945 research outputs found

    Multi-center initiative for evaluation research and capacity building for micronutrient deficiency control programs

    Get PDF
    This project was part of a larger effort entitled ‘Initiative on Successful Micronutrient Programs.’ The research, carried out by national institutions with support from project funding and expertise, established the state of the art in large scale interventions to address deficiencies of iodine, iron, and vitamin A. Findings indicate that systematic application of conventional procedures for project initiation worked, and can be further applied. Materials from the project and related documents have been distributed to training institutions. The capacity building strategy envisages triangular links, with developed-country institutions working to support the development of less experienced institutions

    Stability of Monomer-Dimer Piles

    Full text link
    We measure how strong, localized contact adhesion between grains affects the maximum static critical angle, theta_c, of a dry sand pile. By mixing dimer grains, each consisting of two spheres that have been rigidly bonded together, with simple spherical monomer grains, we create sandpiles that contain strong localized adhesion between a given particle and at most one of its neighbors. We find that tan(theta_c) increases from 0.45 to 1.1 and the grain packing fraction, Phi, decreases from 0.58 to 0.52 as we increase the relative number fraction of dimer particles in the pile, nu_d, from 0 to 1. We attribute the increase in tan(theta_c(nu_d)) to the enhanced stability of dimers on the surface, which reduces the density of monomers that need to be accomodated in the most stable surface traps. A full characterization and geometrical stability analysis of surface traps provides a good quantitative agreement between experiment and theory over a wide range of nu_d, without any fitting parameters.Comment: 11 pages, 12 figures consisting of 21 eps files, submitted to PR

    Water and Fertilizer Influence on Sorghum Grain Quality for Traditional Beer (Dolo) Production in Burkina Faso

    Get PDF
    In the Central Plateau of Burkina Faso, grain sorghum [Sorghum bicolor (L.) Moench] is the major cereal crop used to produce the traditional beer called dolo. Grain sorghum grain samples collected in 2004 and 2005 from experiments combining five water management techniques and four fertilizer treatments in a randomized complete block design with a split plot arrangement of treatments were analyzed for the physicochemical properties of raw grain, and quality of malted grain. Water management techniques were allocated to main plots and fertilizer treatments to subplots. The objective was to determine the best combination of water management technique and fertilizer treatment to optimize grain quality of the red grain sorghum varieties IRAT9 and ICSV1001 (Framida) for dolo production. Results showed that the grain physicochemical properties and malt quality of the two varieties were influenced by both water management technique and fertilizer treatment. Pearson correlations indicated that grain yield was rarely correlated with the physicochemical properties of raw grain and malt quality parameters. Diastatic power was positively correlated with protein concentration and malting losses, but negatively with tannin concentration. Based upon results, recommendation for the production of sorghum grain and malt with the needed characteristics for high dolo quality would be the use of water management techniques that sufficiently improve soil water conditions in combination with a microdose + 20 kg P ha-1 + 30 kg N ha-1 fertilizer application that provides sufficient nutrients and particularly nitrogen to the crop

    Time Resolved Control of Electron Tunnelling Times and Single-shot Spin Readout in a Quantum Dot

    Full text link
    We are pursuing a capability to perform time resolved manipulations of single spins in quantum dot circuits involving more than two quantum dots. In this paper, we demonstrate full counting statistics as well as averaging techniques we use to calibrate the tunnel barriers. We make use of this to implement the Delft protocol for single shot single spin readout in a device designed to form a triple quantum dot potential. We are able to tune the tunnelling times over around three orders of magnitude. We obtain a spin relaxation time of 300 microseconds at 10T.Comment: Submitted to EP2DS 2009 Conference Proceeding

    Superconductor-Insulator Transition in a Capacitively Coupled Dissipative Environment

    Full text link
    We present results on disordered amorphous films which are expected to undergo a field-tuned Superconductor-Insulator Transition.The addition of a parallel ground plane in proximity to the film changes the character of the transition.Although the screening effects expected from "dirty-boson" theories are not evident,there is evidence that the ground plane couples a certain type of dissipation into the system,causing a dissipation-induced phase transition.The dissipation due to the phase transition couples similarly into quantum phase transition systems such as superconductor-insulator transitions and Josephson junction arrays.Comment: 4 pages, 4 figure

    Point interactions in one dimension and holonomic quantum fields

    Get PDF
    We introduce and study a family of quantum fields, associated to delta-interactions in one dimension. These fields are analogous to holonomic quantum fields of M. Sato, T. Miwa and M. Jimbo. Corresponding field operators belong to an infinite-dimensional representation of the group SL(2,\Rb) in the Fock space of ordinary harmonic oscillator. We compute form factors of such fields and their correlation functions, which are related to the determinants of Schroedinger operators with a finite number of point interactions. It is also shown that these determinants coincide with tau functions, obtained through the trivialization of the det∗\mathrm{det}^*-bundle over a Grassmannian associated to a family of Schroedinger operators.Comment: 17 page

    Large-scale assessment of 7-11-year-olds’ cognitive and sensorimotor function within the Born in Bradford longitudinal birth cohort study

    Get PDF
    Background: Cognitive ability and sensorimotor function are crucial aspects of children’s development, and are associated with physical and mental health outcomes and educational attainment. This paper describes cross-sectional sensorimotor and cognitive function data collected on over 15,000 children aged 7-10 years, collected as part of the Born in Bradford (BiB) longitudinal birth-cohort study. Methodological details of the large-scale data collection process are described, along with initial analyses of the data involving the relationship between cognition/sensorimotor ability and age and task difficulty, and associations between tasks. Method: Data collection was completed in 86 schools between May 2016 and July 2019. Children were tested at school, individually, using a tablet computer with a digital stylus or finger touch for input. Assessments comprised a battery of three sensorimotor tasks (Tracking, Aiming, &amp; Steering) and five cognitive tasks (three Working Memory tasks, Inhibition, and Processing Speed), which took approximately 40 minutes. Results: Performance improved with increasing age and decreasing task difficulty, for each task. Performance on all three sensorimotor tasks was correlated, as was performance on the three working memory tasks. In addition, performance on a composite working memory score correlated with performance on both inhibition and processing speed. Interestingly, within age-group variation was much larger than between age-group variation. Conclusions: The current project collected computerised measures of a range of cognitive and sensorimotor functions at 7-10 years of age in over 15,000 children. Performance varied as expected by age and task difficulty, and showed the predicted correlations between related tasks. Large within-age group variation highlights the need to consider the profile of individual children in studying cognitive and sensorimotor development. These data can be linked to the wider BiB dataset including measures of physical and mental health, biomarkers and genome-wide data, socio-demographic information, and routine data from local health and education services.</p

    True Superconductivity in a 2D "Superconducting-Insulating" System

    Full text link
    We present results on disordered amorphous films which are expected to undergo a field-tuned Superconductor-Insulator Transition. Based on low-field data and I-V characteristics, we find evidence of a low temperature Metal-to-Superconductor transition. This transition is characterized by hysteretic magnetoresistance and discontinuities in the I-V curves. The metallic phase just above the transition is different from the "Fermi Metal" before superconductivity sets in.Comment: 3 pages, 4 figure

    Improving tree mortality models by accounting for environmental influences

    Get PDF
    Tree-ring chronologies have been widely used in studies of tree mortality where variables of recent growth act as an indicator of tree physiological vigour. Comparing recent radial growth of live and dead trees thus allows estimating probabilities of tree mortality. Sampling of mature dead trees usually provides death-year distributions that may span over years or decades. Recent growth of dead trees (prior to death) is then computed during a number of periods, whereas recent growth (prior to sampling) for live trees is computed for identical periods. Because recent growth of live and dead trees is then computed for different periods, external factors such as disturbance or climate may influence growth rates and, thus, mortality probability estimations. To counteract this problem, we propose the truncating of live-growth series to obtain similar frequency distributions of the "last year of growth" for the populations of live and dead trees. In this paper, we use different growth scenarios from several tree species, from several geographic sources, and from trees with different growth patterns to evaluate the impact of truncating on predictor variables and their selection in logistic regression analysis. Also, we assess the ability of the resulting models to accurately predict the status of trees through internal and external validation. Our results suggest that the truncating of live-growth series helps decrease the influence of external factors on growth comparisons. By doing so, it reinforces the growth-vigour link of the mortality model and enhances the model's accuracy as well as its general applicability. Hence, if model parameters are to be integrated in simulation models of greater geographical extent, truncating may be used to increase model robustness

    Antimatter from the cosmological baryogenesis and the anisotropies and polarization of the CMB radiation

    Full text link
    We discuss the hypotheses that cosmological baryon asymmetry and entropy were produced in the early Universe by phase transition of the scalar fields in the framework of spontaneous baryogenesis scenario. We show that annihilation of the matter-antimatter clouds during the cosmological hydrogen recombination could distort of the CMB anisotropies and polarization by delay of the recombination. After recombination the annihilation of the antibaryonic clouds (ABC) and baryonic matter can produce peak-like reionization at the high redshifts before formation of quasars and early galaxy formation. We discuss the constraints on the parameters of spontaneous baryogenesis scenario by the recent WMAP CMB anisotropy and polarization data and on possible manifestation of the antimatter clouds in the upcoming PLANCK data.Comment: PRD in press with minor change
    • 

    corecore