Channel-aware low Earth orbit satellite cluster networking for space-to-Earth laser communication: reliability and bandwidth advantages.

The reliability of the space-to-Earth laser communication plays a crucial role in providing uninterrupted real-time services in satellite optical networks. In traditional satellite optical networks, the space-to-Earth laser communication is carried out using a monolithic satellite in close proximity to the target optical ground station. However, the reliability of the communication in this approach is heavily influenced by the atmospheric environment. For instance, variations in cloud thickness can cause fluctuations in the link quality of the space-to-Earth laser communication, significantly reducing its reliability. This study proposes an innovative channel-adaptive space-to-Earth laser communication (CA-S2E-LC) architecture based on satellite cluster optical networking (SCON). SCON provides space-diversity link sets, reducing the probability of space-to-Earth laser communications affected by clouds. By leveraging the perception of link quality, the CA-S2E-LC architecture can adaptively choose the better space-to-Earth laser communication links established by member satellites within a satellite cluster under different environments, and properly schedule the resource, ensuring reliable space-to-Earth laser communication. The principles of the SCON is analyzed and the implementation of the CA-S2E-LC architecture is demonstrated through the explanation of hardware and functional modules, workflows, finite state machines, and strategies. Simulation results demonstrate that the CA-S2E-LC architecture can significantly enhance communication reliability and capacity compared with the traditional monolithic satellite. Furthermore, the workflow of the architecture is demonstrated to validate the feasibility.

Related Risk Factors of Early Childhood Caries in Zhejiang Province, China During the COVID-19 Pandemic.

Objectives: This work aims to examining the latest early childhood caries situation in children aged 3 and 5 and its related risk factors in Zhejiang Province during the COVID-19 pandemic. Method: There are 3,537 children and their main caregivers participate in this study. We used chi square test or U-test to analyze whether there were differences in the prevalence of dental caries under different variables. The risk factors on ECC were determined by multivariate logistic analysis. Results: The ECC rate of children in this study was 57.51%. The mean decayed missing filled teeth (dmft) scores were 3.01. The result of multivariate logistic analysis showed higher ECC prevalence was found in children as age increasing, with lower district economic level, with high frequency of confectionary consumption, having oral medical treatment behavior and bad evaluation of children's oral health by parents. Conclusion: In general, the prevalence rate of ECC in this study was lower than five years ago, but still higher than those developed countries. And it was associated with age, district economic level, frequency of confectionary consumption, oral medical treatment behavior and evaluation of children's oral health by parents.

Guardian Factors Affecting High Prevalence of Dental Caries in Preschool Children.

PURPOSE: This study analysed the relationship between caregiver-related factors (dental knowledge, attitude, behaviour, and health status) and early childhood caries. ?It aimed to explore better intervention methods for reducing caries prevalence in preschool children. MATERIALS AND METHODS: This cross-sectional investigation was carried out in Zhejiang, China. A total of 1344 guardians (parents and grandparents) paired with their children aged 3-5 years old were enrolled. The guardians completed structured questionnaires, which included their attitude, knowledge level and oral health status. The children received dental examinations. All of the data ?were analysed with R software. Chi-squared and Fisher's exact tests were used to analyse different variables. Multinomial logistic regression with stepwise procedures and curve fitting was used to explore the relationship between guardians' risk factors and the level of early childhood caries. RESULTS: Guardians have a great influence on the incidence of early childhood dental caries. ?When guardians pay attention to oral health and have a good command of relevant knowledge, then the risk of early dental caries in children is low (p = 0.027). The guardians' dental problems?, e.g. dental caries (p = 0.0002), gingival bleeding problems (p = 0.049) and chewing discomfort experience (p = 0.049), demonstrated ?statistically significant correlations with early childhood caries levels?. CONCLUSION: Guardians' attitudes, knowledge, and oral health status ?had a statistically significant relationship with the level of early childhood caries? in their children/grandchildren. Instead of instructing schoolchildren about oral health, multiple-level dental knowledge instruction of guardians is needed to prevent early childhood caries.

Association of high-density lipoprotein cholesterol and periodontitis severity in Chinese elderly: a cross-sectional study.

OBJECTIVES: Periodontitis is a local inflammatory disease of high prevalence worldwide. Increasing evidence has shown its association with cardiovascular diseases. While high-density lipoprotein is an important protective factor in preventing cardiovascular diseases, this study aims to examine whether high-density lipoprotein cholesterol (HDL-C) level is associated with different status of periodontitis. MATERIALS AND METHODS: A total of 874 Chinese retirees (≥ 60 years of age) with different statuses of periodontitis were enrolled. Periodontal clinical data were collected to define periodontal disease severity (no, mild-moderate, severe). Peripheral blood was collected for serum lipid profile analysis. Linear and logistic regression analysis with adjustment for potential confounders (gender, age, BMI, alcohol intake, exercise frequency, smoking habits) were used to determine the association of periodontitis with HDL-C. RESULTS: After adjustments for confounders, linear regression analyses revealed a significant relationship between the decreased HDL-C and periodontitis severity (p < 0.05). Although the multivariable-adjusted ORs of decreased HDL-C were not statistically significant, logistic regression analyses showed Chinese elderly with severe periodontitis had higher odds of exhibiting clinically abnormal HDL-C levels than those without periodontitis. CONCLUSIONS: The elderly population with periodontitis showed HDL-C levels significantly lower than those without periodontitis. The severity of periodontitis was positively correlated with serum HDL-C levels. CLINICAL RELEVANCE: Periodontitis reduces HDL-C level in the elderly population, indicating that oral health should be paid attention to in the prevention and treatment of dyslipidemia.