In the paper,we study the strong uniform consistency for the kernal estimates of random window w■th of density function and its derivatives under the condition that the sequence{X_n}of the ■ are the identically Φ-m...In the paper,we study the strong uniform consistency for the kernal estimates of random window w■th of density function and its derivatives under the condition that the sequence{X_n}of the ■ are the identically Φ-mixing random variabks.展开更多
Droughts impact forests by influencing various processes such as canopy greenness,tree growth,and reproduction,but most studies have only examined a few of these processes.More comprehensive assessments of forest resp...Droughts impact forests by influencing various processes such as canopy greenness,tree growth,and reproduction,but most studies have only examined a few of these processes.More comprehensive assessments of forest responses to climate variability and water shortages are needed to improve forecasts of post-drought dynamics.Iberian forests are well-suited for evaluating these effects because they experience diverse climatic conditions and are dominated by various conifer and broadleaf species,many of which exhibit masting.We assessed how greenness,evaluated using the normalized difference vegetation index(NDVI),tree radial growth,and seed or cone production responded to drought in five tree species(three conifers:silver fir(Abies alba),Scots pine(Pinus sylvestris),and stone pine(Pinus pinea);two broadleaves:European beech(Fagus sylvatica)and holm oak(Quercus ilex)inhabiting sites with different aridity.We correlated these data with the standardized precipitation evapotranspiration index(SPEI)using the climate window analysis(climwin)package,which identifies the most relevant climate window.Drought constrained growth more than greenness and seed or cone production.Dry conditions led to high seed or cone production in species found in cool,moist sites(silver fir,beech,and Scots pine).We also found negative associations of cone production with summer SPEI in the drought-tolerant stone pine,which showed lagged growth-cone negative correlations.However,in the seasonally dry holm oak forests,severe droughts constrained both growth and acorn production,leading to a positive correlation between these variables.Drought impacts on greenness,growth,seed,and cone production depended on species phenology and site aridity.A negative correlation between growth and reproduction does not necessarily indicate trade-offs,as both may be influenced by similar climatic factors.展开更多
目的:探讨CT血管造影(CTangiography,CTA)后处理技术容积重建(volumerendering,VR)中阈值、最大密度投影(maximum intensity projection,MIP)中窗宽及窗位、视野(Field of view,FOV)对血管管径测量的影响及相关关系。方法:建立9个不同...目的:探讨CT血管造影(CTangiography,CTA)后处理技术容积重建(volumerendering,VR)中阈值、最大密度投影(maximum intensity projection,MIP)中窗宽及窗位、视野(Field of view,FOV)对血管管径测量的影响及相关关系。方法:建立9个不同密度的血管模型,使用不同的FOV、阈值(VR)、窗宽(MIP)测量不同密度血管模型管径,分析标准阈值、窗宽与血管模型管径的关系,并与CT值进行相关性分析。统计临床脑血管CTA MIP重建病例30例的窗宽及窗位,与实验结果进行比较。结果:VR重建,阈值和血管模型管径呈明显负相关(r=-0.847,P=0.000);MIP重建,窗宽和血管模型管径呈明显正相关(r=0.983,P=0.000);FOV和血管模型管径无相关性(r=-0.042,P=0.381)。临床脑血管CTAMIP重建窗宽明显增宽,夸大了血管真实管径。结论:CTA血管管径测量的准确性受VR重建阈值、MIP重建窗宽窗位的影响,根据血管内对比剂密度对这些参数进行调整,保证测量血管管径的可靠性和准确性。展开更多
在对医学成像仪(CT和MRI)提供的医学数据进行实体三维重构时,我们遇到了这些成像仪特有的专用医学影像存储格式—DICOM(digital imaging and communications in medicine)标准。本文通过对DICOM文件数据结构组成的分析,以VC++6.0为开发...在对医学成像仪(CT和MRI)提供的医学数据进行实体三维重构时,我们遇到了这些成像仪特有的专用医学影像存储格式—DICOM(digital imaging and communications in medicine)标准。本文通过对DICOM文件数据结构组成的分析,以VC++6.0为开发平台,综合运用当前的各种技术,创建DICOM图像核心类,同时实现DICOM图像的显示和与BMP图像的转换。本文简要介绍软件结构及重要函数的功能实现,最后通过比较验证了软件的运行是可靠的。展开更多
基金supported by Natural Science Foun■ion of Henan P■visial Commission of Bdusation
文摘In the paper,we study the strong uniform consistency for the kernal estimates of random window w■th of density function and its derivatives under the condition that the sequence{X_n}of the ■ are the identically Φ-mixing random variabks.
基金funded by the Science and Innovation Ministry of Spain(projects AGL 2012-33465,AGL 2016-76463-P,PID 2021-123675OB-C43,and TED 2021-129770B-C21)support by Margarita Salas postdoctoral fellowship(reference RCMS-22-G1T6IW-17-NLHJ80)of the Universidad Politécnica de Madrid
文摘Droughts impact forests by influencing various processes such as canopy greenness,tree growth,and reproduction,but most studies have only examined a few of these processes.More comprehensive assessments of forest responses to climate variability and water shortages are needed to improve forecasts of post-drought dynamics.Iberian forests are well-suited for evaluating these effects because they experience diverse climatic conditions and are dominated by various conifer and broadleaf species,many of which exhibit masting.We assessed how greenness,evaluated using the normalized difference vegetation index(NDVI),tree radial growth,and seed or cone production responded to drought in five tree species(three conifers:silver fir(Abies alba),Scots pine(Pinus sylvestris),and stone pine(Pinus pinea);two broadleaves:European beech(Fagus sylvatica)and holm oak(Quercus ilex)inhabiting sites with different aridity.We correlated these data with the standardized precipitation evapotranspiration index(SPEI)using the climate window analysis(climwin)package,which identifies the most relevant climate window.Drought constrained growth more than greenness and seed or cone production.Dry conditions led to high seed or cone production in species found in cool,moist sites(silver fir,beech,and Scots pine).We also found negative associations of cone production with summer SPEI in the drought-tolerant stone pine,which showed lagged growth-cone negative correlations.However,in the seasonally dry holm oak forests,severe droughts constrained both growth and acorn production,leading to a positive correlation between these variables.Drought impacts on greenness,growth,seed,and cone production depended on species phenology and site aridity.A negative correlation between growth and reproduction does not necessarily indicate trade-offs,as both may be influenced by similar climatic factors.
文摘在对医学成像仪(CT和MRI)提供的医学数据进行实体三维重构时,我们遇到了这些成像仪特有的专用医学影像存储格式—DICOM(digital imaging and communications in medicine)标准。本文通过对DICOM文件数据结构组成的分析,以VC++6.0为开发平台,综合运用当前的各种技术,创建DICOM图像核心类,同时实现DICOM图像的显示和与BMP图像的转换。本文简要介绍软件结构及重要函数的功能实现,最后通过比较验证了软件的运行是可靠的。
