Nanning Normal University

The OCDMA network using two Dimensional Variable-Weight Optical Orthogonal Codes (2D VWOOC) can support diverse Quality of Services (QoS) classes and multimedia services, and make the better use of bandwidth resources in fiber optical networks. To simplify practical implementation, the At Most One-Pulse Per Wavelength (AM-OPPW) restriction is often appended to a 2D VWOOC. In this paper, the upper bound on the size of AM-OPPW 2D VWOOCs is derived, semicyclic group divisible designs are introduced to construct AM-OPPW 2D VWOOCs, and an equivalence between optimal AM-OPPW 2D VWOOCs and Semicyclic Group Divisible Designs (SCGDDs) is established. Some direct and recursive constructions for SCGDDs are also presented. Consequently, several infinite families of optimal AM-OPPW 2D VWOOCs are obtained.

In this study, we explore how to balance the preservation of the original appearance of ancient villages with their development within the framework of World Heritage protection. We applied resilience theory and constructed a simple checklist, taking cultural ecosystem services into consideration, and selected the Zuojiang Huashan Rock Art Heritage Area in China for field investigation, as well as conducted in-depth interviews, the distribution of short questionnaires, and two rounds of Delphi surveys. This comprehensive approach enabled us to discover the key cultural ecosystem services that villagers rely on for their livelihoods. Then, we tracked how these services enhanced buffering capacity, helped people self-organize, and promoted adaptive learning. The results show that cultural ecosystem services constitute the core framework of the social–ecological resilience of the villages. The quantity and combination of the services directly determine the resilience score, and the resilience of villages within the heritage area shows significant spatial differentiation. High-resilience villages have diverse and mutually reinforcing cultural ecosystem services and local community rules, while low-resilience villages face service loss, weakened social connections, and single development options. Through this study, we aim to further enrich the cultural connotation of resilience theory, provide a practical assessment tool for practitioners of the method, and offer practical guidance and suggestions for transforming heritage protection from static protection to a dynamic, vibrant system that promotes vitality and resilience in practice.

Understanding how different land-use types shape soil bacterial communities and functions is critical for promoting sustainable land management and ecological restoration in fragile karst regions. This study evaluated the effects of different land-use types (pitaya [HF], maize [MF], sugarcane [SF], and paddy [PF] fields, forestland [FL], and grassland [AF]) on soil bacterial diversity, community composition, functional potentials, and co-occurrence networks in karst regions. The results showed that HF, MF, and PF exhibited the highest bacterial diversity (Shannon index), whereas SF had the lowest possibly because of continuous cropping and fertilization. Variance partitioning analysis revealed that soil bacterial community composition and functional potential were largely explained by the combined effects of land-use type and soil properties (34.8% for composition and 59.7% for functional potential), suggesting that land-use effects on bacterial communities are mainly mediated through changes in soil physicochemical properties. Hierarchical partitioning analysis further identified that soil texture, particularly silt and sand, and pH were the primary factors shaping bacterial community composition, whereas pH was the dominant driver of functional potential. Functional analysis indicated that HF enhanced nitrogen cycling processes, such as nitrification, aerobic nitrite oxidation, and aerobic ammonia oxidation; SF promoted carbon-related functions, including chemoheterotrophy, aerobic chemoheterotrophy, and cellulolysis; and PF favored iron and sulfur respiration. Co-occurrence network analysis demonstrated that HF had the most complex microbial interactions, likely attributable to no-tillage practices and favorable soil conditions, whereas PF showed the lowest network connectivity. Core bacterial groups such as Acidobacteria, Proteobacteria, Chloroflexi, and Actinobacteria, dominated in abundance but also functioned as keystone taxa, suggesting their critical roles in driving nutrient cycling and maintaining ecological stability. These findings suggest that no-till pitaya cultivation may help improve soil microbial diversity, functional potential, and ecological stability in fragile karst ecosystems, indicating its potential as a sustainable agricultural land-use practice. However, long-term monitoring and adaptive management are necessary to ensure sustained soil health.