检索结果-南通市图书馆

Direct Simulation Methods for Scalar-Wave Envelopes in Two-Dimensional Layered Random Media Based on the Small-Angle Scattering Approximation

引用

Communications in Computational Physics 2008年第1期3卷 63-84页

作者： tatsuhiko saito Haruo Sato Tsutomu Takahashi Earthquake Research Institute The University of TokyoYayoi 1-1-1Bunkyo-kuTokyo113-0032Japan. CREST Japan Science and Technology Agency(JST). Department of Geophysics Graduate School of ScienceTohoku UniversityAramaki-Aza-Aoba 6-3Aoba-kuSendaiMiyagi980-8578Japan. Institute for Research on Earth Evolution Japan Agency for Marine-Earth Science and TechnologyShowa-machi 3173-25Kanazawa-kuYokohamaKanagawa236-0001Japan.

This study presents stochastic methods to simulate wave envelopes in layeredrandom media. High-frequency Seismograms of small earthquakes are so complexdue to lithospheric inhomogeneity that seismologists often analyze wave envelopesrather than wave traces to quantify the subsurface inhomogeneity. Since thestatistical properties of the inhomogeneity vary regionally, it is important to developand examine direct envelope simulation methods for non-uniform random media. Asa simple example, this study supposes planewave propagation through two-layer randommedia in 2-D composed of weak and strong inhomogeneity zones. The characteristicspatial-scale of the inhomogeneity is supposed to be larger than the wavelength,where small-angle scattering around the forward direction dominates large-angle *** envelope simulation methods based on the small-angle scattering approximationare examined. One method is to solve a differential equation for the twofrequencymutual coherence function with the Markov approximation. The other isto solve the stochastic ray bending process by using the Monte Carlo method basedon the Markov approximation for the mutual coherence function. The resultant waveenvelopes of the two methods showed excellent coincidence both for uniform and fortwo-layer random media. Furthermore, we confirmed the validity of the two methodscomparing with the envelopes made from the finite difference simulations of *** two direct envelope simulation methods presented in this study can be a mathematicalbase for the study of high-frequency wave propagation through randomlyinhomogeneous lithosphere in seismology.

关键词： Seismic wave envelope random media.

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

New simulation model for bone formation markers in osteoporosis patients treated with once-weekly teriparatide

引用

Bone Research 2014年第4期2卷 252-258页

作者： Sakae Tanaka Taiji Adachi tatsuhiko Kuroda Toshitaka Nakamura Masataka Shiraki Toshitsugu Sugimoto Yasuhiro Takeuchi Mitsuru saito John P Bilezikian Department of Orthopaedic Surgery Faculty of MedicineUniversity of TokyoTokyoJapan Department of Biomechanics Institute for Frontier Medical SciencesKyoto UniversityKyotoJapan Medical Affairs Department Asahi Kasei Pharma CorporationTokyoJapan National Center for Global Health and Medicine TokyoJapan Research Institute and Practice for Involutional Diseases NaganoJapan Internal Medicine 1 Shimane University Faculty of MedicineIzumoJapan Toranomon Hospital Endocrine Center TokyoJapan Department of Orthopaedic Surgery Jikei University School of MedicineTokyoJapan Metabolic Bone Diseases Program Division of EndocrinologyDepartment of MedicineCollege of Physicians and SurgeonsColumbia UniversityNew YorkUSA

Daily 20-mg and once-weekly 56.5-mg teriparatide（parathyroid hormone 1–34） treatment regimens increase bone mineral density（BMD） and prevent fractures, but changes in bone turnover markers differ between the two regimens. The aim of the present study was to explain changes in bone turnover markers using once-weekly teriparatide with a simulation model. Temporary increases in bone formation markers and subsequent decreases were observed during once-weekly teriparatide treatment for 72 weeks. These observations support the hypothesis that repeated weekly teriparatide administration stimulates bone remodeling, replacing old bone with new bone and leading to a reduction in the active remodeling surface. A simulation model was developed based on the iterative remodeling cycle that occurs on residual old bone. An increase in bone formation and a subsequent decrease were observed in the preliminary simulation. For each fitted time point, the predicted value was compared to the absolute values of the bone formation and resorption markers and lumbar BMD. The simulation model strongly matched actual changes in bone turnover markers and BMD. This simulation model indicates increased bone formation marker levels in the early stage and a subsequent decrease. It is therefore concluded that remodeling-based bone formation persisted during the entire treatment period with once-weekly teriparatide.

关键词： bone New simulation model for bone formation markers in osteoporosis patients treated with once-weekly teriparatide BMD

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：