Granular transport in a horizontally vibrated sawtooth channel

We present a new mode of transport of spherical particles in a horizontally vibrated channel with sawtooth shaped side walls. The underlying driving mechanism is based on an interplay of directional energy injection transformed by the sidewall collisions and density dependent interparticle collisions. Experiments and matching numerics show that the average particle velocity reaches a maximum at 60% of the maximal filling density. Introducing a spatial phase shift between the channel boundaries increases the transport velocity by an order of magnitude.Comment: 5 pages, 8 figure

Product Bundling: Impacts of Product Heterogeneity and Risk Considerations

Bundling has been extensively studied in the literature and its benefits have been manifested through three perspectives of achieving better price discrimination, helping to save costs, and preserving the power for deterring a potential entrant. In this study, we examine two aspects of bundling which have not been studied before. We examine the impact of product heterogeneity on bundling decisions. We also address risk considerations in a bundling problem. Specifically, we consider a retailer who has the option of selling a bundle of two products (pure bundling policy), or selling the products separately (no-bundling policy). The retailer could also face a product selection problem for which we consider three scenarios of choosing two products with perfectly positively correlated, perfectly negatively correlated or independent reservation prices. We use a Mean-Variance approach to include retailer’s risk through her profit variability when maximizing the expected value of profit. We characterize the conditions under which a policy or scenario performs better than the others under the influence of product heterogeneity and/or retailer’s risk aversion. Among other findings, we show that optimal bundling price chosen by a risk-averse decision maker cannot be larger than the one chosen by a risk neutral decision maker

Iranian Stroke Model-How to Involve Health Policymakers

Stroke in Iran, with more than 83 million population, is a leading cause of disability and mortality in adults. Stroke has higher incidence in Iran comparing the global situation and unfortunately the onset age of first ever stroke is dropping about 10 years.1 Intravenous thrombolysis, as an approved treatment in ischemic stroke, has been used only in some university or private hospitals in Iran since 2008.2 The main limit for this therapy in Iran was the lack of coverage by health insurance companies for tPA. A project for situation analysis of stroke cases entering to Imam Reza Hospital, a tertiary university hospital in North-West of Iran, was performed in 2010 by Neurosciences Research Center. The percentage of cases referring on time and eligible for thrombolysis, barriers, pitfalls and delay gaps in the hospital were detected.3 After analyzing and involving all the related authorities & departments of the Tabriz University of Medical Sciences and performing a maneuver, thrombolysis in all eligible stroke cases was systematically started as pilot in the hospital since 2010. Other centers such as Firoozgar Hospital in Tehran, Ghaem Hospital in Mashhad, Namazi Hospital in Shiraz, and Alzahra Hospital in Isfahan were active in thrombolysis but non-systematically

THE IMPACT OF USING AUDIO-VISUAL AIDS ON TEACHING LISTENING AMONG IRANIAN PRE-INTERMEDIATE EFL LEARNERS

The present study aimed to investigate the effects of audio-visual aids on teaching listening among Iranian pre-intermediate EFL learners. In order to fulfill the objectives of the study, the researcher selected 40 homogeneous pre-intermediate students and divided them into two equal groups. The two groups were the experimental groups (n=20) and a control groups (n=20). Then a listening comprehension pre-test was administered to assess the participants' listening comprehension at the beginning of the course. After the pre-test, the researcher practiced the treatment on the experimental groups. During the treatment sessions, The EG was taught by using authentic video, while the CG used audio Compact Disc (CD) as the teaching aid most often used by ESL teachers in teaching listening. After the treatment which took 15 sessions, the researcher administered a post-test to find out the effect of audio-visual aids on teaching listening. When the data were collected, Independent and Paired Samples T-tests were run to analyze them. The results showed that the EG students taught by using authentic video achieved higher results in listening than the CG ones taught by audio compact disc (CD). The implications of the study suggest that using audio-visual aids can help EFL learners to develop their listening comprehension

INVESTIGATING EXPERIENCED AND NOVICE ENGLISH LANGUAGE LEARNERS` PERCEPTIONS of MOST USEFUL VOCABULARY LEARNING STRATEGIES (VLS)

Purpose of the study: This article report’s findings from a study on the differences and similarities between experienced and novice English language learners with regards to their personal use of VLS. Methodology: Closed questionnaire and semi-structure interviews were applied to collect the data. The questionnaire was distributed among 60 (30 experienced learners and 30 novice learners). In addition, 20 learners (10 experienced learners and 10 novice learners) were asked to answer the questions in the interview. Therefore, descriptive statistics, U Mann Whitney test, and independent-sample t-test were run to compare and analyzed the data. Main Findings: The finding showed that there were significant differences between experienced and novice learners’ thoughts towards vocabulary learning strategies and experienced learners used vocabulary learning strategies while learning new words in English language learning. Applications of this study: If the learners are taught how to use each strategy correctly, their understanding of the language can naturally be improved. Moreover, VLS is beneficial throughout the process of vocabulary learning which makes learners more independent and allows teachers to focus on other things as well. Novelty/Originality of this study: To the best of researchers’ knowledge, no study has been done on investigating Iranian experienced and novice English language learners` perceptions towards most useful vocabulary learning strategies (VLS)

Synthesis and Molecular Docking of 2-Methyl-5-nitro-1-(2-(halophenoxy)ethyl)-1H-imidazole Derivatives as Potential Biologically Active Agents

Introduction: Nowadays, due to many years of taking antibacterial, antifungal and antiprotozoal drugs, human has faced drug resistance. It is predicted that death caused by drug resistance will surpass the death from cancer in future.  Therefore, studies done by world’s pharmacy researchers have been extended to synthesis of new compounds which potentially influence micro-organisms and protozoa. One of the acceptable methods of medicinal chemistry researches is propagation of new molecules according to known previous structures. One of these structures is 5-nitro-2-methyl imidazole that is a component of some drugs such as Metronidazole, Tinidazole and Secnidazole. In the present study we propagated this molecule further and synthesized some of the new derivatives of this family. Subsequently, according to the previous reports for similar compounds and their ability to link to FabH enzyme, new structures were surveyed using molecular docking approaches. Methods and Results: First, the compounds 5a-e were synthesized. The structures of synthesized compounds were determined by IR, 1HNMR and 13CNMRspectra. Then, the components were drawn in ChemDraw software. The structures were energetically optimized by Open Babel software and they were saved in AutoDock software as ligand with PDB format. Then the receptor structure (FabH) was obtained from Protein Data Bank (www.rcsb.org) and refined for docking simulation. AutoDock 4.2 software was applied for molecular docking approach. Results: IR, 1HNMR and 13CNMR spectra indicated that all the derivatives were successfully synthesized in laboratory and they had an appropriate intermolecular binding energy upon docking modeling. Conclusion: According to the docking results, all the synthesized derivatives were accommodated properly in the active site of FabH enzyme and they made hydrogen and hydrophobic bondings with the amino acids. Amongst the synthesized compounds, compound 5b showed the best inhibition activity against enzyme FabH due to its lowest ΔG and highest lipophilicity

The Comparative Effect of Content-based Language Teaching and Task-based Language Teaching on Iranian Pre-intermediate EFL Learners’ Reading Skill

This study aimed to explore the effectiveness of TBLT and CBLT on Iranian Pre-intermediate EFL learners’ reading skill. Forty pre-intermediate EFL learners were pretested and then homogenized and then divided to 2 classes, namely TBLT group and CBLT group. The CBLT group received reading instruction based on CBLT, while the RBLT group received reading instruction based on TBLT. After the treatment, both groups received a posttest. After analyzing the data through using paired and independent samples t-tests, it was shown that both groups (i.e., TBLT & CBLT) progressed considerably with regard to their reading skill from the pretest to the posttest, with the task-based language teaching group outperformed the content-based language teaching group in the posttest. It can be deduced that both task-based language teaching and content-based language teaching methods are effectual in reading comprehension instruction to Iranian Pre-intermediate EFL learners, with TBLT method being more effective

Selecting an Appropriate Express Railway Pavement System Using VIKOR Multi-Criteria Decision Making Model

A gigantic evolution has been brought about in the railway transportation by the emergence of the expressways as the most efficient method of carrying passengers within short and medium interurban distances. Various types of expressway pavements have been offered during the recent years. A considerable amount of the repair and maintenance costs in railroad sector is allocated to the constituents forming the pavements. No thorough and precise research has been so far conducted on the railroad expressways featuring traffics with speeds over 250 km/h and the extant information have merely been trivial changes in the procedures existent for speeds below 200 km/h and these are not deemed of much use and applicability. Thus, the current research paper is devoted to the investigation and selection of express railways pavement system design using VIKOR method. The evaluations indicate that the commencement of the first high-speed train work in 1964 in Japan marked a turning point in the railroad passenger transportation in the world. The development of the high-speed railway transportation is enumerated as an important revolution helping the railroads retake their crucial role in passenger transportation in such a way that it is found overtaking the roadway and aerial transportation and even exposing some airlines to real crisis. The high-speed railroad is undergoing an intensive expansion worldwide and as a safe, sound and sustainable transportation system, it has well proved its role in the social and economic development of the nations