Academic literature on the topic 'Negative sequence current'
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Journal articles on the topic "Negative sequence current"
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Medeiros de Souza Azevedo, Gustavo, Joan Rocabert, Marcelo Cabral Cavalcanti, Francisco de Assis dos Santos Neves, and Pedro Rodríguez. "A Negative-sequence Current Injection Method To Mitigate Voltage Imbalances In Microgrids." Eletrônica de Potência 16, no. 4 (November 1, 2011): 296–303. http://dx.doi.org/10.18618/rep.20114.296303.
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Mochinaga, Yoshifumi, Yuji Ishii, Masuo Goto, and Tomoharu Nakamura. "Static Negative-Phase-Sequence Current Compensator." IEEJ Transactions on Power and Energy 112, no. 7 (1992): 629–34. http://dx.doi.org/10.1541/ieejpes1990.112.7_629.
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Kozlov, Alexander Nikolaevich, Vitaly Alexandrovich Kozlov, and Tatyana Sergeevna Kozlova. "SIMULATION OF A NEGATIVE SEQUENCE CURRENT TRANSDUCER." Messenger AmSU, no. 97 (2022): 66–73. http://dx.doi.org/10.22250/20730268_2022_97_66.
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Farughian, Kumpulainen, and Kauhaniemi. "Earth Fault Location Using Negative Sequence Currents." Energies 12, no. 19 (September 30, 2019): 3759. http://dx.doi.org/10.3390/en12193759.
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In this paper, a new method for locating single-phase earth faults on non-effectively earthed medium voltage distribution networks is proposed. The method requires only current measurements and is based on the analysis of the negative sequence components of the currents measured at secondary substations along medium voltage (MV) distribution feeders. The theory behind the proposed method is discussed in depth. The proposed method is examined by simulations, which are carried out for different types of networks. The results validate the effectiveness of the method in locating single-phase earth faults. In addition, some aspects of practical implementation are discussed. A brief comparative analysis is conducted between the behaviors of negative and zero sequence currents along a faulty feeder. The results reveal a considerably higher stability level of the negative sequence current over that of the zero sequence current.
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Wang, Kai, and Wen Jin Dai. "Research on Negative-Sequence Electric Current Examination Method." Advanced Materials Research 179-180 (January 2011): 1429–34. http://dx.doi.org/10.4028/www.scientific.net/amr.179-180.1429.
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This paper based on traditional ip, iq examination's method , introduces one kind of non-phase-locked loop's ip, iq method. this method avoids the mains frequency displacement the influence, causes the examination to be more conveniently. With the MATLAB simulation of software, obtain the satisfactory results, thus proving the usefulness of this method.
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Ohura, Y., T. Matsuda, M. Suzuki, F. Andow, Y. Kurosawa, and A. Takeuchi. "A digital distance relay using negative sequence current." IEEE Transactions on Power Delivery 5, no. 1 (1990): 79–84. http://dx.doi.org/10.1109/61.107259.
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Castillo, Silvia Oviedo, and Jabid Quiroga Méndez. "On the Use of Positive Sequence Current / Negative Sequence Current Ratio for Fault Detection in Induction Motors." Revista EIA 16, no. 31 (January 21, 2019): 43–56. http://dx.doi.org/10.24050/reia.v16i31.760.
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This paper studied the use of a new stator current feature for detection of winding and cage bars faults in an induction motor, and presents the experimental validation of a detection and identification scheme using Support Vector Machines (SVM). This validation was performed in a test bed using 2 HP, 4 pole motors in which shorted winding and broken bars faults were induced, separately. Both time and frequency domain features like arithmetic mean, RMS value, Central Frequency, Kurtosis, RMS value of Power Spectral Density were assessed and validated using experimental data for several load conditions. PSC/NSC (positive sequence current/ negative sequence current) ratio was successful in most of the classifiers despite the load regime. This new feature was evaluated in terms of fault detection and severity discrimination with satisfactory results.
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Ge, Bao-jun, Wu Guo, Jian Guo, Yun-peng Gao, and Ming-ze Li. "Improvement of the transient negative-sequence rating formula for large generators based on the negative-sequence current component." International Transactions on Electrical Energy Systems 26, no. 3 (May 20, 2015): 539–54. http://dx.doi.org/10.1002/etep.2093.
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Najafi, Foad, Mohsen Hamzeh, and Matthias Fripp. "Unbalanced Current Sharing Control in Islanded Low Voltage Microgrids." Energies 11, no. 10 (October 16, 2018): 2776. http://dx.doi.org/10.3390/en11102776.
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This paper reports a new control strategy to improve sharing of unbalanced currents in islanded LV microgrids. This technique provides fast and effective sharing of positive-, negative- and zero-sequence currents, and is the first example of zero-sequence current sharing in the literature. The controllers are designed in the stationary frame. The control structure consists of four loops: (1) the current controller; (2) the voltage controller; (3) the droop controller and the (4) negative and zero sequence current controllers. The output current is considered unknown for the controller and is added to the control system as a disturbance. The proposed controller features a high gain in fundamental and harmonic frequencies, hence a good voltage quality is obtained in the presence of unbalanced and nonlinear loads. To this aim, a proportional-resonant (PR) controller is adopted as the current controller. By using a multi-resonant controller as current controller, a unified control structure is obtained which is suitable for both grid-connected and islanded modes. The voltage controller is designed using a resonant controller so that the voltage can have low VUF and THD in the presence of unbalanced and nonlinear loads. Furthermore, in this paper, the droop method is applied to the control structure to share real and reactive powers. Simulation studies show that the conventional droop method cannot share the oscillatory part of the output power that is due to the presence of unbalanced loads in the microgrid. This paper relies on using zero and negative sequence virtual impedance controller to share the oscillatory part of output power. By using zero-sequence virtual impedance controller (ZSVIC) and negative-sequence virtual impedance controller (NSVIC), the zero and negative sequence currents in the microgrid are controlled and shared effectively. By compensating zero- and negative-sequence currents locally, the flow of these currents in the microgrid is minimized, and the overall power quality of the islanded LV microgrid is improved.
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Moriyasu, Shoji. "Effects of DC-Current for Short-Time Negative Sequence Current of Synchronous Machine." IEEJ Transactions on Industry Applications 121, no. 5 (2001): 614–15. http://dx.doi.org/10.1541/ieejias.121.614.
Full textDissertations / Theses on the topic "Negative sequence current"
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Kapidou, Alexandra. "Application for Wind Farm Integration Complying with the Grid Code by Designing an Outer Control Strategy for the Converter." Thesis, KTH, Skolan för elektro- och systemteknik (EES), 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-187686.
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The continuously increasing energy penetration from wind farms into the grid raises concerns regarding power quality and the stable operation of the power system. The Grid Code´s requirements give strict guidelines for a wind farm´s behaviour under faulty or abnormal operating conditions.The primary purpose of this project is the application of a STATCOM for wind farm integration complying with the Grid Code. Towards that, an outer control strategy for the converter is designed so as to regulate the voltage at the point of common coupling by providing reactive power compensation. Thus the safe operation of the grid will be ensured since the wind farm will follow the Grid Code´s standards.The existing Grid Code requires only a positive sequence current controller. This study attempts to investigate whether this is sufficient or not and to examine the possibility of extending the Grid Code requirements so as to incorporate a negative sequence current controller as well. The results support the latter suggestion. Also, the use of SiC devices was also considered in this project.Den ständigt ökande penetrationen av vindenergi i elnätet väcker farhågor om elkvalitet och stabil drift av kraftsystemet. Nätkoden (Grid Code) ger strikta riktlinjer för en vindkraftsparks beteende i felfall och under onormala driftsförhållanden.Huvudsyftet med detta projekt är att använda en STATCOM för integration av vindkraftsparker så att nätkoden uppfylls. I detta projekt utformas en yttre reglerstrategi för omriktaren för att reglera spänningen vid anslutningspunkten för vindkraftsparken genom att tillhandahålla reaktiv effektkompensering. Därigenom uppnås en säker drift av nätet eftersom vindkraftparken kommer att följa nätkoden.Den befintliga nätkoden kräver endast styrning av plusföljdskomponenten av strömmen. Denna studie försöker undersöka om detta är tillräckligt samt undersöka möjligheten för att utvidga nätkoden genom att införa ett krav på styrning av negativ-sekvens ström. Resultaten stöder det sistnämnda förslaget. Även användningen av halvledarkomponenter av kiselkarbid-SiC studerades i detta projekt.
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Tománek, Miloslav. "Simulace účinků zkratových proudů v rozvodnách VVN." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2008. http://www.nusl.cz/ntk/nusl-217579.
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This thesis is engaged in a theoretical calculation of short-circuit currents in electric power system in compliance with the norm ČSN 60909-0 and first of all with calculation of dynamical and thermal effects of short-circuit currents in HV switching stations in accordance with the norm ČSN 60865-1. Next the thesis is engaged in a production of programs for simulation of mechanical effects of short-circuit currents with respect to a dimensioning of constructional elements of switching station and afterwards in a practical simulation of selected parts of the real switching station type „H“ in Slavkov u Brna.
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Wu, Long. "Separating Load Torque Oscillation and Rotor Faults in Stator Current Based-Induction Motor Condition Monitoring." Diss., Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/14545.
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Stator current spectral analysis techniques are usually used to detect rotor faults in induction machines. Magnetic field anomalies in the airgap due to the rotor faults result in characteristic side-band harmonic components in the stator current spectrum, which can be measured as rotor fault signatures. A position-varying load torque oscillation at multiples of the rotational speed, however, has exactly the same effect. Stator current harmonics due to a load torque oscillation often obscure and even overwhelm rotor eccentricity fault detection since the magnitude of load oscillation induced harmonics is usually much larger.
Although previous research has suggested some methods to differentiate between these two effects, most of them rely heavily on the accurate estimation of motor parameters. The objective of this research is to develop a far more practical and computationally efficient method to detect rotor faults effectively in the presence of a load torque oscillation. A significant advantage of the proposed scheme is that it does not need any knowledge of motor parameters. The normalized negative sequence information induced by a mixed rotor eccentricity in the stator current or terminal voltage space vector spectra, serves as a reliable rotor fault indicator to eliminate load oscillation effects.
Detailed airgap magnetic field analysis for an eccentric motor is performed and all machine inductance matrices as well as their derivatives are reformulated accordingly. Careful observation of these inductance matrices provides a fundamental understanding of motor operation characteristics under a fault condition. Simulation results based on both induction motor dynamic model and Maxwell 2D Finite Element Model demonstrate clearly the existence of the predicted rotor fault indicator. Extensive experimental results also validate the effectiveness and feasibility of the proposed detection scheme.
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Hartono, Aryudha. "Microgrid Safety and Protection Strategies." Thesis, KTH, Elektroteknisk teori och konstruktion, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-226593.
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One of the challenging issues with the Microgrid is that the bidirectional power flow providedby the distributed generator (DG) which modify the fault current level. Furthermore, theinverter based-renewable energy source (IB-RES) limits the total fault current contributionto the grid due to its thermal capability. Since Microgrid should be able to operate in gridconnectedand islanded mode, protection strategies are needed to solve this challenging issue.By only having IB-RES and battery storage system, the fault condition and normaloperation cannot be distinguished. Apart from fault clearing issue, there is a consideration tostudy the fault isolation in the Microgrid under the limited fault current provided by IB-RES.To have fault isolation capability, the intelligent electrical device (IED) is needed. The firststep is to find a method that can detect a fault under the fault level modification constraint.This thesis presents a zero and negative sequence current protection to detect a fault.However, to make it selective, this protection will be applied directionally. It is common thatthe distribution grid has unbalanced load operation, thus providing zero and negativesequence component in the grid. To apply the directional zero and negative sequence currentprotection, the unbalanced load flow is simulated to distinguish the fault and normaloperation under unbalanced load condition.Safety and regulation are discussed briefly in this thesis. It is important that each of theIB-RES has fault ride-through (FRT) capability that follows a regulation. However, thisregulation is expected to have a coordination with the proposed protection in the Microgridso the reliability, selectivity, and sensitivity can be achieved in grid-connected and islandedmode. This thesis shows the coordination between fuses, IED, and inverter FRT capability.After providing a protection strategy, the adaptability of the proposed protection isassessed regarding of Microgrid expansion. The result shows that by applying the schemeand following the grading margin requirement that is presented in this thesis, the Microgridexpansion will not disrupt the proposed protection coordination. Since it is known that thedistribution grid is expanding its load capacity and microgeneration in continuous basis, it isconvenient that the proposed protection in the IED is expected to be adaptable, means that ithas a fixed IED setting when the grid is expanded. The analysis is performed by electrical transient analysis program (ETAP) and MatlabSimulink. The short circuit analysis, sequence-of-operation, and unbalanced load flow aresimulated by ETAP, while the protection stability is simulated by Matlab Simulink.Ett problem som finns med microgrid är att de distribuerade produktionsgeneratorerna harett dubbelriktat effektflöde som modifierar felströmmen. Dessutom, inverterbaseradeförnyelsebara energikällor (IB-RES) begränsar det totala felströmsbidraget på grund av desstermiska kapacitet. Eftersom microgrids ska vara operativ vid både anslutning till externt nätsamt önätsdrift behövs skyddsstrategier för att kunna hantera fel, speciellt vid önätsdrift.Om endast IB-RES och batterilager används kan feldrift och normal drift inte särskiljas.Bortsätt från felhantering är det viktigt att studera felbortkoppling för microgrid underbegränsad felström som fås av IB-RES. För att kunna åstadkomma felbortkoppling behöveren IED (från engelskans Intelligent Electronic Device). Det första steget är att finna en metodför att kunna detektera fel under fel nivå modifiering. Denna avhandling tittar på att användanoll- och minusföljds ström sekvensskydd för att detektera fel. För att göra skyddet selektivtkommer det att titta på riktningen av effektflödet. I distributionsnät är det vanligt att haobalanserade laster vilket medför noll- och negativa sekvenskomponenter i nätet. För atttillämpa riktningsskydd för noll och negativ sekvens ström simuleras ett obalanserateffektflöde för att särskilja på feldrift och normal drift vid obalanserad last.Säkerhet och förordningar diskuteras kortfattat i denna avhandling. Det är viktigt att varjeIB-RES har en feltålighet som följer vissa förordningar. Denna förordning förväntassamordna det föreslagna skyddet i micronåt så att pålitlighet, selektivitet och känslighet kanåstadkommas vid nätanslutning och önätsdrift. Denna avhandling visar samordningen mellansäkringar, IED och feltåligheten för växelomriktare.Anpassningsförmågan för det föreslagna skyddet bedöms med avseende på expansion avmicrogrid. Resultatet visar att en expansion av ett microgrid inte kommer att störa denföreslagna samordningen om skyddsmetoden och tidsfördröjningskravet som presenteras idenna avhandling följs. Eftersom det är känt att distributionsnätet kommer att fortsätta ökasin lastkapacitet och mikrogenerering, är det lämpligt att skyddet förväntas varaanpassningsbart vilket innebär att det har en fast IED inställning när nätet expanderas.Analysen genomförs med mjukvarorna electrical transient analysis program (ETAP) ochMatlab Simulink. Kortslutningsanalysen, arbetssekvensen och obalanserad lastflödesimuleras av ETAP, medan skyddsstabiliteten simuleras av Matlab Simulink.
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Ho, Ping-Heng, and 何秉衡. "Analysis of Transient Characteristics and Negative Sequence Current of Transmission System." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/67a4qb.
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博士國立臺灣科技大學
電機工程系
99
The transient behaviors and negative sequence currents of electric transmission systems are studied in this dissertation. These characteristics will affect the power quality. The transient characteristics studies include the switching over voltage (SOV), the slow front transient (SFT) over voltage, the transient inrush current (TIC), and the transient recovery voltage (TRV). The stable characteristics studies include the negative sequence current (NSC) when the three-phase circuits are operated in normal or in phase-discrepancy conditions. The impacts to the maximum operating time of generators by the NSC are also studied. Firstly, the transient electrical characteristics of the Taiwan-PenHung submarine power cables are studied. The characteristics contain (1) the SOV in normal operation, (2) the SFT over voltage in fault contingency, (3) the TIC in energizing the no-load transformers and shunt reactors, and (4) the TRV in de-energizing the shunt reactors. The results will be compared to the IEEE standards. Secondly, the strategies for the solutions of the Da-Tan power source lines, such as the multi-phase auto reclosing to meet both the minimum load shedding area and the requirement of system safety operation are studied. Finally, the impacts of NSC under the N-0, N-1, N-2 or N-3 conditions of the power source lines on the generator operation time are evaluated. From the study results, the SOV and the TIC of the Taiwan-PenHung submarine power cables satisfy the transient requirements of relative standards. When the shunt reactors are installed, the contactors of current breakers will not re-strike if they open the current breakers. The MPAR of the Da-Tan power source lines could achieve the system requirement. The effects of NSC could be ignored when the four out-linking circuits are operated in N-0, N-1, and N-2 conditions. The generators can be operated in full loading under these conditions. The modifications to the limits of the power plant of the Taipower are also suggested. The results of this dissertation could be the suggestions to the Taiwan Power Company about operation and planning of new submarine power cables, multi-phase auto reclosing of transmission lines, effect of NSC on operation of generators.
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Lin, Ming-Chuan, and 林明泉. "Negative-Sequence Current Injection Based Islanding Detection and Seamless Transfer for Microgrids." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/51726982250470184442.
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碩士國立清華大學
電機工程學系
100
This thesis presents the seamless transfer between grid-connected and islanded modes for a single voltage-sourced converter (VSC) based microgrid system. Principles of the control strategies at both modes are introduced where current-mode control for grid-connected operations and autonomous-mode control for islanded operations. The smooth transition from grid-connected mode to islanded mode is based on an islanding detection method that actively injects a negative-sequence current (4% of the rated value) as a disturbance signal via a negative-sequence controller which is adopted as the complementary of the conventional VSC controller. The estimated magnitude of the corresponding negative-sequence voltage at the point of common coupling (PCC) is used as the islanding detection signal. A quantitative analysis based on symmetrical component transformations is proposed to support the feasibility of the islanding detection scheme. For the islanded mode to grid-connected mode transition, a phase compensation scheme that increases or decreases the operating frequency of the VSC is applied for grid resynchronization. The detailed process of the seamless transfer between these two modes is illustrated. Finally, simulations in PSCAD software environment and hardware experiments verify the theoretical analysis.
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Bakhri, Syaiful. "Detailed investigation of negative sequence current compensation technique for stator shorted turn fault detection of induction motors." Thesis, 2013. http://hdl.handle.net/2440/83536.
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Online condition monitoring is preferred specifically in critical induction machines for timely analysis of their health and to predict any incipient failures. Negative sequence current monitoring is one of the well-known condition monitoring applications that capable of identifying stator faults in induction motor as well as producing fast and reliable results using a simple measurement technique. However, the technique is sensitive to asymmetrical sources of negative sequence, not only due to motor faults but also due to the disturbances such as sensor calibration, inherent non-idealities (such as inherent machine asymmetries), external effects (such as load change and supply voltage unbalances). This thesis addresses the limitations in shorted turn fault detection while considering real system disturbances and non-linearities using a dynamic motor model which is also verified by the experimental studies. The thesis provides a comprehensive investigation of various negative sequence contributors such as measurement asymmetry, inherent asymmetry, voltage unbalance, shorted turn faults, eccentricity and broken rotor bar faults under load variations, and presents practical results. To allow accurate shorted turn fault detection, this thesis also provides an effective phasor compensation technique for these disturbances. A new detailed compensation by demonstrating step-by-step disturbance extraction to obtain the real negative sequence current due to shorted turn faults are also presented. It is demonstrated that this technique allows even a single stator shorted turn faults to be detected as well as successfully eliminating the effect of inherent asymmetry and voltage unbalances under motor load variations.Thesis (Ph.D.) -- University of Adelaide, School of Electrical and Electronic Engineering, 2013
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Hsu, Che-Wei, and 許哲瑋. "Research of Low Voltage Ride-Through Strategies for Grid-Connected Converters Based on Positive Sequence and Negative Sequence Reactive Current Control." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/84714874914767954785.
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碩士國立清華大學
電機工程學系
98
With more and more distributed energy resources (DERs) being connected to the grid through interface converters, the utility requires the DER generation system to remain grid-connected during grid voltage imbalance to ensure the operating stability of the AC power system. These low voltage ride-through requirements also suggest that the DER generation system injects reactive power to support grid voltages. Traditional reactive power compensation methods can provide request reactive current to meet the low voltage ride-through requirements. However, the resulting peak phase current may exceed the peak rated current of the converter during voltage sag, thus facing the risk of over-current protection tripping of itself. In this thesis, a positive sequence and negative sequence reactive current injection method is proposed to meet the low voltage ride-through requirement. The proposed method can generate the positive sequence and negative sequence reactive current commands so the resulting phase current does not exceed the ampere constraint of the converter，which is very critical for the safe operation of the converter. Its operation principle and control method are explained and analyzed. Simulation and laboratory test results are presented to validate the effectiveness of the proposed method. Comparisons of the proposed method and other low voltage ride-through techniques are also presented.
Books on the topic "Negative sequence current"
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Adkins, Daniel E., Kelli M. Rasmussen, and Anna R. Docherty. Social Epigenetics of Human Behavior. Edited by Rosemary L. Hopcroft. Oxford University Press, 2018. http://dx.doi.org/10.1093/oxfordhb/9780190299323.013.40.
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It is well established that extreme social adversity can lead to negative health outcomes decades after the resolution of the precipitating environmental insult. Although the underlying mechanisms through which such adversity gets “under the skin” to become biologically embedded have long been considered a black box, recent research has indicated an important mediating role for epigenetic mechanisms—molecular modifications that regulate gene activity without changing the DNA sequence. With technical and scientific developments now enabling genome-wide epigenetic studies in humans, behavioral researchers have an unprecedented opportunity to empirically map the ways in which social dynamics become epigenetically embedded, influencing downstream gene expression, health, and behavior. This chapter examines the current state of social epigenetics research and discusses the opportunities and challenges facing this emerging field.
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Bikeev, Igor. LEGAL REGULATION OF ORGANIZATION AND IMPLEMENTATION OF ANTI-CORRUPTION INSPECTIONS IN THE RUSSIAN FEDERATION SUBJECTS. Kazan Innovative University named after V. G. Timiryasov, 2022. http://dx.doi.org/10.21202/978-5-8399-0774-4_2022_1_52.
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The preprint views anti-corruption inspections as one of the effective anti-corruption tools. The anti-corruption tool is proposed to be understood as a set of interconnected means of influ-encing this negative social phenomenon, used with the ultimate goal of reducing its negative con-sequences. Based on the current legislation of the Russian Federation subjects and the doctrinal developments, the authors consider procedural grounds for conducting the said inspections, as well as the methods of their implementation, the specific features of registering the results ob-tained, and the measures to improve the legal regulation of this tool in the Russian regions. The preprint is intended for persons involved in the implementation of the state anti-corruption policy at all levels of public authority, researchers, pedagogical staff, students, as well as all others interested in these issues.
Book chapters on the topic "Negative sequence current"
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Kumar, Shubham, Munna Kumar, and Jitendra Kumar. "Change in Negative Sequence Current-Based Islanding Event Detection." In Lecture Notes in Electrical Engineering, 39–49. Singapore: Springer Singapore, 2022. http://dx.doi.org/10.1007/978-981-16-6970-5_4.
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Xu, Shenao, Qintian Zhang, and Zhiwei Xu. "A Novel Negative Sequence Current Control System for Electrified Railway." In Proceedings of the 11th International Conference on Computer Engineering and Networks, 959–65. Singapore: Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-16-6554-7_104.
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Liu, Zhe, Zhengqing Han, and Shibin Gao. "Using Untransposed Overhead Lines to Reduce Negative Sequence Current Injected by Railway Substation." In Proceedings of the 5th International Conference on Electrical Engineering and Information Technologies for Rail Transportation (EITRT) 2021, 468–75. Singapore: Springer Singapore, 2022. http://dx.doi.org/10.1007/978-981-16-9905-4_54.
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Wang, Ying, Xiuqing Mu, Yalan Wang, and Zhengyou He. "Research on RPC-SC System for Negative Sequence Current Compensation of Electrified Railway." In Proceedings of the 5th International Conference on Electrical Engineering and Information Technologies for Rail Transportation (EITRT) 2021, 372–80. Singapore: Springer Singapore, 2022. http://dx.doi.org/10.1007/978-981-16-9905-4_44.
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Selvaganesan, N. "Fuzzy Based Modeling, Control, and Fault Diagnosis of Permanent Magnet Synchronous Generator." In Handbook of Research on Computational Intelligence for Engineering, Science, and Business, 487–520. IGI Global, 2013. http://dx.doi.org/10.4018/978-1-4666-2518-1.ch019.
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This chapter presents the design methodology of fuzzy based modeling, control, and fault diagnosis of Permanent Magnet Synchronous Generator (PMSG) system. The fuzzy based modeling scheme for PMSG is developed using the general Takagi-Sugeno fuzzy model. Subsequently, fuzzy controller is designed and simulated to maintain three phase output voltage as constant by controlling the speed of generator. The feasibility of the fuzzy model and control scheme is demonstrated using various operating conditions by MATLAB simulation. Also, fuzzy based fault detection scheme for PMSG is developed and presented. The positive and negative sequence currents are used as fault indicators and given as inputs to fuzzy fault detector. The fuzzy inference system is created, and rule base is evaluated, relating the sequence current component to the type of faults. The feasibility of this scheme is demonstrated for different types of fault under various operating conditions using MATLAB/Simulink.
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Yang, Yong, and Yanyan Li. "Perspective Chapter: Novel Diagnostics Methods for SARS-CoV-2." In Current Topics in SARS-CoV-2/COVID-19 - Two Years After [Working Title]. IntechOpen, 2022. http://dx.doi.org/10.5772/intechopen.105912.
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A novel coronavirus of zoonotic origin (SARS-CoV-2) has recently been recognized in patients with acute respiratory disease. COVID-19 causative agent is structurally and genetically similar to SARS and bat SARS-like coronaviruses. The drastic increase in the number of coronavirus and its genome sequence has given us an unprecedented opportunity to perform bioinformatics and genomics analysis on this class of viruses. Clinical tests such as PCR and ELISA for rapid detection of this virus are urgently needed for early identification of infected patients. However, these techniques are expensive and not readily available for point-of-care (POC) applications. Currently, lack of any rapid, available, and reliable POC detection method gives rise to the progression of COVID-19 as a horrible global problem. To solve the negative features of clinical investigation, we provide a brief introduction of the various novel diagnostics methods including SERS, SPR, electrochemical, magnetic detection of SARS-CoV-2. All sensing and biosensing methods based on nanotechnology developed for the determination of various classes of coronaviruses are useful to recognize the newly immerged coronavirus, i.e., SARS-CoV-2. Also, the introduction of sensing and biosensing methods sheds light on the way of designing a proper screening system.
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Dombo, Eileen A., and Christine Anlauf Sabatino. "Trauma and Its Sequelae in Children and Adolescents." In Creating Trauma-Informed Schools, 9–23. Oxford University Press, 2019. http://dx.doi.org/10.1093/oso/9780190873806.003.0002.
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The most current research on trauma and child development demonstrates that there are significant risk factors for school success. At the same time, resilience and protective factors help other children overcome these obstacles. Chapter 2 explores the effects of trauma on children and adolescents. Data from the Adverse Childhood Experiences Study, as well as other academic and epidemiological studies, are used to address the negative impact of traumatic experiences on child development. The neurobiology of trauma is explored along with other bio-psycho-social-spiritual effects of abuse, neglect, and other adverse experiences affecting children in the United States. Internalizing and externalizing disorders present in children who experience abuse are also addressed.
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Choi, Samuel P. M., and Sze Sing Lam. "iChecker." In Scholarly Ethics and Publishing, 232–47. IGI Global, 2019. http://dx.doi.org/10.4018/978-1-5225-8057-7.ch011.
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Academic plagiarism is regarded as a serious offense and much effort in the past has been devoted to build stand-alone plagiarism detection systems for a specific language. This paper proposes a new information retrieval-based plagiarism detection algorithm that handles multilingual documents and enables seamless integration with learning management systems. The proposed algorithm employs information retrieval and sequence matching techniques to identify suspected plagiarized sentences and permits parametric control to reduce both false-positive and false-negative results. The full-featured implementation, called iChecker, not only could quickly identify suspected plagiarized works but also ease academics' effort to evaluate the severity of the offence by a quantified measure. Currently iChecker is adopted by over 300 courses (with some having several hundred of students) and has obtained satisfactory results. During 2012 to 2016, iChecker has processed and verified a total of 276,943 documents in English, Traditional Chinese and Simplified Chinese text.
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Nkwunonwo, Ugonna Chimnonyerem. "Geo-Spatial Technology for Land Resources Management in Nigeria." In Advances in Environmental Engineering and Green Technologies, 62–87. IGI Global, 2020. http://dx.doi.org/10.4018/978-1-7998-5027-4.ch004.
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There is little discussion regarding natural resources management issues in Nigeria, unlike many other places around the world, where such issues have made significant contributions to research growth. This is a troubling situation that complicates Nigeria's present need to address her increasing sequence of aggravations related to land cover modifications. Sustainable use of land, water, solid minerals, and forest is difficult and overwhelms local efforts. Demographic pressures and the corresponding need for developments and societal livability have a proclivity to overuse land resources and impact negatively on their present quality and future regeneration. Traditional and indigenous approaches are still the bases of natural resources management. The cumulative challenges of these issues with other prevalent anomalies are increasingly compromising Nigeria's land resources base. However, geo-spatial technology with its potential for policy and decision-support is being set forth to address these challenges and to fill the current gaps in knowledge of natural resources management.
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"Probes, Allele Mutations, and Restriction Enzymes." In DNA Fingerprinting, edited by Lorne t. Kirby. Oxford University Press, 1993. http://dx.doi.org/10.1093/oso/9780716770015.003.0010.
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Positive identification is the ultimate objective of forensic analysis of blood and other tissue specimens. Nucleotide probes can be very effective tools for detecting genetic markers in this identification process. The genetic markers should be highly polymorphic; allelic variants should be easily and readily detectable; if amplification is required, the alleles should be efficiently amplified using PCR technology; and a statistically sound estimate of the population allele and genotype frequencies should be available. Probes are single-stranded fragments of DNA or RNA containing the complementary code for a specific sequence of genome bases. Probes available for DNA profile analysis will, no doubt, eventually number in the hundreds. Currently, the most valuable detect tandem repetitive sequence fragments either at a specific locus under high-stringency analysis conditions or at numerous loci under low-stringency conditions. Each locus consists of many possible alleles with frequencies that vary depending on the specific population. Other factors also enter into the selection of probes, including ease of amplification, stability, cross-reactivity, and general availability. Rate of allele mutation is also a prime consideration in probe selection. Mutation can be considered at two levels: as the basis for the large number of tandem repeat (VNTR) alleles formed during evolution and as a possible reason for spurious unassignable bands in typing analysis. Although highly unlikely, somatic mutations may be of concern in forensic testing if DNA from different tissues, such as blood and hair roots, are being matched. Germ line (gamete) mutations must be considered when parentage analyses are undertaken. These situations could give rise to false negative results and, therefore, false exclusions. Different considerations also apply for single versus multilocus probes. If a band that is not seen in the putative father is detected in an offspring, the man could incorrectly be excluded if the single-locus probe approach is used. This situation would necessitate testing with more than the usual four or five probes.
Conference papers on the topic "Negative sequence current"
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Wang, John, and Randy Hamilton. "A review of negative sequence current." In 2010 63rd Annual Conference for Protective Relay Engineers. IEEE, 2010. http://dx.doi.org/10.1109/cpre.2010.5469515.
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Shao, Hua, Haobin Zhu, Rong Lin, Guangfu Xu, Qunbing Yu, and Chunguang He. "Analysis on IIDG's negative-sequence current upon asymmetric fault." In 2016 China International Conference on Electricity Distribution (CICED). IEEE, 2016. http://dx.doi.org/10.1109/ciced.2016.7575968.
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Shao, Hua, Haobin Zhu, Rong Lin, Guangfu Xu, Qunbing Yu, and Chunguang He. "Analysis on IIDG's negative-sequence current upon asymmetric fault." In 2016 China International Conference on Electricity Distribution (CICED). IEEE, 2016. http://dx.doi.org/10.1109/ciced.2016.7575973.
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Shamseh, Mohammad Bani, Ruben Inzunza, Issei Fukasawa, Tsuguhiro Tanaka, and Tatsuaki Ambo. "Grid Support During Asymmetrical Faults using Negative Sequence Current Injection." In 2019 IEEE 4th International Future Energy Electronics Conference (IFEEC). IEEE, 2019. http://dx.doi.org/10.1109/ifeec47410.2019.9015036.
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Chaudhary, Sanjay K., Omer Goksu, Remus Teodorescu, and Philip C. Kjaer. "Impact of negative sequence current injection by wind power plants." In 2013 IEEE Power & Energy Society General Meeting. IEEE, 2013. http://dx.doi.org/10.1109/pesmg.2013.6673073.
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Wenjin, Dai, and Wu Songhui. "Real-Time Detecting Method of Negative Sequence Current in Traction System." In 2007 8th International Conference on Electronic Measurement and Instruments. IEEE, 2007. http://dx.doi.org/10.1109/icemi.2007.4351046.
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Antonopoulos, Antonios, and Jan R. Svensson. "Evaluation of negative-sequence-current compensators for high-speed electric railways." In 2016 IEEE Energy Conversion Congress and Exposition (ECCE). IEEE, 2016. http://dx.doi.org/10.1109/ecce.2016.7855091.
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Carunaiselvane, C., Thanga Raj Chelliah, and S. V. Appa Sarma. "Negative Sequence Current in Megawatt Hydro Generators at Uprated Unbalanced Loads." In 2018 IEEE International Conference on Power Electronics, Drives and Energy Systems (PEDES). IEEE, 2018. http://dx.doi.org/10.1109/pedes.2018.8707919.
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Goto, M. "Static negative-phase-sequence current compensator for railway power supply system." In International Conference on Electric Railways in a United Europe. IEE, 1995. http://dx.doi.org/10.1049/cp:19950182.
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Li, Lingda, Jianze Wang, Ningning Li, Zhenlei Yu, and Xiangyu Sai. "Improved Negative Sequence current Injection Balancing Method considering Zero Sequence Voltage for cascaded H-bridge STATCOM." In 2019 22nd International Conference on Electrical Machines and Systems (ICEMS). IEEE, 2019. http://dx.doi.org/10.1109/icems.2019.8922003.
Full textReports on the topic "Negative sequence current"
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Behnke, Michael Robert, Michael Robert Behnke, Gary Custer, Gary Custer, Evangelos Farantatos, Evangelos Farantatos, Normann Fischer, et al. Impact of Inverter Based Resource Negative Sequence Current Injection on Transmission System Protection. Office of Scientific and Technical Information (OSTI), January 2020. http://dx.doi.org/10.2172/1595917.
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Yaron, Zvi, Martin P. Schreibman, Abigail Elizur, and Yonathan Zohar. Advancing Puberty in the Black Carp (Mylopharyngodon Piceus) and the Striped Bass (Morone Saxatilis). United States Department of Agriculture, August 1993. http://dx.doi.org/10.32747/1993.7568102.bard.
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The black carp (bc)GtH IIb cDNA was amplified and isolated, cloned and sequenced. Comparison of the bcGtH IIb deduced a.a. sequence with that of GtH IIb from other teleosts revealed high homology to cyprinid species and a lower homology to salmonid or perciform fish. The gene coding for the GtH IIb was isolated and sequenced. Three bc recombinant phages which hybridized to the goldfish GtH Ib cDNA probe were isolated and are currently being characterized. The region coding for the mature GtH IIb was expressed in a bacterial expression vector resulting in the production of a recombinant protein. In vitro folding resulted in a protein only 1.3% of which displaced the native common carp GtH II in a RIA. Therefore, the common carp GtH RIA was utilized for the physiological studies at the current phase of the project. Two non-functional sites were identified along the brain-pituitary gonadal axis in the immature black carp. The pituitary is refractory to GnRH stimulation due to a block proximal to the activation of PKA and PKC probably at the level of GnRH receptors. The gonads, although capable of producing steroids, are refractory to gonadotropic stimulation but do respond to cAMP antagonists, indicating a block at the GtH receptor level. Attempts to advance puberty in 2 and 3 y old black carp showed that testosterone (T) stimulates GtH synthesis in the pituitary and increases its sensitivity to GnRh. A 2 month treatment combining T+GnRH increased the circulating GFtH level in 3 y old fish. Addition of domperidone to such a treatment facilitated both the accumulation of GtH in the pituitary and its response to GnRH. The cDNA of striped bass GtH a, Ib and IIb subunits were amplified, isolated, cloned and sequenced, and their deduced a.a. sequences were compared with those of other teleosts. A ribonuclease protection assay was developed for a sensitive and simultaneous determination of all GtH subunits, and of b-actin mRNAs of the striped bass. GnRH stimulated dramatically the expression of the a and GtH IIb subunits but the level of GtH Ib mRNA increased only moderately. These findings suggest that GtH-II, considered in salmonids to be involved only in final stages of gametogenesis, can be induced by GnRH to a higher extent than GtH-I in juvenile striped bass. The native GtH II of the striped bass was isolated and purified, and an ELISA for its determination was developed. The production of all recombinant striped bass GtH subunits is in progress using the insect cell (Sf9) culture and the BAC-TO-BAC baculovirus expression system. A recombinant GtH IIb subunit has been produced already, and its similarity to the native subunit was confirmed. The yield of the recombinant glycoprotein can reach 3.5 mg/ml after 3 days culture. All male striped bass reach puberty after 3 y. However, precocious puberty was discovered in 1 and 2 y old males. Females become vitellogenic during their 4th year. In immature 2 y old females, T treatment elevates the pituitary GtH II content while GnRH only potentiates the effect. However, in males GnRH and not T affects GtH accumulation in the pituitary. Neither GnRH, nor T treatment resulted in gonadal growth in 2 y old striped bass, indicating that either the accumulated GtH II was not released, or if released, the gonads were refractory to GtH stimulation, similar to the situation in the immature black carp. In 3 y old female striped bass, 150 day GnRHa treatment resulted in an increase in GSI, while T treatment, with or without GnRHa, resulted in a decrease in oocyte diameter, similar to the effect seen in the black carp. Further attempts to advance puberty in both fish species should take into account the positive effect of T on pituitary GtH and its negative effect of ovarian growth.
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Lers, Amnon, and Pamela J. Green. Analysis of Small RNAs Associated with Plant Senescence. United States Department of Agriculture, March 2013. http://dx.doi.org/10.32747/2013.7593393.bard.
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Senescence is an agriculturally significant process due to its negative impact to crop yield and postharvest quality. The genetic regulatory systems controlling senescence induction and progress respond to both developmental and environmental stress signals and involve numerous gene expression changes. Knowledge about the key molecular factors which control senescence is very limited. MicroRNAs (miRNAs) are a class of small RNAs which typically function by guiding cleavage of target messenger RNAs. They have been shown to play major roles in a variety of plant processes including development, responses to environmental stresses, and senescence. The long-term goal of this work is to elucidate roles of small RNAs associated with plant senescence. The hypothesis underlying this research is that miRNA-mediated regulation makes important contributions to the senescence process in plants. Specific, original research objectives included: 1) Profiling of small RNAs from senescing plants; 2) Data Analysis and public access via a user-friendly web interface; 3) Validation of senescence-associated miRNAs and target RNAs; 4) Development of transgenic plants for functional analysis of miRNAs in Arabidopsis. Major revisions made in the research compared to the original work plan included 1) Exclusion of the planned work with tomato as recommended by the BARD review panel; 2) Performing miRNA study also in senescing Arabidopsis siliques, in addition to senescing leaves. To identify senescenceregulation of miRNAs in Arabidopsis thaliana, eight small RNA libraries were constructed and sequenced at four different stages of development and senescence from both leaves and siliques, resulting in more than 200 million genome-matched sequences. Parallel Analysis of RNA Ends (PARE) libraries, which enable the large-scale examination of miRNA-guided cleavage products, were also constructed and sequenced, resulting in over 750 million genome-matched sequences. These massive datasets lead to the identification of new miRNAs, as well as new regulation of known miRNAs and their target genes during senescence, many of which have established roles in nutrient responsiveness and cell structural integrity. In keeping with remobilization of nutrients thought to occur during senescence, many miRNAs and targets had opposite expression pattern changes between leaf and silique tissues during the progression of senescence. Taken together, these findings highlight the integral role that miRNAs may play in the remobilization of resources and alteration of cellular structure that is known to occur in senescence. Experiments were initiated for functional analysis of specific senescence-associated miRNAs and respective target genes. Transgenic Arabidopsis plants were generated in which miR408, found in this study to be significantly induced in leaf senescence, was over-expressed either constitutively or under a senescence-specific promoter. These plants are currently being characterized for any altered phenotypes. In addition T-DNA knock out mutants for various target genes identified in this research are being analyzed. This work provides insights about specific miRNAs that contribute to leaf and silique senescence. The knowledge generated may suggest new strategies to monitor and alter the progression of senescence in crops for agricultural improvement.
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Morin, Shai, Gregory Walker, Linda Walling, and Asaph Aharoni. Identifying Arabidopsis thaliana Defense Genes to Phloem-feeding Insects. United States Department of Agriculture, February 2013. http://dx.doi.org/10.32747/2013.7699836.bard.
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The whitefly (Bemisia tabaci) is a serious agricultural pest that afflicts a wide variety of ornamental and vegetable crop species. To enable survival on a great diversity of host plants, whiteflies must have the ability to avoid or detoxify numerous different plant defensive chemicals. Such toxins include a group of insect-deterrent molecules called glucosinolates (GSs), which also provide the pungent taste of Brassica vegetables such as radish and cabbage. In our BARD grant, we used the whitefly B. tabaci and Arabidopsis (a Brassica plant model) defense mutants and transgenic lines, to gain comprehensive understanding both on plant defense pathways against whiteflies and whitefly defense strategies against plants. Our major focus was on GSs. We produced transgenic Arabidopsis plants accumulating high levels of GSs. At the first step, we examined how exposure to high levels of GSs affects decision making and performance of whiteflies when provided plants with normal levels or high levels of GSs. Our major conclusions can be divided into three: (I) exposure to plants accumulating high levels of GSs, negatively affected the performance of both whitefly adult females and immature; (II) whitefly adult females are likely to be capable of sensing different levels of GSs in their host plants and are able to choose, for oviposition, the host plant on which their offspring survive and develop better (preference-performance relationship); (III) the dual presence of plants with normal levels and high levels of GSs, confused whitefly adult females, and led to difficulties in making a choice between the different host plants. These findings have an applicative perspective. Whiteflies are known as a serious pest of Brassica cropping systems. If the differences found here on adjacent small plants translate to field situations, intercropping with closely-related Brassica cultivars could negatively influence whitefly population build-up. At the second step, we characterized the defensive mechanisms whiteflies use to detoxify GSs and other plant toxins. We identified five detoxification genes, which can be considered as putative "key" general induced detoxifiers because their expression-levels responded to several unrelated plant toxic compounds. This knowledge is currently used (using new funding) to develop a new technology that will allow the production of pestresistant crops capable of protecting themselves from whiteflies by silencing insect detoxification genes without which successful host utilization can not occur. Finally, we made an effort to identify defense genes that deter whitefly performance, by infesting with whiteflies, wild-type and defense mutated Arabidopsis plants. The infested plants were used to construct deep-sequencing expression libraries. The 30- 50 million sequence reads per library, provide an unbiased and quantitative assessment of gene expression and contain sequences from both Arabidopsis and whiteflies. Therefore, the libraries give us sequence data that can be mined for both the plant and insect gene expression responses. An intensive analysis of these datasets is underway. We also conducted electrical penetration graph (EPG) recordings of whiteflies feeding on Arabidopsis wild-type and defense mutant plants in order to determine the time-point and feeding behavior in which plant-defense genes are expressed. We are in the process of analyzing the recordings and calculating 125 feeding behavior parameters for each whitefly. From the analyses conducted so far we conclude that the Arabidopsis defense mutants do not affect adult feeding behavior in the same manner that they affect immatures development. Analysis of the immatures feeding behavior is not yet completed, but if it shows the same disconnect between feeding behavior data and developmental rate data, we would conclude that the differences in the defense mutants are due to a qualitative effect based on the chemical constituency of the phloem sap.
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Gershoni, Jonathan M., David E. Swayne, Tal Pupko, Shimon Perk, Alexander Panshin, Avishai Lublin, and Natalia Golander. Discovery and reconstitution of cross-reactive vaccine targets for H5 and H9 avian influenza. United States Department of Agriculture, January 2015. http://dx.doi.org/10.32747/2015.7699854.bard.
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Research objectives: Identification of highly conserved B-cell epitopes common to either H5 or H9 subtypes of AI Reconstruction of conserved epitopes from (1) as recombinantimmunogens, and testing their suitability to be used as universal vaccine components by measuring their binding to Influenza vaccinated sera of birds Vaccination of chickens with reconstituted epitopes and evaluation of successful vaccination, clinical protection and viral replication Development of a platform to investigate the dynamics of immune response towards infection or an epitope based vaccine Estimate our ability to focus the immune response towards an epitope-based vaccine using the tool we have developed in (D) Summary: This study is a multi-disciplinary study of four-way collaboration; The SERPL, USDA, Kimron-Israel, and two groups at TAU with the purpose of evaluating the production and implementation of epitope based vaccines against avian influenza (AI). Systematic analysis of the influenza viral spike led to the production of a highly conserved epitope situated at the hinge of the HA antigen designated “cluster 300” (c300). This epitope consists of a total of 31 residues and was initially expressed as a fusion protein of the Protein 8 major protein of the bacteriophagefd. Two versions of the c300 were produced to correspond to the H5 and H9 antigens respectively as well as scrambled versions that were identical with regard to amino acid composition yet with varied linear sequence (these served as negative controls). The recombinantimmunogens were produced first as phage fusions and then subsequently as fusions with maltose binding protein (MBP) or glutathioneS-transferase (GST). The latter were used to immunize and boost chickens at SERPL and Kimron. Furthermore, vaccinated and control chickens were challenged with concordant influenza strains at Kimron and SEPRL. Polyclonal sera were obtained for further analyses at TAU and computational bioinformatics analyses in collaboration with Prof. Pupko. Moreover, the degree of protection afforded by the vaccination was determined. Unfortunately, no protection could be demonstrated. In parallel to the main theme of the study, the TAU team (Gershoni and Pupko) designed and developed a novel methodology for the systematic analysis of the antibody composition of polyclonal sera (Deep Panning) which is essential for the analyses of the humoral response towards vaccination and challenge. Deep Panning is currently being used to monitor the polyclonal sera derived from the vaccination studies conducted at the SEPRL and Kimron.
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Chamovitz, Daniel, and Albrecht Von Arnim. Translational regulation and light signal transduction in plants: the link between eIF3 and the COP9 signalosome. United States Department of Agriculture, November 2006. http://dx.doi.org/10.32747/2006.7696515.bard.
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The COP9 signalosome (CSN) is an eight-subunit protein complex that is highly conserved among eukaryotes. Genetic analysis of the signalosome in the plant model species Arabidopsis thaliana has shown that the signalosome is a repressor of light dependent seedling development as mutant Arabidopsis seedlings that lack this complex develop in complete darkness as if exposed to light. These mutant plants die following the seedling stage, even when exposed to light, indicating that the COP9 signalosome also has a central role in the regulation of normal photomorphogenic development. The biochemical mode of action of the signalosome and its position in eukaryotic cell signaling pathways is a matter of controversy and ongoing investigation, and recent results place the CSN at the juncture of kinase signaling pathways and ubiquitin-mediated protein degradation. We have shown that one of the many CSN functions may relate to the regulation of translation through the interaction of the CSN with its related complex, eukaryotic initiation factor (eIF3). While we have established a physical connection between eIF3 subunits and CSN subunits, the physiological and developmental significance of this interaction is still unknown. In an effort to understand the biochemical activity of the signalosome, and its role in regulating translation, we originally proposed to dissect the contribution of "h" subunit of eIF3 (eIF3h) along the following specific aims: (i) Isolation and phenotypic characterization of an Arabidopsis loss-of-function allele for eIF3h from insertional mutagenesis libraries; (ii) Creation of designed gain and loss of function alleles for eIF3h on the basis of its nucleocytoplasmic distribution and its yeast-two-hybrid interactions with other eIF3 and signalosome partner proteins; (iii) Determining the contribution of eIF3h and its interaction with the signalosome by expressing specific mutants of eIF3h in the eIF3h- loss-of function background. During the course of the research, these goals were modified to include examining the genetic interaction between csn and eif3h mutations. More importantly, we extended our effort toward the genetic analysis of mutations in the eIF3e subunit, which also interacts with the CSN. Through the course of this research program we have made several critical scientific discoveries, all concerned with the apparent diametrically opposed roles of eIF3h and eIF3e. We showed that: 1) While eIF3e is essential for growth and development, eIF3h is not essential for growth or basal translation; 2) While eIF3e has a negative role in translational regulation, eIF3h is positively required for efficient translation of transcripts with complex 5' UTR sequences; 3) Over-accumulation of eIF3e and loss-of-function of eIF3h both lead to cop phenotypes in dark-grown seedlings. These results were published in one publication (Kim et al., Plant Cell 2004) and in a second manuscript currently in revision for Embo J. Are results have led to a paradigm shift in translation research – eIF3 is now viewed in all systems as a dynamic entity that contains regulatory subuits that affect translational efficiency. In the long-term agronomic outlook, the proposed research has implications that may be far reaching. Many important plant processes, including developmental and physiological responses to light, abiotic stress, photosynthate, and hormones operate in part by modulating protein translation [23, 24, 40, 75]. Translational regulation is slowly coming of age as a mechanism for regulating foreign gene expression in plants, beginning with translational enhancers [84, 85] and more recently, coordinating the expression of multiple transgenes using internal ribosome entry sites. Our contribution to understanding the molecular mode of action of a protein complex as fundamental as eIF3 is likely to lead to advances that will be applicable in the foreseeable future.
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Abbo, Shahal, Hongbin Zhang, Clarice Coyne, Amir Sherman, Dan Shtienberg, and George J. Vandemark. Winter chickpea; towards a new winter pulse for the semiarid Pacific Northwest and wider adaptation in the Mediterranean basin. United States Department of Agriculture, January 2011. http://dx.doi.org/10.32747/2011.7597909.bard.
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Original objectives: [a] Screen an array of chickpea and wild annual Cicer germplasm for winter survival. [b] Genetic analysis of winter hardiness in domesticated x wild chickpea crosses. [c] Genetic analysis of vernalization response in domesticated x wild chickpea crosses. [d] Digital expression analysis of a core selection of breeding and germplasm lines of chickpea that differ in winter hardiness and vernalization. [e] Identification of the genes involved in the chickpea winter hardiness and vernalization and construction of gene network controlling these traits. [f] Assessing the phenotypic and genetic correlations between winter hardiness, vernalization response and Ascochyta blight response in chickpea. The complexity of the vernalization response and the inefficiency of our selection experiments (below) required quitting the work on ascochyta response in the framework of this project. Background to the subject: Since its introduction to the Palouse region of WA and Idaho, and the northern Great Plains, chickpea has been a spring rotation legume due to lack of winter hardiness. The short growing season of spring chickpea limits its grain yield and leaves relatively little stubble residue for combating soil erosion. In Israel, chilling temperatures limit pod setting in early springs and narrow the effective reproductive time window of the crop. Winter hardiness and vernalization response of chickpea alleles were lost due to a series of evolutionary bottlenecks; however, such alleles are prevalent in its wild progenitor’s genepool. Major conclusions, solutions, achievements: It appears that both vernalization response and winter hardiness are polygenic traits in the wild-domesticated chickpea genepool. The main conclusion from the fieldwork in Israel is that selection of domesticated winter hardy and vernalization responsive types should be conducted in late flowering and late maturity backgrounds to minimize interference by daylength and temperature response alleles (see our Plant Breeding paper on the subject). The main conclusion from the US winter-hardiness studies is that excellent lines have been identified for germplasm release and continued genetic study. Several of the lines have good seed size and growth habit that will be useful for introgressing winter-hardiness into current chickpea cultivars to develop releases for autumn sowing. We sequenced the transcriptomes and profiled the expression of genes in 87 samples. Differential expression analysis identified a total of 2,452 differentially expressed genes (DEGs) between vernalized plants and control plants, of which 287 were shared between two or more Cicer species studied. We cloned 498 genes controlling vernalization, named CVRN genes. Each of the CVRN genes contributes to flowering date advance (FDA) by 3.85% - 10.71%, but 413 (83%) other genes had negative effects on FDA, while only 83 (17%) had positive effects on FDA, when the plant is exposed to cold temperature. The cloned CVRN genes provide new toolkits and knowledge to develop chickpea cultivars that are suitable for autumn-sowing. Scientific & agricultural implications: Unlike the winter cereals (barley, wheat) or pea, in which a single allelic change may induce a switch from winter to spring habit, we were unable to find any evidence for such major gene action in chickpea. In agricultural terms this means that an alternative strategy must be employed in order to isolate late flowering – ascochyta resistant (winter types) domesticated forms to enable autumn sowing of chickpea in the US Great Plains. An environment was identified in U.S. (eastern Washington) where autumn-sown chickpea production is possible using the levels of winter-hardiness discovered once backcrossed into advanced cultivated material with acceptable agronomic traits. The cloned CVRN genes and identified gene networks significantly advance our understanding of molecular mechanisms underlying plant vernalization in general, and chickpea in particular, and provide a new toolkit for switching chickpea from a spring-sowing to autumn-sowing crop.
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Lers, Amnon, E. Lomaniec, S. Burd, A. Khalchitski, L. Canetti, and Pamela J. Green. Analysis of Senescence Inducible Ribonuclease in Tomato: Gene Regulation and Function. United States Department of Agriculture, February 2000. http://dx.doi.org/10.32747/2000.7570563.bard.
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Natural leaf senescence has a negative influence on yield. Postharvest induced senescence contributes to the losses of quality in flowers, foliage, and vegetables. Strategies designed to control the senescence process in crop plants could therefore have great applied significance. Senescence is regulated by differential gene expression yet, functional characterization of the genes specifically induced and study of their expression control, is still in its infancy. Study of senescence-specific genes is required to allow identification of regulatory elements participating in senescence-induced expression and thus provide insights into the genetic regulation of senescence. A main feature of senescence is the hydrolysis of macromolecules by hydrolases of various types such as RNases and proteases. This study was aimed a analysis of senescence-inducible RNases in tomato with the following objectives: Isolation of senescence-inducible RNase cDNA clones; Expression analyses of RNase genes during senescence; Identification of sequences required for senescence-induced gene expression; Functional analyses of senescence-inducible RNases. We narrowed our aims somewhat to focus on the first three objectives because the budget we were awarded was reduced from that requested. We have expanded our research for identification senescence-related RNase/nuclease activities as we thought it will direct us to new RNase/nuclease genes. We have also carried out research in Arabidopsis and parsley, which enabled us to draw mire general conclusions. We completed the first and second objectives and have made considerable progress on the remaining two. We have defined growth conditions suitable for this research and defined the physiological and biochemical parameters characteristic to the advance of leaf senescence. In tomato and arabidopsis we have focused on natural leaf senescence. Parsley was used mainly for study of postharvest senescence in detached leaves. We have identified a 41-kD a tomato nuclease, LeNUCI, specifically induced during senescence which can degrade both RNA and DNA. This activity could be induced by ethylene in young leaves and was subjected to detailed analysis, which enabled its classification as Nuclease I enzyme. LeNUCI may be involved in nucleic acid metabolism during tomato leaf senescence. In parsley senescing leaves we identified 2 main senescence-related nuclease activities of 41 and 39-kDa. These activities were induced in both naturally or artificially senescing leaves, could degrade both DNA and RNA and were very similar in their characteristics to the LeNUCI. Two senescence-induced RNase cDNAs were cloned from tomato. One RNase cDNA was identical to the tomato LX RNase while the second corresponded to the LE RNase. Both were demonstrated before to be induced following phosphate starvation of tomato cell culture but nothing was known about their expression or function in plants. LX gene expression was much more senescence specific and ethylene could activate it in detached young leaves. LE gene expression, which could be transiently induced by wounding, appeared to be activated by abscisic acid. We suggest that the LX RNase has a role in RNA catabolism in the final stage of senescence, and LE may be a defense-related protein. Transgenic plants were generated for altering LX gene expression. No major visible alterations in the phenotype were observed so far. Detailed analysis of senescence in these plants is performed currently. The LX promoter was cloned and its analysis is performed currently for identification of senescence-specific regulatory elements. In Arabidopsis we have identified and characterized a senescence-associated nuclease 1 gene, BFN1, which is highly expressed during leaf and stem senescence. BFN1, is the first example of a senescence- associated gene encoding a nuclease I enzyme as well as the first nuclease I cloned and characterized from Arabidopsis. Our progress should provide excellent tools for the continued analysis of regulation and function of senescence-inducible ribonucleases and nucleases in plants. The cloned genes can be used in reverse genetic approaches, already initiated, which can yield a more direct evidence for the function of these enzymes. Another contribution of this research will be in respect to the molecular mechanism, which controls senescence. We had already initiated in this project and will continue to identify and characterize regulatory elements involved in senescence-specific expression of the genes isolated in this work.