Permafrost,a critical component of Earth’s climate system,is increasingly subject to abrupt thaw events,which jeopardize infrastructure,reshape landforms,alter hydrological regimes,and disrupt ecosystems,thereby posi...Permafrost,a critical component of Earth’s climate system,is increasingly subject to abrupt thaw events,which jeopardize infrastructure,reshape landforms,alter hydrological regimes,and disrupt ecosystems,thereby posing substantial threats to global sustainability.However,the underlying mechanisms that trigger these abrupt transitions remain incompletely understood.Here,we present decade-long in-situ observations from HRQ1,a marginal permafrost site in the Headwater Area of the Yellow River,northeastern Qinghai-Xizang Plateau.These data reveal the formation and growth of a talik,indicative of a permafrost tipping point.Absent before 2017,the talik subsequently formed and progressively deepened,extending to the maximum observation depth of 300 cm by 2024.The transition from perennially frozen to thawed conditions was accompanied by a substantial increase in mean annual soil temperature(MAST)throughout the entire soil profile.From 2015 to 2023,MAST in the upper 200 cm rose from sub-zero(−0.30 to−0.49℃)to consistently above 0℃(0.07 to 1.08℃).Concurrently,maximum daily soil temperatures in deeper layers(200–300 cm)became positive,indicating thaw propagation into the relict permafrost.This warming coincided with a marked increase in unfrozen soil moisture,particularly within the expanding talik.The rapid,non-linear deepening of the talik,far exceeding rates attributable to conductive heat transfer alone,was driven by a strong convective mechanism(Rayleigh-Darcy instability).This advective process was triggered when the soil profile became fully saturated,a condition resulting from the convergence of intensified rainfall and enhanced water retention linked to decadal vegetation greening.Intriguingly,despite the accelerated subsurface warming,the annual amplitude of ground surface temperature decreased from 29.0±2.8℃ to 24.5±3.6℃ following talik formation,likely due to the buffering effect of increased vegetation cover,which modified the surface energy balance.Our results demonstrate that climatic warming and wetting can initiate a cascade of internal feedbacks,propelling marginal permafrost beyond an abrupt tipping point.These findings emphasize the acute vulnerability of marginal permafrost and highlight the urgent necessity for sustained monitoring to assess ecosystem stability and quantify associated greenhouse gas emissions.展开更多
Antibiotic pollution imposes urgent threats to public health and microbial-mediated ecological processes.Existing studies have primarily focused on bacterial responses to antibiotic pollution,but they ignored the micr...Antibiotic pollution imposes urgent threats to public health and microbial-mediated ecological processes.Existing studies have primarily focused on bacterial responses to antibiotic pollution,but they ignored the microeukaryotic counterpart,though microeukaryotes are functionally important(e.g.,predators and saprophytes)in microbial ecology.Herein,we explored how the assembly of sediment microeukaryotes was affected by increasing antibiotic pollution at the inlet(control)and across the outlet sites along a shrimpwastewater discharge channel.The structures of sedimentmicroeukaryotic community were substantially altered by the increasing nutrient and antibiotic pollutions,whichwere primarily controlled by the direct effects of phosphate and ammonium(−0.645 and 0.507,respectively).In addition,tetracyclines exerted a large effect(0.209),including direct effect(0.326)and indirect effect(−0.117),on the microeukaryotic assembly.On the contrary,the fungal subcommunity was relatively resistant to antibiotic pollution.Segmented analysis depicted nonlinear responses of microeukaryotic genera to the antibiotic pollution gradient,as supported by the significant tipping points.We screened 30 antibiotic concentration-discriminatory taxa of microeukaryotes,which can quantitatively and accurately predict(98.7%accuracy)the in-situ antibiotic concentration.Sediment microeukaryotic(except fungal)community is sensitive to antibiotic pollution,and the identified bioindicators could be used for antibiotic pollution diagnosis.展开更多
The Arctic sea-ice cover has decreased in extent,area,and thickness over the last six decades.Most global climate models project that the summer sea-ice extent(SIE)will decline to less than 1 million(mill.)km^(2) in t...The Arctic sea-ice cover has decreased in extent,area,and thickness over the last six decades.Most global climate models project that the summer sea-ice extent(SIE)will decline to less than 1 million(mill.)km^(2) in this century,ranging from 2030 to the end of the century,indicating large uncertainty.However,some models,using the same emission scenarios as required by the Paris Agreement to keep the global temperature below 2°C,indicate that the SIE could be about 2 mill.km^(2) in 2100 but with a large uncertainty of±1.5 mill.km^(2).Here,the authors take another approach by exploring the direct relationship between the SIE and atmospheric CO_(2) concentration for the summer-fall months.The authors correlate the SIE and In(CO_(2)/CO_(2)r)during the period 1979-2022,where CO_(2)r is the reference value in 1979.Using these transient regression equations with an R2 between 0.78 and 0.87,the authors calculate the value that the CO_(2) concentration needs to reach for zero SIE.The results are that,for July,the CO_(2) concentration needs to reach 691±16.5 ppm,for August 604±16.5 ppm,for September 563±17.5 ppm,and for October 620±21 ppm.These values of CO_(2)for an ice-free Arctic are much higher than the targets of the Paris Agreement,which are 450 ppm in 2060 and 425 ppm in 2100,under the IPCC SSP1-2.6 scenario.If these targets can be reached or even almost reached,the "no tipping point"hypothesis for the summer SIE may be valid.展开更多
There is a long and rich tradition in the social sciences of using models of collective behavior in animals as jump- ing-off points for the study of human behavior, including collective human behavior. Here, we come a...There is a long and rich tradition in the social sciences of using models of collective behavior in animals as jump- ing-off points for the study of human behavior, including collective human behavior. Here, we come at the problem in a slightly different fashion. We ask whether models of collective human behavior have anything to offer those who study animal behavior. Our brief example of tipping points, a model first developed in the physical sciences and later used in the social sciences, suggests that the analysis of human collective behavior does indeed have considerable to offer展开更多
Ecosystems generally have the self-adapting ability to resist various external pressures or disturbances,which is always called resilience.However,once the external disturbances exceed the tipping points of the system...Ecosystems generally have the self-adapting ability to resist various external pressures or disturbances,which is always called resilience.However,once the external disturbances exceed the tipping points of the system resilience,the consequences would be catastrophic,and eventually lead the ecosystem to complete collapse.We capture the collapse process of ecosystems represented by plant-pollinator networks with the k-core nested structural method,and find that a sufficiently weak interaction strength or a sufficiently large competition weight can cause the structure of the ecosystem to collapse from its smallest k-core towards its largest k-core.Then we give the tipping points of structure and dynamic collapse of the entire system from the one-dimensional dynamic function of the ecosystem.Our work provides an intuitive and precise description of the dynamic process of ecosystem collapse under multiple interactions,and provides theoretical insights into further avoiding the occurrence of ecosystem collapse.展开更多
Zhuge Liang,a well-known figure with rich cultural implications in Chinese history,has exerted profound influences on the spiritual life of the Chinese nation.In the ACGN context,new cultural implications have been at...Zhuge Liang,a well-known figure with rich cultural implications in Chinese history,has exerted profound influences on the spiritual life of the Chinese nation.In the ACGN context,new cultural implications have been attached to him,which offset some of the classic implications of the character forged over a long history.Meanwhile,the inherent traditional cultural spirit embodied by him is being reconstructed.In terms of content design,the ACGN games based on traditional realism tend to refresh people’s collective memories of Zhuge Liang to enhance the stickiness factor of the games,thus creating a sense of familiarity to make the transmitted information easier for the game players to accept.The modern fashionable games,however,are good at leveraging the advantages of technologies to form a tipping point and incorporating fashion elements into the traditional image of Zhuge Liang to attract players,thus enhancing the communication effect.In terms of environmental construction,the ACGN games have created a new industrial environment featuring“ACGN+traditional culture,”which changes the traditional image of Zhuge Liang by means of ACGN game technology while retaining its basic cultural characteristics to provide players with a better immersive and interactive experience.展开更多
Being known as the lesbian-themed novel,Tipping the Velvet has always been analyzed with queer theory and Judith But?ler’s sexual performance.Female body discourse is a new perspective to analyze it with the combinat...Being known as the lesbian-themed novel,Tipping the Velvet has always been analyzed with queer theory and Judith But?ler’s sexual performance.Female body discourse is a new perspective to analyze it with the combination of the text analysis and feminine writing put forward by Helene Cixous.Narrating the female body in a novel is a way to deconstruct the patriarchal society and to awaken women to fight against it.It is still of significance in 21st society where gender inequality and discrimination exist everywhere.展开更多
LIBYA is rapidly joining the ranks of Africa＇s better-known failed states： the Central African Re- public, Somalia and South Sudan. The North African country, once boasting one of the continent＇s highest per-capita...LIBYA is rapidly joining the ranks of Africa＇s better-known failed states： the Central African Re- public, Somalia and South Sudan. The North African country, once boasting one of the continent＇s highest per-capita GDPs, is a shadow of its former self： torn apart by armed conflict and now felled by falling oil prices and declining production.展开更多
A MAFIA-LIKE criminal order inspired by a totalitarian ideology threatens North Africa and the Sahel, with Libya now as its centerpiece. As this radical, obscurantist and brutal form of Islam spreads and displaces tr...A MAFIA-LIKE criminal order inspired by a totalitarian ideology threatens North Africa and the Sahel, with Libya now as its centerpiece. As this radical, obscurantist and brutal form of Islam spreads and displaces traditional Islam in Libya, the emergence of the Benghazi Defense Brigades （BDB）, formed in June 2016 to oppose the Libyan national army, has plunged the coun- try into further chaos. The BDB is locked in con- flict with the Libyan army led by Major General Khalifa Haftar.展开更多
THE worst year on record for rhino poaching in South Africa＇s history makes 2013 a dismal period for the endangered animal. Figures released by the South African Department of Environmental Affairs in January show th...THE worst year on record for rhino poaching in South Africa＇s history makes 2013 a dismal period for the endangered animal. Figures released by the South African Department of Environmental Affairs in January show that in 2013, just over 1,000 rhinos were illegally killed in South Africa - the equivalent of nearly three animals a day. The figure is more than 1.5 times the official figure of 668 rhinos killed for their horns in 2012. This brings South Africa＇s white rhino population ever closer to the tipping point, where deaths outnumber births and the population begins a serious decline.展开更多
The coastal zone,situated at the land-ocean interface,represents a complex regional system in which physical,ecological,and social subsystems are highly coupled.Under the dual impacts of global change and human activi...The coastal zone,situated at the land-ocean interface,represents a complex regional system in which physical,ecological,and social subsystems are highly coupled.Under the dual impacts of global change and human activities,shoreline dynamics and ecological degradation have intensified,and the system may be approaching or crossing tipping thresholds.This study addresses the mathematical representation and classification of tipping points in coastal zone systems.Based on dynamical systems theory,we developed a unified mathematical framework that incorporates land-sea interactions and multi-scale processes.We establish a six-category classification system encompassing bifurcation-driven,noise-driven,shock-driven,ratedriven,space-driven,and information-driven tipping points,and further elucidate the spatiotemporal characteristics and triggering mechanisms of each category.Furthermore,a classification model of tipping points was constructed using large language models and literature-based big data,and 91 typical cases worldwide are analyzed,through which the heterogeneous spatial distribution of such events is revealed.The results demonstrate that coastal tipping point research possesses both representativeness and particularity.Future research should focus on key issues of“classification-identification-response”and advance integrated efforts in data fusion,model development,and adaptive management.展开更多
Acquired drug resistance is the major reason why patients fail to respond to cancer therapies.It is a challenging task to deter.mine the tipping point of endocrine resistance and detect the associated molecules.Derive...Acquired drug resistance is the major reason why patients fail to respond to cancer therapies.It is a challenging task to deter.mine the tipping point of endocrine resistance and detect the associated molecules.Derived from new systems biology theory, the dynamic network biomarker (DNB) method is designed to quantitatively identify the tipping point of a drastic system transition and can theoretically identify DNB genes that play key roles in acquiring drug resistance.We analyzed time-course mRNA sequence data generated from the tamoxifen-treated estrogen receptor (ER)-positive MCF-7 cell line, and identified the tipping point of endocrine resistance with its leading molecules.The results show that there is interplay between gene mutations and DNB genes, in which the accumulated mutations eventually affect the DNB genes that subsequently cause the change of transcriptional landscape, enabling full-blown drug resistance. Survival analyses based on clinical datasets validated that the DNB genes were associated with the poor survival of breast cancer patients.The results provided the detection for the pre-resistance state or early signs of endocrine resistance.Our predictive method may greatly benefit the scheduling of treatments for complex diseases in which patients are exposed to considerably different drugs and may become drug resistant.展开更多
Epithelial–mesenchymal transition(EMT) is a complex nonlinear biological process that plays essential roles in fundamental biological processes such as embryogenesis, wounding healing, tissue regeneration,and cancer ...Epithelial–mesenchymal transition(EMT) is a complex nonlinear biological process that plays essential roles in fundamental biological processes such as embryogenesis, wounding healing, tissue regeneration,and cancer metastasis. A hallmark of EMT is the switch-like behavior during state transition, which is characteristic of phase transitions. Hence, detecting the tipping point just before mesenchymal state transition is critical for understanding molecular mechanism of EMT. Through dynamic network biomarkers(DNB) model, a DNB group with 37 genes was identified which can provide the early-warning signals of EMT. Particularly, we found that two DNB genes, i.e., SMAD7 and SERPINE1 promoted EMT by switching their regulatory network which was further validated by biological experiments. Survival analyses revealed that SMAD7 and SERPINE1 as DNB genes further acted as prognostic biomarkers for lung adenocarcinoma.展开更多
Skin,as the outmost layer of human body,is frequently exposed to environmental stressors including pollutants and ultraviolet(UV),which could lead to skin disorders.Generally,skin response process to ultraviolet B(UVB...Skin,as the outmost layer of human body,is frequently exposed to environmental stressors including pollutants and ultraviolet(UV),which could lead to skin disorders.Generally,skin response process to ultraviolet B(UVB)irradiation is a nonlinear dynamic process,with unknown underlying molecular mechanism of critical transition.Here,the landscape dynamic network biomarker(lDNB)analysis of time series transcriptome data on 3D skin model was conducted to reveal the complicated process of skin response to UV irradiation at both molecular and network levels.The advanced l-DNB analysis approach showed that:(i)there was a tipping point before critical transition state during pigmentation process,validated by 3D skin model;(ii)13 core DNB genes were identified to detect the tipping point as a network biomarker,supported by computational assessment;(iii)core DNB genes such as COL7A1 and CTNNB1 can effectively predict skin lightening,validated by independent human skin data.Overall,this study provides new insights for skin response to repetitive UVB irradiation,including dynamic pathway pattern,biphasic response,and DNBs for skin lightening change,and enables us to further understand the skin resilience process after external stress.展开更多
Background:Phase transition and phase separation as well as their tipping points are penetrating phenomena in biology and are intrinsic properties of biological systems ranging from basic molecule complexes to cells a...Background:Phase transition and phase separation as well as their tipping points are penetrating phenomena in biology and are intrinsic properties of biological systems ranging from basic molecule complexes to cells and all way up to entire ecosystems.Results:For example,phase separation has been established as a key mechanism for biological molecules such as protein or RNA to form membraneless organelles to perform complex biological functions.Phase transitions are commonly observed during cellular differentiation,and generally,there are the tipping points or critical states just before the phase transitions.And the stability of ecosystem and extinction of species are systematic manifestation of phase transitions.All phase transition and phase separation phenomena display switch-like behavior and critical transitions.Conclusion:Here we summarize the concepts regarding the epithelial-to・mesenchymal transition(EMT)as a type of phase changes and the implication of critical transitions in EMT,and discuss open questions and challenges in this fast-moving field.展开更多
基金funded by the Science and Technology program of Gansu Province(Grant No.23ZDFA017)Longyuan Young Talents(D.Luo),Western Young Scholars Project of the Chinese Academy of Sciences(D.Luo)National Natural Science Foundation of China(U2243214).
文摘Permafrost,a critical component of Earth’s climate system,is increasingly subject to abrupt thaw events,which jeopardize infrastructure,reshape landforms,alter hydrological regimes,and disrupt ecosystems,thereby posing substantial threats to global sustainability.However,the underlying mechanisms that trigger these abrupt transitions remain incompletely understood.Here,we present decade-long in-situ observations from HRQ1,a marginal permafrost site in the Headwater Area of the Yellow River,northeastern Qinghai-Xizang Plateau.These data reveal the formation and growth of a talik,indicative of a permafrost tipping point.Absent before 2017,the talik subsequently formed and progressively deepened,extending to the maximum observation depth of 300 cm by 2024.The transition from perennially frozen to thawed conditions was accompanied by a substantial increase in mean annual soil temperature(MAST)throughout the entire soil profile.From 2015 to 2023,MAST in the upper 200 cm rose from sub-zero(−0.30 to−0.49℃)to consistently above 0℃(0.07 to 1.08℃).Concurrently,maximum daily soil temperatures in deeper layers(200–300 cm)became positive,indicating thaw propagation into the relict permafrost.This warming coincided with a marked increase in unfrozen soil moisture,particularly within the expanding talik.The rapid,non-linear deepening of the talik,far exceeding rates attributable to conductive heat transfer alone,was driven by a strong convective mechanism(Rayleigh-Darcy instability).This advective process was triggered when the soil profile became fully saturated,a condition resulting from the convergence of intensified rainfall and enhanced water retention linked to decadal vegetation greening.Intriguingly,despite the accelerated subsurface warming,the annual amplitude of ground surface temperature decreased from 29.0±2.8℃ to 24.5±3.6℃ following talik formation,likely due to the buffering effect of increased vegetation cover,which modified the surface energy balance.Our results demonstrate that climatic warming and wetting can initiate a cascade of internal feedbacks,propelling marginal permafrost beyond an abrupt tipping point.These findings emphasize the acute vulnerability of marginal permafrost and highlight the urgent necessity for sustained monitoring to assess ecosystem stability and quantify associated greenhouse gas emissions.
基金supported by the Natural Science Fund for Distinguished Young Scholars of Zhejiang Province (No. LR19C030001)the National Natural Science Foundation of China (Nos. 31872693, 32071549)+1 种基金the Key Public Welfare Technology Application Research Project of Ningbo (No. 202002N3032)the K.C. Wong Magna Fund in Ningbo University
文摘Antibiotic pollution imposes urgent threats to public health and microbial-mediated ecological processes.Existing studies have primarily focused on bacterial responses to antibiotic pollution,but they ignored the microeukaryotic counterpart,though microeukaryotes are functionally important(e.g.,predators and saprophytes)in microbial ecology.Herein,we explored how the assembly of sediment microeukaryotes was affected by increasing antibiotic pollution at the inlet(control)and across the outlet sites along a shrimpwastewater discharge channel.The structures of sedimentmicroeukaryotic community were substantially altered by the increasing nutrient and antibiotic pollutions,whichwere primarily controlled by the direct effects of phosphate and ammonium(−0.645 and 0.507,respectively).In addition,tetracyclines exerted a large effect(0.209),including direct effect(0.326)and indirect effect(−0.117),on the microeukaryotic assembly.On the contrary,the fungal subcommunity was relatively resistant to antibiotic pollution.Segmented analysis depicted nonlinear responses of microeukaryotic genera to the antibiotic pollution gradient,as supported by the significant tipping points.We screened 30 antibiotic concentration-discriminatory taxa of microeukaryotes,which can quantitatively and accurately predict(98.7%accuracy)the in-situ antibiotic concentration.Sediment microeukaryotic(except fungal)community is sensitive to antibiotic pollution,and the identified bioindicators could be used for antibiotic pollution diagnosis.
基金funding support from the Nansen Scientific Society.
文摘The Arctic sea-ice cover has decreased in extent,area,and thickness over the last six decades.Most global climate models project that the summer sea-ice extent(SIE)will decline to less than 1 million(mill.)km^(2) in this century,ranging from 2030 to the end of the century,indicating large uncertainty.However,some models,using the same emission scenarios as required by the Paris Agreement to keep the global temperature below 2°C,indicate that the SIE could be about 2 mill.km^(2) in 2100 but with a large uncertainty of±1.5 mill.km^(2).Here,the authors take another approach by exploring the direct relationship between the SIE and atmospheric CO_(2) concentration for the summer-fall months.The authors correlate the SIE and In(CO_(2)/CO_(2)r)during the period 1979-2022,where CO_(2)r is the reference value in 1979.Using these transient regression equations with an R2 between 0.78 and 0.87,the authors calculate the value that the CO_(2) concentration needs to reach for zero SIE.The results are that,for July,the CO_(2) concentration needs to reach 691±16.5 ppm,for August 604±16.5 ppm,for September 563±17.5 ppm,and for October 620±21 ppm.These values of CO_(2)for an ice-free Arctic are much higher than the targets of the Paris Agreement,which are 450 ppm in 2060 and 425 ppm in 2100,under the IPCC SSP1-2.6 scenario.If these targets can be reached or even almost reached,the "no tipping point"hypothesis for the summer SIE may be valid.
文摘There is a long and rich tradition in the social sciences of using models of collective behavior in animals as jump- ing-off points for the study of human behavior, including collective human behavior. Here, we come at the problem in a slightly different fashion. We ask whether models of collective human behavior have anything to offer those who study animal behavior. Our brief example of tipping points, a model first developed in the physical sciences and later used in the social sciences, suggests that the analysis of human collective behavior does indeed have considerable to offer
基金Project supported by the National Natural Science Foundation of China(Grant Nos.72071153 and 72231008)the Natural Science Foundation of Shaanxi Province(Grant No.2020JM-486)the Fund of the Key Laboratory of Equipment Integrated Support Technology(Grant No.6142003190102)。
文摘Ecosystems generally have the self-adapting ability to resist various external pressures or disturbances,which is always called resilience.However,once the external disturbances exceed the tipping points of the system resilience,the consequences would be catastrophic,and eventually lead the ecosystem to complete collapse.We capture the collapse process of ecosystems represented by plant-pollinator networks with the k-core nested structural method,and find that a sufficiently weak interaction strength or a sufficiently large competition weight can cause the structure of the ecosystem to collapse from its smallest k-core towards its largest k-core.Then we give the tipping points of structure and dynamic collapse of the entire system from the one-dimensional dynamic function of the ecosystem.Our work provides an intuitive and precise description of the dynamic process of ecosystem collapse under multiple interactions,and provides theoretical insights into further avoiding the occurrence of ecosystem collapse.
基金The paper is a phased finding of the projects“Zhuge Liang and Studies of Shu-Han Classics”(20ZGL05)“Research on the Role of Domestic Online Games in Innovating and Communicating the Three Kingdoms Culture”(22ZGL02)granted by Zhuge Liang Research Center,a key research base of social sciences in Sichuan province。
文摘Zhuge Liang,a well-known figure with rich cultural implications in Chinese history,has exerted profound influences on the spiritual life of the Chinese nation.In the ACGN context,new cultural implications have been attached to him,which offset some of the classic implications of the character forged over a long history.Meanwhile,the inherent traditional cultural spirit embodied by him is being reconstructed.In terms of content design,the ACGN games based on traditional realism tend to refresh people’s collective memories of Zhuge Liang to enhance the stickiness factor of the games,thus creating a sense of familiarity to make the transmitted information easier for the game players to accept.The modern fashionable games,however,are good at leveraging the advantages of technologies to form a tipping point and incorporating fashion elements into the traditional image of Zhuge Liang to attract players,thus enhancing the communication effect.In terms of environmental construction,the ACGN games have created a new industrial environment featuring“ACGN+traditional culture,”which changes the traditional image of Zhuge Liang by means of ACGN game technology while retaining its basic cultural characteristics to provide players with a better immersive and interactive experience.
文摘Being known as the lesbian-themed novel,Tipping the Velvet has always been analyzed with queer theory and Judith But?ler’s sexual performance.Female body discourse is a new perspective to analyze it with the combination of the text analysis and feminine writing put forward by Helene Cixous.Narrating the female body in a novel is a way to deconstruct the patriarchal society and to awaken women to fight against it.It is still of significance in 21st society where gender inequality and discrimination exist everywhere.
文摘LIBYA is rapidly joining the ranks of Africa＇s better-known failed states： the Central African Re- public, Somalia and South Sudan. The North African country, once boasting one of the continent＇s highest per-capita GDPs, is a shadow of its former self： torn apart by armed conflict and now felled by falling oil prices and declining production.
文摘A MAFIA-LIKE criminal order inspired by a totalitarian ideology threatens North Africa and the Sahel, with Libya now as its centerpiece. As this radical, obscurantist and brutal form of Islam spreads and displaces traditional Islam in Libya, the emergence of the Benghazi Defense Brigades （BDB）, formed in June 2016 to oppose the Libyan national army, has plunged the coun- try into further chaos. The BDB is locked in con- flict with the Libyan army led by Major General Khalifa Haftar.
文摘THE worst year on record for rhino poaching in South Africa＇s history makes 2013 a dismal period for the endangered animal. Figures released by the South African Department of Environmental Affairs in January show that in 2013, just over 1,000 rhinos were illegally killed in South Africa - the equivalent of nearly three animals a day. The figure is more than 1.5 times the official figure of 668 rhinos killed for their horns in 2012. This brings South Africa＇s white rhino population ever closer to the tipping point, where deaths outnumber births and the population begins a serious decline.
基金supported by the Key Projects of National Natural Science Foundation of China(NSFC)(Grant Nos.42230406,42130103)。
文摘The coastal zone,situated at the land-ocean interface,represents a complex regional system in which physical,ecological,and social subsystems are highly coupled.Under the dual impacts of global change and human activities,shoreline dynamics and ecological degradation have intensified,and the system may be approaching or crossing tipping thresholds.This study addresses the mathematical representation and classification of tipping points in coastal zone systems.Based on dynamical systems theory,we developed a unified mathematical framework that incorporates land-sea interactions and multi-scale processes.We establish a six-category classification system encompassing bifurcation-driven,noise-driven,shock-driven,ratedriven,space-driven,and information-driven tipping points,and further elucidate the spatiotemporal characteristics and triggering mechanisms of each category.Furthermore,a classification model of tipping points was constructed using large language models and literature-based big data,and 91 typical cases worldwide are analyzed,through which the heterogeneous spatial distribution of such events is revealed.The results demonstrate that coastal tipping point research possesses both representativeness and particularity.Future research should focus on key issues of“classification-identification-response”and advance integrated efforts in data fusion,model development,and adaptive management.
基金This work was supported by grants from the National Key R&D Program of China (2017YFA0505500)Strategic Priority Research Program of the Chinese Academy of Sciences (XDBl3040700)+6 种基金the National Natural Science Foundation of China (11771152,91529303,31771476,31571363,31771469,91530320,61134013,81573023,81501203,and 11326035)Pearl River Science and Technology Nova Program of Guangzhou (201610010029)FISRT,Aihara Innovative Mathematical Modeling Project from Cabinet Office,JapanFundamental Research Funds for the Central Universities (2017ZD095)JSPS KAKENHI (15H05707)Grant-in-Aid for Scientific Research on Innovative Areas (3901) and SPS KAKENHI (15KT0084,17H06299,17H06302,and 18H04031)RIKEN Epigenome and Single Cell Project Grants to M.O.-H.This work was performed in part under the International Cooperative Research Program of Institute for Protein Research,Osaka University (ICRa-17-01 to L.C.and M.O.-H.).
文摘Acquired drug resistance is the major reason why patients fail to respond to cancer therapies.It is a challenging task to deter.mine the tipping point of endocrine resistance and detect the associated molecules.Derived from new systems biology theory, the dynamic network biomarker (DNB) method is designed to quantitatively identify the tipping point of a drastic system transition and can theoretically identify DNB genes that play key roles in acquiring drug resistance.We analyzed time-course mRNA sequence data generated from the tamoxifen-treated estrogen receptor (ER)-positive MCF-7 cell line, and identified the tipping point of endocrine resistance with its leading molecules.The results show that there is interplay between gene mutations and DNB genes, in which the accumulated mutations eventually affect the DNB genes that subsequently cause the change of transcriptional landscape, enabling full-blown drug resistance. Survival analyses based on clinical datasets validated that the DNB genes were associated with the poor survival of breast cancer patients.The results provided the detection for the pre-resistance state or early signs of endocrine resistance.Our predictive method may greatly benefit the scheduling of treatments for complex diseases in which patients are exposed to considerably different drugs and may become drug resistant.
基金supported by the National Key Research and Development Program of China (2017YFA0505500)the National Natural Science Foundation of China (31930022, 31771476, 61773196)+5 种基金Shanghai Municipal Science and Technology Major Project (2017SHZDZX01)Key Project of Zhangjiang National Innovation Demonstration Zone Special Development Fund (ZJ2018ZD-013)Ministry of Science and Technology Project (2017YFC0907505)Guangdong Provincial Key Laboratory Funds (2017B030301018, 2019B030301001)Shenzhen Research Funds (JCYJ20170307104535585, ZDSYS20140509142721429)Shenzhen Peacock Plan (KQTD2016053117035204)
文摘Epithelial–mesenchymal transition(EMT) is a complex nonlinear biological process that plays essential roles in fundamental biological processes such as embryogenesis, wounding healing, tissue regeneration,and cancer metastasis. A hallmark of EMT is the switch-like behavior during state transition, which is characteristic of phase transitions. Hence, detecting the tipping point just before mesenchymal state transition is critical for understanding molecular mechanism of EMT. Through dynamic network biomarkers(DNB) model, a DNB group with 37 genes was identified which can provide the early-warning signals of EMT. Particularly, we found that two DNB genes, i.e., SMAD7 and SERPINE1 promoted EMT by switching their regulatory network which was further validated by biological experiments. Survival analyses revealed that SMAD7 and SERPINE1 as DNB genes further acted as prognostic biomarkers for lung adenocarcinoma.
基金partially supported by the National Natural Science Foundation of China(31930022,31771476,12026608,12042104,and 11871456)the Strategic Priority Project of CAS(XDB38040400)+1 种基金the National Key R&D Program of China(2017YFA0505500)JST Moonshot R&D program(JP MJMS2021 to L.C.).
文摘Skin,as the outmost layer of human body,is frequently exposed to environmental stressors including pollutants and ultraviolet(UV),which could lead to skin disorders.Generally,skin response process to ultraviolet B(UVB)irradiation is a nonlinear dynamic process,with unknown underlying molecular mechanism of critical transition.Here,the landscape dynamic network biomarker(lDNB)analysis of time series transcriptome data on 3D skin model was conducted to reveal the complicated process of skin response to UV irradiation at both molecular and network levels.The advanced l-DNB analysis approach showed that:(i)there was a tipping point before critical transition state during pigmentation process,validated by 3D skin model;(ii)13 core DNB genes were identified to detect the tipping point as a network biomarker,supported by computational assessment;(iii)core DNB genes such as COL7A1 and CTNNB1 can effectively predict skin lightening,validated by independent human skin data.Overall,this study provides new insights for skin response to repetitive UVB irradiation,including dynamic pathway pattern,biphasic response,and DNBs for skin lightening change,and enables us to further understand the skin resilience process after external stress.
基金The authors apologize to those colleagues whose relevant studies were not cited owing to space limitations.This work was supported in part by the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB38040400)the National Natural Science Foundation of China(Nos.31930022,31671380 and 31771476)Shanghai Municipal Science and Technology Major Project(No.2017SHZDZX01).
文摘Background:Phase transition and phase separation as well as their tipping points are penetrating phenomena in biology and are intrinsic properties of biological systems ranging from basic molecule complexes to cells and all way up to entire ecosystems.Results:For example,phase separation has been established as a key mechanism for biological molecules such as protein or RNA to form membraneless organelles to perform complex biological functions.Phase transitions are commonly observed during cellular differentiation,and generally,there are the tipping points or critical states just before the phase transitions.And the stability of ecosystem and extinction of species are systematic manifestation of phase transitions.All phase transition and phase separation phenomena display switch-like behavior and critical transitions.Conclusion:Here we summarize the concepts regarding the epithelial-to・mesenchymal transition(EMT)as a type of phase changes and the implication of critical transitions in EMT,and discuss open questions and challenges in this fast-moving field.
