scholarly journals Transgenic snail approach for the control of schistosomiasis

QJM ◽  
2020 ◽  
Vol 113 (Supplement_1) ◽  
Author(s):  
G M Tawfeek
Keyword(s):  
Control Strategy ◽  
Effective Control ◽  
Logical Approach ◽  
Snail Control ◽  
Promising Tool ◽  
Natural Vector ◽  
Genetic Technique ◽  
Future Challenges ◽  
Genetic Techniques ◽  
Resistance Traits

Abstract Schistosomiasis remains the most important tropical snail-borne trematodiasis that threatens many millions of human lives. In achieving schistosomiasis elimination targets, sustainable control of the snail vectors represents a logical approach. Nonetheless, the ineffectiveness of the present snail control interventions emphasizes the need to develop new complementary strategies to ensure more effective control outcomes. Accordingly, the use of genetic techniques aimed at driving resistance traits into natural vector populations has been put forward as a promising tool for integrated snail control. The use of CRISPR/Cas9 based snail modification strategy appears fascinating and potentially effective. However, this approach is currently still underdeveloped in snail molecular research. This review provides knowledge related to this genetic technique without neglecting the current existing gaps and trying to identify ways to bypass potential future challenges, all are requisites for achieving this promising snail control strategy.

scholarly journals Treading the Path towards Genetic Control of Snail Resistance to Schistosome Infection

2018 ◽  
Vol 3 (3) ◽  
pp. 86 ◽  
Author(s):  
Damilare Famakinde
Keyword(s):  
Genetic Control ◽  
Molecular Basis ◽  
Model System ◽  
Effective Control ◽  
Schistosome Infection ◽  
Snail Control ◽  
Promising Tool ◽  
Natural Vector ◽  
Future Challenges ◽  
Genetic Techniques

Schistosomiasis remains the most important tropical snail-borne trematodiasis that threatens many millions of human lives. In achieving schistosomiasis elimination targets, sustainable control of the snail vectors represents a logical approach. Nonetheless, the ineffectiveness of the present snail control interventions emphasizes the need to develop new complementary strategies to ensure more effective control outcomes. Accordingly, the use of genetic techniques aimed at driving resistance traits into natural vector populations has been put forward as a promising tool for integrated snail control. Leveraging the Biomphalaria-Schistosoma model system, studies unraveling the complexities of the vector biology and those exploring the molecular basis of snail resistance to schistosome infection have been expanding in various breadths, generating many significant discoveries, and raising the hope for future breakthroughs. This review provides a compendium of relevant findings, and without neglecting the current existing gaps and potential future challenges, discusses how a transgenic snail approach may be adapted and harnessed to control human schistosomiasis.

scholarly journals Decoupled Control of Three Phase Grid Connected Solar PV System

2019 ◽  
Vol 9 (2) ◽  
pp. 4218-4222
Keyword(s):  
Solar Energy ◽  
Power Factor ◽  
Control Strategy ◽  
Reactive Power ◽  
Standard Test ◽  
Effective Control ◽  
Solar Pv ◽  
Pv System ◽  
Three Phase ◽  
Decoupled Control

A reliable grid connected Photovoltaic (PV) system require effective control schemes for efficient use of solar energy. This paper presents a three-phase grid tied PV system with decoupled real and reactive power control to achieve desired power factor with Maximum Power Point Tracking (MPPT) controller to get maximum solar energy. The synchronous reference frame (dq) control along with decoupling concept is used to control the DC-AC inverter output, while the Phase Locked Loop (PLL) synchronization technique is used to monitor and synchronize the voltage and current at the grid side. The DC-DC converter with Incremental Conductance (InC) based MPPT model is also designed in this paper due to better accuracy compared to Perturb & Observe (P&O) algorithm. The simulation is performed in MATLAB/SIMULINK and a 31.5 kW PV system is modelled to get 30 kW power with the help of MPPT at Standard Test Conditions (STC). Any power factor value between 0.85 lagging to 0.9 leading can be obtained by changingreference q current in this inverter control strategy. The simulation results show that the change of reactive powerdoes not affecttheactive power values of the system, which verifies the effectiveness of the decoupled control strategy of the inverter.

scholarly journals A Fuzzy Logic-Based Control Algorithm for the Recharge/V2G of a Nine-Phase Integrated On-Board Battery Charger

Electronics ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 946 ◽  
Author(s):  
Felice De Luca ◽  
Vito Calderaro ◽  
Vincenzo Galdi
Keyword(s):  
Fuzzy Logic ◽  
Control Strategy ◽  
Energy Demand ◽  
Fuzzy Logic Controller ◽  
Fuzzy Controller ◽  
Energy Resource ◽  
Reference Value ◽  
Active Role ◽  
Effective Control ◽  
Battery Charger

Energy demand associated with the ever-increasing penetration of electric vehicles on worldwide roads is set to rise exponentially in the coming years. The fact that more and more vehicles will be connected to the electricity network will offer greater advantages to the network operators, as the presence of an on-board battery of discrete capacity will be able to support a whole series of ancillary services or smart energy management. To allow this, the vehicle must be equipped with a bidirectional full power charger, which will allow not only recharging but also the supply of energy to the network, playing an active role as a distributed energy resource. To manage recharge and vehicle-to-grid (V2G) operations, the charger has to be more complex and has to require a fast and effective control structure. In this work, we present a control strategy for an integrated on-board battery charger with a nine-phase electric machine. The control scheme integrates a fuzzy logic controller within a voltage-oriented control strategy. The control has been implemented and simulated in Simulink. The results show how the voltage on the DC-bus is controlled to the reference value by the fuzzy controller and how the CC/CV charging mode of the battery is possible, using different charging/discharging current levels. This allows both three-phase fast charge and V2G operations with fast control response time, without causing relevant distortion grid-side (Total Harmonic Distortion is maintained around 3%), even in the presence of imbalances of the machine, and with very low ripple stress on the battery current/voltage.

scholarly journals A reward–punishment feedback control strategy based on energy information for wrist rehabilitation

2020 ◽  
Vol 17 (5) ◽  
pp. 172988142094065
Author(s):  
Jiajin Wang ◽  
Jiaji Zhang ◽  
Guokun Zuo ◽  
Changcheng Shi ◽  
Shuai Guo
Keyword(s):  
Feedback Control ◽  
Control Strategy ◽  
Control Strategies ◽  
Adaptive Controller ◽  
Feedback Mechanism ◽  
Coefficient Of Determination ◽  
Effective Control ◽  
Rehabilitation Robot ◽  
Feedback Control Strategy ◽  
Energy Information

Based on evidence from the previous research in rehabilitation robot control strategies, we found that the common feature of the effective control strategies to promote subjects’ engagement is creating a reward–punishment feedback mechanism. This article proposes a reward–punishment feedback control strategy based on energy information. Firstly, an engagement estimated approach based on energy information is developed to evaluate subjects’ performance. Secondly, the estimated result forms a reward–punishment term, which is introduced into a standard model-based adaptive controller. This modified adaptive controller is capable of giving the reward–punishment feedback to subjects according to their engagement. Finally, several experiments are implemented using a wrist rehabilitation robot to evaluate the proposed control strategy with 10 healthy subjects who have not cardiovascular and cerebrovascular diseases. The results of these experiments show that the mean coefficient of determination ( R 2) of the data obtained by the proposed approach and the classical approach is 0.7988, which illustrate the reliability of the engagement estimated approach based on energy information. And the results also demonstrate that the proposed controller has great potential to promote patients’ engagement for wrist rehabilitation.

scholarly journals Development and application of observable response indicators for design of an effective ozone and fine particle pollution control strategy in China

2019 ◽  
Author(s):  
Jia Xing ◽  
Dian Ding ◽  
Shuxiao Wang ◽  
Zhaoxin Dong ◽  
James T. Kelly ◽  
...  
Keyword(s):  
Control Strategy ◽  
Pollution Control ◽  
Eastern China ◽  
National Level ◽  
Chemical Species ◽  
River Delta ◽  
Effective Control ◽  
Nox Emissions ◽  
Pm2.5 Exposure ◽  
Response Indicators

Abstract. Designing effective control policies requires efficient quantification of the nonlinear response of air pollution to emissions. However, neither the current observable indicators nor the current indicators based on response-surface modeling (RSM) can fulfill this requirement. Therefore, this study developed new observable RSM-based indicators and applied them to ambient fine particulate matter (PM2.5) and ozone (O3) pollution control in China. The performance of these observable indicators in predicting O3 and PM2.5 chemistry was compared with that of the current RSM-based indicators. H2O2 × HCHO/NO3 and total ammonia ratio, which exhibited the best performance among indicators, were proposed as new observable O3- and PM2.5-chemistry indicators, respectively. Strong correlations between RSM-based and traditional observable indicators suggested that a combination of ambient concentrations of certain chemical species can serve as an indicator to approximately quantify the response of O3 and PM2.5 to changes in precursor emissions. The observable RSM-based indicator for O3 (observable peak ratio) effectively captured the strong NOx-saturated regime in January and the NOx-limited regime in July, as well as the strong NOx-saturated regime in northern and eastern China and their key regions, including the Yangtze River Delta and Pearl River Delta. The observable RSM-based indicator for PM2.5 (observable flex ratio) also captured strong NH3-poor condition in January and NH3-rich condition in April and July, as well as NH3-rich in northern and eastern China and the Sichuan Basin. Moreover, analysis of these newly developed observable response indicators suggested that the simultaneous control of NH3 and NOx emissions produces greater benefits in provinces with higher PM2.5 exposure by up to 12 µg m−3 PM2.5 per 10 % NH3 reduction compared with NOx control only. Control of volatile organic compound (VOC) emissions by as much as 40 % of NOx controls is necessary to obtain the co-benefits of reducing both O3 and PM2.5 exposure at the national level when controlling NOx emissions. However, the VOC-to-NOx ratio required to maintain benefits varies significantly from 0 to 1.2 in different provinces, suggesting that a more localized control strategy should be designed for each province.

scholarly journals Defining the larval habitat: abiotic and biotic parameters associated with Anopheles farauti productivity

2019 ◽  
Vol 18 (1) ◽  
Author(s):  
Kimberley McLaughlin ◽  
Thomas R. Burkot ◽  
Jance Oscar ◽  
Nigel W. Beebe ◽  
Tanya L. Russell
Keyword(s):  
Vector Control ◽  
Control Strategy ◽  
World Health ◽  
Effective Control ◽  
Biological Parameters ◽  
Insecticide Treated Nets ◽  
Larval Habitats ◽  
Anopheles Farauti ◽  
Larval Source Management ◽  
Source Management

Abstract Background In the Solomon Island, the dominant malaria vector, Anopheles farauti, is highly anthropophagic and increasingly exophilic and early biting. While long-lasting insecticide-treated nets remain effective against An. farauti, supplemental vector control strategies will be needed to achieve malaria elimination. Presently, the only World Health Organization recommended supplemental vector control strategy is larval source management (LSM). Effective targeted larval source management requires understanding the associations between abiotic, chemical and biological parameters of larval habitats with the presence or density of vector larvae. Methods Potential and actual An. farauti larval habitats were characterized for presence and density of larvae and associated abiotic, chemical and biological parameters. Results A third of all sampled potential habitats harboured An. farauti larvae with 80% of An. farauti positive habitats being in three habitat classifications (swamps/lagoons, transient pools and man-made holes). Large swamps were the most abundant positive habitats surveyed (43% of all An. farauti positive habitats). Habitats with An. farauti larvae were significantly associated with abiotic (pH, nitrate, ammonia and phosphate concentrations and elevated temperature) and biotic (predators) parameters. Conclusion Large swamps and lagoons are the largest and most abundant An. farauti habitats in the Solomon Islands. Positive habitats were more frequently associated with the presence of predators (vertebrates and invertebrates) and higher water temperatures. Cohabitation with predators is indicative of a complex habitat ecosystem and raises questions about the potential of biological control as an effective control strategy. Increased presence of An. farauti with higher water temperature suggests a potential explanation for the coastal distribution of this species which is not found inland at elevated altitudes where temperatures would be cooler.

Control Strategy for VSC-HVDC Power Quality Improvement under Unbalanced Grid Conditions

2011 ◽  
Vol 12 (6) ◽  
Author(s):  
Xiaoyun Wei ◽  
Hui Sun ◽  
Xiaoguang Wei ◽  
Qian Ma ◽  
Fengge Xu
Keyword(s):  
Power Quality ◽  
Control Strategy ◽  
Effective Control ◽  
Negative Sequence ◽  
Control Loops ◽  
Hvdc System ◽  
High Voltage Direct Current ◽  
Component Decomposition ◽  
Improved Performance ◽  
Unbalanced Grid

This paper presents a novel unified dynamic model and control strategy to improve the power quality for VSC based high voltage direct current transmission system (VSC-HVDC) under unbalanced grid conditions. The unified models present the dynamic behavior of VSC-HVDC in the unique positive synchronously rotating reference (dq-p) frame with respect to both the positive- and negative-sequence components. Based on the unified model, a strategy to either eliminate the dc-link ripple or achieve the balanced currents, along with a rather low level harmonics in each grid is introduced by resorting to the resonant integrator and filter based scheme in the two cascaded control loops. The resonant integrator and filter scheme enables effective control of the positive- and negative-sequence currents, and avoid the sequence component decomposition. The simulation studies in PSCAD/EMTDC verify the improved performance of VSC-HVDC system regarding the power quality and the ride-through capability.

Experimental Evaluation of a Control Strategy for Real-Time Optimization of Low Temperature PEM Fuel Cell Stack

2009 ◽  
Author(s):  
Panini Kolavennu ◽  
Susanta K. Das ◽  
K. Joel Berry
Keyword(s):  
Fuel Cell ◽  
Real Time ◽  
Control Strategy ◽  
Pem Fuel Cell ◽  
Effective Control ◽  
Feed Forward ◽  
Fuel Cell Stack ◽  
Feed Forward Control ◽  
Time Optimization ◽  
Real Time Optimization

A robust control strategy which ensures optimum performance is crucial to proton exchange membrane (PEM) fuel cell development. In a PEM fuel cell stack, the primary control variables are the reactant’s stochiometric ratio, membrane’s relative humidity and operating pressure of the anode and cathode. In this study, a 5 kW (25-cell) PEM fuel cell stack is experimentally evaluated under various operating conditions. Using the extensive experimental data of voltage-current characteristics, a feed forward control strategy based on a 3D surface map of cathode pressure, current density and membrane humidity at different operating voltages is developed. The effectiveness of the feed forward control strategy is tested on the Green-light testing facility. To reduce the dependence on predetermined system parameters, real-time optimization based on extremum seeking algorithm is proposed to control the air flow rate into the cathode of the PEM fuel cell stack. The quantitative results obtained from the experiments show good potential towards achieving effective control of PEM fuel cell stack.

scholarly journals A Simplified Minimum DC-Link Voltage Control Strategy for Shunt Active Power Filters

Energies ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 2407 ◽  
Author(s):  
Yu Wang ◽  
Yuewu Wang ◽  
Si-Zhe Chen ◽  
Guidong Zhang ◽  
Yun Zhang
Keyword(s):  
Power Systems ◽  
Control Strategy ◽  
Rational Design ◽  
Control Strategies ◽  
Voltage Control ◽  
Active Power ◽  
Effective Control ◽  
Voltage Control Strategy ◽  
Grid Voltage ◽  
Modulation Ratio

The active power filter (APF) is a popular electrical device to eliminate harmonics in power systems. The rational design and effective control of DC-link capacitor voltage are important for implementing APF functions. In this study, the influences from the DC-link voltage on the APF compensating current characteristic and compensation performance are analyzed, and the reason to maintain DC-link voltage at a minimum value is investigated. On this basis, a simplified minimum DC-link voltage control strategy for APF is proposed. Compared with the existing DC-link voltage control strategies, the minimum DC-link voltage value in proposed strategy is only determined by the grid voltage and modulation ratio, reducing the calculation burden and the implementation difficulty in application, avoiding the interference from external parameters on the compensation effect. Additionally, the reference DC-link voltage varies at different values according to the grid voltage and modulation ratio. A shunt APF prototype is established and the experimental results verify the correctness and effectiveness of the analysis and proposed strategy.

Blueberry IPM: Past Successes and Future Challenges

2019 ◽  
Vol 64 (1) ◽  
pp. 95-114 ◽  
Author(s):  
Cesar Rodriguez-Saona ◽  
Charles Vincent ◽  
Rufus Isaacs
Keyword(s):  
Food Systems ◽  
Insect Pests ◽  
Effective Control ◽  
Regulatory Agencies ◽  
New Production ◽  
Integrated Monitoring ◽  
Invasive Pests ◽  
Production And Consumption ◽  
Maximum Residue Limits ◽  
Future Challenges

Blueberry is a crop native to North America with expanding production and consumption worldwide. In the historical regions of production, integrated pest management (IPM) programs have been developed and provided effective control of key insect pests. These have integrated monitoring programs with physical, cultural, biological, behavioral, and chemical controls to meet the intense demands of consumers and modern food systems. Globalization of the blueberry industry has resulted in new pest-crop associations and the introduction of invasive pests into existing and new blueberry-growing areas. Invasive pests—in particular spotted wing drosophila—have been highly disruptive to traditional IPM programs, resulting in increased use of insecticides and the potential to disrupt beneficial insects. Moreover, regulatory agencies have reduced the number of broad-spectrum insecticides available to growers while facilitating registration and adoption of reduced-risk insecticides that have a narrower spectrum of activity. Despite these new tools, increasing international trade has constrained insecticide use because of maximum residue limits, which are often not standardized across countries. Great potential remains for biological, behavioral, cultural, and physical methods to contribute to blueberry IPM, and with more regions investing in blueberry research, we expect regionally relevant IPM programs to develop in the new production regions.

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