839 research outputs found

    Mother, Infant, and Household Factors Associated with the Type of Food Infants Receive in Developing Countries

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    Objectives: We explore the complex factors associated with infant feeding by analyzing what mother, infant, and household factors are associated with the types of food given to infants. We seek to quantify associations in order to inform public health policy about the importance of target populations for infant feeding programs. Methods: We used data from the Demographic Health Survey in 20 developing countries for multiple years to examine mother, infant, and household factors associated with six types of food given to infants (exclusive breastfeeding, non-exclusive breastfeeding, infant formula, milk liquids, non-milk liquids, and solid foods). We performed a seemingly unrelated regressions analysis with community-year fixed effects to account for correlation between food types and control for confounding factors associated with community resources, culture, time period, and geography in the pooled analysis. Results: We found that several mother, infant, and household characteristics were associated with each of the feeding types. Most notably, mother’s education, working status, and weight are significantly associated with the type of food given to infants. We provide quantified estimates of the association of each of these variables with six types of food given to infants. Conclusion: By identifying maternal characteristics associated with infant feeding and quantifying those associations, we help public health policymakers generate priorities for targeting infant feeding programs to specific populations that are at greatest risk. Higher educated, working mothers are best to target with exclusive breastfeeding programs for young infants. Mothers with lower education are best to target with complementary feeding programs in infants older than 1 year. Finally, while maternal weight is associated with higher levels of exclusive breastfeeding the association is too weak to merit targeting of breastfeeding programs to low-weight mothers

    Crystallographic structure of ultrathin Fe films on Cu(100)

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    We report bcc-like crystal structures in 2-4 ML Fe films grown on fcc Cu(100) using scanning tunneling microscopy. The local bcc structure provides a straightforward explanation for their frequently reported outstanding magnetic properties, i.e., ferromagnetic ordering in all layers with a Curie temperature above 300 K. The non-pseudomorphic structure, which becomes pseudomorphic above 4 ML film thickness is unexpected in terms of conventional rules of thin film growth and stresses the importance of finite thickness effects in ferromagnetic ultrathin films.Comment: 4 pages, 3 figures, RevTeX/LaTeX2.0

    Autodisplay for the co-expression of lipase and foldase on the surface of E. coli: washing with designer bugs

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    Background: Lipases including the lipase from Burkholderia cepacia are in a main focus in biotechnology research since many years because of their manifold possibilities for application in industrial processes. The application of Burkholderia cepacia lipase for these processes appears complicated because of the need for support by a chaperone, the lipase specific foldase. Purification and reconstitution protocols therefore interfere with an economic implementation of such enzymes in industry. Autodisplay is a convenient method to express a variety of passenger proteins on the surface of E. coli. This method makes subsequent purification steps to obtain the protein of interest unnecessary. If enzymes are used as passengers, the corresponding cells can simply be applied as whole cell biocatalysts. Furthermore, enzymes surface displayed in this manner often acquire stabilization by anchoring within the outer membrane of E. coli. Results: The lipase and its chaperone foldase from B. cepacia were co-expressed on the surface of E. coli via autodisplay. The whole cell biocatalyst obtained thereby exhibited an enzymatic activity of 2.73 mU mL-1 towards the substrate p-nitrophenyl palmitate when applied in an OD578 =1. Outer membrane fractions prepared from the same culture volume showed a lipase activity of 4.01 mU mL-1. The lipase-whole cell biocatalyst as well as outer membrane preparations thereof were used in a standardized laundry test, usually adopted to determine the power of washing agents. In this test, the lipase whole cell biocatalyst and the membrane preparation derived thereof exhibited the same lipolytic activity as the purified lipase from B. cepacia and a lipase preparation which is already applied in commercial washing agents. Conclusions: Co-expression of both the lipase and its chaperone foldase on the surface of E. coli yields a lipid degrading whole cell biocatalyst. Therefore the chaperone supported folding process, absolutely required for the lipolytic activity appears not to be hindered by surface display. Furthermore, the cells and the membrane preparations appeared to be stable enough to endure a European standard laundry test and show efficient fat removal properties herein.<br

    Electron-correlation effects in appearance-potential spectra of Ni

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    Spin-resolved and temperature-dependent appearance-potential spectra of ferromagnetic Nickel are measured and analyzed theoretically. The Lander self-convolution model which relates the line shape to the unoccupied part of the local density of states turns out to be insufficient. Electron correlations and orbitally resolved transition-matrix elements are shown to be essential for a quantitative agreement between experiment and theory.Comment: LaTeX, 6 pages, 2 eps figures included, Phys. Rev. B (in press

    A HYBRID ARIMA AND ARTIFICIAL NEURAL NETWORK MODEL FOR SYNTHETIC STREAMFLOW GENERATION

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    For water resources planning and management, streamflow modeling and forecasting is essential in several subjects, such as, flood analysis and hazard mitigation systems, operation and planning of reservoirs, hydropower generation, among others. Good quality streamflow time series are of paramount importance for successfully fitting a hydrological model. However, the representativeness of such datasets may be a relevant issue to be considered. In situations when the historical register of a catchment has little available data, generating synthetic series by using stochastic models is a good way to overcome such problems. Thus, an ensemble of models capable to compute and replicate important statistical features of a series, namely Autoregressive Integrated Moving Average (ARIMA) type models, are still largely used for this purpose by many hydrologists worldwide, presenting a fair representation of the river regimen. However, a problem regarding ARIMA modelling is that those classic models are linear and fail to represent the non-linearity of streamflow and, thus, might not give the best result. Moreover, synthetic series using ARIMA models might present numerical issues related to the integration of the series, whilst Autoregressive Moving Average (ARMA) models, although useful in synthetic generation, are incapable to compute possible nonstationarities of a series. To illustrate such issues, Mann-Kendall and Pettitt statistical trend tests were performed for the Foz do Areia hydropower plant streamflow series, in the Iguaçu river basin. Two analyses were performed: (i) using the original data, and (ii) using residuals of the original data resulting of an ARMA filtering procedure. It is shown that the ARMA filter does not remove the trend detected in analysis (i), which hinders the use of such model for generating synthetic streamflow series. An alternative approach, possible to improve the quality of the results and adequate to deal with non-linear patterns and trends is the artificial neural network (ANN). The next steps of this research will consider the development and training of an ANN model and couple it with the ARIMA approach to produce a hybrid ARIMA-ANN model for streamflow synthetic series generation
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