365 research outputs found
Child malnutrition and antenatal care: Evidence from three Latin American countries
The importance of ever-earlier interventions to help children reach their physical and cognitive potential is increasingly being recognized. In part, as a result of this, in developing countries, antenatal care is becoming an important element of strategies to prevent child stunting in utero and later. Notwithstanding their policy relevance and substantial expansion, empirical evidence on the role of antenatal care (ANC) programs in combating stunting is scarce. This study analyzes the role of ANC programs in determining the level and distribution of child stunting in three Andean countries - Bolivia, Colombia, and Peru - where since the 1990s, expanding access to such care has been an explicit policy intervention to tackle child malnutrition. We find that the use of such services is associated with a reduction in the level of malnutrition and at the same time access to such services is relatively equally distributed. While this is a positive sign, it also suggests that further expansion of ANC programs is unlikely to play a large role in reducing inequalities in malnutrition
In vitro magnetic hyperthermia using polyphenol-coated Fe3O4ÂżFe2O3 nanoparticles from Cinnamomun verum and Vanilla planifolia: The concert of green synthesis and therapeutic possibilities
We report on a new, environment-friendly synthesis route to produce Fe3O4 magnetic nanoparticles (MNPs) from extracts of the plants Vanilla planifolia and Cinnamomun verum. These aqueous plant extracts have the double function of reducing agents due to their phenolic groups, and also capping materials through the -OH bonding over the MNPs surface. The resulting MNPs have average sizes ˜10-14 nm with a core-shell Fe3O4-¿Fe2O3 structure due to surface oxidation driven by the phenolic groups through OH-covalent bonding. Saturation magnetization values of MS= 70.84 emu g-1 (C. verum) and MS = 59.45 emu g-1 (V. planifolia) are among the largest reported so far from biosynthetic samples. Electron microscopy and infrared spectroscopy data showed a thin organic layer coating the Fe3O4 @¿Fe2O3 MNPs, composed by the phenolic groups from the starting extracts of both C. verum and V. planifolia. A proof of concept for these MNPs as heating agents in magnetic hyperthermia experiments (570 kHz, 23.9 kA m-1) was performed in-vitro, showing their efficacy to induce cell death on BV2 microglial cells after 30 min at a target temperature T = 46 °C
Child malnutrition and prenatal care: Evidence from three Latin American countries
Objective. To examine the effect of prenatal care (PNC) on the level and distribution of child stunting in three Andean countries-Bolivia, Colombia, and Peru-where expanding access to such care has been an explicit policy intervention to tackle child malnutrition in utero and during early childhood. Methods. An econometric analysis of cross-sectional Demographic and Health Survey (DHS) data was conducted. The analysis included ordinary least-squares (OLS) regressions, estimates of concentration curves, and decompositions of a concentration index. Results. The analysis shows that the use of PNC in Bolivia, Colombia, and Peru is only weakly associated with a reduction in the level of child malnutrition. Conclusions. Further expansion of PNC programs is unlikely to play a large role in reducing inequalities in malnutrition
Off Equilibrium Study of the Fluctuation-Dissipation Relation in the Easy-Axis Heisenberg Antiferromagnet on the Kagome Lattice
Violation of the fluctuation-dissipation theorem (FDT) in a frustrated
Heisenberg model on the Kagome lattice is investigated using Monte Carlo
simulations. The model exhibits glassy behaviour at low temperatures
accompanied by very slow dynamics. Both the spin-spin autocorrelation function
and the response to an external magnetic field are studied. Clear evidence of a
constant value of the fluctuation dissipation ratio and long range memory
effects are observed for the first time in this model. The breakdown of the FDT
in the glassy phase follows the predictions of the mean field theory for spin
glasses with one-step replica symmetry breaking.Comment: 4 pages, 4 figure
Development of a piezoelectric based energy harvesting system for autonomous wireless sensor nodes
Ordering and Fluctuation of Orbital and Lattice Distortion in Perovskite Manganese Oxides
Roles of orbital and lattice degrees of freedom in strongly correlated
systems are investigated to understand electronic properties of perovskite Mn
oxides such as La_{1-x}Sr_{x}MnO_{3}. An extended double-exchange model
containing Coulomb interaction, doubly degenerate orbitals and Jahn-Teller
coupling is derived under full polarization of spins with two-dimensional
anisotropy. Quantum fluctuation effects of Coulomb interaction and orbital
degrees of freedom are investigated by using the quantum Monte Carlo method. In
undoped states, it is crucial to consider both the Coulomb interaction and the
Jahn-Teller coupling in reproducing characteristic hierarchy of energy scales
among charge, orbital-lattice and spin degrees of freedom in experiments. Our
numerical results quantitatively reproduce the charge gap amplitude as well as
the stabilization energy and the amplitude of the cooperative Jahn-Teller
distortion in undoped compounds. Upon doping of carriers, in the absence of the
Jahn-Teller distortion, critical enhancement of both charge compressibility and
orbital correlation length is found with decreasing doping concentration. These
are discussed as origins of strong incoherence in charge dynamics. With the
Jahn-Teller coupling in the doped region, collapse of the Jahn-Teller
distortion and instability to phase separation are obtained and favorably
compared with experiments. These provide a possible way to understand the
complicated properties of lightly doped manganites.Comment: 22 pages RevTeX including 25 PS figures, submitted to Phys.Rev.B,
replaced version; two figures are replaced by Fig.17 with minor changes in
the tex
Validation of an all-sky imager based nowcasting system for industrial PV plants
Because of the cloud-induced variability of the solar resource, the growing contributions of photovoltaic plants to the overall power generation challenges the stability of electricity grids. To avoid blackouts, administrations started to define maximum negative ramp rates. Storages can be used to reduce the occurring ramps. Their required capacity, durability, and costs can be optimized by nowcasting systems. Nowcasting systems use the input of upward-facing cameras to predict future irradiances. Previously, many nowcasting systems were developed and validated. However, these validations did not consider aggregation effects, which are present in industrial-sized power plants. In this paper, we present the validation of nowcasted global horizontal irradiance (GHI) and direct normal irradiance maps derived from an example system consisting of 4 all-sky cameras (“WobaS-4cam”). The WobaS-4cam system is operational at 2 solar energy research centers and at a commercial 50-MW solar power plant. Besides its validation on 30 days, the working principle is briefly explained. The forecasting deviations are investigated with a focus on temporal and spatial aggregation effects. The validation found that spatial and temporal aggregations significantly improve forecast accuracies: Spatial aggregation reduces the relative root mean square error (GHI) from 30.9% (considering field sizes of 25 m2) to 23.5% (considering a field size of 4 km2) on a day with variable conditions for 1 minute averages and a lead time of 15 minutes. Over 30 days of validation, a relative root mean square error (GHI) of 20.4% for the next 15 minutes is observed at pixel basis (25 m2). Although the deviations of nowcasting systems strongly depend on the validation period and the specific weather conditions, the WobaS-4cam system is considered to be at least state of the art
Bivariate genome-wide association meta-analysis of pediatric musculoskeletal traits reveals pleiotropic effects at the SREBF1/TOM1L2 locus
Bone mineral density is known to be a heritable, polygenic trait whereas genetic variants contributing to lean mass variation remain largely unknown. We estimated the shared SNP heritability and performed a bivariate GWAS meta-analysis of total-body lean mass (TB-LM) and total-body less head bone mineral density (TBLH-BMD) regions in 10,414 children. The estimated SNP heritability is 43% for TBLH-BMD, and 39% for TB-LM, with a shared genetic component of 43%. We identify variants with pleiotropic effects in eight loci, including seven established bone mineral density loci: _WNT4, GALNT3, MEPE, CPED1/WNT16, TNFSF11, RIN3, and PPP6R3/LRP5_. Variants in the _TOM1L2/SREBF1_ locus exert opposing effects TB-LM and TBLH-BMD, and have a stronger association with the former trait. We show that _SREBF1_ is expressed in murine and human osteoblasts, as well as in human muscle tissue. This is the first bivariate GWAS meta-analysis to demonstrate genetic factors with pleiotropic effects on bone mineral density and lean mass
Effects of cholinergic stimulation with pyridostigmine bromide on chronic chagasic cardiomyopathic mice
The aim of the present study was to assess the effects of an anticholinesterase agent, pyridostigmine bromide (Pyrido), on experimental chronic Chagas heart disease in mice. To this end, male C57BL/6J mice noninfected (control:Con) or chronically infected (5 months) with Trypanosoma cruzi (chagasic:Chg) were treated or not (NT) with Pyrido for one month. At the end of this period, electrocardiogram (ECG); cardiac autonomic function; heart histopathology; serum cytokines; and the presence of blood and tissue parasites by means of immunohistochemistry and PCR were assessed. In NT-Chg mice, significant changes in the electrocardiographic, autonomic, and cardiac histopathological profiles were observed confirming a chronic inflammatory response. Treatment with Pyrido in Chagasic mice caused a significant reduction of myocardial inflammatory infiltration, fibrosis, and hypertrophy, which was accompanied by a decrease in serum levels of IFN\u3b3 with no change in IL-10 levels, suggesting a shift of immune response toward an anti-inflammatory profile. Lower nondifferent numbers of parasite DNA copies were observed in both treated and nontreated chagasic mice. In conclusion, our findings confirm the marked neuroimmunomodulatory role played by the parasympathetic autonomic nervous system in the evolution of the inflammatory-immune response to T. cruzi during experimental chronic Chagas heart disease in mice
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