[Objective] This study aimed to investigate the effect of zearalenone (ZEN) on DNA damage of porcine leydig cells. [Method] Porcine leydig cells cultured in vitro were collected to determine the median lethal dose (LD...[Objective] This study aimed to investigate the effect of zearalenone (ZEN) on DNA damage of porcine leydig cells. [Method] Porcine leydig cells cultured in vitro were collected to determine the median lethal dose (LD50) of ZEN with tetrazolium-based colorimetric assay (MTT assay). Comet assay was carried out to detect the DNA damage of porcine leydig cells exposed to at 0 (negative group), 1, 5, 10, 20, 40 μmol/L of ZEN. [Result] The percentage of cell tail was 16.67%, 34.00%, 40.67%, 52.00% and 64.67% under 0, 1, 5, 10 and 20 μmol/L of ZEN, respectively; the differences between the percentages of cell tail in various experimental groups had extremely significant statistical significance compared with the negative group (P<0.01), showing a significant dose-effect relationship; Tail length in various groups was 57.60±4.78, 57.75±6.25, 78.97±5.83, 100.50±6.94 and 146.83±12.31 μm, respectively; Tail DNA % in various groups was 21.29±2.25%, 22.24±2.43%, 31.21±6.27%, 37.45±4.33% and 60.68±9.83%, respectively; Tail length and Tail DNA % in experimental groups with ZEN concentration above 5 μmol/L showed significant differences (P<0.05) compared with the negative group, which showed an upward trend with the increase of ZEN concentration. [Conclusion] ZEN has genotoxic effect on porcine leydig cells, which can cause DNA damage, with a significant dose-effect relationship.展开更多
ROF(Radio Over Fiber)系统中光纤的色散是影响系统性能最主要的因素。传统的光载波双边带调制会引起严重的色散问题。光学单边带调制(OSSB)是最普遍的的方法,SSB能有效地抑制色散带来的能量损耗,并延长信号的传输距离。另外提出了一种...ROF(Radio Over Fiber)系统中光纤的色散是影响系统性能最主要的因素。传统的光载波双边带调制会引起严重的色散问题。光学单边带调制(OSSB)是最普遍的的方法,SSB能有效地抑制色散带来的能量损耗,并延长信号的传输距离。另外提出了一种改进的SSB调制方法,能够克服载波和边带引起的色散,传输距离也比普通的单边带调制更长。展开更多
SSD(Single Shot Multibox Detector) is one of the best object detection algorithms with both high accuracy and fast speed, but fails to detect very small size object which lacks enough resolution and enough feature inf...SSD(Single Shot Multibox Detector) is one of the best object detection algorithms with both high accuracy and fast speed, but fails to detect very small size object which lacks enough resolution and enough feature information. In order to solve this problem, the majority of existing methods improve accuracy at the cost of a heavy loss of speed. In this paper, we propose SFE-SSD(Shallow Feature Enhancement SSD) to improve performance of SSD model on small object detection based on a novel and lightweight way of feature enhancement module. Firstly,we apply deconvolution on the shallowest feature map in SSD’s feature pyramid to enlarge the feature map size and recover more feature details. Then, we introduce semantic information to the enlarged feature map by multi-scale feature fusion. In addition, SFE-SSD is designed to a parallel network structure, which could reduce loss of speed in some degree. Experimental results show that our approach achieved 78.4%m AP and is higher than baseline SSD by 1.2%on PASCAL VOC2007, especially with significant improvement on small object detection. The testing speed of SFE-SSD is 81 FPS at the cost of a little loss of speed.展开更多
在大的空间尺度上,研究了我国苔藓植物多样性的地理分布格局,系统地收集了1534种藓类植物在我国中东部地区80个自然保护区和国家森林公园分布的数据,分析了中国藓类植物主要类群在80个地理单元物种分布的嵌套水平和多样性保护的SLOSS(si...在大的空间尺度上,研究了我国苔藓植物多样性的地理分布格局,系统地收集了1534种藓类植物在我国中东部地区80个自然保护区和国家森林公园分布的数据,分析了中国藓类植物主要类群在80个地理单元物种分布的嵌套水平和多样性保护的SLOSS(single large or several small)策略.研究发现,藓类、侧蒴藓类、顶蒴藓类、金发藓类-烟杆藓类、泥炭藓科(Spagnaceae)、丛藓科(Pottiaceae)、青藓科(Brachytheciaceae)、木灵藓科(Orthotrichaceae)、曲尾藓科(Dicranaceae)和真藓科(Bryaceae)存在明显的嵌套分布现象.不同地区之间的藓类植物,以贵州境内保护区的藓类植物嵌套分布程度最高,浙江和两广地区的为最低.无论从科还是从属和种的水平上,在面积相近的情况下,均倾向于建立一个大的自然保护区(SL)策略,特别是对于木灵藓科、金灰藓科(Pylaisiaceae)、曲尾藓科、泥炭藓科、提灯藓科.对生境专一性强的种类越多的藓类群,越倾向于SL策略.就不同的地理区域来讲,在浙江境内建立自然保护区,更倾向于建立多个小的保护区(SS)策略,在贵州境内更倾向于SL策略.展开更多
文摘[Objective] This study aimed to investigate the effect of zearalenone (ZEN) on DNA damage of porcine leydig cells. [Method] Porcine leydig cells cultured in vitro were collected to determine the median lethal dose (LD50) of ZEN with tetrazolium-based colorimetric assay (MTT assay). Comet assay was carried out to detect the DNA damage of porcine leydig cells exposed to at 0 (negative group), 1, 5, 10, 20, 40 μmol/L of ZEN. [Result] The percentage of cell tail was 16.67%, 34.00%, 40.67%, 52.00% and 64.67% under 0, 1, 5, 10 and 20 μmol/L of ZEN, respectively; the differences between the percentages of cell tail in various experimental groups had extremely significant statistical significance compared with the negative group (P<0.01), showing a significant dose-effect relationship; Tail length in various groups was 57.60±4.78, 57.75±6.25, 78.97±5.83, 100.50±6.94 and 146.83±12.31 μm, respectively; Tail DNA % in various groups was 21.29±2.25%, 22.24±2.43%, 31.21±6.27%, 37.45±4.33% and 60.68±9.83%, respectively; Tail length and Tail DNA % in experimental groups with ZEN concentration above 5 μmol/L showed significant differences (P<0.05) compared with the negative group, which showed an upward trend with the increase of ZEN concentration. [Conclusion] ZEN has genotoxic effect on porcine leydig cells, which can cause DNA damage, with a significant dose-effect relationship.
文摘针对学生注意力分配困难和对学习影响等问题,提出一种基于机器视觉的精准注意力追踪系统。该系统包括图像采集装置和精准的注意力追踪算法。图像采集装置可以获得更清晰的眼部区域图像。瞳孔中心定位算法用轻量级的MobileNet v3替换VGG16(visual geometry group network),采用两级特征融合和中心关键点预测技术,提高了检测速度和准确率。该算法检测速度可达36帧/s,准确率为97.42%。视线追踪算法旨在解决头部偏移的影响,实现对视线的精确追踪。研发了一款面向学龄儿童的阅读认知评价交互软件。该软件利用采集到的视线坐标计算相关眼动指标,再通过心理学理论分析建模来评估学龄儿童的思维认知能力,为心理学和教育学相关领域研究提供了参考和借鉴。
文摘ROF(Radio Over Fiber)系统中光纤的色散是影响系统性能最主要的因素。传统的光载波双边带调制会引起严重的色散问题。光学单边带调制(OSSB)是最普遍的的方法,SSB能有效地抑制色散带来的能量损耗,并延长信号的传输距离。另外提出了一种改进的SSB调制方法,能够克服载波和边带引起的色散,传输距离也比普通的单边带调制更长。
基金Supported by the National Natural Science Foundation of China(Grant Nos.07002157 U1811463)
文摘SSD(Single Shot Multibox Detector) is one of the best object detection algorithms with both high accuracy and fast speed, but fails to detect very small size object which lacks enough resolution and enough feature information. In order to solve this problem, the majority of existing methods improve accuracy at the cost of a heavy loss of speed. In this paper, we propose SFE-SSD(Shallow Feature Enhancement SSD) to improve performance of SSD model on small object detection based on a novel and lightweight way of feature enhancement module. Firstly,we apply deconvolution on the shallowest feature map in SSD’s feature pyramid to enlarge the feature map size and recover more feature details. Then, we introduce semantic information to the enlarged feature map by multi-scale feature fusion. In addition, SFE-SSD is designed to a parallel network structure, which could reduce loss of speed in some degree. Experimental results show that our approach achieved 78.4%m AP and is higher than baseline SSD by 1.2%on PASCAL VOC2007, especially with significant improvement on small object detection. The testing speed of SFE-SSD is 81 FPS at the cost of a little loss of speed.
文摘在大的空间尺度上,研究了我国苔藓植物多样性的地理分布格局,系统地收集了1534种藓类植物在我国中东部地区80个自然保护区和国家森林公园分布的数据,分析了中国藓类植物主要类群在80个地理单元物种分布的嵌套水平和多样性保护的SLOSS(single large or several small)策略.研究发现,藓类、侧蒴藓类、顶蒴藓类、金发藓类-烟杆藓类、泥炭藓科(Spagnaceae)、丛藓科(Pottiaceae)、青藓科(Brachytheciaceae)、木灵藓科(Orthotrichaceae)、曲尾藓科(Dicranaceae)和真藓科(Bryaceae)存在明显的嵌套分布现象.不同地区之间的藓类植物,以贵州境内保护区的藓类植物嵌套分布程度最高,浙江和两广地区的为最低.无论从科还是从属和种的水平上,在面积相近的情况下,均倾向于建立一个大的自然保护区(SL)策略,特别是对于木灵藓科、金灰藓科(Pylaisiaceae)、曲尾藓科、泥炭藓科、提灯藓科.对生境专一性强的种类越多的藓类群,越倾向于SL策略.就不同的地理区域来讲,在浙江境内建立自然保护区,更倾向于建立多个小的保护区(SS)策略,在贵州境内更倾向于SL策略.
