Cooperative and Antagonistic Contributions of Two Heterochromatin Proteins to Transcriptional Regulation of the Drosophila Sex Determination Decision

Eukaryotic nuclei contain regions of differentially staining chromatin (heterochromatin), which remain condensed throughout the cell cycle and are largely transcriptionally silent. RNAi knockdown of the highly conserved heterochromatin protein HP1 in Drosophila was previously shown to preferentially reduce male viability. Here we report a similar phenotype for the telomeric partner of HP1, HOAP, and roles for both proteins in regulating the Drosophila sex determination pathway. Specifically, these proteins regulate the critical decision in this pathway, firing of the establishment promoter of the masterswitch gene, Sex-lethal (Sxl). Female-specific activation of this promoter, SxlPe, is essential to females, as it provides SXL protein to initiate the productive female-specific splicing of later Sxl transcripts, which are transcribed from the maintenance promoter (SxlPm) in both sexes. HOAP mutants show inappropriate SxlPe firing in males and the concomitant inappropriate splicing of SxlPm-derived transcripts, while females show premature firing of SxlPe. HP1 mutants, by contrast, display SxlPm splicing defects in both sexes. Chromatin immunoprecipitation assays show both proteins are associated with SxlPe sequences. In embryos from HP1 mutant mothers and Sxl mutant fathers, female viability and RNA polymerase II recruitment to SxlPe are severely compromised. Our genetic and biochemical assays indicate a repressing activity for HOAP and both activating and repressing roles for HP1 at SxlPe

Real power loss allocation using modified nodal equations

This paper proposes a new method to identify the real power loss allocations caused by generators and loads using modified nodal equations. Based on solved load flow results, the method partitions the Y-bus matrix to decompose the current of the load buses as a function of the generators' currents and load voltages. Then it uses the modified admittance matrix to decompose the load voltage dependent term into components of generator dependent terms. By using these two decompositions of current and voltage terms, the real power loss allocations caused by the generators are obtained. Likewise, in case of real power loss allocations caused by the loads, the generator voltage dependent term can be decomposed into components of load dependent terms. Similarly, by using these two decompositions, the real power loss allocations caused by the loads are determined. The advantages of the proposed methodology are demonstrated by using a simple 5-bus system and the modified IEEE 30-bus system. The proposed methodology provides reasonable and accurate results for real power loss allocation

Implementation of artificial neural network to allocate transmission usage in bilateral trade power market

This paper proposes a method to allocate transmission usage for simultaneous bilateral transactions using artificial neural network (ANN). The basic idea is to use supervised learning paradigm to train the ANN, utilising a conventional circuit theory method as the trainer. Based on solved load flow and followed by a procedure to decouple the line usage on the basis of transaction pairs, the description of inputs and outputs of the training data for the ANN is obtained. The structure of artificial neural network is designed to assess the extent of line usage by each generator while supplying to their respective customer. Most commonly used feed forward architecture has been chosen for the proposed ANN based transmission usage allocation technique. Almost all the system variables obtained from load flow solutions are utilized as an input to the neural network. Moreover, tan-sigmoid activation functions are incorporated in the hidden layer to realize the non linear nature of the transmission usage allocation. The proposed ANN provides promising results in terms of accuracy and computation time. A 6-bus and also the modified IEEE 14-bus network is utilized as test systems to illustrate the effectiveness of the ANN output compared to that of conventional methods

A novel reactive power transfer allocation method with the application of artificial neural network

This paper proposes a novel method to identify the reactive power transfer between generators and load using modified nodal equations. Based on the solved load flow solution and the network parameters, the method partitioned the Y-bus matrix to decompose the current of the load buses as a function of the generator’s current and voltage. These decomposed currents are then used independently to obtain the decomposed load reactive power. The validation of the proposed methodology is demonstrated by using a simple 5-bus system. It further focuses on creating an appropriate artificial neural network (ANN) for practical 25-bus equivalent power system of south Malaysia to illustrate the effectiveness of the ANN output compared to that of the modified nodal equations method. The basic idea is to use supervised learning paradigm to train the ANN. Most commonly used feedforward architecture has been chosen for the proposed ANN reactive power transfer allocation technique. The descriptions of inputs and outputs of the training data for the ANN is easily obtained from the load flow results and developed reactive power transfer allocation method using modified nodal equations respectively. Almost all system variables obtained from load flow solutions are utilized as an input to the neural network. The ANN output provides promising results in terms of accuracy and computation time

History of Gumboro (infectious bursal disease) in Pakistan

Infectious Bursal Disease is the second important viral disease of poultry which affects the young growing pullets. The end fate appears in huge economic losses to poultry industry. Throughout the world, cheapest source of animal protein is chicken meat. It was initially reported in Europe; soon it spreads worldwide and causes drastic losses. In Pakistan, first of all this disease was reported in 1971. It is the first review to track the IBDV history in Pakistan. It provides comprehensive details of forty-six years researchers work in controlling this important disease. Different scientists worked to fill the gap areas to achieve the goal. Present review covers all the research aspects being explored in Pakistan since first report. Keywords: Infectious bursal disease, Forty-six years, Pakista