Island ecosystems,serving as natural laboratories,facilitate geographical isolation,ecological specialization,and species divergence.The Sichuan Basin,surrounded by mountain ranges,represents a typical continental isl...Island ecosystems,serving as natural laboratories,facilitate geographical isolation,ecological specialization,and species divergence.The Sichuan Basin,surrounded by mountain ranges,represents a typical continental island due to its marked environmental spatial heterogeneity.This heterogeneity may contribute to geographical isolation and habitat heterogeneity,resulting in genetic divergence within populations.Therefore,we used the White-browed Laughingthrush(Garrulax sannio)as a model specimen to investigate the genetic divergence in the Sichuan Basin and its surrounding mountain ranges,given its presence in various habitats within and beyond this basin.Employing a RAD-seq dataset of 140 G.sannio individuals from 17 distinct ecological zones in the Sichuan Basin and its surrounding mountain ranges,we conducted PCA,population structure analysis,phylogenetic tree construction,and gene flow analysis to comprehensively analyze G.sannio groups.Additionally,in conjunction with geographical and ecological data,we performed isolation by distance,isolation by environment,PCA,and latent factor mixed model analysis to identify factors influencing the genetic divergence among these G.sannio groups.In summary,the 17 G.sannio groups were categorized into high-elevation,medium-elevation,and lowelevation groups.Genetic divergence in G.sannio may be attributed to both geographical distance and key ecological factors,particularly elevation and key climatic variables.Notably,the high-elevation group exhibited a greater number of SNPs and selected genes associated with the key ecological factors compared to the lowelevation group.The ADCY9 gene and several associated key pathways were identified as crucial elements driving ecological adaptation(elevation and key climatic variables)in the high-elevation group.Furthermore,climate changes during the glacial cycles may have facilitated gene flow among these groups residing in the Sichuan Basin and its surrounding mountain ranges.Our findings provide evidence of genetic divergence in G.sannio influenced by the geographical distance and key ecological factors between the Sichuan Basin and its surrounding mountain ranges.These results lay the groundwork for future research on the molecular systematics of continental islands.展开更多
Background:As one of the reproductive strategies adopted by bird species,variation in investment in egg production and its influencing factors are important and well-studied subjects.Intraclutch changes in egg size as...Background:As one of the reproductive strategies adopted by bird species,variation in investment in egg production and its influencing factors are important and well-studied subjects.Intraclutch changes in egg size associated with laying order may reflect a strategy of"brood survival"or"brood reduction"adopted by female birds in different situations.Methods:We conducted field studies on the breeding parameters of the Saxaul Sparrow(Passer ammodendri)in Gansu Province,China from 2010 to 2017,to clarify the factors affecting the egg investment and reproductive performance of this passerine species.Results:Our results revealed significant differences in clutch size,egg size and the fledging rate between the first and second brood of Saxaul Sparrows and suggested that this typical desert species allocates more breeding resources to the more favourable second brood period,leading to greater reproductive output.Female body size presented a positive relationship with egg size,and male body size presented positive relationships with clutch size and hatchability.The females that started their clutches later laid more eggs,and hatchability and the fledging rate also increased with a later laying date in the first brood period.With successive eggs laid within the 5-egg clutches(the most frequent clutch size),egg size increased for the first three eggs and then significantly decreased.Conclusions:Our results indicate that female Saxaul Sparrows increased egg investment because of good quality of paired males and good environmental conditions.The intraclutch variation of egg size suggests that this species inhabiting an arid environment adopts a"brood reduction"strategy.展开更多
Dust aerosols profoundly influence the radiative balance of the earth–atmosphere system and hence the global and regional climates.In this study,using multi-source satellite and ground-level observations combined wit...Dust aerosols profoundly influence the radiative balance of the earth–atmosphere system and hence the global and regional climates.In this study,using multi-source satellite and ground-level observations combined with meteorological data,we investigated the three-dimensional evolution and transport characteristics of aerosols during a dust event that occurred in Xinjiang,China from 19 to 21 March 2019.Analysis of the meteorological data reveals that the dust air mass initially appeared in the northwest of Xinjiang and was subsequently transported to the Hami and Turpan areas due to the prevailing northwesterly winds,after which the direction of the airflow shifted due to topography,and the dust air masses were transported into southern Xinjiang.The air quality in the affected areas decreased rapidly,accompanied by a significant increase in aerosol optical depth (AOD),with the maximum value exceeding 3.5 in some areas.In addition,the Cloud–Aerosol Lidar and Infrared Pathfinder Satellite Observations(CALIPSO) data reveal that the aerosol particles in the dust-affected areas were mainly dust aerosols,with small amounts of pollutant dust aerosols.A reduction in the attenuated backscatter coefficient (β532||) was found with increasing altitude,with the dust aerosol pollution mainly distributed in the lower troposphere.The size of dust particles in the lower troposphere was relatively small and irregular.The depolarization ratio (PDR) values at altitudes of 8–10 km were relatively lower than those recorded in the lower troposphere,whereas the color ratio (CR)values were higher,which may have been influenced by the sparse vegetation coverage and poor subsurface conditions in Xinjiang,and attributable to the fact that regular large particles of dust are more likely to be dispersed to altitudes between 8 and 10 km within a short period of time.As a consequence of the meteorological conditions and topography,the dusting process in Xinjiang persisted for a relatively long period.These findings will contribute to enhanced understanding of the vertical distribution of aerosols in Northwest China.展开更多
Automatically generating test cases by evolutionary algorithms to satisfy the path coverage criterion has attracted much research attention in software testing.In the context of generating test cases to cover many tar...Automatically generating test cases by evolutionary algorithms to satisfy the path coverage criterion has attracted much research attention in software testing.In the context of generating test cases to cover many target paths,the efficiency of existing methods needs to be further improved when infeasible or difficult paths exist in the program under test.This is because a significant amount of the search budget(i.e.,time allocated for the search to run)is consumed when computing fitness evaluations of individuals on infeasible or difficult paths.In this work,we present a feedback-directed mechanism that temporarily removes groups of paths from the target paths when no improvement is observed for these paths in subsequent generations.To fulfill this task,our strategy first organizes paths into groups.Then,in each generation,the objective scores of each individual for all paths in each group are summed up.For each group,the lowest value of the summed up objective scores among all individuals is assigned as the best aggregated score for a group.A group is removed when no improvement is observed in its best aggregated score over the last two generations.The experimental results show that the proposed approach can significantly improve path coverage rates for programs under test with infeasible or difficult paths in case of a limited search budget.In particular,the feedback-directed mechanism reduces wasting the search budget on infeasible paths or on difficult target paths that require many fitness evaluations before getting an improvement.展开更多
基金supported by the National Science Foundation of China(31372171)Leshan Normal University research grants(205210094,ZZ201805,CGZZ202002,205220114,DGZZ202006).
文摘Island ecosystems,serving as natural laboratories,facilitate geographical isolation,ecological specialization,and species divergence.The Sichuan Basin,surrounded by mountain ranges,represents a typical continental island due to its marked environmental spatial heterogeneity.This heterogeneity may contribute to geographical isolation and habitat heterogeneity,resulting in genetic divergence within populations.Therefore,we used the White-browed Laughingthrush(Garrulax sannio)as a model specimen to investigate the genetic divergence in the Sichuan Basin and its surrounding mountain ranges,given its presence in various habitats within and beyond this basin.Employing a RAD-seq dataset of 140 G.sannio individuals from 17 distinct ecological zones in the Sichuan Basin and its surrounding mountain ranges,we conducted PCA,population structure analysis,phylogenetic tree construction,and gene flow analysis to comprehensively analyze G.sannio groups.Additionally,in conjunction with geographical and ecological data,we performed isolation by distance,isolation by environment,PCA,and latent factor mixed model analysis to identify factors influencing the genetic divergence among these G.sannio groups.In summary,the 17 G.sannio groups were categorized into high-elevation,medium-elevation,and lowelevation groups.Genetic divergence in G.sannio may be attributed to both geographical distance and key ecological factors,particularly elevation and key climatic variables.Notably,the high-elevation group exhibited a greater number of SNPs and selected genes associated with the key ecological factors compared to the lowelevation group.The ADCY9 gene and several associated key pathways were identified as crucial elements driving ecological adaptation(elevation and key climatic variables)in the high-elevation group.Furthermore,climate changes during the glacial cycles may have facilitated gene flow among these groups residing in the Sichuan Basin and its surrounding mountain ranges.Our findings provide evidence of genetic divergence in G.sannio influenced by the geographical distance and key ecological factors between the Sichuan Basin and its surrounding mountain ranges.These results lay the groundwork for future research on the molecular systematics of continental islands.
基金supported by the National Natural Science Foundation of China(Grant Nos.31672296 and 31172104)。
文摘Background:As one of the reproductive strategies adopted by bird species,variation in investment in egg production and its influencing factors are important and well-studied subjects.Intraclutch changes in egg size associated with laying order may reflect a strategy of"brood survival"or"brood reduction"adopted by female birds in different situations.Methods:We conducted field studies on the breeding parameters of the Saxaul Sparrow(Passer ammodendri)in Gansu Province,China from 2010 to 2017,to clarify the factors affecting the egg investment and reproductive performance of this passerine species.Results:Our results revealed significant differences in clutch size,egg size and the fledging rate between the first and second brood of Saxaul Sparrows and suggested that this typical desert species allocates more breeding resources to the more favourable second brood period,leading to greater reproductive output.Female body size presented a positive relationship with egg size,and male body size presented positive relationships with clutch size and hatchability.The females that started their clutches later laid more eggs,and hatchability and the fledging rate also increased with a later laying date in the first brood period.With successive eggs laid within the 5-egg clutches(the most frequent clutch size),egg size increased for the first three eggs and then significantly decreased.Conclusions:Our results indicate that female Saxaul Sparrows increased egg investment because of good quality of paired males and good environmental conditions.The intraclutch variation of egg size suggests that this species inhabiting an arid environment adopts a"brood reduction"strategy.
基金Supported by the National Natural Science Foundation of China(41771470).
文摘Dust aerosols profoundly influence the radiative balance of the earth–atmosphere system and hence the global and regional climates.In this study,using multi-source satellite and ground-level observations combined with meteorological data,we investigated the three-dimensional evolution and transport characteristics of aerosols during a dust event that occurred in Xinjiang,China from 19 to 21 March 2019.Analysis of the meteorological data reveals that the dust air mass initially appeared in the northwest of Xinjiang and was subsequently transported to the Hami and Turpan areas due to the prevailing northwesterly winds,after which the direction of the airflow shifted due to topography,and the dust air masses were transported into southern Xinjiang.The air quality in the affected areas decreased rapidly,accompanied by a significant increase in aerosol optical depth (AOD),with the maximum value exceeding 3.5 in some areas.In addition,the Cloud–Aerosol Lidar and Infrared Pathfinder Satellite Observations(CALIPSO) data reveal that the aerosol particles in the dust-affected areas were mainly dust aerosols,with small amounts of pollutant dust aerosols.A reduction in the attenuated backscatter coefficient (β532||) was found with increasing altitude,with the dust aerosol pollution mainly distributed in the lower troposphere.The size of dust particles in the lower troposphere was relatively small and irregular.The depolarization ratio (PDR) values at altitudes of 8–10 km were relatively lower than those recorded in the lower troposphere,whereas the color ratio (CR)values were higher,which may have been influenced by the sparse vegetation coverage and poor subsurface conditions in Xinjiang,and attributable to the fact that regular large particles of dust are more likely to be dispersed to altitudes between 8 and 10 km within a short period of time.As a consequence of the meteorological conditions and topography,the dusting process in Xinjiang persisted for a relatively long period.These findings will contribute to enhanced understanding of the vertical distribution of aerosols in Northwest China.
基金supported by the National Natural Science Foundation of China(No.61876207)the Natural Science Foundation of Guangdong Province(No.2022A1515011491)the Fundamental Research Funds for the Central Universities(No.2020ZYGXZR014).
文摘Automatically generating test cases by evolutionary algorithms to satisfy the path coverage criterion has attracted much research attention in software testing.In the context of generating test cases to cover many target paths,the efficiency of existing methods needs to be further improved when infeasible or difficult paths exist in the program under test.This is because a significant amount of the search budget(i.e.,time allocated for the search to run)is consumed when computing fitness evaluations of individuals on infeasible or difficult paths.In this work,we present a feedback-directed mechanism that temporarily removes groups of paths from the target paths when no improvement is observed for these paths in subsequent generations.To fulfill this task,our strategy first organizes paths into groups.Then,in each generation,the objective scores of each individual for all paths in each group are summed up.For each group,the lowest value of the summed up objective scores among all individuals is assigned as the best aggregated score for a group.A group is removed when no improvement is observed in its best aggregated score over the last two generations.The experimental results show that the proposed approach can significantly improve path coverage rates for programs under test with infeasible or difficult paths in case of a limited search budget.In particular,the feedback-directed mechanism reduces wasting the search budget on infeasible paths or on difficult target paths that require many fitness evaluations before getting an improvement.