From integrated to expedient: an adaptive framework for river basin management in developing countries

Water resource management / River basin management / Water allocation / Case studies / Africa South of Sahara / Great Ruaha River Basin

Use of a hydrological model for environmental management of the Usangu Wetlands, Tanzania

Wetlands / Rivers / Ecology / Environmental effects / Remote sensing / Hydrology / Simulation models / Water budget / Irrigated sites / Land cover / Time series analysis / Tanzania / Usangu Wetlands / Great Ruaha River

The key components of Schwann cell-like differentiation medium and their effects on gene expression pattern of adipose-derived stem cells.

BackgroundSchwann cell-like cells differentiated from adipose-derived stem cells may have an important role in peripheral nerve regeneration. Herein, we document the individual effects of growth factors in Schwann cell-like differentiation medium.MethodsThere were 6 groups in the study. In the control group, we supplemented the rat adipose-derived stem cells with normal cell culture medium. In group 1, we fed the cells with Schwann cell-like differentiation medium (normal cell culture medium supplemented with platelet-derived growth factor, basic fibroblast growth factor, forskolin, and glial growth factor). In the other groups, we removed the components of the medium one at a time from the differentiation medium so that group 2 lacked glial growth factor, group 3 lacked forskolin, group 4 lacked basic fibroblast growth factor, and group 5 lacked platelet-derived growth factor. We examined the expression of the Schwann cell-specific genes with quantitative reverse transcription polymerase chain reaction and immunofluorescence staining in each group.ResultsGroups 3 and 4, lacking forskolin and basic fibroblast growth factor, respectively, had the highest expression levels of integrin-β4, and p75. Group 1 showed a 3.2-fold increase in the expression of S100, but the expressions of integrin-β4 and p75 were significantly lower compared to groups 3 and 4. Group 2 [glial growth factor (-)] did not express significant levels of Schwann cell-specific genes. The gene expression profile in group 4 most closely resembled Schwann cells. Immunofluorescence staining results were parallel with the quantitative real-time polymerase chain reaction results.ConclusionsGlial growth factor is a key component of Schwann cell-like differentiation medium

Pinning/depinning of crack fronts in heterogeneous materials

The fatigue fracture surfaces of a metallic alloy, and the stress corrosion fracture surfaces of glass are investigated as a function of crack velocity. It is shown that in both cases, there are two fracture regimes, which have a well defined self-affine signature. At high enough length scales, the universal roughness index 0.78 is recovered. At smaller length scales, the roughness exponent is close to 0.50. The crossover length $\xi_c$ separating these two regimes strongly depends on the material, and exhibits a power-law decrease with the measured crack velocity $\xi_c \propto v^{-\phi}$, with $\phi \simeq 1$. The exponents $\nu$ and $\beta$ characterising the dependence of $\xi_c$ and $v$ upon the pulling force are shown to be close to $\nu \simeq 2$ and $\beta \simeq 2$.Comment: 4 pages, latex, and 4 encapsulated postscript figure

Wind-US Code Physical Modeling Improvements to Complement Hypersonic Testing and Evaluation

This report gives an overview of physical modeling enhancements to the Wind-US flow solver which were made to improve the capabilities for simulation of hypersonic flows and the reliability of computations to complement hypersonic testing. The improvements include advanced turbulence models, a bypass transition model, a conjugate (or closely coupled to vehicle structure) conduction-convection heat transfer capability, and an upgraded high-speed combustion solver. A Mach 5 shock-wave boundary layer interaction problem is used to investigate the benefits of k- s and k-w based explicit algebraic stress turbulence models relative to linear two-equation models. The bypass transition model is validated using data from experiments for incompressible boundary layers and a Mach 7.9 cone flow. The conjugate heat transfer method is validated for a test case involving reacting H2-O2 rocket exhaust over cooled calorimeter panels. A dual-mode scramjet configuration is investigated using both a simplified 1-step kinetics mechanism and an 8-step mechanism. Additionally, variations in the turbulent Prandtl and Schmidt numbers are considered for this scramjet configuration

Climate and southern Africa's water-energy-food nexus

In southern Africa, the connections between climate and the water-energy-food nexus are strong. Physical and socioeconomic exposure to climate is high in many areas and in crucial economic sectors. Spatial interdependence is also high, driven for example, by the regional extent of many climate anomalies and river basins and aquifers that span national boundaries. There is now strong evidence of the effects of individual climate anomalies, but associations between national rainfall and Gross Domestic Product and crop production remain relatively weak. The majority of climate models project decreases in annual precipitation for southern Africa, typically by as much as 20% by the 2080s. Impact models suggest these changes would propagate into reduced water availability and crop yields. Recognition of spatial and sectoral interdependencies should inform policies, institutions and investments for enhancing water, energy and food security. Three key political and economic instruments could be strengthened for this purpose; the Southern African Development Community, the Southern African Power Pool, and trade of agricultural products amounting to significant transfers of embedded water