DEAR EDITOR,The key features of functional extinction include continuous reproductive failure,lack of new recruitment,and persistent population decline(Jarićet al.,2016;Roberts et al.,2017).However,the conclusion of f...DEAR EDITOR,The key features of functional extinction include continuous reproductive failure,lack of new recruitment,and persistent population decline(Jarićet al.,2016;Roberts et al.,2017).However,the conclusion of functional extinction for the Chinese pangolin(Manis pentadactyla)by the China Biodiversity Conservation and Green Development Foundation(CBC-GDF)based on preliminary field information is unconvincing as they did not assess reproductive function or new individual recruitment of Chinese pangolin populations(Supplementary Materials).展开更多
In this article, we develop and analyze a continuous-time Markov chain (CTMC) model to study the resurgence of dengue. We also explore the large population asymptotic behavior of probabilistic model of dengue using th...In this article, we develop and analyze a continuous-time Markov chain (CTMC) model to study the resurgence of dengue. We also explore the large population asymptotic behavior of probabilistic model of dengue using the law of large numbers (LLN). Initially, we calculate and estimate the probabilities of dengue extinction and major outbreak occurrence using multi-type Galton-Watson branching processes. Subsequently, we apply the LLN to examine the convergence of the stochastic model towards the deterministic model. Finally, theoretical numerical simulations are conducted exploration to validate our findings. Under identical conditions, our numerical results demonstrate that dengue could vanish in the stochastic model while persisting in the deterministic model. The highlighting of the law of large numbers through numerical simulations indicates from what population size a deterministic model should be considered preferable.展开更多
One caveat to the dinosaur’s extinction is the conclusion that avian dinosaurs survived and became ancestors of birds. Their mobility enabled them to migrate great distances and find the nutrients needed to survive. ...One caveat to the dinosaur’s extinction is the conclusion that avian dinosaurs survived and became ancestors of birds. Their mobility enabled them to migrate great distances and find the nutrients needed to survive. Given this scenario, could the current observable migration of birds (the “dinosaurian offspring”) now be related? Migration is the regular seasonal movement undertaken by many species of birds, with the most common pattern, flying north in the Northern spring to breed in the temperate or Arctic summer and returning in the Northern autumn to wintering grounds in warmer regions of the south. The primary motivation for migration appears to be food. None of the major North-South migratory pathways fly over the Caribbean but three main fly ways, past to the west of the theorized K-T impact centre. Due to their ability to fly, the “avian Dinosaurs” adapted and survived very quickly in response to the disaster that marked the K-T boundary. It is an interesting speculation that the avian migration that we witness today is rooted in an event that occurred 66 million years ago! But it does explain why the migratory birds mostly fly from Polar summer to polar summer when they could just be as easily fly from Polar zone to the warmer equatorial region and back. In the recent article in Nature by Melanie During about identifying the late spring timing of the “Astro disaster”, it can be cited as consistent with my speculation. A late April early May Impact as suggested by During would have seen these migrations completely. The western migratory routes would have been found to be “luxurious” in vegetation in that first northern autumn after the “Astro-impact” while all eastern routes would have still been barren.展开更多
Dust extinction law is crucial to recover the intrinsic energy distribution of celestial objects and infer the characteristics of interstellar dust.Based on the traditional pair method,an improved pair method is propo...Dust extinction law is crucial to recover the intrinsic energy distribution of celestial objects and infer the characteristics of interstellar dust.Based on the traditional pair method,an improved pair method is proposed to model the dust extinguished spectral energy distribution(SED)of an individual star.Instead of the mathematically parameterizing extinction curves,the extinction curves in this work are directly from the silicate-graphite dust model,so that the dust extinction law can be obtained and the dust properties can be analyzed simultaneously.The ATLAS9 stellar model atmosphere is adopted for the intrinsic SEDs in this work,while the silicate-graphite dust model with a dust size distribution of dn da~a^(-a)exp(-a a_(c)),0.005<a<5μmfor each component is adopted for the model extinction curves.One typical extinction tracer in the dense region(V410 Anon9)and one in the diffuse region(Cyg OB2#12)of the Milky Way are chosen to test the reliability and the practicability of the improved pair method in different stellar environments.The results are consistent with their interstellar environments and are in agreement with the previous observations and studies,which prove that the improved pair method is effective and applicable in different stellar environments.In addition to the reliable extinction results,the derived parameters in the dust model can be used to analyze the dust properties,which cannot be achieved by other methods with the mathematical extinction models.With the improved pair method,the stellar parameters can also be inferred and the extinction law beyond the wavelengths of observed data can be predicted based on the dust model as well.展开更多
建立一种基于美国官方分析化学师协会(Association of Official Analytical Chemists,AOAC)方法检测黑果枸杞及其制品中花青素含量的改进pH示差法。考察了黑果枸杞及其制品中花青素的最佳提取和检测条件,通过液相色谱-三重四级杆串联质...建立一种基于美国官方分析化学师协会(Association of Official Analytical Chemists,AOAC)方法检测黑果枸杞及其制品中花青素含量的改进pH示差法。考察了黑果枸杞及其制品中花青素的最佳提取和检测条件,通过液相色谱-三重四级杆串联质谱法鉴别出黑果枸杞中花青素的具体化学结构,并计算出混合花青素的平均摩尔质量。通过分光光度法测得混合花青素的平均摩尔消光系数,对改进后的pH示差法进行方法学验证和花青素的含量测定。结果显示,最佳提取和检测条件如下:黑果枸杞花青素提取溶剂为盐酸-80%(体积分数)乙醇(3∶97,体积比),料液比为1∶100(g∶mL),提取温度为50℃,提取时间为30 min,缓冲溶液稀释5倍后静置平衡20 min。液相色谱-三重四级杆串联质谱法鉴别黑果枸杞中主要以矮牵牛素类花青素为主(占97.96%),黑果枸杞特有的混合花青素平均摩尔质量为912.7 g/mol,平均摩尔消光系数为29591 L/(mol·cm)。pH示差法改进后能够满足方法学验证要求,固体样品和液体样品最低检出限分别为28.2 mg/100 g、0.282 mg/100 mL。方法改进后花青素提取增长率均大于20%,静置平衡20 min后单次检测结果精密度小于0.3%。以矮牵牛素类花青素代替矢车菊素-3-O-葡萄糖苷计算花青素含量平均提高了2.41倍,能真实地反映黑果枸杞及其制品中花青素的含量。展开更多
目的 探讨基于正念的消退和再巩固创伤干预(trauma interventions using mindfulness based extinction and reconsolidation, TIMBER)对意外创伤肢体功能障碍康复期患者创伤后应激症状的影响。方法 采用方便取样的方法,选取2022年3月至...目的 探讨基于正念的消退和再巩固创伤干预(trauma interventions using mindfulness based extinction and reconsolidation, TIMBER)对意外创伤肢体功能障碍康复期患者创伤后应激症状的影响。方法 采用方便取样的方法,选取2022年3月至2023年5月陆军军医大学第一附属医院康复医学科收治的创伤康复期患者(impact of event scale-revised, IES-R总分≥33分)46例,采用随机数字表法分为干预组和对照组,干预组接受TIMBER干预,对照组进行心理健康相关知识宣教。在干预前(T1)、干预结束时(T2)和干预结束后1个月(T3)使用事件影响量表修订版(IES-R)、医院焦虑抑郁量表(HADS)、睡眠状况自评量表(SRSS)对所有被试进行测量,比较两组患者创伤后应激症状、焦虑症状、抑郁症状和睡眠的变化。结果 两组患者人口统计学信息及各心理学变量在T1时差异均无统计学意义(P>0.05);干预组在T2和T3时的IES-R总分及各维度评分、焦虑、抑郁和睡眠评分显著低于对照组(P<0.05);干预组在T2和T3时的IES-R总分及各维度评分、焦虑、抑郁和睡眠评分显著低于T1(P<0.01);与T1相比,对照组T2、T3时的回避、闯入2个维度评分及IES-R总分有一定程度降低,差异有统计学意义(P<0.05),而高警觉、焦虑、抑郁和睡眠评分差异无统计学意义(P>0.05)。结论 TIMBER可以显著改善意外创伤肢体功能障碍康复期患者的创伤后应激症状、焦虑抑郁症状及睡眠。展开更多
基金supported by the National Key Program of Research and Development,Ministry of Science and Technology(2022YFF1301500)National Nature Science Foundation of China(32070522,31572286)+1 种基金China State Forestry and Grassland Administration(2018-HS01)the Ministry of Ecology and Environment of the People’s Republic of China(2019-6-2)。
文摘DEAR EDITOR,The key features of functional extinction include continuous reproductive failure,lack of new recruitment,and persistent population decline(Jarićet al.,2016;Roberts et al.,2017).However,the conclusion of functional extinction for the Chinese pangolin(Manis pentadactyla)by the China Biodiversity Conservation and Green Development Foundation(CBC-GDF)based on preliminary field information is unconvincing as they did not assess reproductive function or new individual recruitment of Chinese pangolin populations(Supplementary Materials).
文摘In this article, we develop and analyze a continuous-time Markov chain (CTMC) model to study the resurgence of dengue. We also explore the large population asymptotic behavior of probabilistic model of dengue using the law of large numbers (LLN). Initially, we calculate and estimate the probabilities of dengue extinction and major outbreak occurrence using multi-type Galton-Watson branching processes. Subsequently, we apply the LLN to examine the convergence of the stochastic model towards the deterministic model. Finally, theoretical numerical simulations are conducted exploration to validate our findings. Under identical conditions, our numerical results demonstrate that dengue could vanish in the stochastic model while persisting in the deterministic model. The highlighting of the law of large numbers through numerical simulations indicates from what population size a deterministic model should be considered preferable.
文摘One caveat to the dinosaur’s extinction is the conclusion that avian dinosaurs survived and became ancestors of birds. Their mobility enabled them to migrate great distances and find the nutrients needed to survive. Given this scenario, could the current observable migration of birds (the “dinosaurian offspring”) now be related? Migration is the regular seasonal movement undertaken by many species of birds, with the most common pattern, flying north in the Northern spring to breed in the temperate or Arctic summer and returning in the Northern autumn to wintering grounds in warmer regions of the south. The primary motivation for migration appears to be food. None of the major North-South migratory pathways fly over the Caribbean but three main fly ways, past to the west of the theorized K-T impact centre. Due to their ability to fly, the “avian Dinosaurs” adapted and survived very quickly in response to the disaster that marked the K-T boundary. It is an interesting speculation that the avian migration that we witness today is rooted in an event that occurred 66 million years ago! But it does explain why the migratory birds mostly fly from Polar summer to polar summer when they could just be as easily fly from Polar zone to the warmer equatorial region and back. In the recent article in Nature by Melanie During about identifying the late spring timing of the “Astro disaster”, it can be cited as consistent with my speculation. A late April early May Impact as suggested by During would have seen these migrations completely. The western migratory routes would have been found to be “luxurious” in vegetation in that first northern autumn after the “Astro-impact” while all eastern routes would have still been barren.
基金supported by the National Natural Science Foundation of China(NSFC)through grant Nos.12133002,U2031209 and 12203025Shandong Provincial Natural Science Foundation through project ZR2022QA064the CSST Milky Way and Nearby Galaxies Survey on Dust and Extinction Project CMS-CSST2021-A09。
文摘Dust extinction law is crucial to recover the intrinsic energy distribution of celestial objects and infer the characteristics of interstellar dust.Based on the traditional pair method,an improved pair method is proposed to model the dust extinguished spectral energy distribution(SED)of an individual star.Instead of the mathematically parameterizing extinction curves,the extinction curves in this work are directly from the silicate-graphite dust model,so that the dust extinction law can be obtained and the dust properties can be analyzed simultaneously.The ATLAS9 stellar model atmosphere is adopted for the intrinsic SEDs in this work,while the silicate-graphite dust model with a dust size distribution of dn da~a^(-a)exp(-a a_(c)),0.005<a<5μmfor each component is adopted for the model extinction curves.One typical extinction tracer in the dense region(V410 Anon9)and one in the diffuse region(Cyg OB2#12)of the Milky Way are chosen to test the reliability and the practicability of the improved pair method in different stellar environments.The results are consistent with their interstellar environments and are in agreement with the previous observations and studies,which prove that the improved pair method is effective and applicable in different stellar environments.In addition to the reliable extinction results,the derived parameters in the dust model can be used to analyze the dust properties,which cannot be achieved by other methods with the mathematical extinction models.With the improved pair method,the stellar parameters can also be inferred and the extinction law beyond the wavelengths of observed data can be predicted based on the dust model as well.
文摘目的 探讨基于正念的消退和再巩固创伤干预(trauma interventions using mindfulness based extinction and reconsolidation, TIMBER)对意外创伤肢体功能障碍康复期患者创伤后应激症状的影响。方法 采用方便取样的方法,选取2022年3月至2023年5月陆军军医大学第一附属医院康复医学科收治的创伤康复期患者(impact of event scale-revised, IES-R总分≥33分)46例,采用随机数字表法分为干预组和对照组,干预组接受TIMBER干预,对照组进行心理健康相关知识宣教。在干预前(T1)、干预结束时(T2)和干预结束后1个月(T3)使用事件影响量表修订版(IES-R)、医院焦虑抑郁量表(HADS)、睡眠状况自评量表(SRSS)对所有被试进行测量,比较两组患者创伤后应激症状、焦虑症状、抑郁症状和睡眠的变化。结果 两组患者人口统计学信息及各心理学变量在T1时差异均无统计学意义(P>0.05);干预组在T2和T3时的IES-R总分及各维度评分、焦虑、抑郁和睡眠评分显著低于对照组(P<0.05);干预组在T2和T3时的IES-R总分及各维度评分、焦虑、抑郁和睡眠评分显著低于T1(P<0.01);与T1相比,对照组T2、T3时的回避、闯入2个维度评分及IES-R总分有一定程度降低,差异有统计学意义(P<0.05),而高警觉、焦虑、抑郁和睡眠评分差异无统计学意义(P>0.05)。结论 TIMBER可以显著改善意外创伤肢体功能障碍康复期患者的创伤后应激症状、焦虑抑郁症状及睡眠。
