Completion of a Prüfer domain

AbstractLet V (resp. D) be a valuation domain (resp. SFT Prüfer domain), I a proper ideal, and V̂ (resp. D̂) be the I-adic completion of V (resp. D). We show that (1) V̂ is a valuation domain, (2) Krull dimension of V̂=dimV/I+1 if I is not idempotent, V̂≅V/I if I is idempotent, (3) dimD̂=dimD/I+1, (4) D̂ is an SFT Prüfer ring, and (5) D̂ is a catenarian ring

The Krull dimension of power series rings over non-SFT rings

AbstractLet R be a commutative ring with identity. We show that the Krull dimension of the power series ring R〚X〛 can be uncountably infinite, i.e., there exists an uncountably infinite chain of prime ideals in R〚X〛, even if dimR is finite. In fact, we show that dimR〚X〛 is uncountably infinite if R is a non-SFT ring, which is an improvement of Arnold’s result

A Comparative study on the ethical perceptions of contractors and designers in the Malaysian Construction Industry

Corporate ethics together with CSR is becoming a new requirement for a successful business in the 21st century. This trend continues to be strengthened throughout the industry and the construction industry cannot be exceptional. Further the construction industry suffers from the notorious image that the ethical standard in construction cannot meet the expectation of the society. The unique feature of construction is that it is based on projects and the primary stakeholders of construction projects are clients, designers and contractors. Therefore, for construction ethics management, different approaches might be required from other industries. In construction projects, designers and contractors both work for clients, but their roles and responsibilities are quite different in many aspects, and often this leads to confrontational situations during the execution of the projects. This paper investigates the ethical perceptions of designers and contractors in the Malaysian construction industry. 18-major ethical issues have been used in the questionnaire survey. 8-construction companies (contractors) and 8-engineering consulting firms (designers) have been involved in the survey. The ethical issues are ranked based on „frequency‟ and „seriousness‟ for contractors and designers respectively. In addition the relationship between demographic factors and ethical issues, comparisons between the ethical perceptions of contractors and designers have been analyzed through SPSS. The outcome shows that there is no significant difference between contractors and designers in terms of „seriousness‟. For „frequency‟ of ethical issues, there seems to be some differences between them. The result also indicates that demographic factors do not influence the ethical perception. Overall, contractors and designers in Malaysia have similar ethical perceptions despite the differences in their roles and responsibilities in construction projects. This result is in line with the previous researches in UK and South Korea. Future researches in other countries are recommended to establish a theoretical background of ethical perceptions of construction professionals

Structural Factorization of Plants to Compute their Functional and Architectural Growth

Numerical simulation of plant growth has been facing a bottleneck due to the cumbersome computation implied by the complex plant topological structure. In this article, the authors present a new mathematical model for plant growth, GreenLab, overcoming these difficulties. GreenLab is based on a powerful factorization of the plant structure. Fast simulation algorithms are derived for deterministic and stochastic trees. The computation time no longer depends on the number of organs and grows at most quadratically with the age of the plant. This factorization finds applications to build trees very efficiently, in the context of geometric models, and to compute biomass production and distribution, in the context of functional structural models

GreenLab: A New Methodology Towards Plant Functional-Structural Model -- Structural Part

GreenLab model is an on-going research program conducted jointly by researchers from France and China since 1998. It is oriented to be a functional-structural model for agronomy/forestry applications. Therefore, while keeping a property of being faithful to botanical knowledge, a new methodology is developed within GreenLab by stressing on simplicity of the model. This paper presents briefly our understanding towards plant functional-structural model, but only a model related to plant structures is given to show some progresses of the GreenLab. For a single stand of plant, GreenLab applies its newly developed "dual-scale automaton" approach to generate stochastic structures of plants. Using graph-based interface, this approach provides users with straightforward means of integrating botanical knowledge, i.e., metamers and growth unit, in construction of topological and morphological structures of plants. On the other hand, for a complex tree or a plantation application, a strategy of substructures is employ d in GreenLab model for fast construction of plants and calculation of yields in terms of organs. Simulation results indicate promising benefits in using the new methodology to develop a generic plant model in regard to the structural part. (Résumé d'auteur

Electrochemical capacitance of a leaky nano-capacitor

We report a detailed theoretical investigation on electrochemical capacitance of a nanoscale capacitor where there is a DC coupling between the two conductors. For this ``leaky'' quantum capacitor, we have derived general analytic expressions of the linear and second order nonlinear electrochemical capacitance within a first principles quantum theory in the discrete potential approximation. Linear and nonlinear capacitance coefficients are also derived in a self-consistent manner without the latter approximation and the self-consistent analysis is suitable for numerical calculations. At linear order, the full quantum formula improves the semiclassical analysis in the tunneling regime. At nonlinear order which has not been studied before for leaky capacitors, the nonlinear capacitance and nonlinear nonequilibrium charge show interesting behavior. Our theory allows the investigation of crossover of capacitance from a full quantum to classical regimes as the distance between the two conductors is changed

Analysis and modeling of the root system architecture of winter wheat seedling

Plant root system plays an essential role in the acquisition of the edaphic resources, which are subject to local depletion. The size as well as the architecture of the root system determines the efficiency of the acquisition. In the present study, a stochastic model of plant root system architecture is formulated. The continuous growth and development of root system is described and modelled by stochastic processes (discrete events associated with a certain probability). The parameters of the model for each growth cycle include branching probability, w (rhythm ratio main axis vs. lateral roots), b (probability of growth) and c (probability of survival). Root segments were presented as connections of individual nodes. As root has no nodes in the sense of the botanical terms, an imaginary node with an elementary length is introduced. In order to obtain the parameters of the model, winter wheat seedlings were grown in a phytotron in sand culture watered by nutrient solution. Individual roots of 19-days-old se dlings were scanned and the images obtained were analysed with a root image-analysing software WinRhizo. Roots were clustered into 3 relatively homogeneous groups after an analysis of similarity according to 4 criteria: length of main axe, diameter of root apex of the main axe, lateral length density (total length of lateral roots per unit of main axe length), lateral root density (number of lateral roots per unit of main axe). In each root group, the parameters were fitted with a non-linear generalised least square method by comparing the theoretical length of root segments of various orders with the experimental data

Stochastic 3D Tree Simulation Using Substructure Instancing

Tree growth is simulated using a stochastic model of organogenesis that is faithful to botanical knowledge. This model is based on the concept of bud "physiological age", on the statistical description of the transition from one physiological age to another as well as of bud death, bud growth and branching processes. In order to enhance simulation efficiency, a recurrent algorithm based on stochastic substructure instancing is proposed. The tree is hierarchically decomposed into substructures that are classified according to their physiological age, and a library of random substructure instances is constructed: the recurrent simulation starts with the simplest peripheral substructures, which are also the physiologically oldest; these substructures are then progressively assembled into more complex substructures, until the tree is completely simulated. When the size of the library of substructure instances is small, the time needed to build a single stochastic tree is much shorter than for a usual tree simul tion that operates on a bud-by-bud basis. in computing a group of trees, the speed gain is even much greater, because the library of substructure instances is built for the first tree, and then is reused for computing subsequent trees. A preliminary sensitivity analysis is carried out according to the size of the library: when the library is large, the simulated distribution of the number of organs fits well with the theoretical mean and variance; the algorithm can thus be tuned in order to obtain accurate predictions. On the other hand, a small library (e.g., with only 2 or 3 instances for each substructure class) is sufficient for generating visually realistic trees. A few examples illustrate the high performance of this algorithm which paves the way for the fast simulation of large forest scenes

Comparative study On The ethical perceptions of contractors and designers in the China construction industry

Ethics is becoming one of the most important requirements for successful business in the 21st century. The construction industry cannot be exceptional from this trend. However construction ethics management requires different approaches from other industries, as the products of the industry are construction projects which are completely different from mass production. Contractors and designers are two major participants in construction projects. The roles and responsibilities of these two project stakeholders decisively influence all aspects of construction project. Practically ethical perceptions of contractors and designers are one of main aspects to be considered for the effective and efficient management of ethics for the construction industry. This research has investigated the ethical perceptions of contractors and designers in the China construction industry. A questionnaire survey which contains 15 ethical issues and 6 demographic factors has been conducted. 170 construction professionals from construction companies and consulting companies have been participated in this survey. These 15 ethical issues are ranked in terms of seriousness, frequency and importance for both contractors and designers as a single group to understand the overall perceptions in the industry. The analysis has also been conducted for contractors and designers respectively to make comparisons between them. The top three serious ethical issues in the industry are ‘Bribery and corruption’, ‘Failure to practice whistle-blowing’ and ‘Improper bidding practices’. Contractors and designers showed similar outcomes for the top five important ethical issues. But for the middle ranged ethical issues, they showed some differences. Further researches are required to identify the causes of the similarity and differences

Search for the Electric Dipole Moment of the tau Lepton

We have searched for a CP violation signature arising from an electric dipole moment (d_tau) of the tau lepton in the e+e- -> tau+tau- reaction. Using an optimal observable method and 29.5 fb^{-1} of data collected with the Belle detector at the KEKB collider at sqrt{s} = 10.58 GeV, we find Re(d_tau) = (1.15 +- 1.70) x 10^{-17} ecm and Im(d_tau) = (-0.83 +- 0.86) x 10^{-17} ecm and set the 95% confidence level limits -2.2 < Re(d_tau) < 4.5 (10^{-17}ecm) and -2.5 < Im(d_tau) < 0.8 (10^{-17}ecm).Comment: 15 pages, LaTeX, 21 figures, submitted to Phys. Lett.