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The objective of the present study was to describe the aspects of feeding habit and lengthweight relationship of keureling fish Tor tambra, this information is crucial to plan a conservation startegy for this species. A series of samples were taken between June and September 2012 and February 2014 in the two main rivers of western Aceh i.e. the Sikundo and Nagan Rivers. A total of 48 and 38 fish were caught during the study in Nagan and Sikundo Rivers, respectively. Stomach content analysis suggested that freshwater green algae and earthworms were the main food items for T. tambra, indicating an omnivorous feeding habit. In addition, the length-weight relationship revealed that T. tambra has an allometric negative growth pattern from all populations, and the condition factors indicate the rivers are still in good condition and support fish life.

Background The prevalence of smoking among adolescents is high in Indonesia. Therefore, this qualitative research aimed to explore the perspectives of Muslim adolescents on smoking habits as a reference for developing effective prevention programs. Methods Three focus group discussions involving 24 junior high school male students (mean age = 13.75 years) were the main source of data for this phenomenological qualitative study. The discussion guide was developed by the researchers based on the reviewed literature and validated by experts. The research findings were analyzed using an inductive content analysis with systematic steps based on the stages of qualitative data analysis. Results Adolescent perspectives on smoking were grouped into two themes: perception of smoking and smoking-related factors. The perception of smoking encompassed three sub-themes: smoking as a social habit, contradictive feelings, and the Islamic perspective. The smoking-related factors included peer pressure, the parents’ smoking status, masculinity and curiosity. The results indicated that adolescents consider smoking as a social habit but with contradictory feelings. The smoking habit was also stimulated by peer pressure, imitating parents who smoke, feeling masculine and curiosity. Conclusion We suggest that health professionals who are interested in developing smoking prevention programs in Indonesia should consider the adolescent perspective on smoking so that the prevention program will be more effective and appropriate for adolescents.

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Carbon dots (CDs) have generated much interest because of their significant fluorescence (FL) properties, extraordinary photophysical attributes, and long-term colloidal stability. CDs have been regarded as a prospective carbon nanomaterial for various sensing applications because of their low toxicity, strong and broad optical absorption, high chemical stability, rapid transfer properties, and easy modification. To improve their functionality, CD/polymer composites have been developed by integrating polymers into CDs. CD/polymer composites have diversified because of their easy preparation and applications in sensing, optoelectronics, semiconductors, molecular delivery, and various commercial fields. Many review articles are available regarding the preparation and applications of CDs. Some review articles describing the production and multiple applications of the composites are available. However, no such article has focused on the types of precursors, optical properties, coating characteristics, and specific sensing applications of CD/polymer composites. This review aimed to highlight and summarize the current progress of CD/polymer composites in the last five years (2017–2021). First, we overview the precursors used for deriving CDs and CD/polymer composites, synthesis methods for preparing CDs and CD/polymer composites, and the optical properties (absorbance, FL, emission color, and quantum yield) and coating characteristics of the composites. Most carbon and polymer precursors were dominated by synthetic precursors, with citric acid and polyvinyl alcohol widely utilized as carbon and polymer precursors, respectively. Hydrothermal treatment for CDs and interfacial polymerization for CDs/polymers were frequently performed. The optical properties of CDs and CD/polymer composites were almost identical, denoting that the optical characters of CDs were well-maintained in the composites. Then, the chemical, biological, and physical sensing applications of CD/polymer composites are categorized and discussed. The CD/polymer composites showed good performance as chemical, biological, and physical sensors for numerous targets based on FL quenching efficiency. Finally, remaining challenges and future perspectives for CD/polymer composites are provided.