For oil company decision-makers,the principal concern is how to allocate their limited resources into the most valuable opportunities.Recently a new management philosophy,＂Beyond NPV＂,has received more and more inte...For oil company decision-makers,the principal concern is how to allocate their limited resources into the most valuable opportunities.Recently a new management philosophy,＂Beyond NPV＂,has received more and more international attention.Economists and senior executives are seeking effective alternative analysis approaches for traditional technical and economic evaluation methods.The improved portfolio optimization model presented in this article represents an applicable technique beyond NPV for doing capital budgeting.In this proposed model,not only can oil company executives achieve trade-offs between returns and risks to their risk tolerance,but they can also employ an ＂operational premium＂ to distinguish their ability to improve the performance of the underlying projects.A simulation study based on 19 overseas upstream assets owned by a large oil company in China is conducted to compare optimized utility with non-optimized utility.The simulation results show that the petroleum optimization model including ＂operational premium＂ is more in line with the rational investors＇ demand.展开更多
神经纤维瘤病2型(neurofbromatosis type 2,NF2)是一种以NF2肿瘤抑制基因突变引起的常染色体显性遗传病,具有特殊的神经系统病变。NF2最常见的临床表现是与双侧前庭神经鞘瘤的发展有关,然而,患者也容易合并其他多部位神经系统肿瘤,包括...神经纤维瘤病2型(neurofbromatosis type 2,NF2)是一种以NF2肿瘤抑制基因突变引起的常染色体显性遗传病,具有特殊的神经系统病变。NF2最常见的临床表现是与双侧前庭神经鞘瘤的发展有关,然而,患者也容易合并其他多部位神经系统肿瘤,包括脑膜瘤、非前庭神经鞘瘤、胶质瘤等。一些患者还可能出现其他特征性表现,如眼部病变等。NF2有较高的发病率和严重的临床表现,相关病变的处理方法主要包括手术切除病损和对症治疗,近年来随着对其分子生物学更深入地了解,也提出了许多假定干预治疗的分子靶点。但目前还没有系统疗法来彻底解决该疾病。在这里,笔者回顾了NF2的相关临床表现、诊断以及目前治疗研究,并进行综述。展开更多
The logistics nodes and logistics enterprises are the core carriers and organiza- tional subjects of the logistics space, and their location characteristics and differentiation strategies are of key importance to opti...The logistics nodes and logistics enterprises are the core carriers and organiza- tional subjects of the logistics space, and their location characteristics and differentiation strategies are of key importance to optimizing urban logistics spatial patterns and ensuring reasonable resource allocation. Based on Tencent Online Maps Platform from December 2014, 4396 logistics points of interest （POI） were collected in Beijing, China. By the methods of industrial concentration evaluation and kernel density analysis, the spatial distribution pattern of logistics in Beijing are explored, the interaction mechanism among the type differ- ence, supply-demand side factors and location choice behavior are clarified, and the internal mechanism of spatial differentiation under the combined influence of transportation, land rent and assets are revealed. The following conclusions are drawn in the paper. （1） Logistics en- terprises and logistics nodes exhibit the characteristic of both co-agglomeration and spatial separation in location, and logistics activities display the spatial pattern of ＂marginal area of downtown area, suburbs and exurban area＂, which have a weak coupling degree with logis- tics employment space. （2） The public logistics space, namely, logistics parks and logistics centers, is produced under the guidance of the government, and the terminal logistics space consisting of logistics distribution centers serving for the specific industries and terminal users is dominated by enterprises. The Iocational differentiation between the two modes of logistics space is significant. （3） In the formation of the logistics spatial location, the government can change the traffic condition by re-planning the transport routes and freight station locations, and control the land rent and availability of different areas by increasing or decreasing the land use of logistics, to impact the enterprise behavior and form different types of logistics space and function differentiation. In comparison, logistics enterprises meet the diverse de- mands of service objects through differentiation of asset allocation to promote the specializa- tion of division and form the object differentiation of logistics space.展开更多
基金financial support from National Science and Technology Major Project of the Ministry of Science and Technology of China"Research on Investment estimation tools and economic appraisal system integration and development"(2011ZX05030-006-04)
文摘For oil company decision-makers,the principal concern is how to allocate their limited resources into the most valuable opportunities.Recently a new management philosophy,＂Beyond NPV＂,has received more and more international attention.Economists and senior executives are seeking effective alternative analysis approaches for traditional technical and economic evaluation methods.The improved portfolio optimization model presented in this article represents an applicable technique beyond NPV for doing capital budgeting.In this proposed model,not only can oil company executives achieve trade-offs between returns and risks to their risk tolerance,but they can also employ an ＂operational premium＂ to distinguish their ability to improve the performance of the underlying projects.A simulation study based on 19 overseas upstream assets owned by a large oil company in China is conducted to compare optimized utility with non-optimized utility.The simulation results show that the petroleum optimization model including ＂operational premium＂ is more in line with the rational investors＇ demand.
文摘神经纤维瘤病2型(neurofbromatosis type 2,NF2)是一种以NF2肿瘤抑制基因突变引起的常染色体显性遗传病,具有特殊的神经系统病变。NF2最常见的临床表现是与双侧前庭神经鞘瘤的发展有关,然而,患者也容易合并其他多部位神经系统肿瘤,包括脑膜瘤、非前庭神经鞘瘤、胶质瘤等。一些患者还可能出现其他特征性表现,如眼部病变等。NF2有较高的发病率和严重的临床表现,相关病变的处理方法主要包括手术切除病损和对症治疗,近年来随着对其分子生物学更深入地了解,也提出了许多假定干预治疗的分子靶点。但目前还没有系统疗法来彻底解决该疾病。在这里,笔者回顾了NF2的相关临床表现、诊断以及目前治疗研究,并进行综述。
基金Foundation： National Natural Science Foundation of China, No.41501123, No.71703219
文摘The logistics nodes and logistics enterprises are the core carriers and organiza- tional subjects of the logistics space, and their location characteristics and differentiation strategies are of key importance to optimizing urban logistics spatial patterns and ensuring reasonable resource allocation. Based on Tencent Online Maps Platform from December 2014, 4396 logistics points of interest （POI） were collected in Beijing, China. By the methods of industrial concentration evaluation and kernel density analysis, the spatial distribution pattern of logistics in Beijing are explored, the interaction mechanism among the type differ- ence, supply-demand side factors and location choice behavior are clarified, and the internal mechanism of spatial differentiation under the combined influence of transportation, land rent and assets are revealed. The following conclusions are drawn in the paper. （1） Logistics en- terprises and logistics nodes exhibit the characteristic of both co-agglomeration and spatial separation in location, and logistics activities display the spatial pattern of ＂marginal area of downtown area, suburbs and exurban area＂, which have a weak coupling degree with logis- tics employment space. （2） The public logistics space, namely, logistics parks and logistics centers, is produced under the guidance of the government, and the terminal logistics space consisting of logistics distribution centers serving for the specific industries and terminal users is dominated by enterprises. The Iocational differentiation between the two modes of logistics space is significant. （3） In the formation of the logistics spatial location, the government can change the traffic condition by re-planning the transport routes and freight station locations, and control the land rent and availability of different areas by increasing or decreasing the land use of logistics, to impact the enterprise behavior and form different types of logistics space and function differentiation. In comparison, logistics enterprises meet the diverse de- mands of service objects through differentiation of asset allocation to promote the specializa- tion of division and form the object differentiation of logistics space.
