263 research outputs found

    Anaemia, vitamin-A deficiency, anthropometric nutritional status and associated factors among young school children in Kodzobi, Ghana, a peri-urban community

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    Anaemia, vitamin-A deficiency and under nutrition are prevalent among children at levels of public health significance in developing countries of which Ghana is no exception. The objective of this study was to assess the anaemia, low vitamin-A level and anthropometric nutritional status of 162 randomly selected young Ghanaian school children 4 – 8 years in Kodzobi, a peri-urban community and establish associated factors. Questionnaires were used to collect background data from parents of study participants. Vitamin-A and haemoglobin concentrations were determined using High Performance Liquid Chromatography and Haemocue hemoglobinometer, respectively. Malaria parasitaemia was examined by the Giemsa staining technique. Weight and height measurements were taken according to WHO’s standard procedures to assess participants’ nutritional status. The mean haemoglobin and serum retinol concentrations were 11.6 ± 1.1 g/dl and 22.8 ± 6.5 μg/dl, respectively. Prevalence of anaemia and vitamin-A deficiency among study participants were 38.3 % and 24.0 %, respectively. The prevalence of underweight, stunting, thinness and overweight were 9.3 %, 9.9 %, 4.3 % and 3.7 %, respectively. Haemoglobin correlated positively and significantly with weight, weight-for-age and body mass index-for-age z scores. Child’s sex, vitamin-A status and parental monthly income associated with anaemia status. Females had a higher risk of being anaemic compared to males (OR = 2.519; 95 % CI: 0.965 - 6.580; p = 0.049). Participants with normal vitamin-A concentration were at lower risk of being anaemic (OR = 0.302; 95 % CI: 0.109 - 0.840; p = 0.022) than those with low vitamin-A concentration. Anaemia and young child age negatively associated with vitamin-A status, at p = 0.039 and p = 0.037, respectively. Anaemia and vitamin-A deficiency are issues of public health importance among school-aged children in Ghana. There is, therefore, the need to invest in actions that prevent their occurrence and management especially among children of school going age.Keywords: Anaemia, vitamin-A deficiency, nutritional status, retinol, haemoglobin, school children, peri-urba

    Hubbard-U calculations for Cu from first-principles Wannier functions

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    We present first-principles calculations of optimally localized Wannier functions for Cu and use these for an ab-initio determination of Hubbard (Coulomb) matrix elements. We use a standard linearized muffin-tin orbital calculation in the atomic-sphere approximation (LMTO-ASA) to calculate Bloch functions, and from these determine maximally localized Wannier functions using a method proposed by Marzari and Vanderbilt. The resulting functions were highly localized, with greater than 89% of the norm of the function within the central site for the occupied Wannier states. Two methods for calculating Coulomb matrix elements from Wannier functions are presented and applied to fcc Cu. For the unscreened on-site Hubbard UU for the Cu 3d-bands we have obtained about 25eV. These results are also compared with results obtained from a constrained local-density approximation (LDA) calculation.Comment: 13 pages, 8 figures, 5 table

    Unscreened Hartree-Fock calculations for metallic Fe, Co, Ni, and Cu from ab-initio Hamiltonians

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    Unscreened Hartree-Fock approximation (HFA) calculations for metallic Fe, Co, Ni, and Cu are presented, by using a quantum-chemical approach. We believe that these are the first HFA results to have been done for crystalline 3d transition metals. Our approach uses a linearized muffin-tin orbital calculation to determine Bloch functions for the Hartree one-particle Hamiltonian, and from these obtains maximally localized Wannier functions, using a method proposed by Marzari and Vanderbilt. Within this Wannier basis all relevant one-particle and two-particle Coulomb matrix elements are calculated. The resulting second-quantized multi-band Hamiltonian with ab-initio parameters is studied within the simplest many-body approximation, namely the unscreened, self-consistent HFA, which takes into account exact exchange and is free of self-interactions. Although the d-bands sit considerably lower within HFA than within the local (spin) density approximation L(S)DA, the exchange splitting and magnetic moments for ferromagnetic Fe, Co, and Ni are only slightly larger in HFA than what is obtained either experimentally or within LSDA. The HFA total energies are lower than the corresponding LSDA calculations. We believe that this same approach can be easily extended to include more sophisticated ab-initio many-body treatments of the electronic structure of solids.Comment: 11 papes, 7 figures, 5 table

    Block-Spin Approach to Electron Correlations

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    We consider an expansion of the ground state wavefunction of quantum lattice many-body systems in a basis whose states are tensor products of block-spin wavefunctions. We demonstrate by applying the method to the antiferromagnetic spin-1/2 chain that by selecting the most important many-body states the technique affords a severe truncation of the Hilbert space while maintaining high accuracy.Comment: 17 pages, 3 Postscript figure

    Calculation of Effective Coulomb Interaction for Pr3+Pr^{3+}, U4+U^{4+}, and UPt3UPt_3

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    In this paper, the Slater integrals for a screened Coulomb interaction of the the Yukawa form are calculated and by fitting the Thomas-Fermi wavevector, good agreement is obtained with experiment for the multiplet spectra of Pr3+Pr^{3+} and U4+U^{4+} ions. Moreover, a predicted multiplet spectrum for the heavy fermion superconductor UPt3UPt_3 is shown with a calculated Coulomb U of 1.6 eV. These effective Coulomb interactions, which are quite simple to calculate, should be useful inputs to further many-body calculations in correlated electron metals.Comment: 8 pages, revtex, 3 uuencoded postscript figure

    Changes of intracellular sodium and potassium ion concentrations in frog spinal motoneurons induced by repetitive synaptic stimulation

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    A post-tetanic membrane hyperpolarization following repetitive neuronal activity is a commonly observed phenomenon in the isolated frog spinal cord as well as in neurons of other nervous tissues. We have now used double-barrelled Na+- and K+-ion-sensitive microelectrodes to measure the intracellular Na+- and K+-concentrations and also the extracellular K+-concentration of lumbar spinal motoneurons during and after repetitive stimulation of a dorsal root. The results show that the posttetanic membrane hyperpolarization occurred at a time when the intracellular [Na+] reached its maximal value, intracellular [K+] had its lowest level and extracellular [K+] was still elevated. The hyperpolarization was blocked by ouabain and reduced by Li+. These data support the previous suggestion that an electrogenic Na+/K+ pump mode may be the mechanism underlying the post-tetanic membrane hyperpolarization

    Experimental implementation of a NMR entanglement witness

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    Entanglement witnesses (EW) allow the detection of entanglement in a quantum system, from the measurement of some few observables. They do not require the complete determination of the quantum state, which is regarded as a main advantage. On this paper it is experimentally analyzed an entanglement witness recently proposed in the context of Nuclear Magnetic Resonance (NMR) experiments to test it in some Bell-diagonal states. We also propose some optimal entanglement witness for Bell-diagonal states. The efficiency of the two types of EW's are compared to a measure of entanglement with tomographic cost, the generalized robustness of entanglement. It is used a GRAPE algorithm to produce an entangled state which is out of the detection region of the EW for Bell-diagonal states. Upon relaxation, the results show that there is a region in which both EW fails, whereas the generalized robustness still shows entanglement, but with the entanglement witness proposed here with a better performance

    Trends in Pharmacotherapy for Bladder Dysfunction among Children in the United States, 2000 to 2013

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    Bladder-related issues such as nocturnal enuresis and incontinence have long been a part of general pediatric practice. Increasingly, clinicians are prescribing medications directed at a variety of types of bladder dysfunction, but no prior population-based data exist. We used MarketScan health care claims data on 32 074 638 insured children to estimate utilization patterns by age, sex, year, and geographic region in the United States from 2000 to 2013, and to assess related diagnosis codes. Approximately 1 in 500 children filled an antimuscarinic prescription. The most common prescriptions were for oxybutynin (78%) and tolterodine (17%). Rates were highest at ages 6 to 10 years (65/100 000 person-months), 31% higher for girls versus boys, peaked in 2011 (44/100 000 person-months), and were highest in the Midwest (59/100 000 person-months). Seventy-three percent of children with prescriptions had diagnosis codes for genitourinary symptoms, and 13% had codes for congenital anomalies. Research is needed regarding the comparative effectiveness and safety of these drugs in children

    Coulomb Correlations and Magnetic Anisotropy in ordered L10L1_0 CoPt and FePt alloys

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    We present results of the magneto-crystalline anisotropy energy (MAE) calculations for chemically ordered L10L1_0 CoPt and FePt alloys taking into account the effects of strong electronic correlations and spin-orbit coupling. The local spin density + Hubbard U approximation (LSDA+U) is shown to provide a consistent picture of the magnetic ground state properties when intra-atomic Coulomb correlations are included for both 3dd and 5dd elements. Our results demonstrate significant and complex contribution of correlation effects to large MAE of these material.Comment: revised version; 4 pages, 2 figure
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