1,688 research outputs found

    Assessing Capacity and Performance of Health Systems Using Principal Component Analysis: Results from Cross Sectional Survey in Kakamega County, Western Kenya

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    Background: Strong health systems are fundamental if countries are to improve health outcomes and accelerate the attainment of the Sustainable Development Goal (SDGs) number 3 ‘Ensure healthy lives and promote well-being for all at all ages.’ Despite the strong consensus on need to strengthen health systems, many health systems lack the capacity to measure or understand their own weakness and constraints which effectively leaves policy makers without ideas of what they should actually strengthen. Methods: Principal Component Analysis (PCA) was used to factor weights which were used to assess individual contribution of indicators to the health system performance.  PCA is a type of a multivariable linear regression of all indicators in one model. PCA index was classify variables from heighted to the lowest indicator and further used to rank the indicator. Indicators of individual health system building block were weighted independently to measure the amount of contribution to the respective health system building block. The weights were then aggregated to produce individual health system building block indices which were the independent variables in the multivariable linear regression model. Coefficients of the regression was used to assess marginal effects and p-value<0.05 were considered statistics significant result Results: Service delivery (p<0.0001), health financing (p<0.0001), health workforce (p=0.005) and medical supplies and commodities (p<0.0001) had significant effect on service provision. Health governance was not a significant factor influencing service provision. Conclusions: Among the health system building blocks that significantly influenced service provision were service delivery, health workforce, and health financing and medical supplies. This is the first study to the best of the knowledge of the researcher to apply principal component analysis, to analyze health system performance in a devolved system Kakamega. The method provides opportunity for future application in health systems analysis even in absence of comparative data Keywords: Principal Component Analysis, Health Systems DOI: 10.7176/JHMN/59-0

    Impact of Electrodes on Recombination in Bulk Heterojunction Organic Solar Cells

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    In recent years, the efficiency of organic solar cells (OSCs) has increased to more than 13%, although different barriers are on the way for reaching higher efficiencies. One crucial barrier is the recombination of charge carriers, which can either occur as the bulk recombination of photogenerated charges or the recombination of photogenerated charges and electrodic induced charges (EICs). This work studies the impact of EICs on the recombination lifetime in OSCs. To this end, the net recombination lifetime of photogenerated charge carriers in the presence of EICs is measured by means of conventional and newly developed transient photovoltage techniques. Moreover, a new approach has been introduced to exclusively measure the bulk recombination lifetime, i.e., in the absence of EICs; this approach was conducted by depositing transparent insulating layers on both sides of the OSC active layer. An examination of these approaches on OSCs with different active layer materials, thicknesses, and varying light intensities determined that the EICs can only reduce the recombination lifetime of the photogenerated charges in OSCs with very weak recombination strength. This work supports that for OSCs with highly reduced recombination strength, eliminating the recombination of photogenerated charges and EICs is critical for achieving better performance. Therefore, the use of a proper blocking layer suppresses EIC recombination in systems with very weak recombination.</p

    Constructive Matrix Theory

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    We extend the technique of constructive expansions to compute the connected functions of matrix models in a uniform way as the size of the matrix increases. This provides the main missing ingredient for a non-perturbative construction of the ϕ4⋆4\phi^{\star 4}_4 field theory on the Moyal four dimensional space.Comment: 12 pages, 3 figure

    Strict polynomial functors and coherent functors

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    We build an explicit link between coherent functors in the sense of Auslander and strict polynomial functors in the sense of Friedlander and Suslin. Applications to functor cohomology are discussed.Comment: published version, 24 pages. Section 2.7 reorganized, and notational distinction between left and right tensor product reinstalle

    Analysis of pin fins with radiation

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    The design of fins for heat transfer enhancement remains a topic of great interest in a number of engineering areas and applications, despite a broad and deep prior literature on the subject. Rapid prediction of the effects of convection, conduction and radiation is still an area of concern. For hot-flow conditions, the fin is normally mounted in a cooled surface, leading to substantial axial conduction. Also, radiation plays a very important role in hot flow conditions. One can apply detailed computational methods for simultaneous convection, conduction and radiation heat transfer, but such approaches are not suitable for rapid, routine design studies. So, there is still a place for approximate analytic methods, and that is the subject of this paper. We have extended the traditional pin fin analysis to include a more realistic radiation treatment and also considered variable thermal conductivity, variable heat transfer coefficients over the tip and sides of the fin with variable area distribution, variable internal heat generation and then produced a MATLAB solution procedure for routine use by designers and analysts.Papers presented at the 13th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Portoroz, Slovenia on 17-19 July 2017 .International centre for heat and mass transfer.American society of thermal and fluids engineers

    Prodsimplicial-Neighborly Polytopes

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    Simultaneously generalizing both neighborly and neighborly cubical polytopes, we introduce PSN polytopes: their k-skeleton is combinatorially equivalent to that of a product of r simplices. We construct PSN polytopes by three different methods, the most versatile of which is an extension of Sanyal and Ziegler's "projecting deformed products" construction to products of arbitrary simple polytopes. For general r and k, the lowest dimension we achieve is 2k+r+1. Using topological obstructions similar to those introduced by Sanyal to bound the number of vertices of Minkowski sums, we show that this dimension is minimal if we additionally require that the PSN polytope is obtained as a projection of a polytope that is combinatorially equivalent to the product of r simplices, when the dimensions of these simplices are all large compared to k.Comment: 28 pages, 9 figures; minor correction

    Field dependence of the electronic phase separation in Pr0.67Ca0.33MnO3 by small angle magnetic neutron scattering

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    We have studied by small angle neutron scattering the evolution induced by the application of magnetic field of the coexistence of ferromagnetism (F) and antiferromagnetism (AF) in a crystal of Pr0.67_{0.67}Ca0.33_{0.33}MnO3_3. The results are compared to magnetic measurements which provide the evolution of the ferromagnetic fraction. These results show that the growth of the ferromagnetic phase corresponds to an increase of the thickness of the ferromagnetic ''cabbage'' sheets

    Helically chiral NHC‐gold(I) complexes: synthesis, chiroptical properties and electronic features of the [5]helicene‐imidazolylidene ligand

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    The golden twist: Monodentate [5]helicene-imidazolylidene gold(I) complexes were prepared in good yields and structurally characterized. Benefiting from the presence of the configurationally stable [5]helicenic unit, they exhibit appealing chiroptical features, such as strong circular dichroism, moderate circularly polarized phosphorescence and dual emission with phosphorescence lifetimes up to the millisecond range

    Aging in a topological spin glass

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    We have examined the nonconventional spin glass phase of the 2-dimensional kagome antiferromagnet (H_3 O) Fe_3 (SO_4)_2 (OH)_6 by means of ac and dc magnetic measurements. The frequency dependence of the ac susceptibility peak is characteristic of a critical slowing down at Tg ~ 18K. At fixed temperature below Tg, aging effects are found which obey the same scaling law as in spin glasses or polymers. However, in clear contrast with conventional spin glasses, aging is remarkably insensitive to temperature changes. This particular type of dynamics is discussed in relation with theoretical predictions for highly frustrated non-disordered systems.Comment: 4 pages, 4 figure

    Comparison of different model solutions to simulate membrane fouling in the ultrafiltration of a secondary effluent from a municipal wastewater treatment plant

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    The quality of the secondary treatment effluent (STE) from a municipal wastewater treatment plant (MWWTP) is not good enough for some applications such as agriculture. Membrane ultrafiltration (UF) has been proven to be a reliable tertiary treatment to achieve the needed water quality. The productivity of the UF processes depends on the membrane fouling. The aim of this work is to prepare a model wastewater that could mimic the fouling trend of a STE wastewater from a MWWTP. Several model wastewaters consisting of different proteins and carbohydrates were used in the UF experiments. UF was also performed with a STE. The membrane used in the UF tests was a UFCM5 from Norit X-flowÂź hydrophilic polyethersulfone/polyvinylpyrrolidone blend hollow-fiber UF membrane of 200 KDa molecular weight cut-off with a fiber diameter of 1.5&#8201;mm. Membrane configuration was inside-out. UF tests with model wastewater and STE wastewater were compared. The results showed that the best model wastewater, which represents the fouling trend of STE wastewater is the model wastewater whose composition is 15&#8201;mg/l of bovine serum albumin and 5.5&#8201;mg/l of dextran.The authors of this work wish to gratefully acknowledge the financial support from the Generalitat Valenciana through the program "Ayudas para la realizacion de proyectos I+D para grupos de investigacion emergentes GV/2013."Tora Grau, M.; Soler Cabezas, JL.; Vincent Vela, MC.; Mendoza Roca, JA.; MartĂ­nez Francisco, FJ. (2014). Comparison of different model solutions to simulate membrane fouling in the ultrafiltration of a secondary effluent from a municipal wastewater treatment plant. Desalination and Water Treatment. 1-7. https://doi.org/10.1080/19443994.2014.939865S17Delgado, S., Dı́az, F., Vera, L., Dı́az, R., & Elmaleh, S. (2004). Modelling hollow-fibre ultrafiltration of biologically treated wastewater with and without gas sparging. Journal of Membrane Science, 228(1), 55-63. doi:10.1016/j.memsci.2003.09.011Qin, J.-J., Oo, M. H., Lee, H., & Kolkman, R. (2004). Dead-end ultrafiltration for pretreatment of RO in reclamation of municipal wastewater effluent. Journal of Membrane Science, 243(1-2), 107-113. doi:10.1016/j.memsci.2004.06.010Konieczny, K. (1998). Disinfection of surface and ground waters with polymeric ultrafiltration membranes. Desalination, 119(1-3), 251-258. doi:10.1016/s0011-9164(98)00166-0Madaeni, S. S., Fane, A. G., & Grohmann, G. S. (1995). Virus removal from water and wastewater using membranes. Journal of Membrane Science, 102, 65-75. doi:10.1016/0376-7388(94)00252-tArnal Arnal, J. M., Sancho FernĂĄndez, M., MartĂ­n VerdĂș, G., & Lora GarcĂ­a, J. (2001). Design of a membrane facility for water potabilization and its application to Third World countries. Desalination, 137(1-3), 63-69. doi:10.1016/s0011-9164(01)00205-3ArĂ©valo, J., GarralĂłn, G., Plaza, F., Moreno, B., PĂ©rez, J., & GĂłmez, M. Á. (2009). Wastewater reuse after treatment by tertiary ultrafiltration and a membrane bioreactor (MBR): a comparative study. Desalination, 243(1-3), 32-41. doi:10.1016/j.desal.2008.04.013Katsoufidou, K., Yiantsios, S. G., & Karabelas, A. J. (2008). An experimental study of UF membrane fouling by humic acid and sodium alginate solutions: the effect of backwashing on flux recovery. Desalination, 220(1-3), 214-227. doi:10.1016/j.desal.2007.02.038Muthukumaran, S., Nguyen, D. A., & Baskaran, K. (2011). Performance evaluation of different ultrafiltration membranes for the reclamation and reuse of secondary effluent. Desalination, 279(1-3), 383-389. doi:10.1016/j.desal.2011.06.040Henderson, R. K., Subhi, N., Antony, A., Khan, S. J., Murphy, K. R., Leslie, G. L., 
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