Gas Chromatography-Mass Spectrometric Analysis of Nematicidal Essential Oil ofValeriana amurensis P Smirn ex Kom (Valerianaceae) Roots and its Activity against Heterodera avenae

Purpose: To investigate the chemical composition and nematicidal activity of the essential oil of Valeriana amurensis roots against cereal cyst nematodes (Heterodera avenae).Methods: The essential oil of V. amurensis roots was obtained by hydrodistillation and analyzed by gas chromatography (GC) and gas chromaotography-mass spectrometry (GC-MS). The nematicidal activity of the essential oil and its major constituents was determined against second stage juveniles of H. avenae.Results: A total of 33 components of the essential oil were identified. The major constituents were bornyl acetate (12.5 %), patchoulol (11.6 %), caryophyllene (8.2 %), 3-methylvaleric acid (7.3 %) and isovaleric acid (6.5 %). The essential oil exhibited nematicidal activity against H. avenae with a medium lethal concentration (LC50) value of 311.6 μg/mL. The major constituents, isovaleric acid and 3- methylvaleric acid, exhibited nematicidal activity against H. avenae with LC50 of 218.2 and 683.8 μg/mL, respectively.Conclusion: The study indicates that the essential oil of V. amurensis roots and its two major constituents, isovaleric acid and 3-methylvaleric acid, have a potential to be developed to natural nematicides for the control of cereal cyst nematodes.Keywords: Valeriana amurensis, Heterodera avenae, Nematicidal activity, Isovaleric acid, 3- Methylvaleric acid, Essential oil, Cereal cyst nematode

An EM algorithm based on an internal list for estimating haplotype distributions of rare variants from pooled genotype data

10.1186/1471-2156-14-82BMC Genetics14-BGME

Electromechanical modeling and experimental analysis of a compression-based piezoelectric vibration energy harvester

Over the past few decades, wireless sensor networks have been widely used in the field of structure health monitoring of civil, mechanical, and aerospace systems. Currently, most wireless sensor networks are battery-powered and it is costly and unsustainable for maintenance because of the requirement for frequent battery replacements. As an attempt to address such issue, this article theoretically and experimentally studies a compression-based piezoelectric energy harvester using a multilayer stack configuration, which is suitable for civil infrastructure system applications where large compressive loads occur, such as heavily vehicular loading acting on pavements. In this article, we firstly present analytical and numerical modeling of the piezoelectric multilayer stack under axial compressive loading, which is based on the linear theory of piezoelectricity. A two-degree-of-freedom electromechanical model, considering both the mechanical and electrical aspects of the proposed harvester, was developed to characterize the harvested electrical power under the external electrical load. Exact closed-form expressions of the electromechanical models have been derived to analyze the mechanical and electrical properties of the proposed harvester. The theoretical analyses are validated through several experiments for a test prototype under harmonic excitations. The test results exhibit very good agreement with the analytical analyses and numerical simulations for a range of resistive loads and input excitation levels. © 2014 The Author(s)

On performance bounds for timing estimation under fading channels

In timing synchronization, the Cramér Rao Bound has been used as performance bounds for timing estimation in AWGN channel. However, the instantaneous CRB for timing estimation in fading channels depends on the channel realizations and may fail to bound the mean square error (MSE) of the estimator because the equivalent signal-to-noise ratio (SNR) is too low. In this paper, we demonstrate that the conventional CRB for timing estimation is no longer valid in fading channels. Furthermore, a new performance bound called Weighted Bayesian CRB (WBCRB) is proposed for the estimation of both single and multiple timing offsets under fading channels. The relationship between the conventional CRB and WBCRB are discussed in details, where numerical results show that the WBCRB is a valid bound for all SNR even under fading channels. ©2009 IEEE.published_or_final_versionThe IEEE Conference on Wireless Communications and Networking (WCNC 2009), Budapest, Hungary, 5-8 April 2009. In Proceedings of IEEE WCNC, 2009, p. 1-

Multiple timing offsets compensation in cooperative communication systems

Cooperative communication systems have attracted much attention recently due to their desirable performance gain while using single antenna terminals. However, most of the existin works on cooperative communications require perfect timing synchronization among users, which is usually not true in practical systems. In this paper, a general framework of the re-synchronization filter design is developed in order to com pensate the multiple timing offsets at the destination. The proposed method is applied to different scenarios with varying degrees of timing misalignment and is numerically shown to provide excellent performances that approach the perfectly synchronized case. © 2009 IEEE.published_or_final_versionThe 16th International Conference on Digital Signal Processing (DSP 2009), Santorini-Hellas, Greece, 5-7 July 2009. In Proceedings of 16th DSP, 2009, p. 1-

Timing synchronization in decode-and-forward cooperative communication systems

Cooperative communication systems have attracted much attention recently due to their desirable performance gain while using single antenna terminals. This paper addresses the joint timing and channel estimation problem, and furthermore the resynchronization of multiple timing offsets in a cooperative relay system. The estimations of timing and channel are conducted in two phases and the associated Cramér-Rao bounds (CRB) are derived for both phases. It is demonstrated that the conventional CRB is not valid for timing parameters under fading conditions, and a new bound called Weighted Bayesian CRB is proposed. With the timing and channel estimates, a general framework of the resynchronization filter design is developed in order to compensate the multiple timing offsets at the destination. The proposed methods are applied to different scenarios with varying degrees of timing misalignment and are numerically shown to provide excellent performances that approach the perfectly synchronized case. © 2009 IEEE.published_or_final_versio

Bayesian CFO estimation in OFDM systems

This paper addresses the problem of carrier frequency offset (CFO) estimation in orthogonal frequency division multiplexing (OFDM) systems using Bayesian method. Depending on the availability of the noise variance, two general CFO estimators are derived. Furthermore, the two general maximum a posteriori (MAP) estimators are developed into several special cases based on different degrees of prior information on parameters. The relationships between the proposed estimators and existing estimators are comprehensively investigated. Finally, numerical results demonstrate the effects of employing different prior information on the estimation performances. © 2009 IEEE.published_or_final_versionThe IEEE Conference on Wireless Communications and Networking (WCNC 2009), Budapest, Hungary, 5-8 April 2009. In Proceedings of IEEE WCNC, 2009, p. 1-

Signal Detection for OFDM-Based Virtual MIMO Systems under Unknown Doubly Selective Channels, Multiple Interferences and Phase Noises

In this paper, the challenging problem of signal detection under severe communication environment that plagued by unknown doubly selective channels (DSCs), multiple narrowband interferences (NBIs) and phase noises (PNs) is investigated for orthogonal frequency division multiplexing based virtual multiple-input multiple-output (OFDM-V-MIMO) systems. Based on the Variational Bayesian Inference framework, a novel iterative algorithm for joint signal detection, DSC, NBI and PN estimations is proposed. Simulation results demonstrate quick convergence of the proposed algorithm, and after convergence, the bit-error-rate performance of the proposed signal detection algorithm is very close to that of the ideal case which assumes perfect channel state information, no PN, and known positions and powers of NBIs plus additive white Gaussian noise. Furthermore, simulation results show that the proposed signal detection algorithm outperforms other state-of-the-art methods.published_or_final_versio

Real-time estimation of lane-based queue lengths at isolated signalized junctions

In this study, we develop a real-time estimation approach for lane-based queue lengths. Our aim is to determine the numbers of queued vehicles in each lane, based on detector information at isolated signalized junctions. The challenges involved in this task are to identify whether there is a residual queue at the start time of each cycle and to determine the proportions of lane-to-lane traffic volumes in each lane. Discriminant models are developed based on time occupancy rates and impulse memories, as calculated by the detector and signal information from a set of upstream and downstream detectors. To determine the proportions of total traffic volume in each lane, the downstream arrivals for each cycle are estimated by using the Kalman filter, which is based on upstream arrivals and downstream discharges collected during the previous cycle. Both the computer simulations and the case study of real-world traffic show that the proposed method is robust and accurate for the estimation of lane-based queue lengths in real time under a wide range of traffic conditions. Calibrated discriminant models play a significant role in determining whether there are residual queued vehicles in each lane at the start time of each cycle. In addition, downstream arrivals estimated by the Kalman filter enhance the accuracy of the estimates by minimizing any error terms caused by lane-changing behavior.postprin

Polymorphism of the H-FABP, MC4R and ADD1 genes in the Meishan and four other pig populations in China

Genes such as the Heart Fatty Acid-Binding Protein (H-FABP), the Melanocortin-4 Receptor (MC4R) and the Adipocyte Determination and Differentiation factor-1 (ADD1) play an important role in meat quality in pigs. The Meishan is one of the most prolific pig breeds in the world, but it is in danger, in China, of being replaced by other exotic pig breeds because of its slow growth rate and high body fat content. To know their present genetic status, the polymorphism of the three genes in the Meishan and four other pig populations (Sutai, Yorkshire×Sutai, Landrace×Sutai and Duroc×Landrace×Yorkshire) in China was analysed, using PCR-RFLP and PCR-SSCP, and were further compared with each other. The results showed that gene and genotype frequencies differed significantly between the Meishan and the other four populations. This is suggested to be one of the reasons for the good meat quality of the Meishan compared to the other breeds. In addition, since half of the genetic background of Sutai is from the Meishan, results also indicated that marker assisted selection (MAS) is very important for the development of new pig breeds. South African Journal of Animal Science Vol. 36(1) 2006: 1-