1,855 research outputs found
Anemia Prevalence among Pregnant Women and Birth Weight in Five Areas in China
Objectives: To investigate the current prevalence of anemia among pregnant women in different areas of China and the association with birth weight and educational level. Methods: A total of 6,413 women aged 24-37 in the third trimester of pregnancy from five areas were randomly selected from all gravidas who gave birth in the hospitals from 1999 to 2003. Blood hemoglobin concentration (Hb) was measured by the cyanomethemoglobin method; Hb <110 g/l was considered as anemia. Results: The overall prevalence of anemia was 58.6%, ranging from 48.1 to 70.5% in the five areas. There was a significant difference in the prevalence of anemia between women who have mental jobs and those who have physical jobs (52.3 vs. 61.1%, p <0.01). The prevalence of anemia depended on the level of education: with 52.9, 62.4 and 66.5%, for college, secondary school and primary education, respectively, and the difference was statistically significant (p = 0.005). Results showed that higher birth weight was associated with Hb concentrations ranging from 90 to 140 g/l, whereas lower birth weight occurred below 80 g/l and above 140 g/l Hb. Conclusions: The prevalence of anemia in Chinese pregnant women was high both in rural areas and towns. Area of residence, education level and type of job influenced the prevalence of anemia. Low maternal Hb concentrations influenced birth weight
Magnetic phase diagrams of the Kagome staircase compound Co3V2O8
At zero magnetic field, a series of five phase transitions occur in Co3V2O8.
The Neel temperature, TN=11.4 K, is followed by four additional phase changes
at T1=8.9 K, T2=7.0 K, T3=6.9 K, and T4=6.2 K. The different phases are
distinguished by the commensurability of the b-component of its spin density
wave vector. We investigate the stability of these various phases under
magnetic fields through dielectric constant and magnetic susceptibility
anomalies. The field-temperature phase diagram of Co3V2O8 is completely
resolved. The complexity of the phase diagram results from the competition of
different magnetic states with almost equal ground state energies due to
competing exchange interactions and frustration.Comment: Proceedings of the 2007 Conference on Strongly Correlated Electron
Systems, 2 pages, 2 figure
Measurement and control systems for an imaging electromagnetic flow meter
Electromagnetic flow metres based on the principles of Faraday's laws of induction have been used successfully in many industries. The conventional electromagnetic flow metre can measure the mean liquid velocity in axisymmetric single phase flows. However, in order to achieve velocity profile measurements in single phase flows with non-uniform velocity profiles, a novel imaging electromagnetic flow metre (IEF) has been developed which is described in this paper. The novel electromagnetic flow metre which is based on the ‘weight value’ theory to reconstruct velocity profiles is interfaced with a ‘Microrobotics VM1’ microcontroller as a stand-alone unit. The work undertaken in the paper demonstrates that an imaging electromagnetic flow metre for liquid velocity profile measurement is an instrument that is highly suited for control via a microcontroller
Transport across nanogaps using semiclassically consistent boundary conditions
Charge particle transport across nanogaps is studied theoretically within the
Schrodinger-Poisson mean field framework and the existence of limiting current
investigated. It is shown that the choice of a first order WKB wavefunction as
the transmitted wave leads to self consistent boundary conditions and gives
results that are significantly different in the non-classical regime from those
obtained using a plane transmitted wave. At zero injection energies, the
quantum limiting current density, J_c, is found to obey the local scaling law
J_c ~ (V_g)^alpha/(D)^{5-2alpha} with the gap separation D and voltage V_g. The
exponent alpha > 1.1 with alpha --> 3/2 in the classical regime of small de
Broglie wavelengths. These results are consistent with recent experiments using
nanogaps most of which are found to be in a parameter regime where classical
space charge limited scaling holds away from the emission dominated regime.Comment: 4 pages, 4 ps figure
Layered hybrid phase Li2NaV2(PO4)3/carbon dot nanocomposite cathodes for Li+/Na+ mixed-ion batteries
PSO-based Parameter Estimation of Nonlinear Kinetic Models for β-Mannanase Fermentation
Particle swarm optimization (PSO), as a novel evolutionary algorithm involved in social interaction for global space search, was firstly used in kinetic parameter estimation. Based on three developed nonlinear kinetic equations for bacterial cell growth, total sugar utilization and β-mannanase production by Bacillus licheniformis under the support of a batch fermentation process, various PSO algorithms as well as gene algorithms (GA) were developed to estimate kinetic parameters. The performance comparison among these algorithms indicates the improved PSO (Trelea 1) is most suitable for kinetic parameter estimation of β-mannanase fermentation. In order to find the physical-chemical-meanings of kinetic parameters from many optimized results, multiobjective optimization with a normalized weight method was adopted. The 9 desired parameters in equations were obtained by the Trelea 1 type PSO with two batches fermentation data, and the results predicted by the models were also in good agreement with the experimental observations
Characterization of a wheat HSP70 gene and its expression in response to stripe rust infection and abiotic stresses
Members of the family of 70-kD heat shock proteins (HSP70 s) play various stress-protective roles in plants. In this study, a wheat HSP70 gene was isolated from a suppression subtractive hybridization (SSH) cDNA library of wheat leaves infected by Puccinia striiformis f. sp. tritici. The gene, that was designated as TaHSC70, was predicted to encode a protein of 690 amino acids, with a molecular mass of 73.54 KDa and a pI of 5.01. Further analysis revealed the presence of a conserved signature that is characteristic for HSP70s and phylogenetic analysis demonstrated that TaHSC70 is a homolog of chloroplast HSP70s. TaHSC70 mRNA was present in leaves of both green and etiolated wheat seedlings and in stems and roots. The transcript level in roots was approximately threefold less than in leaves but light–dark treatment did not charge TaHSC70 expression. Following heat shock of wheat seedlings at 40°C, TaHSC70 expression increased in leaves of etiolated seedlings but remained stable at the same level in green seedlings. In addition, TaHSC70 was differentially expressed during an incompatible and compatible interaction with wheat-stripe rust, and there was a transient increase in expression upon treatment with methyl jasmonate (MeJA) treatment. Salicylic acid (SA), ethylene (ET) and abscisic acid (ABA) treatments had no influence on TaHSC70 expression. These results suggest that TaHSC70 plays a role in stress-related responses, and in defense responses elicited by infection with stripe rust fungus and does so via a JA-dependent signal transduction pathway
Thermal expansion and pressure effect in MnWO4
MnWO4 has attracted attention because of its ferroelectric property induced
by frustrated helical spin order. Strong spin-lattice interaction is necessary
to explain ferroelectricity associated with this type of magnetic order.We have
conducted thermal expansion measurements along the a, b, c axes revealing the
existence of strong anisotropic lattice anomalies at T1=7.8 K, the temperature
of the magnetic lock-in transition into a commensurate low-temperature
(reentrant paraelectric) phase. The effect of hydrostatic pressure up to 1.8
GPa on the FE phase is investigated by measuring the dielectric constant and
the FE polarization. The low- temperature commensurate and paraelectric phase
is stabilized and the stability range of the ferroelectric phase is diminished
under pressure.Comment: 2 pages, 3 figures. SCES conference proceedings, houston, TX, 2007.
to be published in Physica
Study of f_0(980) and f_0(1500) from B_s \to f_0(980)\pi, f_0(1500)\pi Decays
In this paper, we analyze the scalar mesons and from
the decays within Perturbative
QCD approach. From the leading order calculations, we find that (a) in the
allowed mixing angle ranges, the branching ratio of is about , which is smaller than
that of (the difference is a few times even one
order); (b) the decay is better to distinguish
between the lowest lying state or the first excited state for ,
because the branching ratios for two scenarios have about one-order difference
in most of the mixing angle ranges; and (c) the direct CP asymmetries of for two scenarios also exists great difference. In
scenario II, the variation range of the value according to the mixing angle is very small, except for
the values corresponding to the mixing angles being near or
, while the variation range of in scenario I is very large. Compared with the future data for
the decay , it is ease to determine the nature
of the scalar meson .Comment: 16 pages, 3 figures, Revte
The lithospheric thickness control on the compositional variation of continental intraplate basalts: A demonstration using the Cenozoic basalts and clinopyroxene megacrysts from eastern China
Studies on intra‐plate ocean island basalts have demonstrated the control of lithosphere thickness on the extent of melting and pressure of melt extraction (i.e., the lid‐effect). However, whether lithosphere thickness also controls the composition of within‐continent basalts remains unclear. Here we test this hypothesis by studying the Cenozoic basalts containing clinopyroxene megacrysts from 10 localities throughout eastern continental China with a north‐south spatial coverage in excess of 2500 km. Indeed, the geochemical parameters (e.g., abundances and ratios of major and trace elements) correlate well with the depth of the lithosphere‐asthenosphere boundary (LAB) calculated using the clinopyroxene barometry, showing significant lithospheric thickness control on basalt compositions. These observations offer further evidence for melt pooling (a melt rich layer) close beneath the LAB as a “stable magma reservoir” for crystallizing compositionally uniform clinopyroxene megacrysts to be carried by subsequent pulses of melt transport and eruption
- …