NH2 using both DZ and DZP gaussian basis sets. Higher excitations become more important when the bonds are stretched and the self-consistent field (SCF) reference becomes a poorer zeroth-order description of the wave function. The complete active space SCF - multireference configuration-interaction (CASSCF-MRCI) procedure gives excellent agreement with the FCI potentials, especially when corrected with a multi-reference analog of the Davidson correction

On the electron affinity of the oxygen atom

The electron affinity (EA) of oxygen is computed to be 1.287 eV, using 2p electron full configuration-interaction (CI) wave functions expanded in a 6s5p3d2f Slater-type orbital basis. The best complete active space self-consistent field - multireference CI (CASSCF-MRCI) result including only 2p correlation is 1.263 eV. However, inclusion of 2s intrashell and 2s2p intershell correlation increases the computed EA to 1.290 at the CASSCF-MRCI level. At the full CI basis set limit, the 2s contribution to the electron affinity is estimated to be as large as 0.1 eV. This study clearly establishes the synergistic effect between the higher excitations and basis set completeness on the electron affinity when the 2s electrons are correlated

What should an index of school segregation measure?

The article aims to make a methodological contribution to the education segregation literature, providing a critique of previous measures of segregation used in the literature, as well as suggesting an alternative approach to measuring segregation. Specifically, the paper examines Gorard, Fitz and Taylor's finding that social segregation between schools, as measured by free school meals (FSM) entitlement, fell significantly in the years following the 1988 Education Reform Act. Using Annual Schools Census data from 1989 to 2004, the paper challenges the magnitude of their findings, suggesting that the method used by Gorard et al. seriously overstates the size of the fall in segregation. We make the case for a segregation curve approach to measuring segregation, where comparisons of the level of segregation are possible regardless of the percentage FSM eligibility. Using this approach, we develop a new method for describing both the level and the location of school segregation

Impact of the Brush Day & Night Programme on Well-Being, Plaque, and Dental Caries in Children

Objectives: Poor oral hygiene can have an adverse effect on quality of life. School-based interventions can establish positive behaviours that reduce the likelihood of dental caries later in life. The Brush Day & Night programme aims to encourage good oral health behaviour and improve oral health and quality-of-life outcomes. In this article, we report the effect of the programme on well-being and oral hygiene measured by plaque levels at 3, 8, and 24 weeks and dental caries at 24 weeks after programme start date. Methods: This was a superiority cluster randomised trial of children 6-12 years of age from Indonesia (N = 2021) and Nigeria (N = 2104). All children were provided with toothpaste and a toothbrush. Children in the intervention group received the 21-day Brush Day & Night programme, whereas those in the control group did not. Children completed a questionnaire addressing the objectives at all time points. Their oral hygiene was assessed using the Oral Hygiene Index-Simplified (OHI-S). Additionally, at baseline and 24 weeks their caries status was recorded using the decayed, missing, and filled teeth (DMFT) index. Results: In Indonesia, after participation in the programme children demonstrated a 45% increased probability of no worsening in the occurrence of decayed, missing, or filled teeth. In Nigeria, children had a 71% higher probability of having confidence in their smile and the proportion of children with good oral hygiene doubled from 40% to 80% at 24 weeks. Conclusions: The Brush Day & Night programme was successful in improving well-being and oral hygiene in children in Nigeria and reduced the likelihood of worsening in the occurrence of decayed, missing, or filled teeth in children in Indonesia.This article is published as part of a supplement sponsored by Unilever. Medical writing assistance, in the form of preparation and revision of the manuscript, as well as support of the conduct of the research, was supported financially by Unilever

Impact of the Brush Day & Night Programme on Oral Health Knowledge and Behaviour in Children

Objectives: School-based interventions can establish positive behaviours that reduce the likelihood of oral diseases later in life. The Brush Day & Night (BDN) programme is a 21-day school-based educational programme to promote good oral health behaviours. This study aims to evaluate the effect of the BDN programme on oral health knowledge and behaviour outcomes in children after the intervention as compared to a control group over 24 weeks. Methods: This was a superiority cluster randomised trial of children aged 6-12 years from Indonesia (N = 2021) and Nigeria (N = 750). All children were provided with toothpaste and a toothbrush, and the intervention groups (N = 1107 and 439, respectively) received the 21-day BDN programme. Children were followed up at Weeks 3, 8, and 24 after the programme start date and completed a questionnaire addressing the objectives at all timepoints. Improvement in oral health knowledge and behaviour was calculated based on the percentage of positive change in answers and analysed based on a conditional logistic approach for each evaluation timepoint, compared with control, with a 95% CI. Results: After 24 weeks, Indonesian children following the BDN programme presented with a 30% and 60% additional probability, respectively, of adequate timing of toothbrushing and of being aware of the importance of adequate toothbrushing frequency compared with control. In Nigeria, after 24 weeks, children following the BDN programme had a 92% and 73% higher probability of adequate toothbrushing frequency and of using fluoride toothpaste, respectively, compared with control. Conclusions: The BDN programme is effective at improving children's knowledge and behaviour compared with a control population.This article is published as part of a supplement sponsored by Unilever. Medical writing assistance, in the form of preparation and revision of the manuscript, as well as support of the conduct of the research, was supported financially by Unilever