Strategies-based instruction and Libyan adult EFL learners : An action research study.

An area which has gained ground in the field of second language acquisition research for over three decades is the study of language learning strategies (LLS). Learning strategies refer to special actions taken by learners to make learning easier, faster, more self-directed, more effective and more transferable to new situations (Oxford, 1990, 2003, 2011). The favourable results of many intervention studies have provided a strong indication that the use of LLS is likely to lead to achievement in the foreign language and also contribute to learner autonomy.The purpose of this study is to investigate the outcome of providing Libyan adult learners of English with formal training in the use of LLS. This training took the form of strategies-based instruction (SBI) within a collaborative action research framework. The research examines the contribution that SBI might offer the learners in relation to the development of all four language skills (i.e. listening, speaking, reading, and writing) and the development of learner autonomy. The impact of SBI on teacher roles and professionalism was also part of the investigation.The investigation as a case study relied on 61 student participants from three different levels of proficiency: elementary, pre-intermediate and intermediate levels. To implement the SBI approach, all three classes followed the four phases of the Strategies-Based Instructional and Assessment Model which was specifically designed for the current investigation. The model, which adopted a multi-method approach to data collection, was implemented with the collaboration of three different class teachers.Findings of the study revealed that the SBI intervention helped raise both the teachers' and students' awareness of LLS. The programme increased students' overall strategy use and had an impact on their learning efforts and language skill improvement. The development of learner autonomy (closely associated with an increase in metacognitive and social awareness) was a major outcome of the study. Results also showed that the study had an impact on the three participant teachers in terms of professional development having implemented SBI for the first time and also as a result of their collaboration in action research. A construct of teacher beliefs was revealed and attitude change particularly towards learner autonomy was also noticed among the teachers

Prevalence, species differentiation, haemolytic activity, and antibiotic susceptibility of aeromonads in untreated well water

The use of untreated water for drinking and other activities have been associated with intestinal and extraintestinal infections in humans due to Aeromonas species. In the present study aeromonads were isolated from 48.7% of 1,000 water samples obtained from wells and other miscellaneous sources. Aeromonas species were detected in 45% of samples tested in spring, 34.5% in summer, 48% in autumn and 60% of samples tested in winter. Speciation of 382 strains resulted in 225 (59%) being A. hydrophila, 103 (27%) A. caviae, 42 (11%) A. sobria and 11 (3%) atypical aeromonads. Of 171 Aeromonas strains tested for their haemolytic activity, 53%, 49%, 40% and 37% were positive in this assay using human, horse, sheep and camel erythrocytes respectively. The results obtained indicate that potentially enteropathogenic Aeromonas species are commonly present in untreated drinking water obtained from wells in Libya (this may also apply to other neighbouring countries) which may pose a health problem to users of such water supplies. In addition, ceftriaxone and ciprofloxacin are suitable drugs that can be used in the treatment of Aeromonas-associated infections, particularly, in the immunocompromised, resulting from contact with untreated sources of water

MIMO Channel Gain Mechanisms Relative to SISO Channel

In contrast to the rest of wireless communication technologies, multiple-input multiple-output (MIMO) technology enjoys different gain mechanisms that make it very attractive for reliable high data rate wireless communications. This paper presents a study on these gain mechanisms with particular emphasis on the case of high average received signal to noise ratio (SNR) where the MIMO system deployment is most promising. We write the MIMO channel capacity in terms of gains relative to a single- input single-output (SISO) wireless channel. Doing so, spatial multiplexing gain and power gain of MIMO wireless channels become more insightful. Based on this analysis a switching scheme between spatial multiplexing and transmit diversity is proposed. We support our discussion with numerical results which show that under a high data rate spatial multiplexing scheme the contribution of each gain mechanism to the total channel capacity depends on the channel Ricean factor, the average received SNR, and the MIMO system size. The proposed switching scheme gives about 2 dB gain in bit error rate performance relative to the spatial multiplexing mode

Multipath Detection Using Boolean Satisfiability Techniques

A new technique for multipath detection in wideband mobile radio systems is presented. The proposed scheme is based on an intelligent search algorithm using Boolean Satisfiability (SAT) techniques to search through the uncertainty region of the multipath delays. The SAT-based scheme utilizes the known structure of the transmitted wideband signal, for example, pseudo-random (PN) code, to effectively search through the entire space by eliminating subspaces that do not contain a possible solution. The paper presents a framework for modeling the multipath detection problem as a SAT application. It also provides simulation results that demonstrate the effectiveness of the proposed scheme in detecting the multipath components in frequency-selective Rayleigh fading channels

Numerical Assessment of Electromagnetic Radiated Emissions from an UWB Radiators Located Inside Metallic Enclosures with Small Air-Flow Openings

Shielding effectiveness of electronic devices and computing devices is  essential at design stages. Devices should pass electromagnetic interference/compatibility tests for certification purposes. In this paper, we investigate the electromagnetic radiation leakage from modern personal computers and mobile electronic devices due to an ultra-wide band source of noise. Openings and slots are always unavoidable in electronic devices, for instance openings in computers for air-flow and heat dissipation. Three different designs of enclosure’s covers with apertures are modeled for this purpose. The three covers cases comprise the use of rectangular arranged circular holes, hexagonal arranged circular holes, and square openings. For comparison purposes, a shielded enclosure with no openings is considered. The shielding effectiveness is numerically assessed here by capturing electric field strength that is modeled using probes located at two different distances, near- and far-away from the metallic enclosure

A real-time monitoring platform for distributed energy resources in a microgrid—pilot study in oman

This article presents the development of a platform for real-time monitoring of multi-microgrids. A small-scale platform has been developed and implemented as a prototype, which takes data from various types of devices located at a distance from each other. The monitoring platform is interoperable, as it allows several protocols to coexist. While the developed prototype is tested on small-scale distributed energy resources (DERs), it is done in a way to extend the concept for monitoring several microgrids in real scales. Monitoring strategies were developed for DERs by making a customized two-way communication channel between the microgrids and the monitoring center using a long-range bridged wireless local area network (WLAN). In addition, an informative and easy-to-use software dashboard was developed. The dashboard shows real-time information and measurements from the DERs—providing the user with a holistic view of the status of the DERs. The proposed system is scalable, modular, facilitates the interoperability of various types of inverters, and communicates data over a secure communication channel. All these features along with its relatively low cost make the developed real-time monitoring platform very useful for online monitoring of smart microgrids.</jats:p

Phosphorylation of Osteopontin Peptides Mediates Adsorption to and Incorporation into Calcium Oxalate Crystals

Phosphorylated peptides of osteopontin (OPN) have been shown to inhibit the growth of the {100} face of calcium oxalate monohydrate (COM). The inhibitory potency has been shown to be dependent on the phosphate content of the peptide. The purpose of this study is to better understand the means by which phosphate groups promote crystal growth inhibition by OPN peptides. Peptides of rat bone OPN 220-235 peptides have been synthesized with zero (P0), 1 (P1) or 3 (P3) phosphate modifications. COM crystals were grown in the presence of 0.1-10 microg of P0, P1 or P3. P0 incorporation into COM crystals was evident at 10 microg/ml of peptide, whereas the phosphorylated peptides P1 and P3 were incorporated at all tested concentrations. At 5 microg/ml of P3, COM crystals exhibited a \u27dumbbell\u27 morphology. To study the peptide-mineral interaction, surface frequency plots were constructed from molecular dynamics simulations of OPN peptide adsorption. Carboxylate and phosphate groups were found to adsorb in specific orientations to the COM {100} surface. In conclusion, it appears that the phosphate groups on OPN peptides are capable of interacting with the COM {100} surface. This interaction appears to increase the adsorption energy of the peptide to the surface, thus enhancing its inhibitory potency

Earth fault distance estimation using travelling waves provided with triacs-based reclosing in distribution networks

This study presents an earth fault distance determination algorithm for distribution networks using active travelling waves. Three triacs are used in parallel with a three-phase breaker poles to overcome the mechanical inequality of the poles' reclosing times, so that the three phases are simultaneously reclosed. As the proposed fault location technique is an active type with controllable reclosing instant, the arrival time of the reflected surge from the fault point should be stamped precisely. For this purpose, three different travelling-wave detection algorithms are evaluated including the discrete wavelet transform, Hilbert transform, and signal derivative. The fault location performance is evaluated under different fault conditions such as fault distances, fault resistances, and busbar faults. Due to utilising the reclosing transients, the proposed fault location function successfully estimates the fault distance for different earthing concepts such as unearthed, compensated, and earthed networks. This study is accomplished via simulating a typical 20 kV distribution network by the ATP/EMTP program. The results ensure the superior performance of the proposed fault distance estimation algorithm for earth faults in distribution networks.Peer reviewe

MnSOD overexpression prevents liver mitochondrial DNA depletion after an alcohol binge but worsens this effect after prolonged alcohol consumption in mice.

International audienceBoth acute and chronic alcohol consumption increase reactive oxygen species (ROS) formation and lipid peroxidation, whose products damage hepatic mitochondrial DNA (mtDNA). To test whether manganese superoxide dismutase (MnSOD) overexpression modulates acute and chronic alcohol-induced mtDNA lesions, transgenic MnSOD-overexpressing (TgMnSOD(+++)) mice and wild-type (WT) mice were treated by alcohol, either chronically (7 weeks in drinking water) or acutely (single intragastric dose of 5 g/kg). Acute alcohol administration increased mitochondrial ROS formation, decreased mitochondrial glutathione, depleted and damaged mtDNA, durably increased inducible nitric oxide synthase (NOS) expression, plasma nitrites/nitrates and the nitration of tyrosine residues in complex V proteins and decreased complex V activity in WT mice. These effects were prevented in TgMnSOD(+++) mice. In acutely alcoholized WT mice, mtDNA depletion was prevented by tempol, a superoxide scavenger, L-NAME and 1400W, two NOS inhibitors, or uric acid, a peroxynitrite scavenger. In contrast, chronic alcohol consumption decreased cytosolic glutathione and increased hepatic iron, lipid peroxidation products and respiratory complex I protein carbonyls only in ethanol-treated TgMnSOD(+++) mice but not in WT mice. In chronic ethanol-fed TgMnSOD(+++) mice, but not WT mice, mtDNA was damaged and depleted, and the iron chelator, deferoxamine (DFO), prevented this effect. In conclusion, MnSOD overexpression prevents mtDNA depletion after an acute alcohol binge but aggravates this effect after prolonged alcohol consumption, which selectively triggers iron accumulation in TgMnSOD(+++) mice but not in WT mice. In the model of acute alcohol binge, the protective effects of MnSOD, tempol, NOS inhibitors and uric acid suggested a role of the superoxide anion reacting with NO to form mtDNA-damaging peroxynitrite. In the model of prolonged ethanol consumption, the protective effects of DFO suggested the role of iron reacting with hydrogen peroxide to form mtDNA-damaging hydroxyl radical