Youngsters learn that with the right approach,museums can rhyme with fun Desp Ite her childish looks,eight-year-old Meng Ziyu isn’t like other girls her age-infatuated with Barbie dolls or the latest Disney film.What...Youngsters learn that with the right approach,museums can rhyme with fun Desp Ite her childish looks,eight-year-old Meng Ziyu isn’t like other girls her age-infatuated with Barbie dolls or the latest Disney film.What she really gets a kick out of is visiting a museum with her mother on weekends.展开更多
Flowers that have heteromorphic stamens （heterantherous flowers） have intrigued many researchers ever since the phenomenon was discovered in the 19th century. The morphological differentiation in androecia has been ...Flowers that have heteromorphic stamens （heterantherous flowers） have intrigued many researchers ever since the phenomenon was discovered in the 19th century. The morphological differentiation in androecia has been suggested as a reflection of ＂labor division＂ in pollination in which one type of stamens attracts pollinators and satisfies their demand for pollen as food and the other satisfies the plant＇s need for safe gamete dispersal. The extent and patterns of stamen differentiation differ notably among taxa with heterantherous flowers. Seven species with heteromorphic stamens in three genera were sampled from Leguminosae and Melastomataceae, and the morphological difference of androecia, pollen content, pollen histochemistry and viability, pollen micro- morphology, as well as the main pollinators were examined and compared. Pollen number differs significantly between stamen sets of the same flower in most species investigated, and a correlation of pollen number and anther size was substantiated. Higher pollen viabilities were found in the long （pollinating） stamens of Senna alata （L.） Roxb. and S. bicapsularis （L.） Roxb. Dimorphic pollen exine ornamentation is reported here for the first time in Fordiophytonfaberi Stapf. The height of stigma and anther tips of the long stamens in natural conditions was proved to be highly correlated, supporting the hypothesis that they contact similar areas of the pollinator＇s body.展开更多
Transonic rudder buzz responses based on the computational fluid dynamics or computational structural dynamics(CFD/CSD)loosely method are analyzed for a tailless flying wing unmanned aerial vehicle(UAV).The Reynolds-a...Transonic rudder buzz responses based on the computational fluid dynamics or computational structural dynamics(CFD/CSD)loosely method are analyzed for a tailless flying wing unmanned aerial vehicle(UAV).The Reynolds-averaged Navier-Stokes(RANS)equations and finite element methods based on the detailed aerodynamic and structural model are established,in which the aerodynamic dynamic meshes adopt the unstructured dynamic meshes based on the combination of spring-based smoothing and local remeshing methods,and the lower-upper symmetric-Gauss-Seidel(LU-SGS)iteration and Harten-Lax-van Leer-Einfeldt-Wada(HLLEW)space discrete methods based on the shear stress transport(SST)turbulence model are used to calculate the aerodynamic force.The constraints of the rudder motions are fixed at the end of structural model of the flying wing UAV,and the structural geometric nonlinearities are also considered in the flying wing UAV with a high aspect ratio.The interfaces between structural and aerodynamic models are built with an exact match surface where load transferring is performed based on 3Dinterpolation.The flying wing UAV transonic buzz responses based on the aerodynamic structural coupling method are studied,and the rudder buzz responses and aileron,elevator and flap vibration responses caused by rudder motion are also investigated.The effects of attack,height,rotating angular frequency and Mach number under transonic conditions on the flying wing UAV rudder buzz responses are discussed.The results can be regarded as a reference for the flying wing UAV engineering vibration analysis.展开更多
Pollen collection is necessary for bee survival and important for flowering plant reproduction, yet if and how pollen extraction motor routines are modified with experience is largely unknown. Here, we used an automat...Pollen collection is necessary for bee survival and important for flowering plant reproduction, yet if and how pollen extraction motor routines are modified with experience is largely unknown. Here, we used an automated reward and monitoring system to evaluate modification in a common pollen-extraction routine, floral sonication. Through a series of laboratory experiments with the bumblebee, Bombus impatiens, we examined whether variation in sonication frequency and acceleration is due to instrumental learning based on rewards, a fixed behavioral response to rewards, and/or a mechanical constraint. We first investigated whether bees could learn to adjust their sonication frequency in response to pollen rewards given only for specified frequency ranges and found no evidenee of instrumental learning. However, we found that absenee versus receipt of a pollen reward did lead to a predictable behavioral resp on se, which depe nded on bee size. Fin ally, we found some evide nee of mechanical con straints, in that flower mass affected sonication acceleration (but not frequency) through an interaction with bee size. In generalz larger bees showed more flexibility in sonication frequency and acceleration, potentially reflecting a size-based constraint on the range over which smaller bees can modify frequency and accelerati on. Overall our results show that although bees did not display instrumental learning of sonication frequency, their sonication motor routine is nevertheless flexible.展开更多
The changes in vibration, sound, and sound quality with changes in the driving voltage of a power seat motor from 12.5 to 14.5 V were measured and analyzed, which was used in real vehicles. BSR(buzz, squeak, rattle), ...The changes in vibration, sound, and sound quality with changes in the driving voltage of a power seat motor from 12.5 to 14.5 V were measured and analyzed, which was used in real vehicles. BSR(buzz, squeak, rattle), which occurs for the power seat mechanism during sliding operation, was also evaluated. In addition, the results were expressed in terms of sound quality metrics, which measure the RPM change and sound level versus voltage to analyze their statistical correlation. Furthermore, vibration measurement and analysis were conducted simultaneously to determine the noisiest conditions and the source of the noise. The changes in RPM and voltage of a motor, in addition to vibration and noise, were measured at the same time to determine how noise, RPM, and voltage are interrelated.展开更多
Floral traits modify pollinator behavior and shape the plant-pollinator interaction pattern at ecological and evolutionary levels. Biomechanical traits are important in mediating interactions between flowers and their...Floral traits modify pollinator behavior and shape the plant-pollinator interaction pattern at ecological and evolutionary levels. Biomechanical traits are important in mediating interactions between flowers and their pollinators in some cases, such as in buzz pollination. During buzz pollination, a bee produces vibrations using its thoracic muscles and transfers these vibrations primarily through its mandibles as it bites the flower. The interaction between buzz-pollinated flowers and their pollinators is influenced by their physical size relative to each other, but the drivers of these size-dependent associations remain unclear. Using eight beaked louseworts(Pedicularis) as a model system, we combined behavioral observations, biomechanical analyses, and pollinator network analyses to test the hypothesis that the location of where a bee bites should constrain the interaction between Pedicularis and bumblebees during buzz pollination. We found that bumblebees always chose to bite the same site at the base of the floral beak when buzzing Pedicularis, and this site is optimal for transferring vibrations from the bee to release pollen from the anthers. Bee bodies must be long enough for the mandibles to clamp onto the same optimal site on the floral beak, while its pollen-collecting abdomen is positioned at the opening of the floral beak where pollen grains are ejected. Our pollination networks showed size matching between the floral beak length of each Pedicularis species and the body length of individual bumblebees regardless of bee species. These results suggest that the optimal excitation point on the Pedicularis flower links a suite of floral traits to its pollinators' dimensions, potentially contributing to prezygotic isolation among co-flowering, sympatric Pedicularis species.展开更多
Background:Mobile technology has great potential to improve adherence and treatment outcomes in healthcare settings.However,text messaging and phone calls are unaffordable in many resource-limited areas.This study inv...Background:Mobile technology has great potential to improve adherence and treatment outcomes in healthcare settings.However,text messaging and phone calls are unaffordable in many resource-limited areas.This study investigates the use of a no-cost alternative mobile phone technology using missed calls(‘buzzing’)to act as a patient reminder.The use of missed calls as a patient reminder was evaluated for feasibility and effectiveness as an appointment reminder in the follow-up of newly-diagnosed human immunodeficiency virus(HIV)positive patients in an HIV testing and counselling department in rural Swaziland.Methods:This pilot study uses a before-and-after operational research study design,with all patients with mobile phones being offered the intervention.The primary outcome was the rate of attendance at the HIV testing and counselling department for collection of results in those with mobile phones before and after the introduction of the intervention.Results:Over two-thirds,71.8%(459/639),of patients had a mobile phone.All patients with a mobile phone consented to being buzzed.There was no difference in attendance for follow-up at the clinic before and after the intervention was implemented(80.1%versus 83.3%,p=0.401),or after adjusting for confounding factors(OR 1.13,p=0.662).Conclusion:This pilot study illustrates that mobile technology may be feasible in rural,resource-poor settings as there are high rates of mobile phone ownership and the intervention had a 100%uptake rate,with positive feedback from staff and patients.In this particular setting,the intervention did not improve attendance rates.However,further research is planned to investigate the impact on adherence to appointments and medications in other settings,such as HIV chronic care follow-up and as part of an enhanced package to improve adherence.展开更多
Over 50 genera of bees release pollen from flower anthers using thoracic vibrations,a phenomenon known as buzz-pollination.The efficiency of this process is directly affected by the mechanical properties of the buzzes...Over 50 genera of bees release pollen from flower anthers using thoracic vibrations,a phenomenon known as buzz-pollination.The efficiency of this process is directly affected by the mechanical properties of the buzzes,namely the duration,amplitude,and frequency.Nonetheless,although the effects of the former two properties are well described,the role of buzz frequency on pollen release remains unclear.Furthermore,nearly all of the existing studies describing vibrational properties of natural buzz-pollination are limited to bumblebees(Bombus)and carpenter bees(Xvlocopa)constraining our current understanding of this behavior and its evolution.Therefore,we attempted to minimize this shortcoming by testing whether flower anthers exhibit optimal frequency for pollen release and whether bees tune their buzzes to match these(optimal)frequencies.If true,certain frequencies will trigger more pollen release and lighter bees will reach buzz frequencies closer to this optimum to compensate their smaller buzz amplitudes.Two strategies were used to test these hypotheses:(i)the use of(artificial)vibrational playbacks in a broad range of buzz frequencies and amplitudes to assess pollen release by tomato plants(Solarium Ivcopersicum L.)and(ii)the recording of natural buzzes of Neotropical bees visiting tomato plants during pollination.The playback experiment indicates that although buzz frequency does affect pollen release,no optimal frequency exists for that.In addition,the recorded results of natural buzz-pollination reveal that buzz frequencies vary with bee genera and are not correlated with body size.Therefore,neither bees nor plants are tuned to optimal pollen release frequencies.Bee frequency of buzz-pollination is a likely consequence of the insect flight machinery adapted to reach higher accelerations,while flower plant response to buzz-pollination is the likely result of its pollen granular properties.展开更多
Socialism With Chinese Characteristics Socialism with Chinese Characteristics refers to building a socialist system under the leadership of the Communist Party of China(CPC) and in light of China’s basic condition.It...Socialism With Chinese Characteristics Socialism with Chinese Characteristics refers to building a socialist system under the leadership of the Communist Party of China(CPC) and in light of China’s basic condition.It contains five basic components:a peo- ple-oriented approach,a market econo- my,common prosperity,Chinese culture and socialist democracy.展开更多
Voluntary research organizations are becoming more significant forces in the study of ‘lights in the sky’ something unusual was happening on the quiet, clear night in Hangzhou, Zhejiang Province, on July 7 this year...Voluntary research organizations are becoming more significant forces in the study of ‘lights in the sky’ something unusual was happening on the quiet, clear night in Hangzhou, Zhejiang Province, on July 7 this year. Because of sightings of an Unidentified Flying Object (UFO), more than 20 flights were postponed for 56 minutes at the city’s Xiaoshan International Airport. Immediately the event was connected with alien spacecraft. Speculations and rumors were everywhere.展开更多
文摘Youngsters learn that with the right approach,museums can rhyme with fun Desp Ite her childish looks,eight-year-old Meng Ziyu isn’t like other girls her age-infatuated with Barbie dolls or the latest Disney film.What she really gets a kick out of is visiting a museum with her mother on weekends.
基金supported by National Natural Science Foundation of China (30570314)the Knowledge Innovation Program of Chinese Academy of Sciences (Grant No.KSCX2-YW-Z-027)
文摘Flowers that have heteromorphic stamens （heterantherous flowers） have intrigued many researchers ever since the phenomenon was discovered in the 19th century. The morphological differentiation in androecia has been suggested as a reflection of ＂labor division＂ in pollination in which one type of stamens attracts pollinators and satisfies their demand for pollen as food and the other satisfies the plant＇s need for safe gamete dispersal. The extent and patterns of stamen differentiation differ notably among taxa with heterantherous flowers. Seven species with heteromorphic stamens in three genera were sampled from Leguminosae and Melastomataceae, and the morphological difference of androecia, pollen content, pollen histochemistry and viability, pollen micro- morphology, as well as the main pollinators were examined and compared. Pollen number differs significantly between stamen sets of the same flower in most species investigated, and a correlation of pollen number and anther size was substantiated. Higher pollen viabilities were found in the long （pollinating） stamens of Senna alata （L.） Roxb. and S. bicapsularis （L.） Roxb. Dimorphic pollen exine ornamentation is reported here for the first time in Fordiophytonfaberi Stapf. The height of stigma and anther tips of the long stamens in natural conditions was proved to be highly correlated, supporting the hypothesis that they contact similar areas of the pollinator＇s body.
基金supported by the Natural Science Foundation of China(No.61074155)the Shaanxi Provincial Natural Science Foundation of China(No.2013JM015)
文摘Transonic rudder buzz responses based on the computational fluid dynamics or computational structural dynamics(CFD/CSD)loosely method are analyzed for a tailless flying wing unmanned aerial vehicle(UAV).The Reynolds-averaged Navier-Stokes(RANS)equations and finite element methods based on the detailed aerodynamic and structural model are established,in which the aerodynamic dynamic meshes adopt the unstructured dynamic meshes based on the combination of spring-based smoothing and local remeshing methods,and the lower-upper symmetric-Gauss-Seidel(LU-SGS)iteration and Harten-Lax-van Leer-Einfeldt-Wada(HLLEW)space discrete methods based on the shear stress transport(SST)turbulence model are used to calculate the aerodynamic force.The constraints of the rudder motions are fixed at the end of structural model of the flying wing UAV,and the structural geometric nonlinearities are also considered in the flying wing UAV with a high aspect ratio.The interfaces between structural and aerodynamic models are built with an exact match surface where load transferring is performed based on 3Dinterpolation.The flying wing UAV transonic buzz responses based on the aerodynamic structural coupling method are studied,and the rudder buzz responses and aileron,elevator and flap vibration responses caused by rudder motion are also investigated.The effects of attack,height,rotating angular frequency and Mach number under transonic conditions on the flying wing UAV rudder buzz responses are discussed.The results can be regarded as a reference for the flying wing UAV engineering vibration analysis.
文摘Pollen collection is necessary for bee survival and important for flowering plant reproduction, yet if and how pollen extraction motor routines are modified with experience is largely unknown. Here, we used an automated reward and monitoring system to evaluate modification in a common pollen-extraction routine, floral sonication. Through a series of laboratory experiments with the bumblebee, Bombus impatiens, we examined whether variation in sonication frequency and acceleration is due to instrumental learning based on rewards, a fixed behavioral response to rewards, and/or a mechanical constraint. We first investigated whether bees could learn to adjust their sonication frequency in response to pollen rewards given only for specified frequency ranges and found no evidenee of instrumental learning. However, we found that absenee versus receipt of a pollen reward did lead to a predictable behavioral resp on se, which depe nded on bee size. Fin ally, we found some evide nee of mechanical con straints, in that flower mass affected sonication acceleration (but not frequency) through an interaction with bee size. In generalz larger bees showed more flexibility in sonication frequency and acceleration, potentially reflecting a size-based constraint on the range over which smaller bees can modify frequency and accelerati on. Overall our results show that although bees did not display instrumental learning of sonication frequency, their sonication motor routine is nevertheless flexible.
基金supported by the research grant of AMPRIC & RIGCT in Kongju National University, Korea
文摘The changes in vibration, sound, and sound quality with changes in the driving voltage of a power seat motor from 12.5 to 14.5 V were measured and analyzed, which was used in real vehicles. BSR(buzz, squeak, rattle), which occurs for the power seat mechanism during sliding operation, was also evaluated. In addition, the results were expressed in terms of sound quality metrics, which measure the RPM change and sound level versus voltage to analyze their statistical correlation. Furthermore, vibration measurement and analysis were conducted simultaneously to determine the noisiest conditions and the source of the noise. The changes in RPM and voltage of a motor, in addition to vibration and noise, were measured at the same time to determine how noise, RPM, and voltage are interrelated.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences (XDB31000000)the Special Foundation for National Science and Technology Basic Research Program of China (2021FY100200)+2 种基金the National Natural Science Foundation of China (32071670)partially supported by a research grant from the Human Frontier Science Program (RGP0043/2022)partially supported by the National Science Foundation under awards No. CMMI-2221908 to MJ。
文摘Floral traits modify pollinator behavior and shape the plant-pollinator interaction pattern at ecological and evolutionary levels. Biomechanical traits are important in mediating interactions between flowers and their pollinators in some cases, such as in buzz pollination. During buzz pollination, a bee produces vibrations using its thoracic muscles and transfers these vibrations primarily through its mandibles as it bites the flower. The interaction between buzz-pollinated flowers and their pollinators is influenced by their physical size relative to each other, but the drivers of these size-dependent associations remain unclear. Using eight beaked louseworts(Pedicularis) as a model system, we combined behavioral observations, biomechanical analyses, and pollinator network analyses to test the hypothesis that the location of where a bee bites should constrain the interaction between Pedicularis and bumblebees during buzz pollination. We found that bumblebees always chose to bite the same site at the base of the floral beak when buzzing Pedicularis, and this site is optimal for transferring vibrations from the bee to release pollen from the anthers. Bee bodies must be long enough for the mandibles to clamp onto the same optimal site on the floral beak, while its pollen-collecting abdomen is positioned at the opening of the floral beak where pollen grains are ejected. Our pollination networks showed size matching between the floral beak length of each Pedicularis species and the body length of individual bumblebees regardless of bee species. These results suggest that the optimal excitation point on the Pedicularis flower links a suite of floral traits to its pollinators' dimensions, potentially contributing to prezygotic isolation among co-flowering, sympatric Pedicularis species.
文摘Background:Mobile technology has great potential to improve adherence and treatment outcomes in healthcare settings.However,text messaging and phone calls are unaffordable in many resource-limited areas.This study investigates the use of a no-cost alternative mobile phone technology using missed calls(‘buzzing’)to act as a patient reminder.The use of missed calls as a patient reminder was evaluated for feasibility and effectiveness as an appointment reminder in the follow-up of newly-diagnosed human immunodeficiency virus(HIV)positive patients in an HIV testing and counselling department in rural Swaziland.Methods:This pilot study uses a before-and-after operational research study design,with all patients with mobile phones being offered the intervention.The primary outcome was the rate of attendance at the HIV testing and counselling department for collection of results in those with mobile phones before and after the introduction of the intervention.Results:Over two-thirds,71.8%(459/639),of patients had a mobile phone.All patients with a mobile phone consented to being buzzed.There was no difference in attendance for follow-up at the clinic before and after the intervention was implemented(80.1%versus 83.3%,p=0.401),or after adjusting for confounding factors(OR 1.13,p=0.662).Conclusion:This pilot study illustrates that mobile technology may be feasible in rural,resource-poor settings as there are high rates of mobile phone ownership and the intervention had a 100%uptake rate,with positive feedback from staff and patients.In this particular setting,the intervention did not improve attendance rates.However,further research is planned to investigate the impact on adherence to appointments and medications in other settings,such as HIV chronic care follow-up and as part of an enhanced package to improve adherence.
基金support provided by the CAPES Foundation(Brazilian Ministry of Education)the National Council of Scientific and Technological Development(CNPq+1 种基金Brazilian Ministry of Science and Technology)the Minas Gerais State Foundation for Research Aid(FAPEMIG)were also greatly appreciated.
文摘Over 50 genera of bees release pollen from flower anthers using thoracic vibrations,a phenomenon known as buzz-pollination.The efficiency of this process is directly affected by the mechanical properties of the buzzes,namely the duration,amplitude,and frequency.Nonetheless,although the effects of the former two properties are well described,the role of buzz frequency on pollen release remains unclear.Furthermore,nearly all of the existing studies describing vibrational properties of natural buzz-pollination are limited to bumblebees(Bombus)and carpenter bees(Xvlocopa)constraining our current understanding of this behavior and its evolution.Therefore,we attempted to minimize this shortcoming by testing whether flower anthers exhibit optimal frequency for pollen release and whether bees tune their buzzes to match these(optimal)frequencies.If true,certain frequencies will trigger more pollen release and lighter bees will reach buzz frequencies closer to this optimum to compensate their smaller buzz amplitudes.Two strategies were used to test these hypotheses:(i)the use of(artificial)vibrational playbacks in a broad range of buzz frequencies and amplitudes to assess pollen release by tomato plants(Solarium Ivcopersicum L.)and(ii)the recording of natural buzzes of Neotropical bees visiting tomato plants during pollination.The playback experiment indicates that although buzz frequency does affect pollen release,no optimal frequency exists for that.In addition,the recorded results of natural buzz-pollination reveal that buzz frequencies vary with bee genera and are not correlated with body size.Therefore,neither bees nor plants are tuned to optimal pollen release frequencies.Bee frequency of buzz-pollination is a likely consequence of the insect flight machinery adapted to reach higher accelerations,while flower plant response to buzz-pollination is the likely result of its pollen granular properties.
文摘Socialism With Chinese Characteristics Socialism with Chinese Characteristics refers to building a socialist system under the leadership of the Communist Party of China(CPC) and in light of China’s basic condition.It contains five basic components:a peo- ple-oriented approach,a market econo- my,common prosperity,Chinese culture and socialist democracy.
文摘Voluntary research organizations are becoming more significant forces in the study of ‘lights in the sky’ something unusual was happening on the quiet, clear night in Hangzhou, Zhejiang Province, on July 7 this year. Because of sightings of an Unidentified Flying Object (UFO), more than 20 flights were postponed for 56 minutes at the city’s Xiaoshan International Airport. Immediately the event was connected with alien spacecraft. Speculations and rumors were everywhere.
