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To examine associations between Canadian adolescents’ sugar-sweetened beverage (SSB) consumption and several school food environment characteristics, and to investigate differences in these characteristics between schools in provinces with voluntary (Alberta) v. mandatory (Ontario) provincial school nutrition policies.
We used a questionnaire to assess the number of weekdays participants consumed three SSB categories (soft drinks, sweetened coffees/teas, energy drinks) and various sociodemographic and behavioural characteristics. We examined the in-school water fountain accessibility, vending machines’ contents and presence of various food outlets within schools’ 1 km buffer. We developed hierarchical Poisson regression models to identify associations between student- and school-level characteristics and students’ SSB outcomes.
Alberta and Ontario, Canada.
Adolescents (n 41 829) from eighty-nine secondary schools.
Compared with their Ontarian counterparts, Albertan participants had a significantly higher rate of SSB intake across all drink categories and SSB availability was significantly greater in Albertan schools’ vending machines. Availability of sweetened coffees/teas in school vending machines and access to restaurants within the school’s 1 km buffer were associated with increased SSB intake in three of the final models. Overall, the school food environment-level characteristics examined had a modest to negligible impact on student days of SSB intake.
We identified that the school food environment characteristics examined here had little impact on adolescents’ days of SSB consumption. While schools should adopt or maintain a comprehensive policy approach to discourage students’ SSB intake, population-level interventions focusing on other contexts (e.g. home and community) are needed to complement existing school-based interventions.
We present the first demonstration of a general method for the chemical characterization of small surface features at high magnification via simultaneous collection of mass spectrometry (MS) imaging and tandem MS imaging data. High lateral resolution tandem secondary ion MS imaging is employed to determine the composition of surface features on poly(ethylene terephthalate) (PET) that precipitate during heat treatment. The surface features, probed at a lateral resolving power of<200 nm using a surface-sensitive ion beam, are found to be comprised of ethylene terephthalate trimer at a greater abundance than is observed in the surrounding polymer matrix. This is the first chemical identification of PET surface precipitates made without either an extraction step or the use of a reference material. The new capability employed for this study achieves the highest practical lateral resolution ever reported for tandem MS imaging.
The location of a government's capital can profoundly influence the nature and quality of political representation. Yet scholars know very little about what drives the siting of political capitals. In this article, we examine the location and relocation of political capitals in the United States, including the choice of Washington, DC, as the nation's capital and the location and relocation of capitals in the 48 contiguous American states. We argue that the location of capitals in the United States followed a systematic pattern in accord with the theory of representative government developed in the new nation, especially as articulated by Madison. Based on an empirical analysis of historical census and political boundaries data from 1790 to the present, we find that decision makers consistently tended to locate—and especially relocate—the seat of government as near as possible to the population centroid of the relevant political jurisdiction, consistent with the principle of equal representation of citizens. Our analysis contributes to the study of institutional design and change, especially in the area of American political development, as well as to a burgeoning literature on the effects of geographical factors on political outcomes.
In order to achieve the near-ferroelectric order desired in organic electro-optic (EO) chromophore systems, a pseudo-discotic chromophore is under investigation. Calculations suggest head-to-tail inter-chromophore dipole-dipole interactions should drive chromophores with an appropriate aspect ratio into ferroelectric columns similar to those seen in discotic liquid crystals (DLCs). Therefore, the liquid crystalline properties of these chromophores are being examined by differential scanning calorimetery (DSC), polarized optical microscopy (POM), and X-ray diffraction (XRD). Furthermore, the effect of this discotic behavior on the order and EO properties of the system are being examined both dynamically by second harmonic generation (SHG) and statically by attenuated total reflection (ATR). Additionally, these chromophores are being incorporated into waveguide-based photonic devices.
Previous research in organic electro-optics has shown dramatic increases in the hyperpolarizablity of NLO chromophores. However, this large microscopic activity has not been translated to the macroscopic domain. The polymeric electro-optic (E-O) materials continue to lack the high noncentrosymmetric order of the poled chromophores within the matrix necessary for high E-O response (r33). This deficiency of order represents one major obstacle that must be overcome before E-O device commercialization can be achieved. This lack of order is partially due to the large dipole moments of high μβ chromophores, which cause the chromophores to align in a centrosymmetric fashion through intermolecular electrostatic interactions. However, quantum calculations show that when the aspect ratio between the width and length of the chromophore system is adjusted to be greater than 1.4:1 by adding bulky side groups around the center of the chromophore, it would prevent side on pairing of the chromophores. This would cause a decrease in the large areas of centrosymmetric aggregation and thus allow for easier poling of the system. Here we report the synthesis of a nanoscale NLO architecture in which dendritic moieties have been incorporated around the center of the chromophore to give a three dimensional structure in order to achieve the 1.4:1 aspect ratio and maximize the macroscopic order of the system.
Mass casualty triage is a critical skill. Although many systems exist to guide providers in making triage decisions, there is little scientific evidence available to demonstrate that any of the available systems have been validated. Furthermore, in the United States there is little consistency from one jurisdiction to the next in the application of mass casualty triage methodology. There are no nationally agreed upon categories or color designations. This review reports on a consensus committee process used to evaluate and compare commonly used triage systems, and to develop a proposed national mass casualty triage guideline. The proposed guideline, entitled SALT (sort, assess, life-saving interventions, treatment and/or transport) triage, was developed based on the best available science and consensus opinion. It incorporates aspects from all of the existing triage systems to create a single overarching guide for unifying the mass casualty triage process across the United States. (Disaster Med Public Health Preparedness. 2008;2(Suppl 1):S25–S34)