Vespicochory, seed dispersal by hornets, is a rare seed dispersal mechanism in angiosperms and, to date, there are few records of this phenomenon.Through field investigations and behavioral assays conducted in four po...Vespicochory, seed dispersal by hornets, is a rare seed dispersal mechanism in angiosperms and, to date, there are few records of this phenomenon.Through field investigations and behavioral assays conducted in four populations of Stemona tuberosa from 2011–2016, we demonstrate that hornets are the primary seed dispersers of S. tuberosa and play an important role in "long-distance" seed dispersal in this species. Furthermore, some ant species act as secondary dispersers and may transport the seeds to safe sites.Hornets and ants provide complementary seed dispersal at different spatial scales. This unique example of insect-plant mutualism may be an underestimated but important strategy to ensure "long-distance" seed dispersal in other myrmecochorous plants.展开更多
Vespa velutina is an invasive hornet species that is colonising Europe,generating considerable impacts on honeybees,beekeeping and biodiversity.Control and early warning strategies for this species are mainly based on...Vespa velutina is an invasive hornet species that is colonising Europe,generating considerable impacts on honeybees,beekeeping and biodiversity.Control and early warning strategies for this species are mainly based on monitoring plans and procedures of nest detection and destruction.Technological tools(harmonic radar,radio-telemetry)have been developed to increase the probabilities of nest detection in new outbreaks.Since hornets are able to regulate nest temperature,thermography may represent an additional technique that may be used,both alone or in support to other techniques.In this study,the viability of thermal imaging in detecting nests of V.velutina was evaluated in controlled conditions.The influence of different environmental and operative variables(time of the day,presence/absence of leaves covering the nest,distance between the nest and the operator)were tested on three nests detected during August 2018 in Italy.All the nests were detectable by thermal imaging,but environmental and operative variables affect their detectability.The temperature difference between the nests and the surrounding reaches its maximum before sunrise and without a tree canopy covering the nests.Although nests were visible in some cases from 30 m,the detectability was higher at shorter distances,even if this variable may also depend on infrared camera resolution.An increase in the environmental temperature also generates a decrease of nest detectability.Although some limitations could occur,these results show the applicability of thermography in detecting V velutina nests before the beginning of the reproductive phase,and consequently its potentiality in control strategies.展开更多
An improved unslotted CSMA/CA MAC scheme of HORNET based on the node structure with variable optical buffer is reported. It can be used for transmitting high effectively all variable IP packets in the WDM network.
The Yellow-legged hornet, Vespa velutina , was accidentally introduced in France in 2004, and then spread rapidly through the French territory but also to adjacent European countries (Spain, Portugal, and Belgium). Du...The Yellow-legged hornet, Vespa velutina , was accidentally introduced in France in 2004, and then spread rapidly through the French territory but also to adjacent European countries (Spain, Portugal, and Belgium). During summer and autumn, V. velutina workers hunt domestic honeybees, Apis mellifera, for feeding their larvae. The impact of this alien species is mainly economic, beekeepers experiencing heavy colony losses, but also ecological, V. velutina hunting other pollinators. In their year-round life cycle, nest initiation by single queen during spring is the critical stage. In invaded areas, spring queen trapping using food baits has been promoted by apicultural unions in order to limit V. velutina population expansion. The goals of this work were 1) to evaluate the yield of this method, 2) to identify appropriate sites for trapping, 3) to identify potential optimal climatic windows of capture, and 4) to quantify the impact on local entomofauna. Our results showed that water proximity enhances trapping but not beehives proximity, and that trapping is inefficient if average week temperatures are below 10°C. Although the trapping effect on biodiversity should be studied more carefully, spring queen trapping is highly questionable unless specific attractants could be proposed.展开更多
针对夜间行人检测任务中存在的检测速度慢、漏检率高、黑夜场景下识别效果差等问题,提出一种改进YOLOv7的夜间行人检测算法。改进算法中,使用YOLOv7-tiny网络作为baseline,以满足准确率的同时兼具较高的检测速度,在网络head部分,使用CSP...针对夜间行人检测任务中存在的检测速度慢、漏检率高、黑夜场景下识别效果差等问题,提出一种改进YOLOv7的夜间行人检测算法。改进算法中,使用YOLOv7-tiny网络作为baseline,以满足准确率的同时兼具较高的检测速度,在网络head部分,使用CSP HorNet模块实现关键特征之间的高阶交互,并引入SimAM注意力机制,在不增加模型复杂度的情况下,使网络聚焦更多重要的特征信息。实验结果表明,改进算法在测试集上准确率(Precision,P)达到91.7%,召回率(Recall,R)达到81.4%,均值平均精度(mean Average Precision,mAP)提升2.9个百分点。改进算法在真实场景检测任务中,有效降低了漏检率及错检率,表现出良好的性能。展开更多
All optical network （AON） is a hot topic in recent studies of optical fiber communications. Key techniques in AON include optical switching/routing, optical cross connection （OXC）, all optical wavelength conversi...All optical network （AON） is a hot topic in recent studies of optical fiber communications. Key techniques in AON include optical switching/routing, optical cross connection （OXC）, all optical wavelength conversion （AOWC）, all optical buffering, etc. Opti- cal switching/routing is in fact wavelength switching/ routing. OXC and wavelength conversion （WC） are introduced into cross nodes so that a virtual wavelength path is established. With WC, communication route is formed only if there is unused wavelength in an individual segment link. The rate wavelength usage is thus greatly increased. The blocking rate of network can be reduced by adding WCs, especially for huge capacity multiple nodes ones. Therefore, WC has attracted much attention in basic research of optical communication and is used in some experimental networks.This dissertation studies all optic wavelength conversion and its application, with the contributions in the following five aspects.展开更多
基金Support for this study was provided by grants from the NSFC-Yunnan joint fund to support key projects(U1602266)the National Natural Science Foundation of China(31670322)the Young Academic and Technical Leader Raising Foundation of Yunnan Province(2015HB091)to G.Chen
文摘Vespicochory, seed dispersal by hornets, is a rare seed dispersal mechanism in angiosperms and, to date, there are few records of this phenomenon.Through field investigations and behavioral assays conducted in four populations of Stemona tuberosa from 2011–2016, we demonstrate that hornets are the primary seed dispersers of S. tuberosa and play an important role in "long-distance" seed dispersal in this species. Furthermore, some ant species act as secondary dispersers and may transport the seeds to safe sites.Hornets and ants provide complementary seed dispersal at different spatial scales. This unique example of insect-plant mutualism may be an underestimated but important strategy to ensure "long-distance" seed dispersal in other myrmecochorous plants.
文摘Vespa velutina is an invasive hornet species that is colonising Europe,generating considerable impacts on honeybees,beekeeping and biodiversity.Control and early warning strategies for this species are mainly based on monitoring plans and procedures of nest detection and destruction.Technological tools(harmonic radar,radio-telemetry)have been developed to increase the probabilities of nest detection in new outbreaks.Since hornets are able to regulate nest temperature,thermography may represent an additional technique that may be used,both alone or in support to other techniques.In this study,the viability of thermal imaging in detecting nests of V.velutina was evaluated in controlled conditions.The influence of different environmental and operative variables(time of the day,presence/absence of leaves covering the nest,distance between the nest and the operator)were tested on three nests detected during August 2018 in Italy.All the nests were detectable by thermal imaging,but environmental and operative variables affect their detectability.The temperature difference between the nests and the surrounding reaches its maximum before sunrise and without a tree canopy covering the nests.Although nests were visible in some cases from 30 m,the detectability was higher at shorter distances,even if this variable may also depend on infrared camera resolution.An increase in the environmental temperature also generates a decrease of nest detectability.Although some limitations could occur,these results show the applicability of thermography in detecting V velutina nests before the beginning of the reproductive phase,and consequently its potentiality in control strategies.
文摘An improved unslotted CSMA/CA MAC scheme of HORNET based on the node structure with variable optical buffer is reported. It can be used for transmitting high effectively all variable IP packets in the WDM network.
文摘The Yellow-legged hornet, Vespa velutina , was accidentally introduced in France in 2004, and then spread rapidly through the French territory but also to adjacent European countries (Spain, Portugal, and Belgium). During summer and autumn, V. velutina workers hunt domestic honeybees, Apis mellifera, for feeding their larvae. The impact of this alien species is mainly economic, beekeepers experiencing heavy colony losses, but also ecological, V. velutina hunting other pollinators. In their year-round life cycle, nest initiation by single queen during spring is the critical stage. In invaded areas, spring queen trapping using food baits has been promoted by apicultural unions in order to limit V. velutina population expansion. The goals of this work were 1) to evaluate the yield of this method, 2) to identify appropriate sites for trapping, 3) to identify potential optimal climatic windows of capture, and 4) to quantify the impact on local entomofauna. Our results showed that water proximity enhances trapping but not beehives proximity, and that trapping is inefficient if average week temperatures are below 10°C. Although the trapping effect on biodiversity should be studied more carefully, spring queen trapping is highly questionable unless specific attractants could be proposed.
文摘针对夜间行人检测任务中存在的检测速度慢、漏检率高、黑夜场景下识别效果差等问题,提出一种改进YOLOv7的夜间行人检测算法。改进算法中,使用YOLOv7-tiny网络作为baseline,以满足准确率的同时兼具较高的检测速度,在网络head部分,使用CSP HorNet模块实现关键特征之间的高阶交互,并引入SimAM注意力机制,在不增加模型复杂度的情况下,使网络聚焦更多重要的特征信息。实验结果表明,改进算法在测试集上准确率(Precision,P)达到91.7%,召回率(Recall,R)达到81.4%,均值平均精度(mean Average Precision,mAP)提升2.9个百分点。改进算法在真实场景检测任务中,有效降低了漏检率及错检率,表现出良好的性能。
文摘All optical network （AON） is a hot topic in recent studies of optical fiber communications. Key techniques in AON include optical switching/routing, optical cross connection （OXC）, all optical wavelength conversion （AOWC）, all optical buffering, etc. Opti- cal switching/routing is in fact wavelength switching/ routing. OXC and wavelength conversion （WC） are introduced into cross nodes so that a virtual wavelength path is established. With WC, communication route is formed only if there is unused wavelength in an individual segment link. The rate wavelength usage is thus greatly increased. The blocking rate of network can be reduced by adding WCs, especially for huge capacity multiple nodes ones. Therefore, WC has attracted much attention in basic research of optical communication and is used in some experimental networks.This dissertation studies all optic wavelength conversion and its application, with the contributions in the following five aspects.
