A note on certain useful colour reactions of anthoxanthins and related compounds

Proceedings - Mathematical Sciences - Employing a large number of natural and synthetic flavones, flavonols, flavanones and certain related compounds the scope of the following colour reactions has...     

The functions that do not change types of minimal fillings

It is proved that a function changing distances in finite metric spaces and preserving the types of their minimal fillings has the form f (x) = kx + b. It is sufficient to assume that the types of fillings are preserved for spaces consisting of at most five points.     

A polarographic study of mercuric cyanide complexes with alkali halides

The processes by which the movements of the surface of the earth due to its rotation around the polar axis can influence the atmosphere above are considered in detail. It emerges that the fast-moving areas in the equatorial belt on the surface of the earth play a highly important role in determining the behaviour of the atmosphere. The jet-stream in the sub-tropical regions, the westerly zonal winds in the region of middle latitudes and the easterly surface-winds in the equatorial belt are explained on this basis and shown to stand in close relationship with each other. The winds observed in the polar belt are also discussed and explained.     

影响中学生数学成绩因素的通径分析

用绵阳市 6 0 0名初中学生构成样本 ,采用J¨oreskog提出的线性结构方程式模型理论 ,以及J¨oreskog和S¨orbom开发的软件系统LIREL8.3对调查的资料进行分析。结果表明 :用 2 0个显在变量和 10个隐在变量研究影响中学生数学成绩的因素 ,最后有 13个显在变量入选构成外生模型 ,有 7个隐在变量变量入选构成内生模型。Homeback、Attitud、Views、EQ、IQ和Class这 6个内生的隐在变量对中学生的数学成绩均存在不同程度的影响 ,其中以Attitud、Homeback、IQ和EQ对数学成绩的贡献最大。内生模型中 6个内生的隐在变量的R2 的平均值为 0 .2 0 ,该模型中数学成绩(Mathachi)这一变量中可预测的方差占到了 4 1% (R2 =0 .4 1) ,将这两者结合起来考虑 ,所建立的模型应当是比较有说服力的。     

Optimal controls that maximize the probability of hitting a set of targets: A numerical study

A two-dimensional random motion of a point is dealt with. The point velocity (v cos ?,v sin ?) is subjected to two different kinds of perturbations, the first represented by a vector of independent standard Wiener processes and the second by a generalized type of Poisson process. The control function is ?, whilev is kept fixed. We assume given a configuration ofn+1 target sets,A ₀,...,A _n , in the plane, all of these sets being surrounded by an open and bounded setD. We denote by ? _x (?(?)∈A _i the probability thatX _t , the location of the point, whereX ₀=x∈D, will reach the setA _i beforeX _i reaches any other setA _j ,i≠j, and before it leavesD. The problem dealt with here is to find an optimal control law ?*, ?*=?*(x),x∈D, such that the function $$V\left( {x;\theta } \right) = \sum\limits_{i = 0}^n {\lambda _i \mathbb{P}_x \left( {X_\tau \left( \theta \right) \in A_i } \right),}$$ where λ₁,i=0,...,n, are given nonnegative numbers, will be maximized on a given class of admissible control laws. Sufficient conditions on optimal controls, of a dynamic programming type, are derived. These conditions require the existence of a smooth solution to a nonlinear partial integrodifferential equation, which is solved here by applying a finite-difference scheme. Two examples are dealt with numerically.     

The assembly of printed circuit boards: A case with multiple machines and multiple board types

In this paper a typical situation arising in the assembly of printed circuit boards is investigated. The planning problem we face is how to assemble boards of different types using a single line of placement machines. From a practical viewpoint, the multiplicity of board types adds significantly to the complexity of the problem, which is already very hard to solve in the case of a single board type. In addition, relatively few studies deal with the multiple board type case. We propose a solution procedure based on a hierarchical decomposition of the planning problem. An important subproblem in this decomposition is the so-called feeder rack assignment problem. By taking into account as much as possible the individual board type characteristics (as well as the machine characteristics) we heuristically solve this problem. The remaining subproblems are solved using constructive heuristics and local search methods. The solution procedure is tested on real-life instances. It turns out that, in terms of the makespan, we can substantially improve the current solutions.     

A study of the cavities that form in dynamic phenomena in coal mines

We give a classification of the cavities formed by sudden subsidences in the Donbass mines as functions of their shape. We propose a method of computing the maximal extent of the zone of fracture of coal in the direction perpendicular to the face line of the excavation. It is shown that the parameters that characterize the dimensions and location of the cavities that form in actual subsidences in drifts do not exceed the theoretical values obtained from the mathematical model of the process of sudden extrusion. Translated fromTeoreticheskaya i Prikladnaya Mekhanika, No. 24, 1993, pp. 98–104.     

应急管理关键因素的混合型识别方法研究

如何细致识别出自然灾害下应急管理的关键因素,对于开展科学有效的应急管理具有重要的现实意义。本文提出一种新的应急管理关键因素的混合型识别方法,该方法通过构建三角模糊数为基本语言集、三角区间模糊数为补充语言集的评价尺度集,建立混合型初始直接关联矩阵并将之转化为区间数直接关联矩阵,进而实现中心度和原因度的综合排序,从而据此有效的识别出应急管理的关键因素,为制订高效科学的应急管理政策提供良好的方法论支持。同时,通过一个算例表明了本方法具有良好的识别效果。本混合型识别方法突破了已有研究单一性模糊评价尺度集的局限性,具有方法论创新价值,并在关键因素识别领域具有较好的应用普适性。     

The one dimensional Compartmentalised Knapsack Problem: A case study

The Compartmentalised Knapsack Problem (CKP) is similar to the ordinary Knapsack Problem except that items to be packed belong to separate classes, and items can only be packed, in knapsack compartments, amongst items in their own class. This paper addresses a case study in the cutting of steel rolls in which the CKP arises. The rolls are cut in two-phases: the first phase produces sub-rolls (compartments) which are, after reducing the thickness, cut in a second phase to produce ribbons (a class consists of ordered items with the same thickness). Finally, two methods of solving CKP are presented, and these are used to generate columns in the classical linear optimisation model of Gilmore and Gomory. Results of computational experiments are presented.     

The node capacitated graph partitioning problem: A computational study

In this paper we consider the problem ofk-partitioning the nodes of a graph with capacity restrictions on the sum of the node weights in each subset of the partition, and the objective of minimizing the sum of the costs of the edges between the subsets of the partition. Based on a study of valid inequalities, we present a variety of separation heuristics for cycle, cycle with ears, knapsack tree and path-block cycle inequalities among others. The separation heuristics, plus primal heuristics, have been implemented in a branch-and-cut routine using a formulation including variables for the edges with nonzero costs and node partition variables. Results are presented for three classes of problems: equipartitioning problems arising in finite element methods and partitioning problems associated with electronic circuit layout and compiler design. © 1998 The Mathematical Programming Society, Inc. Published by Elsevier Science B.V.Corresponding author.     

A geometric decomposition of spaces into cells of different types II: Homology theory

We develop the homology theory of CW(A)-complexes, generalizing the classical cellular homology theory for CW-complexes. A CW(A)-complex is a topological space which is built up out of cells of a certain core A.     

Anticipated responses: The positive side of elicited reactions to competitive action

This study advances the action-oriented perspective on strategy dynamics. Strategy research suggests that a firm’s profit will decrease when facing rival responses, yet anecdotal evidence indicates that countermoves may enhance its performance. What is the interaction effect of simultaneous negative- and positive-side competitive responses on organisational performance? We propose that the answer depends not only on the actor’s characteristics but also the action’s characteristics. Grounded in empirical facts, our formal model of competitive dynamics examines the possibility of anticipated responses that are deliberately elicited by the attacking firm. We show that against attentive rivals, a firm with high attention and low aggressiveness can utilise visible actions to achieve its strategic intention and deployment. Our study offers significant implications for theory and practice.     

Enterprise resource planning: A taxonomy of critical factors

This paper presents a novel taxonomy of the critical success factors in enterprise resource planning (ERP) implementation process. ERP benefits cannot be fully realised unless a strong alignment and reconciliation mechanism is established between technical and organisational imperatives based on the principles of process orientation. It is suggested in the taxonomy that measurement takes place in a balanced perspective, and for the purpose of providing useful information that can enable the decision making process and, which can help deliver the corporate objectives and therefore lead the business competitively forward. Upon this premise, the taxonomy is based on a comprehensive analysis of ERP literature combining research studies and organisational experiences. The taxonomy reflects the essential features of ERP systems, as being built based on the principles of business process management. Furthermore, it illustrates that ERP benefits are realised when a tight link is established between implementation approach and business process performance measures.     

A study of factors impacting elementary mathematics preservice teachers: Improving mindfulness,anxiety, self-efficacy,and mindset

Innovation is more imperative now than ever before given the upcoming shortage in prepared teachers and the need to produce students with a strong knowledge of mathematics. A sense of urgency is impacting teacher education/preparation programs as instructional practices need to discover how to arm teachers to increase the number of students to be not only college-ready but also desiring to pursue Science, Technology, Engineering, and Mathematics majors. As such, the purpose of this study, was to determine how the four variables (mindfulness, mathematics anxiety, self-efficacy, and mindset) are interconnected within preservice elementary teachers (PSETs), and how we as teacher educators can better address these variables within our own PSETs. Each semester included three seminars with similar overall foci including the four variables. Participants in this study were recruited from Elementary Education students at an east south central regional university enrolled in a mathematics methods course. Thirty-seven participants were divided into control (N = 20) and treatment (N = 17). In this article, we present both qualitative and quantitative results from our mixed-methods study that considered these questions. With the results of this study revealing an inter-connectedness among the four variables, this research further informs the teacher educator community.     

The role of matrices that are convergent to zero in the study of semilinear operator systems

In this paper we explain the advantage of vector-valued norms and the role of matrices that are convergent to zero in the study of semilinear operator systems by means of some basic methods of nonlinear analysis: the contraction principle, Schauder’s fixed point theorem, the Leray–Schauder continuation principle and Krasnoselskii’s cone fixed point theorem. A vector version of Krasnoselskii’s theorem is also established.     

Fostering construction of a meaning for multiplication that subsumes whole-number and fraction multiplication: A study of the Learning Through Activity research program

We report on a teaching experiment intended to foster a concept of multiplication that would both subsume students’ multiple-groups concept of whole number multiplication and provide a conceptual basis for understanding multiplication of fractions. The teaching experiment, which used a rigorous single-subject methodology, began with an attempt to build on students’ multiple-groups concept by promoting generalizing assimilation. This was not totally successful and led to a redesign aimed at promoting reflective abstraction. Analysis of this latter phase led to several significant conclusions, which in turn led to a revised hypothetical learning trajectory. The revised trajectory aims to foster a concept of multiplication as a change in units.     

The effect of noise on the Chafee-Infante equation: A nonlinear case study

We investigate the effect of perturbing the Chafee-Infante scalar reaction diffusion equation, , by noise. While a single multiplicative Itô noise of sufficient intensity will stabilise the origin, its Stratonovich counterpart leaves the dimension of the attractor essentially unchanged. We then show that a collection of multiplicative Stratonovich terms can make the origin exponentially stable, while an additive noise of sufficient richness reduces the random attractor to a single point.