Memory and mutualism in species sustainability: a time-fractional Lotka-Volterra model with harvesting

We first present a predator-prey model for two species and then extend the model to three species where the two predator species engage in mutualistic predation. Constant effort harvesting and the impact of by-catch issue are also incorporated. Necessary sufficient conditions for the existence and stability of positive equilibrium points are examined. It is shown that harvesting is sustainable, and the memory concept of the fractional derivative damps out oscillations in the population numbers so that the system as a whole settles on an equilibrium quicker than it would with integer time derivatives. Finally, some possible physical explanations are given for the obtained results. It is shown that the stability requires the memory concept in the model

Effet de la conception sur les demandes d’eseignement de l’anglais des étudiantes iraniens

The Research into interlanguage pragmatics has prominent significance nowadays. Due to severe negative consequences of failure in performing and interpreting speech acts such as request, the present study investigated the effect of concept mapping on learning English requests by Iranian high school students. To this aim, 72 intermediate male English students (ranging in age from 15 to 18) that were in two intact groups from a city in northeastern Iran, voluntarily took part in the study. Data for this study were collected using English Test- Beginner (proficiency test) and Multiple Discourse Completion Task Test (MDCT). The results indicated there was a statistically significant difference between the request speech act knowledge of those learners who were taught requests through concept mapping and those who were taught traditionally. The results of the current study have important implications for syllabus designers and material developers particularly in EFL contexts.La investigación en la pragmática entre lenguas tiene un significado prominente en la actualidad. Debido a las graves consecuencias negativas del fracaso en la realización e interpretación de actos de habla como la solicitud, el presente estudio investigó el efecto del mapeo de conceptos en el aprendizaje de solicitudes de inglés por parte de estudiantes iraníes de secundaria. Para este objetivo, 72 estudiantes de inglés varones intermedios (de 15 a 18 años de edad) que formaban parte de dos grupos intactos de una ciudad en el noreste de Irán, participaron voluntariamente en el estudio. Los datos para este estudio se recopilaron utilizando la Prueba de inglés para principiantes (prueba de competencia) y la Prueba de tarea de finalización de múltiples discursos (TCMD). Los resultados indicaron que hubo una diferencia estadísticamente significativa entre el conocimiento del acto de habla de la solicitud de los alumnos a quienes se les enseñó las solicitudes a través del mapeo de conceptos y los que se les enseñó tradicionalmente. Los resultados del estudio actual tienen implicaciones importantes para los diseñadores de programas de estudio y los desarrolladores de materiales, particularmente en contextos de EFL.La recherche sur la pragmatique interlangue a une importance prééminente de nos jours. En raison des graves conséquences négatives de l’échec lors de l’exécution et de l’interprétation d’actes de langage tels que ceux demandés, la présente étude a examiné les effets de la cartographie conceptuelle sur l’apprentissage des demandes en anglais des lycéens iraniens. À cette fin, 72 étudiants anglais masculins d’âge intermédiaire (âgés de 15 à 18 ans) appartenant à deux groupes intacts d'une ville du nord-est de l'Iran ont participé volontairement à l'étude. Les données de cette étude ont été recueillies à l'aide de l'anglais Test Débutant (test de compétence) et du test de fin de discours multiple (MDCT). Les résultats ont indiqué qu'il existait une différence statistiquement significative entre la connaissance des actes de parole des apprenants à qui les demandes étaient traitées via le mappage de concepts et celle des apprenants de manière traditionnelle. Les résultats de la présente étude ont des implications importantes pour les concepteurs de programmes et les concepteurs de matériaux, en particulier dans les contextes EFL

The Effect of Concept Mapping on Learning English Requests by Iranian High School Students

The Research into interlanguage pragmatics has prominent significance nowadays. Due to severe negative consequences of failure in performing and interpreting speech acts such as request, the present study investigated the effect of concept mapping on learning English requests by Iranian high school students. To this aim, 72 intermediate male English students (ranging in age from 15 to 18) that were in two intact groups from a city in northeastern Iran, voluntarily took part in the study. Data for this study were collected using English Test- Beginner (proficiency test) and Multiple Discourse Completion Task Test (MDCT). The results indicated there was a statistically significant difference between the request speech act knowledge of those learners who were taught requests through concept mapping and those who were taught traditionally. The results of the current study have important implications for syllabus designers and material developers particularly in EFL contexts

Comparing the Effects of L1 and L2 Definition on Incidental Vocabulary Learning through Listening to Stories

Vocabulary is an essential component of language proficiency which provides the basis for learners’ performance in other skills. This study investigated the effect of three kinds of definition conditions, that is L1, L2, and L1+L2 on incidental vocabulary knowledge of EFL learners. To this aim, three experimental and one control groups took part in the current study so as to examine the effectiveness of definitions with 96 target words through listening. The participants were 74 fourth-grade high school students. Eight stories with each with 12 target words (total 96 words) were given to the learners. Participants in each group listened to eight short stories under one of the three mentioned conditions for experimental groups, with no definition offered for control group. They all answered vocabulary list, eight immediate post-tests and eight delayed posttests of vocabulary. The data were analyzed using t-tests and one-way ANOVA for both immediate and delayed post-tests. The results indicated that definition groups significantly outperformed the other group in terms of vocabulary acquisition on both immediate and delayed retention of target words. However, the findings showed a significant loss from the immediate to the delayed post-tests. These findings are discussed and implications are offered for foreign language syllabus designers and instructors

Evaluación dinámica de grupo concurrente del tamaño del vocabulario receptivo y productivo de los estudiantes EFL intermedios

Although research studies on dynamic assessment (DA) yielded promising results to the field of language teaching, scant research attention has been paid to examining the effectiveness of group dynamic assessment (G-DA) in relation to vocabulary development. To this effect, the present mixed-methods study was designed to inspect the potential of concurrent G-DA in enlarging receptive and productive vocabulary size of 56 Iranian intermediate EFL learners. The study used two modalities: the control group, which was taught the selected lexical items through traditional procedures such as using word lists; and the experimental group, which was offered group-based supportive prompts for doing vocabulary exercises within the G-DA framework. The results of a series of independent-samples t-tests indicated the significant effect of G-DA in enhancing receptive and productive vocabulary size of EFL learners. The qualitative data underscored the role of group mediation in increasing learners’ motivation to increase vocabulary uptake within the G-DA framework and maintaining their positive attitude toward G-DA.Aunque los estudios de investigación sobre la valoración dinámica (DA) arrojaron resultados prometedores en el campo de la enseñanza de idiomas, se ha prestado escasa atención al examen de la eficacia de la valoración dinámica de grupos (G-DA) en relación con el desarrollo del vocabulario. A tal efecto, el presente estudio de método mixto se diseñó para inspeccionar el potencial del G-DA concurrente para ampliar el tamaño del vocabulario receptivo y productivo de 56 estudiantes iraníes con nivel intermedio de inglés como lengua extranjera. El estudio utilizó dos modalidades: el grupo de control, al que se le enseñaron los vocabularios seleccionados mediante procedimientos tradicionales como el uso de lista de palabras; y el grupo experimental que recibió apoyo grupal para hacer ejercicios de vocabulario dentro del marco G-DA. Los resultados de una serie de pruebas t de muestras independientes indicaron el efecto significativo de G-DA en la mejora del tamaño del vocabulario receptivo y productivo de los estudiantes de inglés como lengua extranjera. Los datos cualitativos enfatizaron el papel de la mediación grupal en mejorar la motivación del alumnado al incrementar la adquisición del vocabulario en el marco de GDA y mantener su actitud positiva hacia el G-DA

Relationship between EFL Learners’ Perceived Social Self-Efficacy and their Foreign Language Classroom Anxiety

The present study was conducted to investigate the relationship between the perceived social self-efficacy of the students of English and their foreign language classroom anxiety. The required data were gathered through the application of the original versions of two standard questionnaires: Smith and Betz’s (2000) 25-item Scale of Perceived Social Self-Efficacy (SPSSE) and Horwitz, Horwitz and Cope’s (1986) 33-item Foreign Language Classroom Anxiety Scale (FLCAS). A total of 151 participants (including 127 students of English Language and Literature in B.A. level and 24 students of Teaching English as a Foreign Language at M.A. level) took part in the study. Correlational analysis was employed to determine the relationship between perceived social self-efficacy and foreign language classroom anxiety. Pearson Product-Moment correlation analysis results (r = -.164, p < .05) showed that the participants’ perceived social self-efficacy had a reverse relationship with their foreign language classroom anxiety. Further calculations were done for the type and rate of the influence of demographic variables (namely age, gender, academic seniority, and educational level) on students’ PSSE and FLCA. According to the One-Way ANOVA results, no meaningful relationship was observed between age, gender, academic seniority, and educational level of the participants, and their perceived social self-efficacy or foreign language classroom anxiety. Based on the findings of this study, the rate of perceived social self-efficacy (i.e. trust in self in social situations) seems to play a key role in the intensity of foreign language learners’ anxiety and a vital parameter in their full-functioning and efficient learning

Stabilization of DC–DC buck converter with unknown constant power load via passivity-based control plus proportion-integration

Abstract It is known that constant power load (CPL) may cause a negative impedance, which seriously affects the stability of power system. In this paper, a new control algorithm for DC–DC buck converter feeding unknown CPL is proposed. First, under the assumption of known extracted power load, the standard passivity–based control (PBC) is presented to reshape the system energy and compensate for the negative impedance and a proportion‐integration (PI) action around passive output is added to improve disturbance rejection performance, which forms the PBC plus PI (PBC+PI). Then, a parameter estimation algorithm is developed, based on immersion and invariance (I&I) technique, in order to online estimate the extracted power load. In the next step, the online estimation scheme is adopted to construct an adaptive strategy. Finally, the stability analysis of the cascaded system containing a closed‐loop control system and observer error dynamics is conducted. Simulation and experimental results are demonstrated to validate the performance of the proposed controller

Teachers’ Assessment Literacy and Its Correlation with IELTS Students’ Achievement in Writing Skill

The role of teachers in their students’ success is an undeniable factor which has already been dealt with in diverse literature. The challenge is their knowledge pertaining to the scale of their prevailing awareness related to one of the leading issues in the testing domain that is assessment literacy. The aim of the study was to investigate the effectiveness of teachers’ assessment - literacy effectiveness in IELTS writing practice, Task 2, by administrating an in-service training course for a group of teachers instructing IELTS candidates and measuring the effect of their literacy on the writing skill developments of their students. The result shows that those teachers who received the literacy of the IELTS writing assessment procedure have earned consciousness of the genre principles and are more successful in their profession as they are capable of producing more literate learners, who achieve higher scores than their fellow candidates. The findings of the present paper reveals that assessment literates tend to communicate their knowledge through a more effective approach to their students than their colleagues, emphasizing the fact that teachers who try to secure their profession in an optimal manner should equip themselves with the needs of the assessment. Assessment literacy, then, acts as a dual instrument both for the well-being of the teachers in the first step and for the objectively literate students meeting their test demands in the second step