The dynamics of phase farming in dryland salinity abatement

Farm Management, Land Economics/Use,

Dynamic trade-offs in water use between irrigation and reservoir aquaculture in Vietnam

Conflicts of interest between irrigation and aquaculture in water use from reservoirs in Vietnam can be resolved when trade-offs in the economic value of water can be quantified over time. Determining these trade-offs can be used as a benchmark for making decisions about managing reservoirs tending to develop rural areas in Vietnam. To solve this problem, a stochastic dynamic programming model was constructed. This model maximizes the expected net present values generated by both agriculture and aquaculture by finding the optimal release paths throughout a year, under conditions of uncertain rainfall. The model was constructed using two main components. First, a dated water production function is used to evaluate responses of crop yields for different levels of applied irrigation. Second, a bio-economic model for reservoir fisheries is employed to estimate fish yields at different levels of water during a harvest season. Using this model, we present a case study of reservoir water management in Vietnam.irrigation, reservoir aquaculture, stochastic dynamic programming, and dynamic trade-offs, Community/Rural/Urban Development,

Resource savings by urban mining : the case of desktop and laptop computers in Belgium

Waste electrical and electronic equipment (WEEE) has become increasingly important over the last years. Additionally, the European Union recognizes the growing importance of raw materials, and the crucial role of recycling. In this study the performance of WEEE recycling was assessed for the case of desktop and laptop computers in Belgium in 2013. The analysis was performed in four steps. First, the recycling chain is analyzed through material flow analysis (MFA) at the level of specific materials. Second, an indicator is calculated, which quantifies the effectively recycled weight ratios of the specific materials. Third, a second indicator expresses the recycling efficiency of so-called critical raw materials. Finally, the natural resource consumption of the recycling scheme in a life cycle perspective is calculated using the Cumulative Exergy Extraction from the Natural Environment (CEENE) method, and is benchmarked with a landfill scenario. Overall, the results show that base metals such as ferrous metals, aluminium and copper are recycled to a large extent, but that for precious metals improvements still can be made. The input of criticality (arising from the incoming mass, as well as the individual criticality value of the assessed material) mainly comes from base metals, resulting in a high recovery performance of raw materials criticality. Finally, the natural resource consumption of the recycling scenario is much smaller than in case of landfilling the WEEE: 80 and 87% less resource consumption is achieved for desktops and laptops respectively, hence saving significant primary raw materials

Shiga toxin production and translocation during microaerobic human colonic infection with Shiga toxin-producing E. coli O157:H7 and O104:H4

Haemolytic uraemic syndrome caused by Shiga toxin-producing E. coli (STEC) is dependent on release of Shiga toxins (Stxs) during intestinal infection and subsequent absorption into the bloodstream. An understanding of Stx-related events in the human gut is limited due to lack of suitable experimental models. In this study, we have used a vertical diffusion chamber system with polarized human colon carcinoma cells to simulate the microaerobic (MA) environment in the human intestine and investigate its influence on Stx release and translocation during STEC O157:H7 and O104:H4 infection. Stx2 was the major toxin type released during infection. Whereas microaerobiosis significantly reduced bacterial growth as well as Stx production and release into the medium, Stx translocation across the epithelial monolayer was enhanced under MA versus aerobic conditions. Increased Stx transport was dependent on STEC infection and occurred via a transcellular pathway other than macropinocytosis. While MA conditions had a similar general effect on Stx release and absorption during infection with STEC O157:H7 and O104:H4, both serotypes showed considerable differences in colonization, Stx production, and Stx translocation which suggest alternative virulence strategies. Taken together, our study suggests that the MA environment in the human colon may modulate Stx-related events and enhance Stx absorption during STEC infection

A Numerical Scheme for Wave Turbulence: 3-Wave Kinetic Equations

We introduce a finite volume scheme to solve isotropic 3-wave kinetic equations. We test our numerical solution against theoretical results concerning the long time behavior of the energy and observe that our solutions verify the energy cascade phenomenon. To our knowledge, this is the first numerical scheme that can capture the long time asymptotic behavior of solutions to isotropic 3-wave kinetic equations, where the energy cascade can be observed. Our numerical energy cascade rates are in good agreement with previously obtained theoretical results. The finite volume scheme given here relies on a new identity, allowing one to reduce the number of terms needed in the collision operators

Numerical Schemes for 3-Wave Kinetic Equations: A Complete Treatment of the Collision Operator

In our previous work, numerical schemes for a simplified version of 3-wave kinetic equations, in which only the simple forward-cascade terms of the collision operators are kept, have been successfully designed, especially to capture the long time dynamics of the equation given the multiple blow-up time phenomenon. In this second work in the series, we propose numerical treatments for the complete 3-wave kinetic equations, in which the complete, much more complicated collision operators are fully considered based on a novel conservative form of the equation. We then derive an implicit finite volume scheme to solve the equation. The new discretization uses an adaptive time-stepping method which allows for the simulations to be carried to very long times. Our computed solutions are compared with previously derived long-time asymptotic estimates for the decay rate of total energy of time-dependent solutions of 3-wave kinetic equations and found to be in excellent agreement

Probiotics Effect on Healthspan in the Model Organism Caenorhabditis elegans

In America, there are high rates of obesity and obesity related diseases partially due to a high glucose diet. Possessing a propensity towards reversing a glucose rich diet, probiotics, live microorganisms such as yogurt, were used to combat this. To experiment with humans let alone mice would be tedious, so, another organism-the microscopic nematode, Caenorhabditis elegans was used. Because C. elegans possesses homology with humans, they can be used to study probiotics with application in humans. Sponsored by the Creative Inquiry program, this project analyzed the relationship between different probiotics and their effect on lifespan. With Escherichia coli OP50 as the control and varying Lactobacillus strains as the experimental groups, lifespan assays were conducted. Our results show that certain probiotics increase the lifespan and reverse the consequences of a high glucose diet. Conversely, certain probiotic species, such as Lactobacillus plantarum, can decrease and promote negative health consequences in C. elegans. From these results, the understanding of the human microbiome and better treatments for obesity and obesity related diseases can be made