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Purpose: This study aimed to investigate the rate of COVID-19 breakthrough infection and adverse events in medical students.Methods: Iranian medical students receiving two doses of COVID-19 vaccines were included in this retrospective cohort study. The medical team gathered the demographic characteristics, comorbidities, type of vaccine, adverse events following vaccination, and history of COVID-19 infection data through a phone interview. The frequency of adverse events and breakthrough infection was stratified by vaccine type (ChAdOx1-S, Gam-COVID-Vac, and BIBP-CorV).Results: A total of 3591 medical students enrolled in this study, of which 57.02% were females, with a mean age of 23.31 + 4.87. A PCR-confirmed and suspicious-for-COVID-19 breakthrough infection rate of 4.51% and 7.02% was detected, respectively. There was no significant relation between breakthrough infection and gender, BMI, blood groups, and comorbidities. However, there was a significant difference in breakthrough infection rate among different types of vaccines (P=0.001) and history of COVID-19 infection (P=0.001). A total of 16 participants were hospitalized for COVID-19 infection, and no severe infection or death was observed in the studied population.Conclusion: Vaccination prevented severe COVID-19 infection, although a high breakthrough infection rate was evident among Iran medical students during the Delta variant’s peak. Vaccine effectiveness may be fragile during emerging new variants and in high-exposure settings. Moreover, adverse events are rare, and the benefits of vaccination outweigh the side effects. However, many limitations challenged this study, and the results should be cautious.

Complex piers (CPs), consisting of a column, pile cap and pile group, are commonly built as foundations for hydraulic and marine structures. Scour-hole development around CPs is studied in this paper. A total of 52 tests is carried out on 4 CP models, with experiments durations ranging from 24 to 120 h. All of the available experimental data for clear-water scour around CPs including the collected data of the present study and those previously published are reviewed and combined into a database. A special case of bridge piers with deep foundation or caisson instead of pile caps is also considered, which is herein called compound piers. The database contains 367 experiments for CPs and 162 experiments for compound piers. The predictive equations of the maximum scour-hole depth at complex piers including HEC-18 and FDOT equations are revisited and a new equation is proposed. Comparisons of the prediction equations shows that for CP data, the absolute error is 28%, 79% and 108% for the proposed, HEC-18 and FDOT equations, respectively. Underestimation below −20% error line occurs for 11%, 15%, and 7% of the cases in the proposed, HEC-18, and FDOT equations, respectively. For compound piers, the proposed equation has 41% absolute error while HEC-18 equation has 93% absolute error.

The authors used a meshless Lagrangian method to solve continuity and momentum equations of incompressible, inviscid and homogenous (ideal) fluid with the capability of considering container excitation and solving various wave related problems. Through algebraic manipulations, governing equations are written in terms of Laplace's equation for pressure deviation from hydrostatic as ∇2pH=0. The numerical solution procedure consists of building a series solution with each term being a general solution of Laplace's equation and calculating coefficients by imposing free surface and solid wall boundary conditions through collocation at several discrete points. This discussion questions the validity of using Laplace's equation for pressure for the case of ideal fluid; and by applying chain rule of differentiation we prove that positions of divergence operator and material derivative are not readily interchangeable, i.e. ∇·Du/Dt ≠ D(∇·u)/Dt.

It is important to teach students how to write essays in second/foreign (L2) effectively by various instructional techniques. Moreover, persuasive writing is one of the means by which students can be encouraged to create meaning. This study then investigates whether strategy-based instruction is an effective classroom-based practice in raising the ability in persuasive type of writing. Additionally, it compares the effectiveness of process-oriented strategy-based instruction with a nonstrategy-based instruction in an advanced writing course. In so doing, it employed Self-Regulated Strategy Development (SRSD) and non-SRSD (i.e. a more product-oriented traditional method) models in two writing classes at two universities. The SRSD model included six stages (Develop Background Knowledge, Discuss Strategy, Model It, Memorize It, Support It, and Independent Performance) using POW + TREE mnemonic chart, persuasive essay examples, TREE graphic organizer, and transition word chart. To probe the objectives of study, 60 Iranian EFL undergraduates participated in the study which used a pretest-posttest control group design. The analyses of covariance revealed that both SRSD and non-SRSD instructions had a significant impact on the EFL participants’ persuasive writing ability. But SRSD model was significantly more effective in improving the persuasive writing ability of the EFL learners (i.e., format and content, organization and coherence, sentence construction and vocabulary in writing). By implication, if L2 learners have the necessary metacognitive knowledge and self-regulation strategies of L2 writing, they will come to achieve competence in L2 writing sooner, which allows them to attain a positive sense of self-efficacy in their writing.

This study generally endeavoured to explore the development of literacy acquisition in Persian first language learners. To achieve this goal, the study did not focus on a narrow range of variables. There was a strong need for multivariate research taking into consideration phonological awareness, orthographic knowledge and working memory. The study comprised five phases. Phase One addressed the interrelation and development of two levels of phonological awareness: syllable awareness and phoneme awareness. Phase Two focused on the interrelation and development of various levels of orthographic knowledge including alphabetic knowledge, reading words, reading nonwords, spelling words, spelling nonwords, orthographic choice as well as the use of analogy and phonology in reading and spelling of nonwords. An attempt was made in Phase Three to examine the development of working memory. In Phase Four, the interrelation and contribution of phonological awareness, orthographic knowledge and working memory to reading and spelling achievement were surveyed jointly and individually. In the final phase, Phase Five, the factoring of all variables together and their functions in group distinction were determined. The sample consisted of 156 Persian-speaking students: 21 kindergartners, 121 elementary students enrolled in Grades one to five, and 14 undergraduate university students. This study offers several suggestions for further research and important educational implications for teachers, material developers as well as test and curriculum designers working with Persian language learners. (Abstract shortened by UMI.)