Etude numérique de l'impact du filtrage optique sur les propriétés régénératives d'un convertisseur de longueur d'onde interférométrique en configuration différentielle

Session affiches 19 « Systèmes et réseaux de Télécommunication » [A10.2]National audienceDans cet article, nous présentons l'étude numérique des propriétés régénératives d'un convertisseur de longueur d'onde interférométrique à base d'amplificateurs optiques à semiconducteurs, en configuration différentielle. Nous avons démontré qu'en optimisant le filtrage optique, nous pouvons améliorer la qualité du signal en sortie du convertisseur en réduisant notamment l'effet de « patterning » lié à la réponse lente de l'amplificateur optique à semiconducteurs

The chemokine Sdf-1 and its receptor Cxcr4 are required for formation of muscle in zebrafish

<p>Abstract</p> <p>Background</p> <p>During development cell migration takes place prior to differentiation of many cell types. The chemokine receptor Cxcr4 and its ligand Sdf1 are implicated in migration of several cell lineages, including appendicular muscles.</p> <p>Results</p> <p>We dissected the role of <it>sdf1</it>-<it>cxcr4 </it>during skeletal myogenesis. We demonstrated that the receptor <it>cxcr4a </it>is expressed in the medial-anterior part of somites, suggesting that chemokine signaling plays a role in this region of the somite. Previous reports emphasized co-operation of Sdf1a and Cxcr4b. We found that during early myogenesis Sdf1a co-operates with the second Cxcr4 of zebrafish – Cxcr4a resulting in the commitment of myoblast to form fast muscle. Disrupting this chemokine signal caused a reduction in <it>myoD </it>and <it>myf5 </it>expression and fast fiber formation. In addition, we showed that a dimerization partner of MyoD and Myf5, E12, positively regulates transcription of <it>cxcr4a </it>and <it>sdf1a </it>in contrast to that of Sonic hedgehog, which inhibited these genes through induction of expression of <it>id2</it>.</p> <p>Conclusion</p> <p>We revealed a regulatory feedback mechanism between <it>cxcr4a</it>-<it>sdf1a </it>and genes encoding myogenic regulatory factors, which is involved in differentiation of fast myofibers. This demonstrated a role of chemokine signaling during development of skeletal muscles.</p

Vocabulary Coverage in a High School Vietnamese EFL Textbook: A Corpus-based Preliminary Investigation

In the context of English as a foreign language (EFL) teaching, textbooks play a crucial role in the classroom as the primary source of lexical input for learners. Thus, it is essential that textbooks can sufficiently facilitate learners in their overall comprehension and vocabulary learning, especially with the most frequent words in English. The study examined the vocabulary load of a locally-published EFL textbook in Vietnam for high school students focusing on the vocabulary coverage in relation to the 95% and 98% thresholds for text comprehension and the coverage of high-frequency word families in the textbook. To fulfil these objectives, a frequency-based analysis of word families using the Vocabprofilers on the https://www.lextutor.ca/ website was conducted with the 41,137-word textbook corpus. It is revealed that students need to have a vocabulary size of 3,000 and 5,000-word families to reach the coverage of 95% and 98% of the whole textbook, which would be too challenging for Vietnamese high school students. Moreover, the textbook was found not to represent the second 1,000-word list very well with the appearance of just over half of the second most frequent 1,000-word families. These findings highlight the role of teachers in adapting the textbook for more effective vocabulary learning and general comprehension of the materials

Applying Cognitive Linguistics to Enhance Vietnamese English-Major Undergraduates’ Learning of English Modal Verbs

English modal verbs (EMV) have long been regarded as a challenge for English as a Foreign Language (EFL) learners, partly due to the widely used conventional speech act teaching method. The Cognitive Linguistics approach, which is believed to offer a more systematic explanation of English modals, has been introduced and applied to the teaching of English modal verbs in various international contexts. In this study, the researchers aim to investigate the perceptions and attitudes of Vietnamese EFL learners toward the application of Cognitive Linguistics at the tertiary education level, and whether this approach can improve their performance in using modal verbs through a Cognitive Linguistics intervention. To achieve the research objectives, two tests (pretest and post-test), questionnaires, and semi-structured interviews were conducted with 18 Vietnamese English-major undergraduates. Analyzed using SPSS 26, the research findings revealed a significant improvement in the students’ performance in using English modals following the intervention. Additionally, the participants reported that the systematic explanation of modal verbs enhanced their ability to distinguish between social and logical functions of EMV more effectively than traditional methods. Ultimately, this study provides valuable insights into the perception of modal verbs among Vietnamese EFL learners, with implications for English language teaching and curriculum design

High Performance and Polarisation Insensitive BER Assessment of a 42.66 Gbit/s All-Optical Clock Recovery

regular session Mo.3.C « Towards 100 Gb/s » [Mo.3.C.6]International audienceWe propose a Bit-Error Rate assessment, and polarisation sensitivity characterization of an all-optical clock-recovery at 42.66 Gbit/s in a system environment

Place-based education: outdoor and environmental education approaches

By analyzing the relationships among place-based education, outdoor education, and environmental education, the authors developed the proposal for the practical work in place-based education and its application to guide instruction and research in Vietnam. Some examples are given as evidence. Trên cơ sở phân tích các mối quan hệ giữa giáo dục tại thực địa, ngoài lớp học và giáo dục môi trường của những tác giả khác. Các tác giả phát triển chương trình định hướng thực hành trong giáo dục môi trường tại thực địa để ứng dụng trong giảng dạy và nghiên cứu tại Việt Nam. Các ví dụ được đề cập như là những minh chứng thực tiễn

Caractérisation de dispositifs de récupération d'horloge tout-optique par la mesure de taux d'erreur binaire

session affiches A5 « Systèmes et Réseaux de télécommunications » [A5.2]National audienceNous proposons de caractériser différentes récupérations d'horloge tout-optiques, à base de lasers auto-pulsants à semiconducteurs, par la mesure de taux d'erreur binaire à 42,66 Gbit/s. Nous utilisons pour cela une technique de remodulation de l'horloge optique qui permet, via la mesure de taux d'erreur binaire, de comparer leurs performances et de quantifier leur sensibilité à la polarisation

Characterisation of semiconductor optical amplifiers for all-optical regeneration

OralInternational audienceWe report on the characterisations of different semiconductor optical amplifiers (SOA) which are designed and fabricated for All-Optical Regeneration. Dynamic measurements in pump-probe configuration show short time response of around 50 ps. Chirp measurements by FROG technique are also reported. The characterisations demonstrate the potential of these components to be associated with interferometer and optical filtering in order to achieve regeneration functions at bit rates of 40 Gbit/s and above