DETERMINANTS OF FERTILIZER ADOPTION BY AFRICAN FARMERS: POLICY ANALYSIS FRAMEWORK, ILLUSTRATIVE EVIDENCE, AND IMPLICATIONS

Crop Production/Industries,

Universal trapping scaling on the unstable manifold for a collisionless electrostatic mode

An amplitude equation for an unstable mode in a collisionless plasma is derived from the dynamics on the two-dimensional unstable manifold of the equilibrium. The mode amplitude $\rho(t)$ decouples from the phase due to the spatial homogeneity of the equilibrium, and the resulting one-dimensional dynamics is analyzed using an expansion in $\rho$. As the linear growth rate $\gamma$ vanishes, the expansion coefficients diverge; a rescaling $\rho(t)\equiv\gamma^2\,r(\gamma t)$ of the mode amplitude absorbs these singularities and reveals that the mode electric field exhibits trapping scaling $|E_1|\sim\gamma^2$ as $\gamma\rightarrow0$. The dynamics for $r(\tau)$ depends only on the phase $e^{i\xi}$ where $d\epsilon_{{k}} /dz=|{\epsilon_{{k}}}|e^{-i\xi/2}$ is the derivative of the dielectric as $\gamma\rightarrow0$.Comment: 11 pages (Latex/RevTex), 2 figures available in hard copy from the Author ([email protected]); paper accepted by Physical Review Letter

Who is eating where? Findings from the SESAW study

Objective: Foods prepared outside of the home have been linked to less-than-ideal nutrient profiles for health. We examine whether the locations where meals are prepared and consumed are associated with socio-economic predictors among women.Design: A cross-sectional study using self-reported data. We examined multiple locations where meals are prepared and consumed: (i) at home; (ii) fast food eaten at home; (iii) fast food eaten at the restaurant; (iv) total fast food; (v) non-fast-food restaurant meals eaten at home; (vi) non-fast-food restaurant meals eaten at the restaurant; and (vii) all non-fast-food restaurant meals. Multilevel logistic regression was used to determine whether frequent consumption of meals from these sources varied by level of education, occupation, household income and area-level disadvantage.Setting: Metropolitan Melbourne, Australia.Subjects: A total of 1328 women from forty-five neighbourhoods randomly sampled for the SocioEconomic Status and Activity in Women study.Results: Those with higher educational qualifications or who were not in the workforce (compared with those in professional employment) were more likely to report frequent consumption of meals prepared and consumed at home. High individual and area-level socio-economic characteristics were associated with a lower likelihood of frequent consumption of fast food and a higher likelihood of frequent consumption of meals from non-fast-food sources. The strength and significance of relationships varied by place of consumption.Conclusions: The source of meal preparation and consumption varied by socioeconomic predictors. This has implications for policy makers who need to continue to campaign to make healthy alternatives available in out-of-home food sources.<br /

Scaling and singularities in the entrainment of globally-coupled oscillators

The onset of collective behavior in a population of globally coupled oscillators with randomly distributed frequencies is studied for phase dynamical models with arbitrary coupling. The population is described by a Fokker-Planck equation for the distribution of phases which includes the diffusive effect of noise in the oscillator frequencies. The bifurcation from the phase-incoherent state is analyzed using amplitude equations for the unstable modes with particular attention to the dependence of the nonlinearly saturated mode $|\alpha_\infty|$ on the linear growth rate $\gamma$. In general we find $|\alpha_\infty|\sim \sqrt{\gamma(\gamma+l^2D)}$ where $D$ is the diffusion coefficient and $l$ is the mode number of the unstable mode. The unusual $(\gamma+l^2D)$ factor arises from a singularity in the cubic term of the amplitude equation.Comment: 11 pages (Revtex); paper submitted to Phys. Rev. Let

Understanding environmental influences on nutrition and physical activity behaviors: where should we look and what should we count?

Research interest in the influence of environmental factors on nutrition and physical activity behaviors has surged internationally in recent years. This is evident from a rapidly expanding literature and facilitated by advances in methodological and analytical approaches to assessing multiple levels of influence on health behaviors. However, a number of conceptual challenges complicate research endeavours in this field. The purpose of this paper is to provide a 'state of the science' overview of evidence regarding environmental influences on nutrition and physical activity behaviors. We focus particularly on a number of key conceptual and methodological issues, including: a consideration of how the environment is defined; the selection and operationalization of environmental exposures; and the importance of integrating existing understanding of individual influences on behavior with the emerging data on the role of the environment. We draw on examples from the published literature including our own research studies to illustrate these issues. We conclude by proposing a research agenda to progress understanding of the influences of the environment on population nutrition and physical activity behaviors

ShopSmart 4 Health - protocol of a skills-based randomised controlled trial promoting fruit and vegetable consumption among socioeconomically disadvantaged women

BackgroundThere is a need for evidence on the most effective and cost-effective approaches for promoting healthy eating among groups that do not meet dietary recommendations for good health, such as those with low incomes or experiencing socioeconomic disadvantage. This paper describes the ShopSmart 4 Health study, a randomised controlled trial conducted by Deakin University, Coles Supermarkets and the Heart Foundation, to investigate the effectiveness and cost-effectiveness of a skill-building intervention for promoting increased purchasing and consumption of fruits and vegetables amongst women of low socioeconomic position (SEP).Methods/designShopSmart 4 Health employed a randomised controlled trial design. Women aged 18&ndash;60 years, holding a Coles store loyalty card, who shopped at Coles stores within socioeconomically disadvantaged neighbourhoods and met low-income eligibility criteria were invited to participate. Consenting women completed a baseline survey assessing food shopping and eating habits and food-related behaviours and attitudes. On receipt of their completed survey, women were randomised to either a skill-building intervention or a wait-list control condition. Intervention effects will be evaluated via self-completion surveys and using supermarket transaction sales data, collected at pre- and post-intervention and 6-month follow-up. An economic evaluation from a societal perspective using a cost-consequences approach will compare the costs and outcomes between intervention and control groups. Process evaluation will be undertaken to identify perceived value and effects of intervention components.DiscussionThis study will provide data to address the currently limited evidence base regarding the effectiveness and cost-effectiveness of skill-building intervention strategies aimed at increasing fruit and vegetable consumption among socioeconomically disadvantaged women, a target group at high risk of poor diets.<br /

Quantum-ionic features in the absorption spectra of homonuclear diatomic molecules

Under the terms of the Creative Commons Attribution License 3.0 (CC-BY).We show that additional features can emerge in the linear absorption spectra of homonuclear diatomic molecules when the ions are described quantum mechanically. In particular, the widths and energies of the peaks in the optical spectra change with the initial configuration, mass, and charge of the molecule. We introduce a model that can describe these features and we provide a quantitative analysis of the resulting peak energy shifts and width broadenings as a function of the mass.We acknowledge financial support from the European Research Council Advanced Grant DYNamo (Grant No. ERC-2010-AdG-267374), Spanish Grants No. FIS2013-46159-C3-1-P and No. PIB2010US-00652, and Grupo Consolidado UPV/EHU del Gobierno Vasco (Grant No. IT578-13). A.C.-U. acknowledges financial support from the Departamento de Educacion, Universidades e Investigacion del Gobierno Vasco (Reference No. BFI-2011-26).Peer Reviewe

Molecular Hydrogen in Diffuse Interstellar Clouds of Arbitrary Three-Dimensional Geometry

We have constructed three-dimensional models for the equilibrium abundance of molecular hydrogen within diffuse interstellar clouds of arbitrary geometry that are illuminated by ultraviolet radiation. The position-dependent photo- dissociation rate of H$_2$ within such clouds was computed using a 26-ray approximation to model the attenuation of the incident ultraviolet radiation field by dust and by H$_2$ line absorption. We have applied our modeling technique to the isolated diffuse cloud G236+39, assuming that the cloud has a constant density and that the thickness of the cloud along the line of sight is at every point proportional to the 100 um continuum intensity measured by IRAS. We find that our model can successfully account for observed variations in the ratio of 100 umu continuum intensity to HI column density, with larger values of that ratio occurring along lines of sight in which the molecular hydrogen fraction is expected to be largest. Using a standard chi^2 analysis to assess the goodness of fit of our models, we find (at the 60sigma level) that a three-dimensional model is more successful in matching the observational data than a one-dimensional model in which the geometrical extent of the cloud along the line of sight is assumed to be very much smaller than its extent in the plane-of-the-sky. If D is the distance to G236+39, and given standard assumptions about the rate of grain-catalysed H_2 formation, we find that the cloud has an extent along the line of sight that is 0.9+-0.1 times its mean extent projected onto the plane of the sky; a gas density of (53+-8)(100 pc/D) cm^-3; and is illuminated by a radiation field of (1.1+-0.2) (100 pc/D) times the mean interstellar radiation field estimated by Draine (1978). The derived 100 um emissivity per nucleon is (1.13+-0.06)x10^-20 MJy sr^-1 cm^2.Comment: 27 pages LaTex, uses aaspp4.sty, ApJ August

Is the perception of time pressure a barrier to healthy eating and physical activity among women?

Objectives To describe the proportion of women reporting time is a barrier to healthy eating and physical activity, the characteristics of these women and the perceived causes of time pressure, and to examine associations between perceptions of time as a barrier and consumption of fruit, vegetables and fast food, and physical activity.Design A cross-sectional survey of food intake, physical activity and perceived causes of time pressure.Setting A randomly selected community sample.Subjects A sample of 1580 women self-reported their food intake and their perceptions of the causes of time pressure in relation to healthy eating. An additional 1521 women self-reported their leisure-time physical activity and their perceptions of the causes of time pressure in relation to physical activity.Results Time pressure was reported as a barrier to healthy eating by 41 % of the women and as a barrier to physical activity by 73 %. Those who reported time pressure as a barrier to healthy eating were significantly less likely to meet fruit, vegetable and physical activity recommendations, and more likely to eat fast food more frequently.Conclusions Women reporting time pressure as a barrier to healthy eating and physical activity are less likely to meet recommendations than are women who do not see time pressure as a barrier. Further research is required to understand the perception of time pressure issues among women and devise strategies to improve women&rsquo;s food and physical activity behaviours

Understanding determinants of nutrition, physical activity and quality of life among older adults : the Wellbeing, Eating and Exercise for a Long Life (WELL) study

Background : Nutrition and physical activity are major determinants of health and quality of life; however, there exists little research focusing on determinants of these behaviours in older adults. This is important, since just as these behaviours vary according to subpopulation, it is likely that the determinants also vary. An understanding of the modifiable determinants of nutrition and physical activity behaviours among older adults to take into account the specific life-stage context is required in order to develop effective interventions to promote health and well-being and prevent chronic disease and improve quality of life. Methods : The aim of this work is to identify how intrapersonal, social and environmental factors influence nutrition and physical activity behaviours among older adults living in urban and rural areas. This study is a cohort study of adults aged 55-65 years across urban and rural Victoria, Australia. Participants completed questionnaires at baseline in 2010 and will complete follow-up questionnaires in 2012 and 2014. Self-report questionnaires will be used to assess outcomes such as food intake, physical activity and sedentary behaviours, anthropometry and quality of life. Explanatory variables include socioeconomic position, and measures of the three levels of influence on older adults\u27 nutrition and physical activity behaviours (intrapersonal, social and perceived environmental influences). Discussion : Obesity and its determinant behaviours, physical inactivity and poor diet are major public health concerns and are significant determinants of the quality of life among the ageing population. There is a critical need for a better understanding of the determinants of nutrition and physical activity in this important target group. This research will provide evidence for the development of effective policies and programs to promote and support increased physical activity and healthy eating behaviours among older adults. <br /