Background: Changes and increased mechanisation of agricultural practices have influenced the biodiversity composition of farmland habitats and caused a decline of bird communities in many European countries. The remo...Background: Changes and increased mechanisation of agricultural practices have influenced the biodiversity composition of farmland habitats and caused a decline of bird communities in many European countries. The removal of shrubs and large trees rich in natural cavities, has also led to a drastic decrease in nest site availability for cavity-nesting bird species. Nest-boxes are a common conservation tool used to improve nest-site availability, and have helped to reverse declines in many endangered bird populations. Nonetheless to maximize the results of such interventions it is crucial to know where nest-boxes should be sited. The objective of this study was to investigate the effectiveness of the nest-box program for the European Roller (Coracias garrulus) population of Lazio region (Central Italy). More specifically, we focused on what landscape features were preferred (or avoided) in the process of nest box selection and how they influenced population’s breeding parameters. Particular attention was paid to identifying potential limitations and to provide management recommendations for future interventions. Methods: Using data from 70 nest boxes sited on power lines monitored over a 7-year period (representing 140 breeding attempts), we developed probability functions to evaluate if nest box location, in terms of distance from habitat resources and habitat composition and structure, had an effect on nest box occupancy and on the main reproductive parameters. Results: Nest boxes were more likely to be occupied if they were located near arable fields and in areas characterized by a higher amount of incoming solar radiation. Higher fledging success was associated with fallow fields and with a moderate/low habitat structural complexity. Higher breeding success was associated with solar radiation and with greater distance from urban areas. Conclusions: Our results highlight the importance of specific habitat variables in influencing nest occupancy, and show which drivers primarily affect species’ reproduction and persistence over time. Siting nest boxes in habitats where occupancy rate and fledging success is higher, such as in arable and fallow fields and on south-facing slopes where solar radiation is maximised, may help to extend the suitable habitat for rollers and facilitate its local expansion.展开更多
MADS box proteins play an important role in floral development. To find genes involved in the floral transition of Prunus species, cDNAs for two MADS box genes, PpMADS1 and PpMADSIO, were cloned using degenerate prime...MADS box proteins play an important role in floral development. To find genes involved in the floral transition of Prunus species, cDNAs for two MADS box genes, PpMADS1 and PpMADSIO, were cloned using degenerate primers and 5＇- and T-RACE based on the sequence database of P. persiea and P. duleis. The full length of PpMADS1 cDNA is 1,071 bp containing an open reading frame （ORF） of 717 bp and coding for a polypeptide of 238 amino acid residues. The full length of PpMADSIO cDNA is 937 bp containing an ORF of 633 bp and coding for a polypeptide of 210 amino acid residues. Sequence comparison revealed that PpMADS1 and PpMADSIO were highly homologous to genes API and PI in Arabidopsis, respectively. Phylogenetic analysis indicated that PpMADS1 belongs to the euAP1 clade of class A, and PpMADSIO is a member of GLO/PI clade of class B. RT-PCR analysis showed that PpMADS1 was expressed in sepal, petal, carpel, and fruit, which was slightly different from the expression pattern ofAPl; PpMADS10 was expressed in petal and stamen, which shared the same expression pattern as PI. Using selective mapping strategy, PpMADSI was assigned onto the Binl：50 on the G1 linkage group between the markers MCO44 and TSA2, and PpMADSIO onto the Bin1：73 on the same linkage group between the markers Lap- 1 and FGA8. Our results provided the basis for further dissection of the two MADS box gene function.展开更多
Genetically heterogenous mouse population served as the basis for experiment designed to select mice for the high levels of extrapolation ability. Extrapolation task (which belongs to the category of cognitive tasks) ...Genetically heterogenous mouse population served as the basis for experiment designed to select mice for the high levels of extrapolation ability. Extrapolation task (which belongs to the category of cognitive tasks) was the following: hungry and thirsty mouse was placed in the experimental box facing the cup with milk which could be reached via the small opening in the frontal wall. After several seconds of drinking the food moved behind this wall to the right or to the left and disappeared from animal view. Mouse can find the food only if it moves in the direction of food movement. The direction could be chosen at random or based on animal apprehension of elementary logic of this task. Mice were selected not only for high scores of this task solution but also for lack of anxiety signs during test performance. Extrapolation task scores in selected strain mice were above the chance levels in F9 but non-significantly different from those of control unselected mouse population. The performance of F9 mice in the “puzzle box” cognitive test, based on animal tendency to avoid the brightly lit area in the dark compartment with increasing “difficulty” of reaching this compartment, was measured as mean escape latencies of the respective group. The latencies of mice from selected strain were significantly shorter than those of control animals. This fact is interpreted as the sign that the selection for one cognitive trait (yet still not efficient) resulted in positive changes in the ability to solve another cognitive task. The relationship of cognitive task solutions success and anxiety behavior scores in F9 is discussed.展开更多
针对传统船舶图像去噪算法难以对图像的边缘细节进行保留和分析,以及传统非局部均值去噪算法相似框选择困难等问题,提出基于简单线性迭代聚类(simple linear iterative clustering,SLIC)超像素分割的非局部均值船舶图像去噪算法。通过S...针对传统船舶图像去噪算法难以对图像的边缘细节进行保留和分析,以及传统非局部均值去噪算法相似框选择困难等问题,提出基于简单线性迭代聚类(simple linear iterative clustering,SLIC)超像素分割的非局部均值船舶图像去噪算法。通过SLIC算法对图像进行分割处理,界定图像的纹理区域和平滑区域;使用相似框搜索和匹配策略,提升匹配效果,并适当保留更多边缘细节,从而改善图像去噪的效果。实验结果表明,所提出的算法相较于其他传统的船舶图像去噪算法不仅能很好地保留船舶图像的边缘细节特点,而且能在一定程度上提高船舶图像的峰值信噪比,具有良好的去噪效果,可以用于智能航海领域船舶图像的去噪。展开更多
复杂场景下小目标检测是目标检测领域的研究难点和热点。传统的two-stage和one-stage检测模型都是通过预先设定锚点框与真实目标框的交并比(intersection over union,IoU)阈值来划分正负样本集,同时这组预定义的固定锚点框还用于获取候...复杂场景下小目标检测是目标检测领域的研究难点和热点。传统的two-stage和one-stage检测模型都是通过预先设定锚点框与真实目标框的交并比(intersection over union,IoU)阈值来划分正负样本集,同时这组预定义的固定锚点框还用于获取候选框,进而得到检测结果。然而,在复杂场景下,预先设定的IoU阈值会带来正负样本不均衡问题;针对小尺寸目标(船舶)检测,预定义的锚点框也很难保证覆盖目标的位置和密度,因此限制了检测模型的准确率。为了解决上述问题,提出自适应锚点框(adaptive anchor boxes,AAB)的方法优化目标检测网络,采用基于形状相似度距离的聚类算法生成锚点框,提高目标区域定位技术;采用利用聚类的锚点框计算自适应IoU阈值(adaptive threshold selection,ATS),划分正负样本,保证样本均衡。对复杂场景下的小目标(船舶目标)进行检测,实验结果表明,采用自适应锚点框方法和自适应阈值选择方法的目标检测模型在复杂场景中检测均能提升准确,对比faster R-CNN、FPN、Yolo3和pp-Yolo,融合了上述新方法的模型均提升了检测准确率,分别提升了9.6、2.6、9.8和9.9个百分点。展开更多
文摘Background: Changes and increased mechanisation of agricultural practices have influenced the biodiversity composition of farmland habitats and caused a decline of bird communities in many European countries. The removal of shrubs and large trees rich in natural cavities, has also led to a drastic decrease in nest site availability for cavity-nesting bird species. Nest-boxes are a common conservation tool used to improve nest-site availability, and have helped to reverse declines in many endangered bird populations. Nonetheless to maximize the results of such interventions it is crucial to know where nest-boxes should be sited. The objective of this study was to investigate the effectiveness of the nest-box program for the European Roller (Coracias garrulus) population of Lazio region (Central Italy). More specifically, we focused on what landscape features were preferred (or avoided) in the process of nest box selection and how they influenced population’s breeding parameters. Particular attention was paid to identifying potential limitations and to provide management recommendations for future interventions. Methods: Using data from 70 nest boxes sited on power lines monitored over a 7-year period (representing 140 breeding attempts), we developed probability functions to evaluate if nest box location, in terms of distance from habitat resources and habitat composition and structure, had an effect on nest box occupancy and on the main reproductive parameters. Results: Nest boxes were more likely to be occupied if they were located near arable fields and in areas characterized by a higher amount of incoming solar radiation. Higher fledging success was associated with fallow fields and with a moderate/low habitat structural complexity. Higher breeding success was associated with solar radiation and with greater distance from urban areas. Conclusions: Our results highlight the importance of specific habitat variables in influencing nest occupancy, and show which drivers primarily affect species’ reproduction and persistence over time. Siting nest boxes in habitats where occupancy rate and fledging success is higher, such as in arable and fallow fields and on south-facing slopes where solar radiation is maximised, may help to extend the suitable habitat for rollers and facilitate its local expansion.
基金supported by the National Natural Science Foundation of China(No.30500395)the National High Technology Research and Development Program(863 Projects)of China(No.2006AA10Z130 and 2006AA100108-3-7).
文摘MADS box proteins play an important role in floral development. To find genes involved in the floral transition of Prunus species, cDNAs for two MADS box genes, PpMADS1 and PpMADSIO, were cloned using degenerate primers and 5＇- and T-RACE based on the sequence database of P. persiea and P. duleis. The full length of PpMADS1 cDNA is 1,071 bp containing an open reading frame （ORF） of 717 bp and coding for a polypeptide of 238 amino acid residues. The full length of PpMADSIO cDNA is 937 bp containing an ORF of 633 bp and coding for a polypeptide of 210 amino acid residues. Sequence comparison revealed that PpMADS1 and PpMADSIO were highly homologous to genes API and PI in Arabidopsis, respectively. Phylogenetic analysis indicated that PpMADS1 belongs to the euAP1 clade of class A, and PpMADSIO is a member of GLO/PI clade of class B. RT-PCR analysis showed that PpMADS1 was expressed in sepal, petal, carpel, and fruit, which was slightly different from the expression pattern ofAPl; PpMADS10 was expressed in petal and stamen, which shared the same expression pattern as PI. Using selective mapping strategy, PpMADSI was assigned onto the Binl：50 on the G1 linkage group between the markers MCO44 and TSA2, and PpMADSIO onto the Bin1：73 on the same linkage group between the markers Lap- 1 and FGA8. Our results provided the basis for further dissection of the two MADS box gene function.
文摘Genetically heterogenous mouse population served as the basis for experiment designed to select mice for the high levels of extrapolation ability. Extrapolation task (which belongs to the category of cognitive tasks) was the following: hungry and thirsty mouse was placed in the experimental box facing the cup with milk which could be reached via the small opening in the frontal wall. After several seconds of drinking the food moved behind this wall to the right or to the left and disappeared from animal view. Mouse can find the food only if it moves in the direction of food movement. The direction could be chosen at random or based on animal apprehension of elementary logic of this task. Mice were selected not only for high scores of this task solution but also for lack of anxiety signs during test performance. Extrapolation task scores in selected strain mice were above the chance levels in F9 but non-significantly different from those of control unselected mouse population. The performance of F9 mice in the “puzzle box” cognitive test, based on animal tendency to avoid the brightly lit area in the dark compartment with increasing “difficulty” of reaching this compartment, was measured as mean escape latencies of the respective group. The latencies of mice from selected strain were significantly shorter than those of control animals. This fact is interpreted as the sign that the selection for one cognitive trait (yet still not efficient) resulted in positive changes in the ability to solve another cognitive task. The relationship of cognitive task solutions success and anxiety behavior scores in F9 is discussed.
文摘针对传统船舶图像去噪算法难以对图像的边缘细节进行保留和分析,以及传统非局部均值去噪算法相似框选择困难等问题,提出基于简单线性迭代聚类(simple linear iterative clustering,SLIC)超像素分割的非局部均值船舶图像去噪算法。通过SLIC算法对图像进行分割处理,界定图像的纹理区域和平滑区域;使用相似框搜索和匹配策略,提升匹配效果,并适当保留更多边缘细节,从而改善图像去噪的效果。实验结果表明,所提出的算法相较于其他传统的船舶图像去噪算法不仅能很好地保留船舶图像的边缘细节特点,而且能在一定程度上提高船舶图像的峰值信噪比,具有良好的去噪效果,可以用于智能航海领域船舶图像的去噪。
