The artemisia weevil, Adosomus sp., has become an important wormwood （Artemisa ordosoca and A. sphaerocephala） pest in recent years in Ningxia Province, China. The number of larval instars should be determined befor...The artemisia weevil, Adosomus sp., has become an important wormwood （Artemisa ordosoca and A. sphaerocephala） pest in recent years in Ningxia Province, China. The number of larval instars should be determined before further studies on its life history, biology and integrate management of pest （IMP）. In this study, we measured the length and width of head capsule, based on frequency histograms and Dyar＇s law, from which we concluded that the larvae ofAdosomus sp. have four instars. Of the two variables measured, the width of head capsule provided the best division of instars. The average width of head capsule of the 1st instar larvae was 1.348±0.152 mm, the 2nd 2.109±0.199 mm, the 3rd 3.563±0.492 mm and the 4th 5.974±0.581 mm.展开更多
Farmland protection and delimitation in the urban fringe considers not only natural factors but also the spatial characters and site factors. Taking Daxing District, Beijing in China as a case study, this paper used l...Farmland protection and delimitation in the urban fringe considers not only natural factors but also the spatial characters and site factors. Taking Daxing District, Beijing in China as a case study, this paper used landscape ecology and power-law methods to ana- lyze and evaluate farmland loss during the period of 2004~2007 based on the interpretation results of SPOT5 remote sensing images in 2004 and 2007. At the patch level, we selected four landscape indices, namely patch size, shape index, the nearest neighbor distance between farmland and construction land （including residential land and other construction land）, and cropping type, to evaluate the risk of farmland loss and establish a farmland site analysis indicator system. The results showed that patch size and shape index have a sig- nificant positive correlation with farmland loss, whereas the distance to construction land has a clear negative correlation with farmland loss. As regards cropping type, fallow farmland is much easier for non-agriculUlral use than cultivated farmland. The relative transition ratio among vegetable land, fallow farmland and cultivated farmland is 1 ： 5.6 ： 1. The patch size of lost farmland follows a power-law distribution, indicating that not only small parcels but also large parcels can be lost. Patch size less than 4 ha or more than 15 ha is in high loss risk, between 4 ha and 10 ha in medium loss risk, and larger than 10 ha and less than 15 ha in low risk. Farmland with a more regular shape has a higher likelihood of loss. Patch shape index less than 2.0 is in high loss risk, between 2.0 and 3.0 in medium loss risk, and larger than 3.0 in low risk. Construction land has a varying impact on farmland loss, the residential land effeeted distance is 1000 m, and that of the other construction land is 2000 m. This analysis showed the relationships between site factors and farmland loss, and the analysis framework can provide support and reference for farmland protection and delimitation of prime farmland in China.展开更多
This paper mainly studies the strong convergence properties for weighted sums of extended negatively dependent(END,for short)random variables.Some sufficient conditions to prove the strong law of large numbers for wei...This paper mainly studies the strong convergence properties for weighted sums of extended negatively dependent(END,for short)random variables.Some sufficient conditions to prove the strong law of large numbers for weighted sums of END random variables are provided.In particular,the authors obtain the weighted version of Kolmogorov type strong law of large numbers for END random variables as a product.The results that the authors obtained generalize the corresponding ones for independent random variables and some dependent random variables.As an application,the authors investigate the errors-in-variables(EV,for short)regression models and establish the strong consistency for the least square estimators.Simulation studies are conducted to demonstrate the performance of the proposed procedure and a real example is analysed for illustration.展开更多
基金supported by the National Project of ScienceTechnology for the 11th Five-Year Plan in China (Grant No. 2006BADO8A12)
文摘The artemisia weevil, Adosomus sp., has become an important wormwood （Artemisa ordosoca and A. sphaerocephala） pest in recent years in Ningxia Province, China. The number of larval instars should be determined before further studies on its life history, biology and integrate management of pest （IMP）. In this study, we measured the length and width of head capsule, based on frequency histograms and Dyar＇s law, from which we concluded that the larvae ofAdosomus sp. have four instars. Of the two variables measured, the width of head capsule provided the best division of instars. The average width of head capsule of the 1st instar larvae was 1.348±0.152 mm, the 2nd 2.109±0.199 mm, the 3rd 3.563±0.492 mm and the 4th 5.974±0.581 mm.
基金Under the auspices of National Natural Science Foundation of China(No.41130526)Beijing Municipal Natural Science Foundation(No.8122020)
文摘Farmland protection and delimitation in the urban fringe considers not only natural factors but also the spatial characters and site factors. Taking Daxing District, Beijing in China as a case study, this paper used landscape ecology and power-law methods to ana- lyze and evaluate farmland loss during the period of 2004~2007 based on the interpretation results of SPOT5 remote sensing images in 2004 and 2007. At the patch level, we selected four landscape indices, namely patch size, shape index, the nearest neighbor distance between farmland and construction land （including residential land and other construction land）, and cropping type, to evaluate the risk of farmland loss and establish a farmland site analysis indicator system. The results showed that patch size and shape index have a sig- nificant positive correlation with farmland loss, whereas the distance to construction land has a clear negative correlation with farmland loss. As regards cropping type, fallow farmland is much easier for non-agriculUlral use than cultivated farmland. The relative transition ratio among vegetable land, fallow farmland and cultivated farmland is 1 ： 5.6 ： 1. The patch size of lost farmland follows a power-law distribution, indicating that not only small parcels but also large parcels can be lost. Patch size less than 4 ha or more than 15 ha is in high loss risk, between 4 ha and 10 ha in medium loss risk, and larger than 10 ha and less than 15 ha in low risk. Farmland with a more regular shape has a higher likelihood of loss. Patch shape index less than 2.0 is in high loss risk, between 2.0 and 3.0 in medium loss risk, and larger than 3.0 in low risk. Construction land has a varying impact on farmland loss, the residential land effeeted distance is 1000 m, and that of the other construction land is 2000 m. This analysis showed the relationships between site factors and farmland loss, and the analysis framework can provide support and reference for farmland protection and delimitation of prime farmland in China.
基金supported by the National Natural Science Foundation of China under Grant Nos.11671012 and 11871072the Natural Science Foundation of Anhui Province under Grant Nos.1808085QA03,1908085QA01,1908085QA07+1 种基金the Provincial Natural Science Research Project of Anhui Colleges under Grant No.KJ2019A0003the Students Innovative Training Project of Anhui University under Grant No.201910357002。
文摘This paper mainly studies the strong convergence properties for weighted sums of extended negatively dependent(END,for short)random variables.Some sufficient conditions to prove the strong law of large numbers for weighted sums of END random variables are provided.In particular,the authors obtain the weighted version of Kolmogorov type strong law of large numbers for END random variables as a product.The results that the authors obtained generalize the corresponding ones for independent random variables and some dependent random variables.As an application,the authors investigate the errors-in-variables(EV,for short)regression models and establish the strong consistency for the least square estimators.Simulation studies are conducted to demonstrate the performance of the proposed procedure and a real example is analysed for illustration.
