Assisted reproductive techniques offer a valuable tool for rescuing deceased germplasm for the establishment of replacement stock as well as conservation of valuable/threatened germplasm. The techniques assume greater importance for the preservation of the adapted dairy germplasm raised through decades of up-gradation using exotic semen, especially in the ecologically sensitive Himalayan region. Gamete retrieval from deceased animals is of special importance in countries where cattle slaughter is prohibited, thus rendering the abattoir-derived gonad availability impossible. The present study envisages the developmental competence of oocytes retrieved from dead Jersey cows. From 112 ovaries, derived from 56 deceased cows, 847 COCs were recovered and grouped by post-mortem interval (PMI): 0–6 h (Group I) versus 6–12 h (Group II). The proportion of Grade A & B oocytes did not differ significantly between the groups (65.4% vs. 59.0%). In vitro maturation (IVM) was significantly higher in group I (80.6 ± 2.0%) than in group II (46.2 ± 2.7%; p < 0.0001). With unsexed semen, cleavage was higher in Group I than Group II (55.7 ± 5.9% vs. 38.3 ± 7.9%; p = 0.012); while blastocyst yield showed only a non-significant trend in favour of Group I. Sex-sorted semen reduced cleavage and blastocyst rates overall, with no significant difference between groups. On days 7–8, 44 blastocysts from Group I and 2 from Group II were vitrified. Survival after thawing was 90.9% (40/44) and 100% (2/2), respectively. The results demonstrated that post-mortem ovaries from naturally deceased Jersey cows can supply developmentally competent oocytes suitable for IVEP, though demanding further technical refinements to be at par with the results obtained from oocyte retrieval from live animals using the OPU technique.
Some important aspects of the history of ethnogenesis in South Siberia have been reconstructed using data on two Y-haplogroups: N-M178 (n = 113) and O-M175 (n = 24). In Tuvans, who make up two-thirds of the indigenous South Siberian population, these haplogroups constitute 20% of the gene pool, and their branches form well discriminated ethno-specific clusters within the phylogenetic network of 37 Y-STR marker haplotypes. N-Y24317(xB499) is thought to have arrived in Tuva from Mongolia or Northwest China during the Bronze Age or Early Iron Age. According to our hypothesis, the spread of N-Y16319(xY16223) and N-Y16223(xZ35328, F2288) with DYS385 = 11,11 is linked to the development of the Ulug-Khem culture in Tuva around 2100 YBP as a result of the growth and expansion of the Xiongnu. Three branches (N-Z35328, N-F2288, N-Y16223(xZ35328, F2288) with DYS385 = 11,13) widespread among the Turkic-Mongolian populations are rare in Tuvans. The arrival of these haplogroups, as well as O-M175, in Tuva is associated with the Medieval Mongol expansion. However, the Turkic-Mongolian contribution of O-M175 to the Tuvan gene pool is insignificant: the ancestors of most Tuvan lineages might have been the Han forcibly moved by the Yuan Empire to the settlements of craftsmen and farmers located in what is now the territory of modern Tuva.
In this study, the trajectory planning and control problem for quadrotor unmanned aerial vehicles (UAVs) in logistics-oriented delivery scenarios. A smooth trajectory generation method based on spline curves is proposed to ensure continuous, stable, and feasible flight paths for quadrotor UAVs under dynamic constraints. The proposed method focuses on general UAV path planning rather than a specific express delivery optimization problem. A simulation platform is developed to evaluate the effectiveness of the trajectory planning and control framework, where a PID-based controller is implemented for trajectory tracking and attitude stabilization. The performance of the proposed method is validated through two representative emergency delivery scenarios, demonstrating accurate path tracking and stable flight behavior under environmental disturbances. The results indicate that the proposed framework provides a reliable simulation tool for UAV trajectory planning and control analysis, contributing to general UAV motion planning research rather than a specific delivery optimization formulation.
Against the backdrop of homogeneous mass tourism, reverse tourism, as a trend where tourists avoid popular destinations and pursue niche experiences, is reshaping the paradigm of rural tourism development. This paper systematically analyzes the connotation, framework, and feasibility of reverse tourism using comparative analysis, model derivation, and practical verification. The study reveals that reverse tourism is characterized by three key dimensions: reflection on the essence of tourism, aberration in tourist behavior, and distinction in tourist experience, forming a dynamic cycle mechanism of “willingness-behavior-experience”. Additionally, centering on tourists is crucial for constructing the analytical framework, classifying visitors based on their travel participation history, and creating a role transition matrix, which helps uncover the endogenous driving forces of tourist behavior. Furthermore, evolving tourist demands, improvements in rural public services, and the successful replication of “small yet beautiful” models have created favorable conditions for implementing reverse tourism in rural areas. Finally, the virtuous cycle of “protection-development-benefit” formed by supply-demand coupling provides a systematic solution for rural revitalization that balances ecology, culture, and economy. This paper systematically expounds the theoretical logic, mechanism, and practical path of reverse tourism as a new paradigm for rural tourism transformation, offering research conclusions with both theoretical innovation and practical guidance for promoting rural sustainable development.
Tidal range power plants (TPPs) are reliable electricity generators with the la Rance TPP in France serving as an example of long-term (60+ years) s uccess. Despite their potential for energy delivery, the challenges surrounding TPP development remain substantial. High initial investment and concerns about environmental impacts on marine ecosystems have made it difficult to progress major proposals. With rising sea levels and more frequent, intense storm surges expected to lead to greater inundation of key coastal zones, co-benefits to ecosystems and infrastructure that TPPs may offer are being reconsidered. Using the UK as a case study, we map appropriate tidal resource (>5 m tidal range), 2050 1:25 flood risk areas (1 m rise), coastal zones with conservation specification and areas of high human density. Overlap in these factors reveals specific locations in which further research would usefully estimate potential costs and benefits, socially, ecologically and financially. Viewed together, reduced flood risk to people and infrastructure, ecosystem conservation opportunity and stable energy generation may highlight the future opportunity of TPPs.
