Evidence-based conservation seeks to incorporate sound scientific information into environmental decision making. The application of this concept in urban forest management has tremendous potential, but to date has be...Evidence-based conservation seeks to incorporate sound scientific information into environmental decision making. The application of this concept in urban forest management has tremendous potential, but to date has been little applied, largely because existing scientific studies emphasize the importance of urban forests in large-scale ecological and anthropogenic processes, but in practice, scientific evidence is ostensibly incorporated into North American urban forest management only when deciding the fate of individual trees. Even under these disjunctive conditions, the degree to which evidence influences tree-level decisions remains debatable. In analyzing preliminary data from a case study from Toronto, Canada, we sought to test if and how scientific evidence factored into the decision to remove or preserve 53 trees, located in close proximity to a provincially significant area of natural and scientific interest (ANSI). We found that by far the strongest tree-level correlate of the recommendation to remove or preserve trees was whether or not an individual tree was in conflict with proposed development. In comparison, species identity, tree condition, and suitability for conservation were statistically unrelated to the final recommendation. Our findings provide the basis to expand our analysis to multiple case studies across Canada, and internationally. Furthermore, when interpreted with available research and policy, our preliminary (and future) analysis highlights clear opportunities where scientific evidence can and should be readily incorporated into urban forestry management and policy.展开更多
Modeling landscape with high-resolution digital elevation model (DEM) in a geographic information system can provide essential morphological and structural information for modeling surface processes such as geomorphol...Modeling landscape with high-resolution digital elevation model (DEM) in a geographic information system can provide essential morphological and structural information for modeling surface processes such as geomorphologic process and water systems. This paper introduces several DEM-based spatial analysis processes applied to characterize spatial distribution and their interactions of ground and surface water systems in the Greater Toronto Area (GTA), Canada. The stream networks and drainage basin systems were derived from the DEM with 30 m resolution and the regularities of the surface stream and drainage patterns were modeled from a statistical/multifractal point of view. Together with the elevation and slope of topography, other attributes defined from modeling the stream system, and drainage networks were used to associate geological, hydrological and topographical features to water flow in river systems and the spatial locations of artesian aquifers in the study area. Stream flow data derived from daily flow measurements recorded at river gauging stations for multi-year period were decomposed into 'drainage-area dependent' and 'drainage-area independent' flow components by two-step 'frequency' and 'spatial' analysis processes. The latter component was further demonstrated to relate most likely to the ground water discharge. An independent analysis was conducted to model the distribution of aquifers with information derived from the records of water wells. The focus was given on quantification of the likelihood of ground water discharge to river and ponds through flowing wells, springs and seepages. It has been shown that the Oak Ridges Moraine (ORM) is a unique glacial deposit that serves as a recharge layer and that the aquifers in the ORM underlain by Hilton Tills and later deposits exposed near the steep slope zone of the ridges of ORM provide significant discharge to the surface water systems (river flow and ponds) through flowing wells, springs and seepages. Various statistics (cross- and auto-correlation coefficients, fractal R/S exponent) were used in conjunction with GIS to demonstrate the influence of land types, topography and geometry of drainage basins on short- and long-term persistence of river flows as well as responding time to precipitation events. The current study has provided not only insight in understanding the interaction of water systems in the GTA, but also a base for further establishment of an on-line GIS system for predicting spatial-temporal changes of river flow and groundwater level in the GTA.展开更多
The Institute of Medical Science (IMS) was established as an institute within the School of Graduate Studies at the University of Toronto in 1968 to serve as a graduate unit for the Clinical Departments in the Faculty...The Institute of Medical Science (IMS) was established as an institute within the School of Graduate Studies at the University of Toronto in 1968 to serve as a graduate unit for the Clinical Departments in the Faculty of Medicine. In this role,the IMS offers a doctoral stream program in medical science leading to the Master of Science and Doctor of Philosophy degrees. Translational research,as a means of moving new discovery to improvement in patient outcome,has become a central theme of graduate education in our Institute. To this end,we have developed a curriculum offering which is intended to provide all new students with a defined skill set relevant to Translational Research and at the same time,to provide students with flexible offerings which would enhance their specific research programs. The course,spread over two years,will have three separate components:(1) there will be lectures focusing on research fundamentals and the basics of translational research; (2) there will be student presentations to hone presentation skills and get valuable feedback from fellow students and faculty mentors; (3) there will be elective modules,where students can select from a number of course offerings in order to round out training. These modules include subjects such as the fundamentals of clinical trials,the basics of qualitative research,an approach to the role of proteomics and genomics in research and the business of science. As part of this modular program,we have created a program 'clinical exposure for non-clinicians' with the hope that graduate students will be able to gain some understanding of the clinical relevance of their research activities. Over time,these modular offerings will be expanded based on a needs assessment from our students. The presentation will describe the IMS and its mission and will overview the structure and content of this course offering.展开更多
[目的/意义]通过最大瓦解结构准确识别科学研究前沿中的关键节点并追踪其演化路径,为把握领域发展规律、优化科研资源配置提供支持,突破现有研究聚焦孤立节点的局部特征,以及难以捕捉知识网络中具有协同作用且对全局连通性有级联破坏力...[目的/意义]通过最大瓦解结构准确识别科学研究前沿中的关键节点并追踪其演化路径,为把握领域发展规律、优化科研资源配置提供支持,突破现有研究聚焦孤立节点的局部特征,以及难以捕捉知识网络中具有协同作用且对全局连通性有级联破坏力的关键节点集合的问题。[方法/过程]以量子通信领域为例,基于2015—2024年Web of Science的6538篇文献构建关键词共现网络,融合多中心性指标并利用熵权法评估节点重要性,采用贪心算法识别MDS,分析其功能协同特征与演化轨迹。[结果/结论]研究表明,MDS仅占网络规模的18%~22%,移除该集合后网络最大连通组件规模下降超过70%,效果显著优于传统方法。关键节点在功能上呈现“主题—方法—工具—目标”的互补协同结构,其演化路径清晰展示了量子通信从理论奠基、技术攻坚到应用落地的三阶段发展轨迹,验证了MDS框架的有效性和实用性。展开更多
The mechanistic target of rapamycin(m TOR) is a serine/threonine kinase that plays a pivotal role in cellular growth, proliferation, survival, and metabolism. In the central nervous system(CNS), the mTOR pathway regul...The mechanistic target of rapamycin(m TOR) is a serine/threonine kinase that plays a pivotal role in cellular growth, proliferation, survival, and metabolism. In the central nervous system(CNS), the mTOR pathway regulates diverse aspects of neural development and function. Genetic mutations within the m TOR pathway lead to severe neurodevelopmental disorders, collectively known as “mTORopathies”(Crino, 2020). Dysfunctions of m TOR, including both its hyperactivation and hypoactivation, have also been implicated in a wide spectrum of other neurodevelopmental and neurodegenerative conditions, highlighting its importance in CNS health.展开更多
Background:A significant challenge regarding notable historical figures is determining the accuracy of the words and actions attributed to them with the limited available evidence,when their biographers have presented...Background:A significant challenge regarding notable historical figures is determining the accuracy of the words and actions attributed to them with the limited available evidence,when their biographers have presented a biased life assessment.Lauded as a founding suffragette,the first female school principal,and the first white female practicing physician in Canada,Dr.Emily Stowe did not help historians.She destroyed her records,leaving her life story to be told by her daughter,who portrayed her as a heroine–a view that has persisted since the start of the 20th century.To improve the accuracy of assessing the life of Emily Stowe,as much information as possible about Stowe must be collected and interpreted.Methods:Presented is a narrative research method for analyzing historical figures that examines 22 life-changing events in the life of Stowe by answering six types of questions about each event:when,where,who,what,how,and why.Results:This narrative research,representing a psychoanalytic research process,finds that much of the repeated story of Stowe is either exaggerated or likely false.Conclusion:Following the example of Emily Stowe,this unique method is applicable for improving the historical accuracy in assessing the lives of other notable figures.It represents a method extendable to those currently alive,outside the public eye,searching to develop their own narrative.展开更多
The giant impact hypothesis for the Moon's origin has had difficulty explaining the nearly identical isotopic compositions of Moon rocks and rocks from Earth's silicate mantle and crust.These similarities are ...The giant impact hypothesis for the Moon's origin has had difficulty explaining the nearly identical isotopic compositions of Moon rocks and rocks from Earth's silicate mantle and crust.These similarities are instead more compatible with the Darwin-Wise hypothesis that the Moon arose by fission of a rapidly spinning Earth.To overcome problems with the fission model concerning structural stability and angular momentum conservation,some authors suggested that lunar fission was feasible on a more slowly rotating Earth if assisted by a nuclear explosion near the core-mantle boundary.In this light we consider the possible roles of the large low-velocity provinces(LLVPs).These long-lived structures have been implicated in diverse geophysical processes ranging from deep mantle plumes to continental breakup and mass extinction events.While the LLVPs have been seen as possible remnants of the giant imp actor,we propose that one of them was the site of lunar ejection.Internal heating of the liquid core is suggested to have given rise to an equatorial belt just under the core-mantle boundary analogous to the one recently detected by Ma and Tkalcic[Sci Adv 10(35):eadn5562,2024].Upwellings of heat and volatiles from this belt then generated two antipodal,equatorial bulges:the precursors of the Pacific and African LLVPs.Prior to the emergence of plate tectonics,core heat was mainly dissipated by networks of deep mantle plumes extending above the proto-LLVPs.These plume networks represent conduits of weakened mantle through which proto-lunar materials could later rise in a focused ejection.Continuing heat buildup in the core eventually triggered a cataclysmic explosion in the Pacific proto-LLVP,possibly analogous to a planetary-scale kimberlite eruption.This explosion launched LLVP and overlying mantle material into a low Earth orbit,where it coalesced to form the Moon.Some possible sources of additional energy to power the explosion are considered,including nuclear fission,bolide impacts and a hypothetical gravitational decay process culminating in a'A event'.展开更多
In recent years,development of strategies to treat central nervous system(CNS) diseases has attracted extensive attention.A major obstacle in this field is the blood-brain barrier(BBB),which significantly limits the e...In recent years,development of strategies to treat central nervous system(CNS) diseases has attracted extensive attention.A major obstacle in this field is the blood-brain barrier(BBB),which significantly limits the efficient delivery of therapeutic agents to the brain and hinders the treatment of CNS diseases.Overcoming the restrictive nature of the BBB has thus emerged as a key objective in CNS drug development.Nanomaterials have garnered growing interest due to their unique physicochemical properties and potential to traverse the BBB,enabling targeted drug delivery to brain tissue and improving therapeutic efficacy.In this review,we present current insights into the structure and function of the BBB and highlight a range of nanomaterial-based strategies for BBB penetration,including receptor-mediated transport(RMT),adsorptive-mediated transcytosis,reversible BBB disruption,and intranasal administration.Finally,we summarize recent advances in enhancing BBB permeability for CNS therapeutics and discuss persisting challenges,offering perspectives for future research in this field.展开更多
Skeletal muscle health and function are essential determinants of metabolic health,physical performance,and overall quality of life.The quality of skeletal muscle is heavily dependent on the complex mitochondrial reti...Skeletal muscle health and function are essential determinants of metabolic health,physical performance,and overall quality of life.The quality of skeletal muscle is heavily dependent on the complex mitochondrial reticulum that contributes toward its unique adaptability.It is now recognized that mitochondrial perturbations can activate various innate immune pathways,such as the nucleotide-binding oligomerization domain(NOD)-like receptor protein 3(NLRP3)inflammasome complex by propagating inflammatory signaling in response to damage-associated molecular patterns(DAMPs).The NLRP3 inflammasome is a multimeric protein complex and is a prominent regulator of innate immunity and cell death by mediating the activation of caspase-1,pro-inflammatory cytokines interleukin-1βand interleukin-18 and pro-pyroptotic protein gasdermin-D.While several studies have begun to demonstrate the relationship between various mitochondrial DAMPs(mtDAMPs)and NLRP3 inflammasome activation,the influence of various metabolic states on the production of these DAMPs and subsequent inflammatory profile remains poorly understood.This narrative review aimed to address this by highlighting the effects of skeletal muscle use and disuse on mitochondrial quality mechanisms including mitochondrial biogenesis,fusion,fission and mitophagy.Secondly,this review summarized the impact of alterations in mitochondrial quality control mechanisms following muscle denervation,aging,and exercise training in relation to NLRP3 inflammasome activation.By consolidating the current body of literature,this work aimed to further the understanding of innate immune signaling within skeletal muscle,which can highlight areas for future research and therapeutic strategies to regulate NLRP3 inflammasome activation during divergent metabolic conditions.展开更多
Climate change is impacting forests in Central Europe,causing increased mortality and degradation of forest ecosystem services(FES).As global warming intensifies,these effects are likely to worsen,particularly through...Climate change is impacting forests in Central Europe,causing increased mortality and degradation of forest ecosystem services(FES).As global warming intensifies,these effects are likely to worsen,particularly through more severe droughts and increased biotic disturbances.Understanding how forests respond to different levels of warming is essential for adaptation planning.Therefore,this study analyzed changes in forest structure and FES,including timber production,climate change mitigation,recreation,and structural diversity,under three global warming scenarios.Using the LandClim model,we compared warming levels of 1.5,2,and 3℃above preindustrial temperatures,based on 30-year periods from RCP data,to historical climate.Our research focused on Freiburg's forests in southwestern Germany,characterized by diverse tree species and an elevation range of 200–1,250 m a.s.l.A warming of 1.5℃could temporarily increase productivity,but at 2℃,biomass losses of up to 10%would occur below elevations of 450 m due to drought mortality.Under 3℃,losses would intensify below 650 m up to 40%,with even drought-resistant species like pedunculate oak experiencing mortality.At higher elevations,bark beetle outbreaks caused mortality of Norway spruce,while European beech capitalized on the changing ecological conditions.Higher warming levels significantly deteriorated FES,particularly timber production,climate change mitigation,and structural diversity,while recreation was less affected.These findings emphasize the urgency of meeting Paris Agreement targets,as limiting warming below 2℃can reduce severe impacts.If warming exceeds this critical threshold,even species presently considered drought-resistant,such as native sessile and pedunculate oaks and non-native red oak,could face serious threats at lower elevations.This would undermine the effectiveness of current management strategies,as these tree species are key to providing multiple FES.展开更多
Efficient energy utilization in covert communication sustains covertness while assuring communication quality and efficiency.This paper investigates covert communication energy efficiency(EE)in direct uplink satellite...Efficient energy utilization in covert communication sustains covertness while assuring communication quality and efficiency.This paper investigates covert communication energy efficiency(EE)in direct uplink satellite-ground communications,focusing on enhancing system EE via optimized transmit beamforming and satellite orbit altitude selection.This paper first establishes an optimization problem to maximize system EE in a direct uplink satelliteground covert communication scenario.To solve this non-convex optimization problem,it is decomposed into two subproblems and solved using the successive convex approximation(SCA)method.Based on the above methods,this paper proposes an overall iterative optimization algorithm.Simulation results demonstrate that the proposed algorithm surpasses the conventional baseline algorithms in terms of system EE.Furthermore,they elucidate the correlation between the amount of information received by the receiver and the variations in the satellite’s orbital altitude.展开更多
Sustained and spatially explicit monitoring of the United Nations 2030 Agenda for Sustainable Development is critical for effectively tracking progress toward the global Sustainable Development Goals(SDGs).Although la...Sustained and spatially explicit monitoring of the United Nations 2030 Agenda for Sustainable Development is critical for effectively tracking progress toward the global Sustainable Development Goals(SDGs).Although land cover information has long been recognized as an essential component for monitoring SDGs,a standardized scientific framework for identifying and prioritizing land cover related essential variables does not exist.Therefore,we propose a novel expert-and data-driven framework for identifying,refining,and selecting a priority list of Essential Land cover-related Variables for SDGs(ELcV4SDGs).This framework integrates methods including expert knowledge-based analysis,clustering of variables with similar attributes,and quantified index calculation to establish the priority list.Applying the framework to 15 specific SDG indicators,we found that the ELcV4SDGs priority list comprises three main categories,type and structure,pattern and intensity,and process and evolution of land cover,which are further divided into 19 subcategories and ultimately encompass 50 general variables.The ELcV4SDGs will support detailed spatial monitoring and enhance their scientific applications for SDG monitoring and assessment,thereby guiding future SDG priority actions and informing decision-making to advance the 2030 SDGs agenda at local,national,and global levels.展开更多
BACKGROUND.The effective reproduction number Re(t)is a critical measure of epidemic potential.Re(t)can be calculated in near real time using an incidence time series and the generation time distribution:the time betwe...BACKGROUND.The effective reproduction number Re(t)is a critical measure of epidemic potential.Re(t)can be calculated in near real time using an incidence time series and the generation time distribution:the time between infection events in an infector-infectee pair.In calculating Re(t),the generation time distribution is often approximated by the serial interval distribution:the time between symptom onset in an infector-infectee pair.However,while generation time must be positive by definition,serial interval can be negative if transmission can occur before symptoms,such as in COVID-19,rendering such an approximation improper in some contexts.METHODS.We developed a method to infer the generation time distribution from parametric definitions of the serial interval and incubation period distributions.We then compared estimates of Re(t)for COVID-19 in the Greater Toronto Area of Canada using:negative-permitting versus non-negative serial interval distributions,versus the inferred generation time distribution.RESULTS.We estimated the generation time of COVID-19 to be Gamma-distributed with mean 3.99 and standard deviation 2.96 days.Relative to the generation time distribution,non-negative serial interval distribution caused overestimation of Re(t)due to larger mean,while negative-permitting serial interval distribution caused underestimation of Re(t)due to larger variance.IMPLICATIONS.Approximation of the generation time distribution of COVID-19 with non-negative or negative-permitting serial interval distributions when calculating Re(t)may result in over or underestimation of transmission potential,respectively.展开更多
Background:Investigators from low-,middle-,and high-income countries representing 6 continents contributed to the development of the Global Adolescent and Child Physical Activity Questionnaire(GAC-PAQ).The GAC-PAQ is ...Background:Investigators from low-,middle-,and high-income countries representing 6 continents contributed to the development of the Global Adolescent and Child Physical Activity Questionnaire(GAC-PAQ).The GAC-PAQ is designed to assess physical activity(PA)across all key domains(i.e.,school,chores,work/volunteering,transport,free time,outdoor time).It aimed to address multiple gaps in global PA surveillance(e.g.,omission of important PA domains,insufficient cultural adaptation,underrepresentation of rural areas in questionnaire validation studies).The purpose of this study was to assess the content validity of the GAC-PAQ among PA experts,8-to 17-year-olds,and one of their parents/guardians,and to discuss changes made to the questionnaire based on participants'feedback.Methods:Sixty-two experts in PA measurement and/or surveillance from 24 countries completed an online survey that included both closed-and open-ended questions about the content validity of the GAC-PAQ.The proportion of experts who agreed or strongly agreed with the items was calculated.Child-parent/guardian dyads from 15 countries(n=250;10-40 per country)participated in a structured cognitive interview to assess the clarity of the questions and response options,and they were encouraged to provide suggestions to improve clarity and facilitate completion of the questionnaire.Participating countries are:Aotearoa New Zealand,Brazil,Canada,China,Colombia,Czech Republic,India,Malawi,Mexico,Nepal,Nigeria,Spain,Sweden,Thailand,and the United Arab Emirates.Interviews were conducted in 13 different languages and structured by PA domain.Generic images were included to help participants in answering questions about PA intensity.Results:Expert agreement with the items for each domain exceeded 75%,and their qualitative feedback was used to revise the questionnaire before cognitive interviews.In general,participants found the questionnaire to be comprehensive.Adolescents(12-17 years)found it easier than children(8-11 years)to answer the questions.Several children struggled to answer questions about the duration and intensity of activities and/or concepts related to travel modes,active trips,and organized activities.Many parents/guardians were unsure about the frequency,duration,and intensity of their children's or adolescents'PA at school and/or recommended using more culturally relevant and appropriate images.Some participants misunderstood the concept of activities that“make you stronger”(intended to assess resistance activities)and/or struggled to differentiate between work,volunteering,and chores.Conclusion:Participants'feedback was used to develop a revised,simplified,and culturally adapted GAC-PAQ,which will be pilot-tested in all15 countries in an App that will include country-specific images and narration in local languages.Further research is needed to assess the reliability and validity of the revised GAC-PAQ.展开更多
文摘Evidence-based conservation seeks to incorporate sound scientific information into environmental decision making. The application of this concept in urban forest management has tremendous potential, but to date has been little applied, largely because existing scientific studies emphasize the importance of urban forests in large-scale ecological and anthropogenic processes, but in practice, scientific evidence is ostensibly incorporated into North American urban forest management only when deciding the fate of individual trees. Even under these disjunctive conditions, the degree to which evidence influences tree-level decisions remains debatable. In analyzing preliminary data from a case study from Toronto, Canada, we sought to test if and how scientific evidence factored into the decision to remove or preserve 53 trees, located in close proximity to a provincially significant area of natural and scientific interest (ANSI). We found that by far the strongest tree-level correlate of the recommendation to remove or preserve trees was whether or not an individual tree was in conflict with proposed development. In comparison, species identity, tree condition, and suitability for conservation were statistically unrelated to the final recommendation. Our findings provide the basis to expand our analysis to multiple case studies across Canada, and internationally. Furthermore, when interpreted with available research and policy, our preliminary (and future) analysis highlights clear opportunities where scientific evidence can and should be readily incorporated into urban forestry management and policy.
文摘Modeling landscape with high-resolution digital elevation model (DEM) in a geographic information system can provide essential morphological and structural information for modeling surface processes such as geomorphologic process and water systems. This paper introduces several DEM-based spatial analysis processes applied to characterize spatial distribution and their interactions of ground and surface water systems in the Greater Toronto Area (GTA), Canada. The stream networks and drainage basin systems were derived from the DEM with 30 m resolution and the regularities of the surface stream and drainage patterns were modeled from a statistical/multifractal point of view. Together with the elevation and slope of topography, other attributes defined from modeling the stream system, and drainage networks were used to associate geological, hydrological and topographical features to water flow in river systems and the spatial locations of artesian aquifers in the study area. Stream flow data derived from daily flow measurements recorded at river gauging stations for multi-year period were decomposed into 'drainage-area dependent' and 'drainage-area independent' flow components by two-step 'frequency' and 'spatial' analysis processes. The latter component was further demonstrated to relate most likely to the ground water discharge. An independent analysis was conducted to model the distribution of aquifers with information derived from the records of water wells. The focus was given on quantification of the likelihood of ground water discharge to river and ponds through flowing wells, springs and seepages. It has been shown that the Oak Ridges Moraine (ORM) is a unique glacial deposit that serves as a recharge layer and that the aquifers in the ORM underlain by Hilton Tills and later deposits exposed near the steep slope zone of the ridges of ORM provide significant discharge to the surface water systems (river flow and ponds) through flowing wells, springs and seepages. Various statistics (cross- and auto-correlation coefficients, fractal R/S exponent) were used in conjunction with GIS to demonstrate the influence of land types, topography and geometry of drainage basins on short- and long-term persistence of river flows as well as responding time to precipitation events. The current study has provided not only insight in understanding the interaction of water systems in the GTA, but also a base for further establishment of an on-line GIS system for predicting spatial-temporal changes of river flow and groundwater level in the GTA.
文摘The Institute of Medical Science (IMS) was established as an institute within the School of Graduate Studies at the University of Toronto in 1968 to serve as a graduate unit for the Clinical Departments in the Faculty of Medicine. In this role,the IMS offers a doctoral stream program in medical science leading to the Master of Science and Doctor of Philosophy degrees. Translational research,as a means of moving new discovery to improvement in patient outcome,has become a central theme of graduate education in our Institute. To this end,we have developed a curriculum offering which is intended to provide all new students with a defined skill set relevant to Translational Research and at the same time,to provide students with flexible offerings which would enhance their specific research programs. The course,spread over two years,will have three separate components:(1) there will be lectures focusing on research fundamentals and the basics of translational research; (2) there will be student presentations to hone presentation skills and get valuable feedback from fellow students and faculty mentors; (3) there will be elective modules,where students can select from a number of course offerings in order to round out training. These modules include subjects such as the fundamentals of clinical trials,the basics of qualitative research,an approach to the role of proteomics and genomics in research and the business of science. As part of this modular program,we have created a program 'clinical exposure for non-clinicians' with the hope that graduate students will be able to gain some understanding of the clinical relevance of their research activities. Over time,these modular offerings will be expanded based on a needs assessment from our students. The presentation will describe the IMS and its mission and will overview the structure and content of this course offering.
文摘[目的/意义]通过最大瓦解结构准确识别科学研究前沿中的关键节点并追踪其演化路径,为把握领域发展规律、优化科研资源配置提供支持,突破现有研究聚焦孤立节点的局部特征,以及难以捕捉知识网络中具有协同作用且对全局连通性有级联破坏力的关键节点集合的问题。[方法/过程]以量子通信领域为例,基于2015—2024年Web of Science的6538篇文献构建关键词共现网络,融合多中心性指标并利用熵权法评估节点重要性,采用贪心算法识别MDS,分析其功能协同特征与演化轨迹。[结果/结论]研究表明,MDS仅占网络规模的18%~22%,移除该集合后网络最大连通组件规模下降超过70%,效果显著优于传统方法。关键节点在功能上呈现“主题—方法—工具—目标”的互补协同结构,其演化路径清晰展示了量子通信从理论奠基、技术攻坚到应用落地的三阶段发展轨迹,验证了MDS框架的有效性和实用性。
基金supported by grants from Simons Foundation (SFARI 479754),CIHR (PJT-180565)the Scottish Rite Charitable Foundation of Canada (to YL)funding from the Canada Research Chairs program。
文摘The mechanistic target of rapamycin(m TOR) is a serine/threonine kinase that plays a pivotal role in cellular growth, proliferation, survival, and metabolism. In the central nervous system(CNS), the mTOR pathway regulates diverse aspects of neural development and function. Genetic mutations within the m TOR pathway lead to severe neurodevelopmental disorders, collectively known as “mTORopathies”(Crino, 2020). Dysfunctions of m TOR, including both its hyperactivation and hypoactivation, have also been implicated in a wide spectrum of other neurodevelopmental and neurodegenerative conditions, highlighting its importance in CNS health.
文摘Background:A significant challenge regarding notable historical figures is determining the accuracy of the words and actions attributed to them with the limited available evidence,when their biographers have presented a biased life assessment.Lauded as a founding suffragette,the first female school principal,and the first white female practicing physician in Canada,Dr.Emily Stowe did not help historians.She destroyed her records,leaving her life story to be told by her daughter,who portrayed her as a heroine–a view that has persisted since the start of the 20th century.To improve the accuracy of assessing the life of Emily Stowe,as much information as possible about Stowe must be collected and interpreted.Methods:Presented is a narrative research method for analyzing historical figures that examines 22 life-changing events in the life of Stowe by answering six types of questions about each event:when,where,who,what,how,and why.Results:This narrative research,representing a psychoanalytic research process,finds that much of the repeated story of Stowe is either exaggerated or likely false.Conclusion:Following the example of Emily Stowe,this unique method is applicable for improving the historical accuracy in assessing the lives of other notable figures.It represents a method extendable to those currently alive,outside the public eye,searching to develop their own narrative.
文摘The giant impact hypothesis for the Moon's origin has had difficulty explaining the nearly identical isotopic compositions of Moon rocks and rocks from Earth's silicate mantle and crust.These similarities are instead more compatible with the Darwin-Wise hypothesis that the Moon arose by fission of a rapidly spinning Earth.To overcome problems with the fission model concerning structural stability and angular momentum conservation,some authors suggested that lunar fission was feasible on a more slowly rotating Earth if assisted by a nuclear explosion near the core-mantle boundary.In this light we consider the possible roles of the large low-velocity provinces(LLVPs).These long-lived structures have been implicated in diverse geophysical processes ranging from deep mantle plumes to continental breakup and mass extinction events.While the LLVPs have been seen as possible remnants of the giant imp actor,we propose that one of them was the site of lunar ejection.Internal heating of the liquid core is suggested to have given rise to an equatorial belt just under the core-mantle boundary analogous to the one recently detected by Ma and Tkalcic[Sci Adv 10(35):eadn5562,2024].Upwellings of heat and volatiles from this belt then generated two antipodal,equatorial bulges:the precursors of the Pacific and African LLVPs.Prior to the emergence of plate tectonics,core heat was mainly dissipated by networks of deep mantle plumes extending above the proto-LLVPs.These plume networks represent conduits of weakened mantle through which proto-lunar materials could later rise in a focused ejection.Continuing heat buildup in the core eventually triggered a cataclysmic explosion in the Pacific proto-LLVP,possibly analogous to a planetary-scale kimberlite eruption.This explosion launched LLVP and overlying mantle material into a low Earth orbit,where it coalesced to form the Moon.Some possible sources of additional energy to power the explosion are considered,including nuclear fission,bolide impacts and a hypothetical gravitational decay process culminating in a'A event'.
基金funded by the Fundamental Research Funds for the Central Universities (No.2242022R42012)。
文摘In recent years,development of strategies to treat central nervous system(CNS) diseases has attracted extensive attention.A major obstacle in this field is the blood-brain barrier(BBB),which significantly limits the efficient delivery of therapeutic agents to the brain and hinders the treatment of CNS diseases.Overcoming the restrictive nature of the BBB has thus emerged as a key objective in CNS drug development.Nanomaterials have garnered growing interest due to their unique physicochemical properties and potential to traverse the BBB,enabling targeted drug delivery to brain tissue and improving therapeutic efficacy.In this review,we present current insights into the structure and function of the BBB and highlight a range of nanomaterial-based strategies for BBB penetration,including receptor-mediated transport(RMT),adsorptive-mediated transcytosis,reversible BBB disruption,and intranasal administration.Finally,we summarize recent advances in enhancing BBB permeability for CNS therapeutics and discuss persisting challenges,offering perspectives for future research in this field.
文摘Skeletal muscle health and function are essential determinants of metabolic health,physical performance,and overall quality of life.The quality of skeletal muscle is heavily dependent on the complex mitochondrial reticulum that contributes toward its unique adaptability.It is now recognized that mitochondrial perturbations can activate various innate immune pathways,such as the nucleotide-binding oligomerization domain(NOD)-like receptor protein 3(NLRP3)inflammasome complex by propagating inflammatory signaling in response to damage-associated molecular patterns(DAMPs).The NLRP3 inflammasome is a multimeric protein complex and is a prominent regulator of innate immunity and cell death by mediating the activation of caspase-1,pro-inflammatory cytokines interleukin-1βand interleukin-18 and pro-pyroptotic protein gasdermin-D.While several studies have begun to demonstrate the relationship between various mitochondrial DAMPs(mtDAMPs)and NLRP3 inflammasome activation,the influence of various metabolic states on the production of these DAMPs and subsequent inflammatory profile remains poorly understood.This narrative review aimed to address this by highlighting the effects of skeletal muscle use and disuse on mitochondrial quality mechanisms including mitochondrial biogenesis,fusion,fission and mitophagy.Secondly,this review summarized the impact of alterations in mitochondrial quality control mechanisms following muscle denervation,aging,and exercise training in relation to NLRP3 inflammasome activation.By consolidating the current body of literature,this work aimed to further the understanding of innate immune signaling within skeletal muscle,which can highlight areas for future research and therapeutic strategies to regulate NLRP3 inflammasome activation during divergent metabolic conditions.
基金funded by the HORIZON EUROPE's project"eco2adapt"(Ecosystem-based Adaptation and Changemaking to Shape,Project,and Sustain the Resilience of Tomorrow's Forests,Grant no:101059498)。
文摘Climate change is impacting forests in Central Europe,causing increased mortality and degradation of forest ecosystem services(FES).As global warming intensifies,these effects are likely to worsen,particularly through more severe droughts and increased biotic disturbances.Understanding how forests respond to different levels of warming is essential for adaptation planning.Therefore,this study analyzed changes in forest structure and FES,including timber production,climate change mitigation,recreation,and structural diversity,under three global warming scenarios.Using the LandClim model,we compared warming levels of 1.5,2,and 3℃above preindustrial temperatures,based on 30-year periods from RCP data,to historical climate.Our research focused on Freiburg's forests in southwestern Germany,characterized by diverse tree species and an elevation range of 200–1,250 m a.s.l.A warming of 1.5℃could temporarily increase productivity,but at 2℃,biomass losses of up to 10%would occur below elevations of 450 m due to drought mortality.Under 3℃,losses would intensify below 650 m up to 40%,with even drought-resistant species like pedunculate oak experiencing mortality.At higher elevations,bark beetle outbreaks caused mortality of Norway spruce,while European beech capitalized on the changing ecological conditions.Higher warming levels significantly deteriorated FES,particularly timber production,climate change mitigation,and structural diversity,while recreation was less affected.These findings emphasize the urgency of meeting Paris Agreement targets,as limiting warming below 2℃can reduce severe impacts.If warming exceeds this critical threshold,even species presently considered drought-resistant,such as native sessile and pedunculate oaks and non-native red oak,could face serious threats at lower elevations.This would undermine the effectiveness of current management strategies,as these tree species are key to providing multiple FES.
基金supported in part by the National Natural Science Foundation of China under Grants 62025110,62271093sponsored by Natural Science Foundation of Chongqing,China,under Grant CSTB2023NSCQ-LZX0108.
文摘Efficient energy utilization in covert communication sustains covertness while assuring communication quality and efficiency.This paper investigates covert communication energy efficiency(EE)in direct uplink satellite-ground communications,focusing on enhancing system EE via optimized transmit beamforming and satellite orbit altitude selection.This paper first establishes an optimization problem to maximize system EE in a direct uplink satelliteground covert communication scenario.To solve this non-convex optimization problem,it is decomposed into two subproblems and solved using the successive convex approximation(SCA)method.Based on the above methods,this paper proposes an overall iterative optimization algorithm.Simulation results demonstrate that the proposed algorithm surpasses the conventional baseline algorithms in terms of system EE.Furthermore,they elucidate the correlation between the amount of information received by the receiver and the variations in the satellite’s orbital altitude.
基金supported by the Key Program of National Natural Science Foundation of China(Grant No.41930650)Young Scientists Fund of the National Natural Science Foundation of China(Grant No.42301310).
文摘Sustained and spatially explicit monitoring of the United Nations 2030 Agenda for Sustainable Development is critical for effectively tracking progress toward the global Sustainable Development Goals(SDGs).Although land cover information has long been recognized as an essential component for monitoring SDGs,a standardized scientific framework for identifying and prioritizing land cover related essential variables does not exist.Therefore,we propose a novel expert-and data-driven framework for identifying,refining,and selecting a priority list of Essential Land cover-related Variables for SDGs(ELcV4SDGs).This framework integrates methods including expert knowledge-based analysis,clustering of variables with similar attributes,and quantified index calculation to establish the priority list.Applying the framework to 15 specific SDG indicators,we found that the ELcV4SDGs priority list comprises three main categories,type and structure,pattern and intensity,and process and evolution of land cover,which are further divided into 19 subcategories and ultimately encompass 50 general variables.The ELcV4SDGs will support detailed spatial monitoring and enhance their scientific applications for SDG monitoring and assessment,thereby guiding future SDG priority actions and informing decision-making to advance the 2030 SDGs agenda at local,national,and global levels.
基金The study was supported by:the Natural Sciences and Engineering Research Council of Canada(NSERC CGS-D)Ontario Early Researcher Award No.ER17-13-043(Canada)the 2020 COVID-19 Centred Research Award from the St Michael’s Hospital Foundation Research Innovation Council(Canada).
文摘BACKGROUND.The effective reproduction number Re(t)is a critical measure of epidemic potential.Re(t)can be calculated in near real time using an incidence time series and the generation time distribution:the time between infection events in an infector-infectee pair.In calculating Re(t),the generation time distribution is often approximated by the serial interval distribution:the time between symptom onset in an infector-infectee pair.However,while generation time must be positive by definition,serial interval can be negative if transmission can occur before symptoms,such as in COVID-19,rendering such an approximation improper in some contexts.METHODS.We developed a method to infer the generation time distribution from parametric definitions of the serial interval and incubation period distributions.We then compared estimates of Re(t)for COVID-19 in the Greater Toronto Area of Canada using:negative-permitting versus non-negative serial interval distributions,versus the inferred generation time distribution.RESULTS.We estimated the generation time of COVID-19 to be Gamma-distributed with mean 3.99 and standard deviation 2.96 days.Relative to the generation time distribution,non-negative serial interval distribution caused overestimation of Re(t)due to larger mean,while negative-permitting serial interval distribution caused underestimation of Re(t)due to larger variance.IMPLICATIONS.Approximation of the generation time distribution of COVID-19 with non-negative or negative-permitting serial interval distributions when calculating Re(t)may result in over or underestimation of transmission potential,respectively.
基金supported by a Project Grant(Grant No.PJT183705)an Early Career Investigator Prize(Grant No.ECP 184184)from the Canadian Institutes of Health Research+7 种基金a Prentice Institute Research Affiliate Fund Grant from the Prentice Institute for Global Population and Economy(Grant No.G00004116)a Te Herenga Waka Victoria University of Wellington Division of Science Health Engineering Architecture and Design Innovation Faculty Strategic Research Grant(Grant No.FSRG-SHEADI-10724)The Thailand Physical Activity Knowledge Development Centre(TPAK)/Thai Health Promotion Foundation provided funding for the cognitive interviews and pilot study in Thailand(Grant No.66-P1-0473)The University Pablo de Olavide provided a scholarship for 2 undergraduate students working on the project(codes PPI2207 and PPI2308)In the Czech Republicthe study was supported by Palacky University IGA(Grant No.IGA_FTK_2023_017)supported by the Division of Intramural Research at the National Institute on Minority Health and Health Disparities of the National Institutes of Healthsupported by the Key Project of the National Philosophy and Social Science Foundation of China(23&ZD197)。
文摘Background:Investigators from low-,middle-,and high-income countries representing 6 continents contributed to the development of the Global Adolescent and Child Physical Activity Questionnaire(GAC-PAQ).The GAC-PAQ is designed to assess physical activity(PA)across all key domains(i.e.,school,chores,work/volunteering,transport,free time,outdoor time).It aimed to address multiple gaps in global PA surveillance(e.g.,omission of important PA domains,insufficient cultural adaptation,underrepresentation of rural areas in questionnaire validation studies).The purpose of this study was to assess the content validity of the GAC-PAQ among PA experts,8-to 17-year-olds,and one of their parents/guardians,and to discuss changes made to the questionnaire based on participants'feedback.Methods:Sixty-two experts in PA measurement and/or surveillance from 24 countries completed an online survey that included both closed-and open-ended questions about the content validity of the GAC-PAQ.The proportion of experts who agreed or strongly agreed with the items was calculated.Child-parent/guardian dyads from 15 countries(n=250;10-40 per country)participated in a structured cognitive interview to assess the clarity of the questions and response options,and they were encouraged to provide suggestions to improve clarity and facilitate completion of the questionnaire.Participating countries are:Aotearoa New Zealand,Brazil,Canada,China,Colombia,Czech Republic,India,Malawi,Mexico,Nepal,Nigeria,Spain,Sweden,Thailand,and the United Arab Emirates.Interviews were conducted in 13 different languages and structured by PA domain.Generic images were included to help participants in answering questions about PA intensity.Results:Expert agreement with the items for each domain exceeded 75%,and their qualitative feedback was used to revise the questionnaire before cognitive interviews.In general,participants found the questionnaire to be comprehensive.Adolescents(12-17 years)found it easier than children(8-11 years)to answer the questions.Several children struggled to answer questions about the duration and intensity of activities and/or concepts related to travel modes,active trips,and organized activities.Many parents/guardians were unsure about the frequency,duration,and intensity of their children's or adolescents'PA at school and/or recommended using more culturally relevant and appropriate images.Some participants misunderstood the concept of activities that“make you stronger”(intended to assess resistance activities)and/or struggled to differentiate between work,volunteering,and chores.Conclusion:Participants'feedback was used to develop a revised,simplified,and culturally adapted GAC-PAQ,which will be pilot-tested in all15 countries in an App that will include country-specific images and narration in local languages.Further research is needed to assess the reliability and validity of the revised GAC-PAQ.
