918 research outputs found
Re-imagining the NS/NNS dichotomy: bicultural teachers
EFL teachers have been categorized using the NS/NNS (native speaker/non-native speaker) dichotomy into NESTs (native English speaking teachers) and NNESTs (non-native English speaking teachers). However, this inaccurate dichotomy does not take into account other possible categories that may fall between these two extreme notions, and has shown to have several ramifications. First, students\u27 perception of teacher nativeness may influence students\u27 attitudes and learning (Sahin, 2005). In addition, this perception could have an effect on students\u27 evaluations of their teachers (Al-Issa & Sulieman, 2007). Further, this biased dichotomy contributes to NNESTs\u27 low self-confidence (Butler, 2007). Finally, it may cause unequal job opportunities in the EFL market (Canagarajah, 1999). This qualitative study explores how students identify the ideal EFL teacher and how they perceive bicultural teachers (BCTs). BCTs represent one of many categories that do not fit in the dichotomy and are defined as teachers that have acquired native or near native competence in two languages. They have also been immersed in the cultures of both languages, where one of these two languages is the mother tongue of the learners. The participants included 61 undergraduate and 32 graduate upper-intermediate EFL students at the American University in Cairo. The students were surveyed on their opinions about teacher nativeness and the ideal teacher using a questionnaire. In addition, focus groups were conducted to clarify the results obtained from the questionnaire. Results show that students perceive the ideal teacher as possessing a combination of different qualities, only some of which are influenced by nativeness. In addition, students have difficulty identifying BCTs, although a few students are able to see beyond the dichotomy and use a different conceptual approach to identify them. Moreover, once students are able to identify BCTs, they see them as possibly highly competent teachers that combine qualities of both NESTs and NNESTs. Results also imply that the NS fallacy still exists as the participants tended to associate accent, appearance and names with teacher-competence. Therefore, the dichotomy should be modified so that the EFL community will refrain from judging teachers based on a pre-conceived notion of the NEST being the ideal EFL teacher
A Critical Role of Fuel Molar Ratio in the Microwave Combustion Synthesis of Nano Size α-Al2O3
Nano size highly crystalline α-Al2O3 powders have been synthesized by the microwave combustion approach. A study of the evolution of crystalline phase of obtained powders and the morphology of the particles were accomplished through X-ray diffraction and High resolution transmission electronic microscopy. The effect of metal to fuel molar ratios on the crystal structure, particle size, and morphology of the powders was examined. Microwave combustion gave finer particles with very small agglomerate size as revealed by TEM analysis. Also the results obtained allow the identification of the highly crystalline single-phase αAl2O3 powder was obtained after microwave combustion at 900 w for 5 min with metal/fuel molar ratio as 1:3. Keywords: Microwave Combustion, Mixed Oxide, Synthesis, Characterization.
Soybean resilience to drought is supported by partial recovery of photosynthetic traits
Climate change affects precipitation dynamics and the variability of drought frequency, intensity, timing, and duration. This represents a high risk in spring-sown grain legumes such as soybean. Yet, under European conditions, no evidence supports the potential recovery and resilience of drought-tolerant soybean cultivars after episodic drought, at different growth stages. A field experiment was conducted using a representative drought-tolerant cultivar of soybean (cv. Acardia), in 2020 and 2021, on sandy soils in Germany, applying four water regimes (irrigated, rainfed, early-drought, and late-drought stress). Drought stress was simulated by covering the plots during the event of rain with 6 x 6 m rainout shelters, at the vegetative (V-stage) and flowering (Fl-stage) stages. Drought response was quantified on plant height, chlorophyll fluorescence ratio (ChlF ratio), chlorophyll content (Chlc), and leaf surface temperature (LST), at different intervals after simulating drought until pod filling. Grain yield and yield components were quantified at the end of the growing season. Compared to rainfed conditions, a drought at V-stage and Fl-stage reduced significantly plant height, ChlF ratio, and Chlc by 20%, 11%, and 7%, respectively, but increased LST by 21% during the recovery phase. There was no recovery from drought except for Chlc after V-stage in 2021, that significantly recovered by 40% at the end of the growing season, signifying a partial recovery of the photochemical apparatus. Especially, there was no recovery observed in LST, implying the inability of soybean to restore LST within the physiological functional range (Graphical abstract). Under rainfed conditions, the grain yield reached 2.9 t ha(-1) in 2020 and 5.2 t ha(-1) in 2021. However, the episodic drought reduced the yield at V-stage and Fl-stage, by 63% and 25% in 2020, and 21% and 36% in 2021, respectively. To conclude, the timing of drought was less relevant for soybean resilience; however, pre-and post-drought soil moisture, drought intensity, and drought duration were likely more important. A drought-tolerant soybean cultivar may partially be drought resilient due to the recovery of photosynthetic traits, but not the leaf thermal traits. Overall, these findings will accelerate future efforts by plant breeders, aimed at improving soybean drought resilience
Removal of Heavy Metals via Adsorption using Natural Clay Material
Removal of heavy metals from its solution has been investigated by using adsorption clay material from El-Hammam district (Alexandria), with high silica content ~ 53 wt % was selected to verify this purpose. The clay material has been characterized by applying different techniques; x-ray analyses to investigate the crystalline structure (x-ray diffraction), the constitutes of the clay material (x-ray florescence) and thermal analysis to trace the structure changes that accompanying the thermal treatment.FeCl2, Ni(NO3)2.6H2O, and ZnCl2 solutions have been used as metal model compounds to evaluate the adsorption efficiency of the clay material. Results indicated that the adsorption of heavy metals from its single metal solutions followed the order Fe> Zn > Ni. Key words: Adsorption, Adsorbent, Bentonite, Montmorillonite, Heavy metal
Adsorptive Power Evaluation of the Nano-Crystalline Mo-W Bimetallic Oxides
Novel nanosized molybdenum-tungsten bimetallic oxides were prepared by modified Pechini method based on the low temperature polymerization-complexation steps. The physical properties of the prepared nanoparticles were characterized by: X-ray diffraction (XRD), Fourier transformer inferred spectroscopy (FT-IR), differential thermal analyses (DCS), and high resolution transmission electron microscopy (HRTEM). The influence of metal molar ratios (Mo/W) on the morphology and the crystallization the samples was also investigated. The adsorptive power of prepared samples was evaluated through the removal of dimethyl disulfide sulfur compound (in cyclohexane as fuel). The results indicate that all the prepared Mo-W oxide materials are nanoparticles with diameter ranging between 1 and 70 nm. And the smallest nanosize particles enhanced the adsorptive power of the prepared nanostructured Mo-W bimetallic oxide. Keywords : Mixed Oxide, Synthesis, Characterization, Sulfur Adsorption
Interleukin-12 levels in Egyptian children with type 1 diabetes mellitus
Background: Type 1 diabetes mellitus (T1DM), arising through a complex interaction of immune, genetic and environmental factors, results from autoimmune destruction of insulin-producing β cells. Cytokines are critical to the function of both innate and adaptive immune responses. Interleukin-12 p40 production influences T cell response, and may therefore be important in T1DM pathogenesis. Objective: to study the changes in IL12 levels in children with T1DM. Study design: fifty T1DM children among those attending diabetes clinic at Zagazig University hospitals, were included in the study. They were 27 males and 23 females (mean age, 9.19 ± 3.3 years). Thirty age and sex matched healthy children were serving as a control group. All children were subjected to full history taking, physical examination, complete blood count (CBC), random blood sugar, glycated hemoglobin (HBA1C) and serum IL-12 levels assessed by ELISA. Results: Diabetic children had significantly higher white blood cell count, HBA1C, and IL12 levels than healthy children. While there was no effect of gender on IL12 levels, there were significant increase in IL12 levels in newly diagnosed cases, those with higher body mass index and those who had the poorest glycemic control. Conclusion: type 1 diabetes is associated with elevation of IL-12 levels. This association is more evident in both newly diagnosed and poorly controlled patients indicating a relevant role of IL-12 in the pathogenesis of the disease.Keywords: Type 1 Diabetes Mellitus, Interleukin 12, EgyptEgypt J Pediatr Allergy Immunol 2013;11(1):41-4
Synthesis, Characterization and Antibacterial Activity of Some New 5,5'-diphenyl-4,4',5,5'-tetrahydro-1H,1'H-3,3'-bipyrazole Derivatives
An efficient and practical synthesis of five compounds of pyrazoline derivatives structures was achieved through cyclization of hydrazine hydrate with 1,6-diphenylhexa-1,5-diene-3,4-dione using glacial acetic acid as catalyst under thermal conditions. These compounds have been characterized by FT-IR, elemental analysis (C.H.N.) and 1H NMR spectroscopy. Keywords:pyrazoline, chalcone, heterocycli
N-Terminal Phosphorylation Sites of Herpes Simplex Virus 1 ICP0 Differentially Regulate Its Activities and Enhance Viral Replication
This is the publisher's version, also available electronically from http://jvi.asm.org/content/87/4/2109The herpes simplex virus 1 (HSV-1) infected cell protein 0 (ICP0) is an immediate-early phosphoprotein that transactivates viral gene expression. Evidence suggests that phosphorylation regulates the functions of ICP0, and three regions (termed regions I, II, and III) in the protein are known to be phosphorylated. Mutation of the putative phosphorylation sites within region I, termed Phos 1, which lies in the N-terminal portion of ICP0, impairs the E3 ubiquitin (Ub) ligase and ND10-disrupting activities of ICP0 in cell culture and diminishes viral replication. To identify the specific phosphorylation site(s) or residues responsible for the phenotypes observed with Phos 1, individual residues within region I were mutated to alanine (S224A, T226A, T231A, and T232A) and one double mutant S224A/T226A was constructed. Tissue culture studies demonstrated that the S224A, S224A/T226A, T231A, and T232A mutants were unable to dissociate the cellular protein PML from ND10 and that the S224/T226A mutant was defective in its ability to dissociate the cellular protein Sp100 from ND10. Additionally, the transactivation activity of ICP0 was impaired in the S224A and S224A/T226A mutants. The S224A and S224A/T226A mutant forms were more stable than wild-type ICP0, suggesting that their ability to autoubiquitinate was limited. Moreover, one ICP0 ubiquitination target, USP-7, was also more stable after infection with these two mutants. Lastly, the replication of the S224A and S224A/T226A mutant viruses was reduced in cell culture and in vivo. Overall, our data suggest that specific phosphorylation sites within region I differentially regulate the activities of ICP0, which are required for efficient viral replication
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