A phase-space approach to directional switching in semiconductor ring lasers

We show that a topological investigation of the phase space of a Semiconductor Ring Laser can be used to devise switching schemes which are alternative to optical pulse injection of counter-propagating light. To provide physical insight in these switching mechanisms, a full bifurcation analysis and an investigation of the topology is performed on a two-dimensional asymptotic model. Numerical simulations confirm the topological predictions.Comment: 9 pages, 7 figure

Explanations for infrequent reading in primary and secondary school students:Reading motivation, selection of appropriate books, and behavioral routines

Many students in the upper grades of primary education and in secondary education infrequently read during leisure time, which could have negative consequences for their reading proficiency. The aim of this dissertation, therefore, was to investigate possible reasons for infrequent reading. In Chapter 2, we examined whether there is support for the hypothesis that infrequent reading is explained by a lack of reading motivation. A meta-analysis was conducted to investigate to what extent fostering reading motivation contributes to higher reading motivation and, as a consequence of more frequent reading, to better reading skills. Based on a literature search, 39 relevant effect studies were identified. The interventions had small, positive effects on reading motivation and reading comprehension, supporting the hypothesis that low reading motivation is one viable explanation for infrequent reading. Interventions that aimed to trigger students’ interest had the largest effects on both reading motivation and reading comprehension, suggesting that infrequent reading could additionally be explained by the fact that students are often confronted with texts that are not of interest to them. Chapter 3 focused on the selection of appropriate books as an explanation for infrequent reading. In two studies, we investigated whether personalized expert guidance in selecting books led to a more positive reading attitude, higher familiarity with books, and better reading comprehension. Study 1 focused on students in prevocational secondary education and Study 2 on students in primary education. Students in the experimental condition met with a librarian every two weeks to discuss their book choices. Overall, guidance in book selection positively affected students’ reading attitude, although no effects were found for struggling readers in prevocational secondary education. For the most proficient readers in primary education, a positive effect on reading comprehension was found as well. These outcomes support the hypothesis that difficulties in selecting appropriate books are an explanation for infrequent reading. In Chapter 4, we examined behavioral routines as an explanation for infrequent reading. Due to fast, unconscious decisions, students may overlook the possibility of reading as a leisure time activity. In two studies, conducted in primary education and prevocational secondary education, we investigated the effects of nudging on familiarity with books, reading attitude, and reading comprehension. Regular reminders were sent to students or their parents. In primary education, the nudges positively influenced parents’ familiarity with books and children’s reading attitude. A positive effect on students’ familiarity with books was found in prevocational secondary education. All effects were limited to parents and students most prone to reading. The outcomes thus provide partial support for the hypothesis that behavioral routines can explain infrequent reading. The studies in this dissertation reveal that several factors play a role in infrequent reading, namely low reading motivation, difficulties in selecting appropriate books, and behavioral routines. Based on this dissertation, it can be concluded that students need more guidance during reading than is usually provided. This guidance should be focused on fostering students’ reading motivation, helping in selecting books, or bringing reading to students’ attention. Further, the outcomes of this dissertation indicate the importance of more intensive or additional guidance for struggling, reluctant readers. They may need more support in order to prevent reading difficulties from turning reading into an activity that evokes resistance. Future studies should reveal how this guidance could be effectively implemented in practice, so students have more positive reading experiences, ultimately resulting in more frequent, more motivated, and more proficient reading