Analysis of phasor measurement method in tracking the power frequency of distorted signals

This paper presents an analysis of phasor measurement method for tracking the fundamental power frequency to show if it has the performance necessary to cope with the requirements of power system protection and control. In this regard, several computer simulations presenting the conditions of a typical power system signal especially those highly distorted by harmonics, noise and offset, are provided to evaluate the response of the Phasor Measurement (PM) technique. A new method, which can shorten the delay of estimation, has also been proposed for the PM method to work for signals free of even-order harmonics.

A Survey of Viruses Affecting Dry Bean and Cowpea in Lebanon

A survey was conducted to identify viruses affecting dry bean (Phaseolus vulgaris) and cowpea (Vigna unguiculata) in Lebanon. Three hundred and thirty four samples exhibiting virus-like symptoms were collected from 13 different locations during the fall growing season of 1984. Samples were stored at 20 deg C until they were tested by the enzyme-linked immunosorbent assay (ELISA) for the presence of blackeye cowpea mosaic virus (B1CMV), bean yellow mosaic virus (BYMV), bean common mosaic virus (BCMV) and cucumber mosaic virus (CMV). In preliminary tests, the extraction buffer 0.1M phosphate + O.1MEDTA, pH 7.4 was found to be far better than the standard extraction buffer and, accordingly, was used for virus extraction for all field samples. Results obtained indicated that around 50% of the bean samples tested were infected with B1CMV. Incidence of BCMV, BYMV and CMV in the samples tested were 4,4 and 1.7%, respectively. B1CMV was detected in 10 locations, whereas, BYMV, BCMV and CMV were found in 1,4 and 4 locations, respectively. Mixed infections such as BCMV, BICMV, BCMV+CMV, BYMV+CMV and BICMV+BCMV+CMV were detected. In 35% of the samples assayed, the causal virus was not identified

Broad Bean Stain Virus: Identification, Detectability with ELISA in Faba Bean Leaves and Seeds, Occurrence in West Asia and North Africa and Possible Wild Hosts

Abstract During a survey of faba bean viruses in West Asia and North Africa a virus was identified as broad bean stain virus (BBSV) based on host reactions, electron microscopy, physical properties and serology. An antiserum to a Syrian isolate was prepared. With this antiserum both the direct double antibody sandwich ELISA (DAS-ELISA) and dot-ELISA were very sensitive in detecting BBSV in leaf extracts, ground whole seeds and germi nated embryos. Sens it i vity was not reduced when the two-day procedure was replaced by a one-day procedure. us i ng ELISA the vi rus was detected in 73 out of 589 faba bean samples with virus-like symptoms collected from Egypt (4 out of 70 samples tested), Lebanon (6/44) , Morocco (017), Sudan (19/254), Syria (36/145) and Tunisia (8/69). This is the first report of BBSV infection of faba bean in Lebanon, Sudan, Syria and Tunisia. speci es i ndi genous to Syri a were Fourteen wild legume susceptible to BBSV infection, with only two producing obvious symptoms. The virus was found to be seed transmitted ~n Vicia palaestina.

Survey of Viruses Affecting Faba Bean in Six Arab Countries

A field survey of faba bean (Vicia [aba L.) for viruses in six Arab countries showed the presence of nine viruses. Bean leaf roll virus (BLRV), bean yellow mosaic virus (BYMV), broad bean mottle virus (BBMV) and to a lesser extent broad bean stain virus (BBSV) were the most common. When testing with ELISA 789 samples with symptoms suggestive of virus infection collected from Egypt, Lebanon, Morocco, Sudan, Syria and Tunisia, BBMV was detected in 203 samples, BBSV in 151, broad bean true mosaic virus (BBTMV) in 7, broad bean wilt virus (BBWV) in 47, BYMV in 314, cucumber mosaic virus (CMV) in 96, pea enation mosaic virus (PEMV) in 31, and pea seed-borne mosaic virus (PSbMV) in 49 samples. Identity of selected field isolates was confirmed by electron microscopy and host reaction studies. In a yield experiment, infection with BYMV, BBMV and BBSV 11 weeks after sowing (pre-flowering) led to 81, 54 and 84% yield loss, respectively. Inoculation with the same viruses 15 weeks after sowing (flowering) and 20 weeks after sowing (pod setting) led to 56, 84 and 18%, and 39, 37 and 18% yield loss, respectively.

Test and evaluation of non conventional instrument transformers and sampled value process bus on Powerlink's transmission network

IEC 61850 Process Bus technology has the potential to improve cost, performance and reliability of substation design. Substantial costs associated with copper wiring (designing, documentation, construction, commissioning and troubleshooting) can be reduced with the application of digital Process Bus technology, especially those based upon international standards. An IEC 61850-9-2 based sampled value Process Bus is an enabling technology for the application of Non-Conventional Instrument Transformers (NCIT). Retaining the output of the NCIT in its native digital form, rather than conversion to an analogue output, allows for improved transient performance, dynamic range, safety, reliability and reduced cost. In this paper we report on a pilot installation using NCITs communicating across a switched Ethernet network using the UCAIug Implementation Guideline for IEC 61850-9-2 (9-2 Light Edition or 9-2LE). This system was commissioned in a 275 kV Line Reactor bay at Powerlink Queensland’s Braemar substation in 2009, with sampled value protection IEDs 'shadowing' the existing protection system. The results of commissioning tests and twelve months of service experience using a Fibre Optic Current Transformer (FOCT) from Smart Digital Optics (SDO) are presented, including the response of the system to fault conditions. A number of remaining issues to be resolved to enable wide-scale deployment of NCITs and IEC 61850-9-2 Process Bus technology are also discussed.

Genome-wide identification and expression analysis of the NF-Y family of transcription factors in Triticum aestivum

Nuclear Factor Y (NF-Y) is a trimeric complex that binds to the CCAAT box, a ubiquitous eukaryotic promoter element. The three subunits NF-YA, NF-YB and NF-YC are represented by single genes in yeast and mammals. However, in model plant species (Arabidopsis and rice) multiple genes encode each subunit providing the impetus for the investigation of the NF-Y transcription factor family in wheat. A total of 37 NF-Y and Dr1 genes (10 NF-YA, 11 NF-YB, 14 NF-YC and 2 Dr1) in Triticum aestivum were identified in the global DNA databases by computational analysis in this study. Each of the wheat NF-Y subunit families could be further divided into 4-5 clades based on their conserved core region sequences. Several conserved motifs outside of the NF-Y core regions were also identified by comparison of NF-Y members from wheat, rice and Arabidopsis. Quantitative RT-PCR analysis revealed that some of the wheat NF-Y genes were expressed ubiquitously, while others were expressed in an organ-specific manner. In particular, each TaNF-Y subunit family had members that were expressed predominantly in the endosperm. The expression of nine NF-Y and two Dr1 genes in wheat leaves appeared to be responsive to drought stress. Three of these genes were up-regulated under drought conditions, indicating that these members of the NF-Y and Dr1 families are potentially involved in plant drought adaptation. The combined expression and phylogenetic analyses revealed that members within the same phylogenetic clade generally shared a similar expression profile. Organ-specific expression and differential response to drought indicate a plant-specific biological role for various members of this transcription factor family.

Comparison of scoring systems for invasive pests using ROC analysis and Monte Carlo simulation

Different international plant protection organisations advocate different schemes for conducting pest risk assessments. Most of these schemes use structured questionnaire in which experts are asked to score several items using an ordinal scale. The scores are then combined using a range of procedures, such as simple arithmetic mean, weighted averages, multiplication of scores, and cumulative sums. The most useful schemes will correctly identify harmful pests and identify ones that are not. As the quality of a pest risk assessment can depend on the characteristics of the scoring system used by the risk assessors (i.e., on the number of points of the scale and on the method used for combining the component scores), it is important to assess and compare the performance of different scoring systems. In this article, we proposed a new method for assessing scoring systems. Its principle is to simulate virtual data using a stochastic model and, then, to estimate sensitivity and specificity values from these data for different scoring systems. The interest of our approach was illustrated in a case study where several scoring systems were compared. Data for this analysis were generated using a probabilistic model describing the pest introduction process. The generated data were then used to simulate the outcome of scoring systems and to assess the accuracy of the decisions about positive and negative introduction. The results showed that ordinal scales with at most 5 or 6 points were sufficient and that the multiplication-based scoring systems performed better than their sum-based counterparts. The proposed method could be used in the future to assess a great diversity of scoring systems.

Network interactions and performance of a multi-function IEC 61850 process bus

New substation technology, such as non-conventional instrument transformers,and a need to reduce design and construction costs, are driving the adoption of Ethernet based digital process bus networks for high voltage substations. Protection and control applications can share a process bus, making more efficient use of the network infrastructure. This paper classifies and defines performance requirements for the protocols used in a process bus on the basis of application. These include GOOSE, SNMP and IEC 61850-9-2 sampled values. A method, based on the Multiple Spanning Tree Protocol (MSTP) and virtual local area networks, is presented that separates management and monitoring traffic from the rest of the process bus. A quantitative investigation of the interaction between various protocols used in a process bus is described. These tests also validate the effectiveness of the MSTP based traffic segregation method. While this paper focusses on a substation automation network, the results are applicable to other real-time industrial networks that implement multiple protocols. High volume sampled value data and time-critical circuit breaker tripping commands do not interact on a full duplex switched Ethernet network, even under very high network load conditions. This enables an efficient digital network to replace a large number of conventional analog connections between control rooms and high voltage switchyards.

An analysis of corporate related-party disclosure in the Asia-Pacific region

Related-party (RP) transactions are said to be commonly used opportunistically in business and contribute to corporate failures. While periodic disclosure is widely accepted as an effective means of monitoring such transactions, research is scant, particularly in countries where business dealings may be more susceptible to corruption. This study investigates the nature and extent of corporate RP disclosures across six countries in the Asia-Pacific region. The key finding indicates that companies in countries with stronger regulatory enforcement, shareholders’ protection, and control for corruption, have more transparent RP disclosures. This evidence potentially contributes to reforms aimed at strengthening RP disclosure and compliance.

Variation in leaf morphology of the invasive cat's claw creeper Dolichandra unguis-cati (Bignoniaceae)

The invasive liana cat’s claw creeper Dolichandra unguis-cati (L.) L.G. Lohmann (syn. Macfadyena unguis-cati (L.) A.H. Gentry) exhibits intraspecific variation in leaf morphology, but this is rarely noted in the published literature. The present study documents variation in leaf morphology in two forms of the species that occur in Australia (long pod and short pod). Leaf morphology is compared between the two forms and the position of the shoots (trunk and ground) at the only two sites in which they co-occur. Leaves were categorised on the basis of leaflet number and the presence or absence of tendrils. Simple leaves were produced mainly on shoots growing along the ground and were more abundant in the short-pod form. Long-pod plants were dominated by bifoliate leaves with tendrils. Cat’s claw creeper exhibits considerably wider variation in leaf morphology than recorded previously. Variations in leaf morphology may be linked to differences in the genotype, developmental stage and plastic responses of the plants. Understanding these variations may have implications for taxonomic delimitation and improved management, particularly biological control involving leaf-feeding insects.

A proteomic view into infection of greyback canegrubs (Dermolepida albohirtum) by Metarhizium anisopliae

Metarhizium anisopliae is a naturally occurring cosmopolitan fungus infecting greyback canegrubs (Dermolepida albohirtum). The main molecular factors involved in the complex interactions occurring between the greyback canegrubs and M. anisopliae (FI-1045) were investigated by comparing the proteomes of healthy canegrubs, canegrubs infected with Metarhizium and fungus only. Differentially expressed proteins from the infected canegrubs were subjected to mass spectrometry to search for pathogenicity related proteins. Immune-related proteins of canegrubs identified in this study include cytoskeletal proteins (actin), cell communication proteins, proteases and peptidases. Fungal proteins identified include metalloproteins, acyl-CoA, cyclin proteins and chorismate mutase. Comparative proteome analysis provided a view into the cellular reactions triggered in the canegrub in response to the fungal infection at the onset of biological control.