Optimal barrier subdivision for Kramers' escape rate

We examine the effect of subdividing the potential barrier along the reaction coordinate on Kramers' escape rate for a model potential. Using the known supersymmetric potential approach, we show the existence of an optimal number of subdivisions that maximises the rate.Comment: 8 pages, 3 figures, To appear in Pramana - J. Phys, Indi

Effect of Landauer's blowtorch on the equilibration rate in a bistable potential

Kinetic aspect of Landauer's blowtorch effect is investigated for a model double-well potential with localized heating. Using the supersymmetric approach, we derive an approximate analytical expression for the equilibration rate as function of the strength, width and the position of the hot zone, and the barrier height. We find that the presence of the hot zone enhances the equilibration rate, which is found to be an increasing function of the strength and width of the hot zone. Our calculations also reveal an intriguing result, namely, that placing the hot zone away from the top of the potential barrier enhances the rate more than when it is placed close to it. A physically plausible explanation for this is attempted. The above analytical results are borne out by detailed numerical solution of the associated Smoluchowski equation for the inhomogeneous medium.Comment: 15 pages in LaTeX format and 6 figures in postscript E-Mail : [email protected] [email protected]

Multilocular Cystic Nephroma of the kidney in a young adult: case report

We report the case of a 20-year-old female patient who presented with a left abdominal mass of 4 years duration. Ultrasonography showed a multicystic left renal mass, and intravenous urography revealed a non-functioning kidney. Based on these findings a multicystic renal cell carcinoma was suspected and radical nephrectomy was performed. Histological examination of the resected specimen confirmed the diagnosis of multilocular cystic nephroma. This is a very rare renal tumor with only few cases described in the literature. Based on our case and a review of the literature the epidemiology, pathogenesis and diagnostic features are discussed.Key Words: Cystic nephroma, renal cell carcinoma, kidne

Practices in the Teaching of Listening in Grade 9 EFL Classrooms of Mote Secondary School

This study was designed to examine the practices in the teaching of listening in Grade 9 EFL classrooms of Mote Secondary School. The study employed a descriptive survey design to attain the objective. The research used 108 Grade 9 students and 6 English language teachers who were teaching English as subjects of the study. To gather proper data for the study, questionnaire (both for students and teachers) and classroom observations were used. The data collected through questionnaire and classroom observations were analyzed both quantitatively and qualitatively. The findings of the study indicated that the teaching of listening in EFL classrooms (and that of English language teaching in general) is at a critical risk since teachers do not use the pre-listening, the while-listening and the post-listening activities to promote and facilitate the development of listening comprehension and because they never adapt or adopt activities which help students learn the skill effectively. Hence, the study recommended that an intensive training on classroom teaching and on the teaching materials which are currently in use are required for EFL teachers

Inter Simple Sequence Repeat (ISSR) analysis of wild and cultivated rice species from Ethiopia

The genetic diversity of three wild rice populations of Ethiopia along with three cultivated rice populations were studied using Inter simple sequence repeats (ISSRs) as a molecular marker. A total of 93 clear and reproducible bands were generated using four dinucleotides and two tetra nucleotides primers. Both UPGMA and neighbor joining trees were constructed for each individual and population using Jaccard’s similarity coefficient. The trees and PCO clearly indicated six distinct groups which are based on populations of origin. Oryza glaberrima, Oryza sativa and NERICA-3 clustered as a major group while Oryza barthii and Oryza longistaminata were clustered as the second major group. Such clustering of O. glaberrima with O. sativa and NERICA-3 is considered to be due to genetic admixture of O. glaberrima with O. sativa. The over all gene diversity and percent polymorphisms were found to be higher in wild rice (0.14; 38.3 respectively) than in cultivars (0.11; 28.3 respectively). The Shannon’s diversity index also confirmed the existence of higher diversity in wild rice populations than cultivated species. Furthermore, partitioning of the Shannon’s diversity showed that the majority of the variations were observed among population (63%). Similarly, AMOVA demonstrate highly significant (P = 0.00) genetic differences among populations (72.9) than within populations (27.1).Key words: Genetic diversity, wild rice populations, cultivated rice, Oryza sativa, Oryza glaberrima, NERICA, ISSR

Experimental study of physical, chemical and mechanical properties of enset and sisal fibers

The properties of composites depend on type and properties of the fiber, fiber structure and treatment. In this study, effects of NaOH treatment on the physical, chemical and mechanical properties of fibers collected from South-West Ethiopia were investigated using untreated, 5% and 10% alkali treated enset and sisal fibers. The effects of NaOH on diameter, moisture absorption, density, lignin and hemicellulose was experimentally studied. In addition, tenacity of both fibers was investigated by using optical microscopy, Fourier transform infrared spectroscopy and single fibers tensile strength tester. The 5% and 10% NaOH treatment significantly improved the moisture absorption and diameters. The moisture absorption of 5% and 10% NaOH treated enset fibers improved by 33% and 34%, while the same treatment on sisal fibers improved the moisture absorption by 30% and 40% respectively. The 5% NaOH treated enset and sisal fiber showed better tenacity, which is an indication of the tensile strength of single fiber, than untreated and 10% NaOH treated fibers. Improving moisture content, diameter, lignin and hemicellulose contents of the fibers contributes to better bonding as interlock with the matrix materials enhancing the mechanical properties of composites.publishedVersio

Spatiotemporal information extraction from a historic expedition gazetteer

Historic expeditions are events that are flavored by exploratory, scientific, military or geographic characteristics. Such events are often documented in literature, journey notes or personal diaries. A typical historic expedition involves multiple site visits and their descriptions contain spatiotemporal and attributive contexts. Expeditions involve movements in space that can be represented by triplet features (location, time and description). However, such features are implicit and innate parts of textual documents. Extracting the geospatial information from these documents requires understanding the contextualized entities in the text. To this end, we developed a semi-automated framework that has multiple Information Retrieval and Natural Language Processing components to extract the spatiotemporal information from a two-volume historic expedition gazetteer. Our framework has three basic components, namely, the Text Preprocessor, the Gazetteer Processing Machine and the JAPE (Java Annotation Pattern Engine) Transducer. We used the Brazilian Ornithological Gazetteer as an experimental dataset and extracted the spatial and temporal entities from entries that refer to three expeditioners’ site visits (which took place between 1910 and 1926) and mapped the trajectory of each expedition using the extracted information. Finally, one of the mapped trajectories was manually compared with a historical reference map of that expedition to assess the reliability of our framework

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Effects of nitrogen, phosphorus and vermicompost fertilizers on productivity of groundnut (Arachis hypogaea L.) in Babile, Eastern Ethiopia

ArticleThough groundnut (Arachis hypogaea L.) is a main cash crop for smallholder farmers in several districts of eastern Ethiopia, its yield is very low. Farmers apply little or no fertilizers to grow the crop possibly because no generic or recommended fertilizers rates available for farmers. Therefore field experiments were conducted for two consecutive cropping seasons in Babile district, to prove the hypothesis that one of the major factors that severely reduce the yield of the crop was lack of nutrients in the soil with the objective of investigating the effects of applying mineral NP fertilizers and vermicompost on the productivity of improved groundnut variety ‘BaHa-Gudo’. The experiment was 3 × 3 × 3 factorial with three replications laid down in a randomized complete block design comprising nitrogen (0, 23 and 46 kg N ha-1 ), phosphorus (0, 46 and 92 kg P2O5 ha-1 ) and vermicompost (0, 2.5 and 5 t vermicompost ha-1 ). The data on crop growth, nodulation and yield were collected and subjected to analysis of SAS 9.2 software. Means separation were made using Duncans Multiple Range Test (DMRT) at 5% level of significance. The results revealed that growth, yield attributes, and yields were significantly (P < 0.01) affected by the main and interactions effect of the treatments. The pod yield obtained from combined application of 46: 46 kg N: P2O5 ha-1 and 2.5 t vermicompost ha-1 exceeded the pod yield produced from nil application of fertilizers by about 100%. The economic analysis also indicated that the highest marginal rate of return (671%) and net benefit ($ 1,830) ha-1 were obtained from combined application of 46: 46 kg N: P2O5 ha-1 and 2.5 t vermicompost ha-1 . From the results it could be concluded that applying the aforementioned doses of fertilizers combination would enable farmers increase productivity of groundnut so as to enhance farmers’ income and livelihoods

Exploration of Mechanical Properties of Enset–Sisal Hybrid Polymer Composite

Enset and sisal fibers are among the most widely used reinforcement to fabricate natural fiber-based composite materials. Hand lay-up techniques were employed in this study to fabricate enset–sisal (E/S) hybrid fiber composite with volume ratios of 100/0, 75/25, 50/50, 25/75, and 0/100 and constant polyester resin. The tensile, flexural, impact strength, water absorption and morphological properties of the fabricated composite were investigated experimentally. The effects of hybridization to volume ratio were determined and the results show that hybrid composites excel in mechanical properties, compared with single composites. For better mechanical properties, the enset fiber has been hybridized with sisal fiber. Tensile and flexural strengths were enhanced by 47.3% and 41.03%, respectively, at 50/50 E/S volume ratio compared with 100/0 E/S composite. The impact strength of sisal fiber composite was improved by adding enset fiber in the composites. The inherent benefits and limitations of these two fibers were balanced out by each other in a positive way. While sisal fiber helped the composite intermesh of tensile, flexural, and reduction of water absorption, enset ensured impact strength. Morphological analysis was carried out in order to observe the fracture behavior and fiber pull-out of the samples by means of scanning electron microscopy.publishedVersio