Pareto Optimization of Water Resources Using the Nexus Approach

The continuously growing population in combination with the escalating urbanization and economic growth increase the pressure on water, energy and food resources of our planet. This entails an urgent need for proper water resources management within the water-energy-food (WEF) nexus concept. The WEF nexus considers water, energy and food as three continuously interconnected sectors, whose complex interactions lead to an increased number of trade-offs and potential conflicts. Computational modeling can be used to quantify these interactions, reduce trade-offs and promote synergies. We investigate the water resources in the Upper Blue Nile River (UBNR) basin, one of the two main sources of the Nile, using the Hydronomeas tool. Hydronomeas is based on the parameterization-simulation-optimization method; optimization is implemented in two levels, using a holistic approach and multiple criteria. We assign various targets, constraints and priorities to the UBNR system of reservoirs, hydropower plants and irrigation projects and derive a Pareto front that contains alternative, optimal solutions, for which improvement of one objective can be achieved only at the expense of another. By visualizing the trade-offs between the conflicting objectives of hydropower and irrigation, we aim to help decision makers understand changes due to different management policies and thus, achieve greater efficiency in water resources management in the Nile region.     

Long short-term memory for predicting daily suspended sediment concentration

Frequent and accurate estimation of suspended sediment concentration (SSC) in surface waters and hydraulic schemes is of prime importance for proper design, operation and management of many hydraulic projects. in the present study, a long short-term memory (LSTM) was considered for predicting daily suspended sediment concentration in a river. The LSTM extends recurrent neural network with memory cells, instead of recurrent units, to store and output information, easing the learning of temporal relationships on long time scales. To build the model, daily observed time series of river discharge (Q) and SSC in the Schuylkill River in the United States were used. The results of the proposed model were evaluated and compared with the feedforward neural network and the adaptive neuro fuzzy inference system models which were trained using three different learning algorithms and widely used in the literature for prediction of daily SSC. The comparison of prediction accuracy of the models demonstrated that the LSTM model could satisfactory predict SSC time series, and adequately estimate cumulative suspended sediment load (SSL).

     

A placebo-controlled trial of didanosine plus stavudine, with and without hydroxyurea, for HIV infection. The Swiss HIV Cohort Study

OBJECTIVE: To explore the short-term effects on surrogate markers for HIV progression of didanosine (ddl) plus stavudine (d4T), with or without hydroxyurea. DESIGN: Randomized, double-blinded, prospective study. SETTING: Swiss HIV Cohort Study. PATIENTS: A total of 144 patients (75% antiretroviral-naive) were studied (mean baseline HIV-1 RNA, 4.53 log10 copies/ml; mean CD4 cell count, 370 x 10(6)/l). INTERVENTION: Patients received ddl (200 mg twice daily) plus d4T (40 mg twice daily), with additional hydroxyurea (500 mg twice daily) or placebo. MAIN OUTCOME MEASURES: The primary endpoint was a reduction of viraemia below 200 copies/ml after 12 weeks. At that time, patients who did not reach the primary endpoint were withdrawn in the hydroxyurea arm, whereas patients in the placebo group had the option of adding hydroxyurea to ddl and d4T. All patients were followed until week 24. RESULTS: After 12 weeks, 54% of the patients randomized to hydroxyurea had viraemia below 200 copies/ml, compared with 28% on placebo (P < 0.001). Using an ultrasensitive assay with a limit of detection of 20 copies/ml, 19% of patients receiving hydroxyurea had viraemia levels below 20 copies/ml, compared with 8% on placebo (P = 0.05). Mean decrease in HIV-1 RNA was 2.3 and 1.7 log10 copies/ml for hydroxyurea and placebo groups, respectively (P = 0.001). Hydroxyurea was found to induce lymphopenia (-124 x 10(6)/l). Increase in CD4 cell counts was +28 x 10(6)/l during hydroxyurea treatment compared with +107 x 10(6)/l on placebo (P = 0.001). CONCLUSIONS: Hydroxyurea improved the antiviral activity of d4T and ddl over a 12-week period, but was associated with a smaller increase in CD4 cell counts due to hydroxyurea-induced lymphopenia.     

Vasopressin dilates the rat carotid artery by stimulating V1 receptors

1. The effect of the intraperitoneal administration of cholecystokinin sulphated octapeptide (CCK-8S) (10 nmol/kg i.p.) on endogenous levels of several amino acids in five areas of the rat brain was analyzed. The olfactory bulb, hypothalamus, hippocampus, cerebral frontal cortex, and corpus striatum were evaluated. In addition, the effects of CCK-8S and PD 135,158 (1 mg/kg), a selective CCK(B) antagonist, on the performance of rats submitted to a dark/light transition test were also studied. 2. Upon administration of CCK-8S, the concentration of glutamate was reduced (27%) in the olfactory bulb. The same was observed when the levels of glycine (31%) or alanine (43%) were determined. No significant effects were produced by CCK-8S on cortical and hypothalamic levels. In the hippocampus, the concentration of both glutamate (27%) and taurine (29%) were reduced, whereas the levels of GABA in the striatum (29%) were increased. 3. After a single injection of CCK-8S, the time spent by the rats in the illuminated site of the dark/light transition test box, was not changed. On the contrary, the administration of PD 135,158 increased the time spent in the lighted compartment. 4. These results show that systemic administration of CCK-8S produced regional specific changes in brain amino acids, without producing any significant behavioral modification in the rat exposed to a dark/light box. In contrast, the selective CCKB receptor antagonist, PD 135,158, induces anxiolytic-like action in an animal model of anxiety.     

Flood Discharge Prediction using Two-Dimensional Inverse Modeling

A new approach to estimate flood discharges in complex river geometries is presented. Discharges are determined through the combination of nonintrusive measurements of surface velocities and water levels with a Navier–Stokes solver and an inverse optimization algorithm. The numerical model is based on a finite-element solution of the two-dimensional Reynolds-averaged Navier–Stokes equations with a k–ε turbulence model, allowing for computation of the free water surface on adaptive, unstructured grids. The inverse modeling technique uses the Levenberg–Marquardt minimizing algorithm. In order to rule out uncertainties from the numerical model and to strictly quantify the effect of measuring errors, measurements are generated synthetically through forward computations. The methodology is illustrated for the gaging station of the Saltina River at Brig, Switzerland, which involves a complex bed geometry and where laboratory measurements for transcritical flows were available. For perfect measurements the discharge can in principle be estimated to an accuracy of ≈2%, independently of the number of measurements. Measurement errors in the water level have a small influence on the estimated discharge, whereas errors in velocity lead to a major discharge error. This error can be minimized by increasing the number of measurement points and choosing appropriate measurement positions.     

Migration from the gaskets of lids into oily foods: first results on polyadipates

The migration from the gaskets of plasticized PVC in metal closures usually far exceeds the legal limits if the packed food contains some free oil. If the gaskets continue to consist of PVC, polyadipates seem to be the only acceptable plasticizers, although difficult to work with: they render the plastisol highly viscous and make it difficult to place a uniform ring into the lid. This suggests dilution with plasticizers of low viscosity. Results from simulating tests (olive oil in direct contact) confirm that the migration of polyadipates is far lower, but also that even the migration of minor portions of diluting plasticizers is critical for the overall migration. The first tests with 11 packed foods, stored and repeatedly shaken for up to 2 years, show migration of polyadipate clearly below the limits. It was lower than that determined by simulating tests, whereas the migration of ESBO was several times higher, questioning the suitability of presently applied testing.     

Modeling 3D Supercritical Flow with Extended Shallow-Water Approach

Despite the three-dimensional (3D) nature of the flow, the classical shallow-water equations are often used to simulate supercritical flow in channel transitions. A closer comparison with experimental data, however, often shows large discrepancies in the height and pattern of the shock waves that increase with the Froude number. An extension to the classical shallow-water approach is derived considering higher-order distribution functions for pressure and horizontal and vertical velocities, therefore taking nonhydrostatic pressure distribution and vertical momentum into account. The approach is applied to highly supercritical flow in a channel contraction (F0 = 4.0), a channel junction (F0 ≈ 4.5 for both branches), and a channel expansion (F0 = 8.0). Specific problems of such flows—wetting and drying of computational cells and wave breaking due to steep free-surface gradients—are discussed and solved numerically. The solutions with the extended approach are compared both with experimental data and classical shallow-water computations, and the influence of the additional terms considering the 3D nature of such flows is illustrated.     

Genetic polymorphism of CCR5 gene and HIV disease: the heterozygous (CCR5/delta ccr5) genotype is neither essential nor sufficient for protection against disease progression. Swiss HIV Cohort

Homozygous (delta ccr5/delta ccr5) and heterozygous (CCR5/delta ccr5) deletions in the beta-chemokine receptor 5 (CCR5) gene, which encodes for the major co-receptor for macrophage-tropic HIV-1 entry, have been implicated in resistance to HIV infection and in protection against disease progression, respectively. The CCR5/delta ccr5 genotype was found more frequently in long-term nonprogressors (LTNP) (31.0%) than in progressors (10.6%, p < 0.0001), in agreement with previous studies. Kaplan-Meier survival analyses showed that a slower progression of disease, i.e. higher proportion of subjects with CD4+ T cell counts > 500/microl (p = 0.0006) and a trend toward a slower progression to AIDS (p = 0.077), was associated with the CCR5/delta ccr5 genotype. However, when LTNP were analyzed separately, no significant differences in CD4+ T cell counts (p = 0.12) and viremia levels (p = 0.65) were observed between the wild-type (69% of LTNP) and the heterozygous (31.0%) genotypes. Therefore, there are other factors which play a major role in determining the status of nonprogression in the majority of LTNP. Furthermore, there was no evidence that the CCR5/delta ccr5 genotype was associated with different rates of disease progression in the group of progressors. Taken together, these results indicate that the CCR5/delta ccr5 genotype is neither essential nor sufficient for protection against the progression of HIV disease.