First psychological research at Arctowski station were conducted in 1979. In the nineties the American team under direction of prof. L. Palinkas conducted research in order to determine the patterns of multicultural psychosocial adaptation. The author discusses stress as a result of isolation and extreme conditions.
In this fast-changing environmental condition, the effect of fossil fuel in vehicle is a significant concern. Many sustainable sources are being studied to replace the exhausting fossil fuel in most of the countries. This paper surveys the types of electric vehicle’s energy sources and current scenario of the onroad electric vehicle and its technical challenges. It summarizes the number of state-of-the-art research progresses in bidirectional dcdc converters and its control strategies reported in last two decades. The performance of the various topologies of bidirectional dc-dc converters is also tabulated along with their references. Hence, this work will present a clear view on the development of state-of-the-art topologies in bidirectional dc-dc converters. This review paper will be a guide for the researchers for selecting suitable bidirectional traction dc-dc converters for electric vehicle and it gives the clear picture of this research field.
Stem canker and black scurf of potato (Solanum tuberosum L.) caused by Rhizoctonia solani Kühn are important and epidemic diseases in potato-growing regions worldwide, including Iran. In this study, 120 isolates were retrieved from infected stem canker from six potato- growing regions in Iran (Isfahan, Ardebil, Fars, Hamedan, Kurdestan and Kerman). Out of these, 30 isolates were selected as representatives for genetic and virulence analysis. The isolates were analyzed by one sequence analyzes of the ITS-rDNA region, random amplified polymorphic DNA (RAPD) and inter-simple sequence repeat (ISSR), as well as virulence studies. Based on sequence analysis of the ITS-rDNA region, all 30 isolates were assigned to the anastomosis group (AG) and all were assigned to AG-3 PT. Cluster analysis using the unweighted pair group method with the arithmetic averages (UPGMA) method for both RAPD and ISSR markers revealed that they were divided into three main groups, with no correlation to geographical regions of the isolates. Pathogenicity tests showed that all isolates were pathogenic on potato cv. Agria; however, virulence variability was observed among the isolates. The grouping based on RAPD analysis and virulence variability was not correlated.
RNA extraction involves several main stages, regardless of the method of extraction: homogenization, effective denaturation of proteins from RNA, inactivation of ribonuclease and removal of any DNA, protein, and some residual contamination. Isolation of undamaged intact RNA is challenging when the related tissue contains high levels of polysaccharides and phenols. Several efforts have been made towards the comparison and optimization of extraction and purification methods for RNA from plant tissues. This is dictated by the necessity of obtaining RNA of a good quality and in a sufficient quantity for further molecular analyzes. Plant storage organs (such as bulbs or seeds) rich in polysaccharide and polyphenolic compounds present distinct challenges for total RNA isolation. Such components, considered in this case as contamination, may bind and co-precipitate with nucleic acids and negatively affect later assays. Since standard routine protocols yield unacceptable results in bulbs, we have designed a new method for RNA extraction. We used two modified procedures (based on CTAB and sarkosyl reagents) of RNA extraction from so called “difficult plant material” and compared them to a popular RNA isolation base on the column isolation kit and TriPure reagent. Our modified protocols dealt with problems of both RNA degradation and low yield caused by co-purification with polysaccharides present in plant bulbs. In this study we have shown that improvement of the CTAB and sarkosyl method with a lyophilization step of plant tissues leads to isolation of high quality RNA from difficult material like storage organs of bulbous plants. The main changes in the procedure compared to the previously described methods concerned the different order of lithium chloride and sodium acetate addition, lithium chloride concentration increase and modification of centrifugation conditions. Gel electrophoresis and spectrophotometer analysis confirmed the high quality and integrity of the obtained RNA. The modified procedures allowed for obtaining a satisfying amount of RNA concentration in the range from 280 to 950 ng/μl depending on the plant species. Thus, the demonstrated RNA isolation methods are efficient and can be used for plant material rich in polysaccharides, such as bulbs.
Field surveys were undertaken in 1997–1999 across five ecological zones in Nigeria to collect isolates of Maize streak virus (MSV), genus Mastrevirus. Apart from maize (Zea mays L.), 15 other grass species were found with MSV symptoms in Nigeria. These hosts showed two types of symptoms viz: mild (with or without mottle) or severe (typical symptoms in maize). When Cicadulina storeyi China was used to attempt transmission of these isolates of MSV to seedlings a susceptible maize hybrid CML 254 X CML 247, six isolates were not transmissible to maize. Seven isolates that were transmissible to maize produced mild symptoms. The viral agents causing typical or severe streak symptoms in Axonopus compressus (Sw.) P. Beauv., Brachiaria distichophylla (Trn.) Stapf, Dactyloctenium aegyptium (Linn.) P. Beauv. and Setaria barbata (Lam.) Kunth produced symptoms that were typical of MSV in farmers fields, when transmitted to maize. Out of 33 plant species that seedlings were challenged with MSV, only eight proved susceptible. Four of them showed mild symptoms while the other four showed severe symptoms of MSV. Only three isolates collected during the surveys did not react with a MSV polyclonal antiserum produced in mice in Double Antibody Sandwich-Enzyme-Linked Immunosorbent Assay (DAS-ELISA). These isolates were found in Andropogon gayanus Kunth (from Kaduna), Thelepogon elegans Roth ex Toem & Schult (from Kadawa) and Rottboellia cochinchinensis (Lour.) Clayton (from Jos) exhibited mild streak/mottle symptoms. Specific monoclonal antibodies, raised against MSV, reacted with 12 out of 25 samples tested. The DAS-ELISA data also showed significant variation in concentration of the virus in the different plant hosts. The relationship dendogram through SDS-PAGE among eight purified virus isolates show 55–90% variation. At 0.55 coefficient of similarity, the dendogram divided the samples into two groups while at 0.9 coefficient of similarity, the 8 isolates were identified as distinct genetic entities.
The present paper describes a new architecture of a high-voltage solid-state pulse generator. This generator combines the two types of energy storage systems: inductive and capacitive, and consequently operates two types of switches: opening and closing. For the opening switch, an isolated gate bipolar transistor (IGBT) was chosen due to its interesting characteristics in terms of controllability and robustness. For the closing switch, two solutions were tested: spark-gap (SG) for a powerful low-cost solution and avalanche mode bipolar junction transistor (BJT) for a fully semiconductor structure. The new architecture has several advantages: simple structure and driving system, high and stable controllable repetition rate that can reach 1 kHz, short rising time of a few nanoseconds, high gain and efficiency, and low cost. The paper starts with the mathematical analysis of the generator operation followed by numerical simulation of the device. Finally add a comma the results were confirmed by the experimental test with a prototype generator. Additionally, a comparative study was carried out for the classical SG versus the avalanche mode BJT working as a closing switch.