Synergy of climate change and local pressures on saltwater intrusion in coastal urban areas: effective adaptation for policy planning

ABSTRACT

This article examines the relative impacts of anthropogenic interventions and global climate change on the dynamics of saltwater intrusion in highly urbanized coastal aquifers. For this purpose, simulations of the impacts of sea-level rise and abstraction scenarios for the near future were undertaken for a pilot aquifer using a multi-objective 3D variable-density flow and solute transport model. We find that sea-level rise associated with climate change has less influence on the encroachment of salinity than anthropogenic abstraction, which has a more appreciable impact on saltwater intrusion through greater sensitivity to water consumption and seasonality.     

Computer-controlled mechanical simulation of the artificially ventilated human respiratory system

A mechanical lung simulator can be used to simulate specific lung pathologies, to test lung-function equipment, and in instruction. A new approach to mechanical simulation of lung behavior is introduced that uses a computer-controlled active mechatronic system. The main advantage of this approach is that the static and dynamic properties of the simulator can easily be adjusted via the control software. A nonlinear single-compartment mathematical model of the artificially ventilated respiratory system has been derived and incorporated into the simulator control system. This model can capture both the static and dynamic compliance of the respiratory system as well as nonlinear flow-resistance properties. Parameters in this model can be estimated by using data from artificially ventilated patients. It is shown that the simulation model fits patient data well. This mathematical model of the respiratory system was then matched to a model of the available physical equipment (the simulator, actuators, and the interface electronics) in order to obtain the desired lung behavior. A significant time delay in the piston motion control loop has been identified, which can potentially cause oscillations or even instability for high compliance values. Therefore, a feedback controller based on the Smith-predictor scheme was developed to control the piston motion. The control system, implemented on a personal computer, also includes a user-friendly interface to allow easy parameter setting.     

Performance of Layered Steered Space–Time Codes in Wireless Systems

Layered Steered Space–Time Codes (LSSTC) is a recently proposed multiple-input multiple-output (MIMO) system that combines the benefits of vertical Bell Labs space–time (VBLAST) scheme, space–time block codes (STBC) and beamforming. In this paper, we derive the error performance and capacity of a single-user LSSTC system. The analysis is general enough to any layer ordering and modulation schemes used. In addition, the derived analysis is general for any LSSTC structure in which layers may have different number of antenna arrays and may be assigned power according to any power allocation. Furthermore, we analytically investigate the tradeoff between the main parameters of the LSSTC system, i.e., diversity, multiplexing and beamforming. Our results give recursive expressions for the probability of error for LSSTC which showed nearly perfect match to the simulation results. Results have also revealed the possibility of designing an adaptive system in which it was shown that combining beamforming, STBC, and VBLAST has better performance than VBLAST at high SNR range.     

Synthesis,Biological Evaluation of 1,1‐Diarylethylenes as a Novel Class of Antimitotic Agents

The cytotoxic activities of 23 new isocombretastatin A derivatives with modifications on the B‐ring were investigated. Several compounds exhibited excellent antiproliferative activity at nanomolar concentrations against a panel of human cancer cell lines. Compounds isoFCA‐4 ( 2 e ), isoCA‐4 ( 2 k ) and isoNH₂CA‐4 ( 2 s ) were the most cytotoxic, and strongly inhibited tubulin polymerization with IC₅₀ values of 4, 2 and 1.5 μM , respectively. These derivatives were found to be 10‐fold more active than phenstatin and colchicine with respect to growth inhibition but displayed similar activities as tubulin polymerization inhibitors. In addition, cell cycle arrest in the G₂/M phase and subsequent apoptosis was observed in three cancer cell lines when treated with these compounds. The disruptive effect of 2 e , 2 k and 2 s on the vessel‐like structures formed by human umbilical vein endothelial cells (HUVEC) suggest that these compounds may act as vascular disrupting agents. Both compounds 2 k and 2 s have the potential for further prodrug modification and development as vascular disrupting agents for treatment of solid tumors.     

Stepwise Formation of Some Bivalent Metal Chelates with Sodium Alizarin Sulphonate

The stepwise protonation constants of the ligand and the stability constants of Alizarin Red S with some bivalent metal ions, Pb²⁺, Cu²⁺, Zn²⁺, and Hg²⁺ have been determined at 30° and at various ionic strengths viz. 0.02, 0.05, 0.15 and 0.20, maintained by sodium perchlorate solution. The formation of the chelate is evident from the shift between the (i) ligand and (ii) ligand and metal titration curves. From the values of the stepwise protonation constants and metal ligand stability constants at various ionic strengths, thermodynamic formation constants were evaluated by extrapolation to zero ionic strength. The order of stability constants was found to be: Cu > Pb > Zn > Hg     

A stochastic optimization model for real-time ambulance redeployment

When ambulances are engaged in responding to emergency calls, the ability to respond quickly to future calls is considerably compromised. The available ambulances are typically relocated to reestablish maximal coverage. We present a two-stage stochastic optimization model for the ambulance redeployment problem that minimizes the number of relocations over a planning horizon while maintaining an acceptable service level. We conduct computational testing based on the real historical data from the Region of Waterloo Emergency Medical Services. The results show that the optimal relocation strategies can be computed within 40 s of computational time for a desired service level of 90%.     

Distributed Bayesian diagnosis for modular assembly systems—A case study

The growing interest in modular and distributed approaches for the design and control of intelligent manufacturing systems gives rise to new challenges. One of the major challenges that have not yet been well addressed is monitoring and diagnosis in distributed manufacturing systems. In this paper we propose the use of a multi-agent Bayesian framework known as Multiply Sectioned Bayesian Networks (MSBNs) as the basis for multi-agent distributed diagnosis in modular assembly systems. We use a close-to-industry case study to demonstrate how MSBNs can be used to build component-based Bayesian sub-models, how to verify the resultant models, and how to compile the multi-agent models into runtime structures to allow consistent multi-agent belief update and inference.     

Simulink behavioral modeling of a 10-bit pipelined ADC

The increasing architecture complexity of data converters makes it necessary to use behavioral models to simulate their electrical performance and to determine their relevant data features. For this purpose, a specific data converter simulation environment has been developed which allows designers to perform time-domain behavioral simulations of pipelined analog to digital converters (ADCs). All the necessary blocks of this specific simulation environment have been implemented using the popular Matlab simulink environment. The purpose of this paper is to present the behavioral models of these blocks taking into account most of the pipelined ADC non-idealities, such as sampling jitter, noise, and operational amplifier parameters (white noise, finite DC gain, finite bandwidth, slew rate, and saturation voltages). Simulations, using a 10-bit pipelined ADC as a design example, show that in addition to the limits analysis and the electrical features extraction, designers can determine the specifications of the basic blocks in order to meet the given data converter requirements.     

1‐Arylsulfonyl‐5‐(N‐hydroxyacrylamide)indolines Histone Deacetylase Inhibitors Are Potent Cytokine Release Suppressors

A series of 1‐arylsulfonyl‐5‐(N‐hydroxyacrylamide)indolines ( 7 – 15 ) has been developed; the compounds exhibited potent histone deacetylase (HDAC) inhibitory activities. Notably, almost all of this series exhibited better HDAC‐inhibitory and antiproliferative activities than 3‐(1‐benzenesulfonyl‐1H‐indol‐5‐yl)‐N‐hydroxyacrylamide ( 6 ), as reported in a previous study. Among these compounds, 3‐[1‐(4‐methoxybenzenesulfonyl)‐2,3‐dihydro‐1H‐indol‐5‐yl]‐N‐hydroxyacrylamide ( 9 ) showed a two‐ to tenfold increase in activity compared to SAHA ( 1 ) in the suppression of lipopolysaccharide‐induced cytokine production. Compound 9 also caused a marked reduction in carrageenan‐induced acute inflammation in a rat model. Taken together, these data indicated that 1‐arylsulfonyl‐5‐(N‐hydroxyacrylamide)indolines HDAC inhibitors exhibit potent anti‐inflammatory activity.