This study aimed at comparing the impact of two types of teacher feedback on Iranian EFL learners’ writing ability and their verb tense consistency in L2 writing. Following the administration of a standardized language proficiency test (Preliminary English Test), sixty-two participants were selected and were randomly assigned to the control (direct-only correction) and experimental (direct metalinguistic correction) groups. The comparison of the groups on the pre-test observation confirmed the homogeneity of the subjects before the instruction. During the study, the control group (direct-only correction) received some feedback on the location of errors along with the correct form of errors. The experimental group (direct metalinguistic correction), however, received the same type of feedback plus metalinguistic comments explaining the reason behind the errors. After the treatment, both groups took a post and a delayed post-test. The results of the study showed that direct metalinguistic correction was more effective than direct-only correction in improving EFL learners’ writing ability. The study also showed that the effect of instruction lasted over time.

The free vibrations of a rod are governed by a differential equation of the form $(a(x)y^\prime)^\prime+\lambda a(x)y(x)=0$, where $a(x)$ is the cross sectional area and $\lambda$ is an eigenvalue parameter. Using the finite element method (FEM) we transform this equation to a generalized matrix eigenvalue problem of the form $(K-\Lambda M)u=0$ and, for given $a(x)$, we correct the eigenvalues $\Lambda$ of the matrix pair $(K,M)$ to approximate the eigenvalues of the rod equation. The results show that with step size $h$ the correction technique reduces the error from $O(h^2i^4)$ to $O(h^2i^2)$ for the $i$-th eigenvalue. We then solve the inverse spectral problem by imposing numerical algorithms that approximate the unknown coefficient $a(x)$ from the given spectral data. The cross section is obtained by solving a nonlinear system using Newton's method along with a regularization technique. Finally, we give numerical examples to illustrate the efficiency of the proposed algorithms.

The general circulation models (GCMs) are state-of-art tools available to investigate the response of climate system to external and internal forcing. They are used to predict/project climate in seasonal to decadal time scales. The general circulation models (GCMs) have more or less biases, and bias correction methods are the techniques used to correct their biases. The Coupled model intercomparison project phase 6 (CMIP6) has been widely used to simulate the historical period and project the future climate. However, due to the uncertainty of the models and their coarse resolution, GCMs are not directly used to assess the impacts of climate change. Therefore, to reduce the uncertainty in CMIP6 models, bias correction is necessary in the first step. This study evaluates three methods of bias correction including, Linear Scaling, Variance Scaling of Temperature, Empirical Quantile Mapping, Quantile mapping using a smoothing spline and Empirical Robust Quantile Mapping for two variables of minimum and maximum temperature against 46 synoptic stations in Iran during 1980-2014 using the EC-Earth3-CC. To evaluate direct model output (DMO) and bias correction methods, we used three metrics including root-mean-square error (RMSE), percent bias (PBIAS), index of agreement (d), and interannual variability skill score (IVS). The results showed that the direct model output of the EC-Earth3-CC model has a cold bias (underestimation) for both minimum and maximum temperature in all climate zones of Iran, as well as the area-averaged values of the country. The bias correction methods examined in this research have significantly reduced the bias in Iran. It is found that the bias decreased to 51.8 percent for the minimum temperature in the highlands of Azerbaijan, northeastern Iran, as well as parts of the Alborz and Zagros mountains. In general, the results of the three methods are close and they are not much different from each other. Based on the analysis of RMSE values, bias correction methods significantly reduced RMSE in comparison with DMO. So that the value of this metric in DMO has been more than 2 oC in most of Iran's climate zones, while the use of bias correction methods has reduced the error value to less than 1 oC. Also, bias correction methods have increased the index of agreement (d) by more than two times in average climate zones. Since the EC-Earth3-CC DMO has a good performance in depicting interannual climate variability (IVS) and is close to the observations, this has caused the DMO not to differ greatly from the results of using bias correction methods such as linear scaling. Finally, the bias correction methods used in this research estimate the maximum temperature with higher accuracy than that for the minimum temperature. There is no single bias correction method that provides the best performance in all regions. Therefore, each of these methods has its own advantages and limitations, which are caused by spatiotemporal differences and local geographical features.

This paper develops a flux-linkage estimator using voltage model in stator reference based on an improved integrator with DC-offset PI-correction loop having the reference flux magnitude in the correction error. The DCoffset and drift from acquisition channels and the flux-vector initial error are canceled. A phase locked-loop state estimator extracts the speed and position from the estimated rotor flux. This robust solution can be applied in all AC drives with sinusoidal flux distribution in wide speed range, including sensorless control. A sensorless DTC is investigated for both PMSM and IM drives. Simulation results for PMSM drive and also experimental results for IM drive prove highdynamic performances in large speed range step reversal, for zero to rated load-torque step.

The usefulness of error correction in improving students’ grammatical accuracy has been the focus of attention in the past decades, and hot debates have raged on over this issue. There is yet no clear answer, to date, as to the efficacy of feedback and its various types. The aim of this study is, thus, to shed more light on the relative effectiveness of feedback per se and also the efficiency of some types of grammatical feedback, delivered electronically through MS Word software, over the others in improving students’ written accuracy. Research questions Is there any effect, whatsoever, for different types of feedback (i. e. direct, indication only & indication plus location) when delivered electronically in improving students’ level of grammatical accuracy? Is there any priority for each of the above feedback types over the others? Method Participants The participants of this study included 85 Iranian English majors. Of the total participants, 53 were female and 32 were male. The number of females and males were 15 and 11, 13 and 6, 12 and 8 and, 13 and 7 for control group, direct feedback group, indication group and indication and location group respectively. Design and procedure This study employed a pretest-treatment-posttest format. Of the four groups involved in the study, three were treatment groups and one was the control group. In the first treatment group, direct feedback group, the correct form of the students’ grammatical errors was provided. The two other treatment groups were, however, both provided with indirect feedback. In one of them, the indication-only group, the students were provided with an indication in the margin of the line in which the error was committed to show that an error or errors have occurred. The indication and location group was provided with feedback as to the exact word or phrase in the text that included a grammatical error. Analysis To answer the first research question (i. e. its three sub-questions), three paired sample T-test were used. The second research question (i. e. its three sub-questions) was answered using one-way ANOVA. Results Significant difference was found between the pretest and the posttest of the direct feedback group in the mean rate of errors (t=3. 475; p‹ . 05). It means that the provision of direct written corrective feedback has been effective in improving students’ level of accuracy to a statistically significant level. However, the second group of the study, the indication only group, did not show any significant improvement in accuracy from the pretest to the posttest (t=1. 627; p› . 05). No significant improvement in grammatical accuracy was also observed for the indication and location group. The primary result of the analysis indicated that there was a significant difference between the four groups with respect to their improvement from the pretest to the posttest (F=6. 771; p‹ . 001). To further investigate the details of this comparison Tukey’ s post hoc measure was used. Tukey’ s index indicated that there were significant differences between direct feedback group on the one hand and control group (p‹ . 001), indication only group (p‹ . 05) and indication and location group (p‹ . 05). It was, in fact, the direct corrective feedback group whose improvement in accuracy was statistically significantly higher than the other groups. No other significant difference was found between other pairs of the groups with respect to accuracy improvement. Conclusion An explanation for the findings of the first question can be offered with regard to Schmidt (1990) noticing hypothesis. Among the three types of feedback offered to the groups of the study, direct feedback is apparently the most noticeable. This characteristic may lend this type of feedback to longer retention and quicker internalization. Comparison of the means of improvement for the three treatment groups clearly indicates that the direct group made the most substantial improvement of all. The second substantial improvement is made by indication and location group and the lowest improvement was made by the indication only group. This ranking of improvement is in other words a ranking of noticeability of feedback, and although not consistent with many parts of the literature, is totally consistent with some others especially Schmidt’ s noticing hypothesis. The findings of the second research question can also be interpreted and justified in light of the noticing hypothesis. This point that the direct feedback turned out to make a significant difference and is significantly different from other types of feedback can be justified in light of the fact that the participants of this study were roughly (and not definitely) of the intermediate level of proficiency. For these students, getting involved in problem solving (as the indirect types of feedback requires) while at the same time involved in the quite demanding task of following the ideas might be rather over-demanding, hence distracting their attention. Also, there are many grammatical points which are yet totally unknown to intermediate students and therefore any involvement in problem solving will lead nowhere, no matter how much effort the student makes. This point is also well recognized by Ferris and Roberts (2001) who suggest that direct feedback is perhaps more efficient than indirect corrective feedback with writers of low levels of proficiency.

Introduction: High volumes of wastewater along with contaminants, such as colloids and dyes are discharged from different industries into the environment. These wastewaters create major problems and serious threats for water resources. Therefore, it is essential to treat such wastewaters and reach the effluent discharge standards. In this regard, chitosan as a coagulant has a comparable performance with other coagulants. Moreover, the addition of chitosan and removal of turbidity probably lead to higher efficiency of nanoparticles in lower dosages which is investigated in the current study. Therefore, the purpose of this study was to investigate the efficiency of chitosan and magnesium oxide (MgO) nanoparticles for the removal of color and turbidity. Materials & Methods: Synthetic wastewater was prepared by mixing specific amounts of bentonite and direct blue 71 dye in distilled water. After the preparation of different concentrations of color and turbidity, the experiments were conducted with different dosages of chitosan and MgO separately and in combination. The influence of variables such as pH, initial concentration of dye and turbidity, MgO and chitosan dosages on removal efficiency was investigated in this study. Fidings: According to the results, the highest rate of color and turbidity removal was obtained at 1. 5 mg/L chitosan in combination with 1. 5 g/L MgO with the efficiency of 97. 5%. In addition, the highest removal efficiency was obtained at pH of 7. Discussion & Conclusions: Due to the need for high doses of MgO in high turbidities, the use of chitosan as a coagulant can be effective in reducing the use of MgO.

Direct orthogonal signal correction(DOSC) and Savitzky-Golay filters (SGF) were applied as preprocessing methods on the original and first derivative absorbance data. Principle component regression (PCR), partial least squares (PLS) and iterative target transformation factor analysis (ITTFA), were used in spectrophotometric simultaneous determination of heavy divalent metal ions, lead, zinc, mercury and cadmium, using 4-(2-pyridylazo) resorcinol (PAR) as metallochromic indicator. The optimum values of the parameters for DOSC and SGF were obtained according to REP, R2 and RMSEP functions for calibration and prediction sets. The concentration for Hg2+, Pb2+, Zn2+ and Cd2+ ions in calibration set were varied between 0 - 12.24, 0 - 9.81, 0 - 0.87 and 0-3.96 ppm, respectively. The experimental calibration set was composed of 35 sample solutions and the 7 solutions as prediction set using a simple lattice (4, 4) mixture design. The absorption spectra were recorded from 450 to 600 nm and absorbance data were autoscaled. The effect of pH on the sensitivity and selectivity was studied in the range of 1.00 - 11.00 and pH=7.50 was chosen according to net analyte signal (NAS) as a function of pH.

Introduction Human Papilloma Virus (HPV) is one of the most common sexually transmitted viruses and the main cause of urogenital tract cancers. Cervical cancer is the fourth common cause of cancer death in women and in more than 90% is associated with a persistent infection with one of the High-Risk HPV types. This study was performed with aim to determine HPV genotypes in DNAs extracted from tissue samples of people suspected to HPV infection. Methods In this cross-sectional epidemiological study, 201 tissue samples were obtained from people suspected to HPV infection that had referred to Dr. Mozaffari pathobiology laboratory for diagnosis in Tabriz from 2016-2019. Viral DNA was extracted using high pure viral nucleic acid extraction kit and genotyping was studied using HPV Direct Flow CHIP Kit. Data were analyzed by Excel software. Results Viral DNA amplification was observed in 45 samples (73%) and considered as HPV-positive. Among them, 8 samples (6%) were infected by high-risk types, 36 samples (34%) by both high & low-risk types and 56 samples (60%) by low-risk types. HPV types 6, 11 and 43 with frequency f 107, 23 and 10, respectively out of 145 people were identified as the most common low-risk types and HPV-18, 39 and 16 with frequency of 23, 11 and 10, respectively were identified as the common high-risk types. Most of the infected women were in the age range of 25-35 years and the age range for men was 35-40 years. Conclusion This study showed that determining the genotypes of HPV is considered as an important step in the management of HPV-infected people, especially people with persistent infection by High-risk types.