Defining the risk of SARS-CoV-2 variants on immune protection

The global emergence of many severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants jeopardizes the protective antiviral immunity induced after infection or vaccination. To address the public health threat caused by the increasing SARS-CoV-2 genomic diversity, the National Institute of Allergy and Infectious Diseases within the National Institutes of Health established the SARS-CoV-2 Assessment of Viral Evolution (SAVE) programme. This effort was designed to provide a real-time risk assessment of SARS-CoV-2 variants that could potentially affect the transmission, virulence, and resistance to infection- and vaccine-induced immunity. The SAVE programme is a critical data-generating component of the US Government SARS-CoV-2 Interagency Group to assess implications of SARS-CoV-2 variants on diagnostics, vaccines and therapeutics, and for communicating public health risk. Here we describe the coordinated approach used to identify and curate data about emerging variants, their impact on immunity and effects on vaccine protection using animal models. We report the development of reagents, methodologies, models and notable findings facilitated by this collaborative approach and identify future challenges. This programme is a template for the response to rapidly evolving pathogens with pandemic potential by monitoring viral evolution in the human population to identify variants that could reduce the effectiveness of countermeasures

An interdisciplinary approach to urban reconstruction after the 2011 Tsunami

Students of hydraulic engineering, geotechnical engineering, transport infrastructure, urban drainage engineering and urbanism studied the recovery of the city of Yuriage using the goal integration method. Much can be learned from the bold approach of the Japanese to disaster reconstruction and fighting shrinkage in regional spatial planning

Impacts of extreme events on hydrodynamic characteristics of a submerged floating tunnel

A submerged floating tunnel (SFT) is a promising alternative to conventional bridges and tunnels, and can be potentially built in the Qiongzhou Strait in China. However, this area is under the threat of disasters including mega tsunamis and severe storm surges. To evaluate the hydrodynamic loads of the SFT in this hazardous zone subject to severe tsunami and typhoon impacts, the Delft3D-FLOW hydrodynamic model and SWAN wave model are coupled, and a Computational Fluid Dynamics (CFD) method is adopted. The maximum probable tsunami and typhoon Rammasun (July 2014) are selected as hazard assessment conditions in the Qiongzhou Strait. Whether the tsunami and hindcast storm surge cause extreme forcing and bring challenges to the SFT engineering design, operation, and maintenance in the Qiongzhou Strait are discussed in this study. We reveal that the typhoon impacts are more devastating than tsunami for an SFT in the Qiongzhou Strait. In order to determine the optimal SFT cross-section under extreme events, we use a parametric Bezier curve profile compared with two simpler shapes including circular and elliptical cross sections. In-line force and lift are respectively applied to evaluate the SFT's hydrodynamic behaviour. Our results reveal that the gross horizontal force on the parametric Bezier curve shape is more sensitive to flow acceleration, while the circular cross-section is dominated by current speed. The parametric Bezier curve cross-section shape has the preferable property of reducing the in-line force and postponing serious vortex shedding compared with the two simpler shapes.</p

Feasibility of Pumped Hydro Energy Storage in a River Cascade: Case Study of the Meuse

The Meuse river in the Netherlands has been made navigable by the construction of a cascade of seven low head weirs. Because of environmental regulations, hydropower facilities exist at only two weirs. This implies the full hydropower potential of the Meuse cascade is not utilized. By using pump-turbines the river sections upstream of the weirs could be additionally usable as energy storage reservoirs and could improve and ensure river navigability under changed climate conditions.The main goal of this study is to assess the possible utilization of the full energy storage- and hydropower potential of the Meuse cascade within Dutch environmental regulations. The novelty of this study is the evaluation of the concept of using canalized river sections for pumped-storage purposes within conditions of fluctuating discharge and -water levels throughout the year.In order to meet the goal of the study the relatively fish-friendly Archimedean screw has been selected as pump-turbine. Next a conceptual design of a pumped-storage hydropower plant equipped with screws has been compiled. By using this design, the assessment of utilizing the hydropower- and energy storage potential of the cascade has been carried out by constructing and applying a numerical model.The study shows it is possible to utilize the full hydropower- and the majority of the energy storage potential of the Meuse cascade. The cumulative installed turbine capacity for the cascade turns out to be 81 MW. The Annual Energy Yield (AEY) from regular hydropower alone is 225 GWh. In addition, the yearly surplus power that can be processed for energy storage purposes is 137.2 GWh, of which 77.2 GWh is returned to the grid by a round-trip efficiency of 56.25 %. In total 302.2 GWh can be delivered to the grid which can power up to 75.000 households. The specific cost is relatively high: roughly 15,000 euro/kW.The method developed here can be applied to evaluate the storage- and hydropower potential of other canalized rivers as well, such as the upper Mississippi

Ecological risk assessment for eutrophication and heavy metal pollution of Suyahu Reservoir sediments

Focusing on the sediment in Suyahu Reservoir (a typical plain reservoir in Henan Province, China), concentrations of eutrophication-causing substances (TOC, TN and TP) and heavy metal contamination (Zn, Pb, Cd, Cu, Cr, Ni, As and Hg) were measured. Spatial distribution of these contaminants and the resulting potential ecological risk were investigated in detail. The results indicated that the eutrophication-causing substances were concentrated in the reservoir sediment, with high concentrations in the south and low concentrations in the north due to hydrodynamics. The reservoir sediments were polluted and had an eutrophication problem due to the high average organic index. Heavy metals were deposited at the bottom near the centre of the reservoir. The comprehensive potential ecological risk index was Moderate, whereas Cd and Hg contributed 78.8% to the total risk-index values, and were the main factors of heavy mental pollution. Therefore, it was necessary to prevent and treat polluted sediments to prevent secondary pollution

Effects of roughness on hydrodynamic characteristics of a submerged floating tunnel subject to steady currents

The effects of surface roughness as induced by marine fouling on the hydrodynamic forces on a submerged floating tunnel (SFT) are experimentally and numerically investigated in detail at Reynolds numbers Re = 8.125 × 103–5.25 × 104. A sensitivity analysis to different roughness parameters including roughness height, skewness, coverage ratio, and spatial arrangement is performed. In addition, an optimized parametric cross-section for an SFT is proposed, and the hydrodynamic performance of the parametric shape and circular SFT cross-section shape with roughness elements is compared. The pressure distribution along the SFT, flow separation and wake characteristics are analyzed to provide a systematic insight into the fundamental mechanism relating the roughness parameters and flow around an SFT. In order to better understand the nonlinear relationships among structural geometry, roughness parameters, flow states, and structural response, an artificial intelligence method using Random Forest (RF) for feature importance ranking is applied. The results show that with the parametric shape, the hydrodynamic forces on the fouled SFT can be effectively mitigated. The roughness height and coverage ratio affect the equivalent blockage and hence, change flow separation and recirculation length in the wake. Lower skewness of the roughness elements can increase the critical Re by changing the relative roughness parameter. Horizontal arrangement of the roughness elements on an SFT generally results in the largest hydrodynamic forces, compared to staggered and vertical distributions. Throughout the feature importance ranking, the flow regime is found to be the most important feature of the hydrodynamics of the SFT. In addition, the SFT cross-section shape and roughness coverage ratio play a dominant role.</p

Factors responsible for the limited inland extent of sand deposits on Leyte Island during 2013 Typhoon Haiyan

Previous geological studies suggest that the maximum inland extent of storm-induced sand deposits is shorter, but their thickness is larger, than those of tsunami-induced sand deposits. However, factors that determine the maximum extent and thickness of storm deposits are still uncertain. We conducted numerical simulations of storm surge, waves, and sediment transport during Typhoon Haiyan in order to understand the distribution and sedimentary processes responsible for storm deposits. Numerical results showed that wave-induced currents slightly offshore were strong, but attenuated rapidly in the inland direction after wave breaking. Therefore, sediments were not transported far inland by waves and storm surge. Consequently, the maximum inland extent of storm deposits was remarkably shorter than the inland extent of inundation. We also revealed that vegetation (roughness coefficient) and typhoon intensity greatly affect the calculation of maximum extent and thickness distribution of storm deposits. As the duration of wave impact on a coast is relatively long during a storm (hours, compared to minutes for a tsunami), sediments are repeatedly supplied by multiple waves. Therefore, storm deposits tend to be thicker than tsunami deposits, and multiple layers can form in the internal sedimentary structure of the deposits. We infer that limitation of the sand deposit to within only a short distance inland from the shoreline and multiple layers found in a deposit can be used as appropriate identification proxies for storm deposits.</p

Optimization of submerged floating tunnel cross section based on parametric Bézier curves and hybrid backpropagation - genetic algorithm

The cross-section geometry of a submerged floating tunnel (SFT) has a large effect on hydrodynamic characteristics, structural behavior and service level, making the tunnel cross section the primary factor in optimizing efficiency. Minimizing the mean drag and the dynamic variability in the lift of the SFT cross section under bi-directional (i.e., tidal) flow has a dramatic impact on the reduction of structural displacements and mooring loads. Based on a parametric Bézier curve dynamically comprising the leading-edge radius, tunnel height and width to define the SFT geometry, a sensitivity analysis of the Bézier curve parameters for a fixed aspect ratio with prototype dimensions under uniform flow conditions was conducted by applying Computational Fluid Dynamics (CFD), and the pressure distribution around the SFT cross-section surface was analyzed. A theoretical method comprising the Kármán vortex street parameters was employed to verify the CFD simulation results. In order to determine the SFT cross section with optimal hydrodynamic properties, the mean drag and Root Mean Square (RMS) lift coefficients were selected as optimization objectives, and four Bézier curve parameters were the input variables, in a neural network and genetic algorithm optimization process (a hybrid BP-GA structure), which is less likely to become trapped in local minima. The results show the optimal tunnel cross section has a mean drag and a RMS lift coefficient reduced by 0.9% and 6.3%, respectively, compared to the original CFD dataset.Hydraulic Structures and Flood RiskEnvironmental Fluid Mechanic