bluuebunny/crossref_metadata_2025_split huggingface dataset:
Structural Evidence for an Intramolecular CH–π Interaction in Ternary Metal (Cu(II), Pd(II)) Complexes Involving o-/m-/p-Methyl Substituted Phenylalanine and 1,10-Phenanthroline
Authors: Mizutani Mamoru , Tomosue Shinya , Kinoshita Hitoshi , Jitsukawa Koichiro , Masuda Hideki , Einaga Hisahiko 
Published: December 2003

Abstract
The existence of a CH-π interaction has clearly been demonstrated by use of the ternary metal (Cu(II), Pd(II)) complexes involving o-/m-/p-methyl substituted l-phenylalanine (l-o-mPhe, l-m-mPhe, l-p-mPhe) and 1,10-phenanthroline (phen) on the basis of 1H NMR, electronic absorption, and CD spectroscopies, and X-ray diffraction method. The crystal structure of [{Cu(p-mPhe)(phen)}2{Cu(phen)2}(μ3-CO3)](ClO4)2 has revealed a marked structural feature suggesting CH-π and/or π–π interactions, although [Cu(l-o-mPhe)(phen)(H2O)]ClO4 does not show any interaction. CD spectra in the d–d region for [Cu(l-o-mPhe)(phen)]ClO4, [Cu(l-m-mPhe)(phen)]ClO4, and [Cu(l-p-mPhe)(phen)]ClO4 in aqueous solution have exhibited an obvious negative Cotton effect, and the magnitudes have significantly been reduced in dioxane/water in the order: [Cu(l-p-mPhe)(phen)]ClO4 ≤ [Cu(l-m-mPhe)(phen)]ClO4 &lt; [Cu(l-o-mPhe)(phen)]ClO4. 1H NMR spectra of [Pd(l-o-mPhe)(phen)]ClO4, [Pd(l-m-mPhe)(phen)]ClO4, and [Pd(l-p-mPhe)(phen)]ClO4 have exhibited larger ring current shifts for m- and p-CH3 protons of the latter two complexes both in D2O and in DMSO-d6, whereas o-CH3 protons for the former complex do not. The magnitudes have greatly been reduced in this order: [Pd(l-p-mPhe)(phen)]ClO4 ≤ [Pd(l-m-mPhe)(phen)]ClO4 in D2O–dioxane-d8, but not for [Pd(l-o-mPhe)(phen)]ClO4.
Emission Quenching of Double-Complex Salt Crystals of [RuL3]3[Co(bpydc)3]2·nH2O (L: 2,2′-Bipyridine, 2,2′-Bipyrazine or 4,4′-Dimetyl-2,2′-bipyridine, and bpydc: 2,2′-Bipyridine-4,4′-dicarboxylate)
Authors: Uddin Md Jamal , Yoshimura Akio , Ohno Takeshi 
Published: December 2003

Abstract
The emission quenching of double-complex salt crystals, [RuL3]3[Co(bpydc)3]2·nH2O (L: 2,2′-bipyridine, 4,4′-dimetyl-2,2′-bipyridine or 2,2′-bipyrazine and bpydc: 2,2′-bipyridine-4,4′-dicarboxylate), were studied over a wide temperature range. Electron-transfer (ET) quenching of the phosphorescent emission of RuL32+ in the presence of an anionic Co(bpydc)33− and the yields of ET-product formation were examined for aqueous solutions by means of laser transient-absorption spectroscopy. The high fraction of ET-product formation in the quenching and the slow rate of the reverse ET reaction establish the mechanism of emission quenching of Ru(bpy)32+ and Ru(dmbpy)32+ in the solution. The decreasing rate of uni-molecular quenching within the encounter complexes formed between 3[RuL3]2+ and Co(bpydc)33−, Ru(bpy)32+ &gt; Ru(dmbpy)32+ &gt; Ru(bpz)32+, was found for emission quenching of double-complex salt crystals. The magnitude and temperature independence of the emission quenching rate for the double-complex salt are discussed from an ET point of view, except for Ru(bpz)32+.
Complex Metal Halide Oxides (3). Structural Characteristics and Catalytic Performance of Lanthanum-Substituted X1X2 Type Complex Bismuth Chloride Oxides
Authors: Lin Sui Wen , Ueda Wataru 
Published: December 2003

Abstract
The replacement of bismuth ions with lanthanum ions in the cation-oxygen sheets of layered Bi3SrCl3O4 catalyst promoted the activity for the oxidative dehydrogenation of ethane prominently. The structure of Bi3−nLanSrCl3O4 remained in the X1X2 structure by the replacement untill the lanthanum ion content (n) was in excess of 0.75, and the value of a of the sub-unit cell and the value of c representing thickness of the layer structure were changed reversely. The Rietveld analysis of the Bi2.25La0.75SrCl3O4 catalyst revealed that the thickness of the double chlorine sheet decreased when the coordination number of lanthanum ion facing the double chlorine sheet increased from 8 to 9, suggesting that the interaction between the metal-oxide sheet and the chlorine sheet became stronger. This is supported by a reduced binding energy of chlorine in Bi2.25La0.75SrCl3O4 observed by XPS analysis. The activation of structural chlorine into a radical form is promoted by the replacement with lanthanum ion, which turns out to cause an increase of the oxidation activity of ethane.
A Novel Decyanogenative Coupling of α-Cyanoimines Mediated by Samarium. A Facile Route to α-Diketimines
Authors: Thakur Ashim J , Prajapati Dipak , Sandhu Jagir S 
Published: December 2003

Abstract
Conversion of α-cyanoimines 1 into α-diketimines 2 has been achieved successfully by using samarium diiodide in dry tetrahydrofuran in high yields without formation of anilinoanil 3, 1,2-diamines 4 or anilides 5.
Self-promoted Aldol Reaction between Aldehyde Having Lewis Base Moiety and Trimethylsilyl Enolate
Authors: Nakagawa Takashi , Fujisawa Hidehiko , Mukaiyama Teruaki 
Published: December 2003

Abstract
Self-promoted aldol reaction between aldehydes having Lewis base moieties and trimethylsilyl enolates proceeded smoothly to afford the corresponding aldols in good to high yields. It is noted that various functionalized aldols can be directly obtained without protection of functional groups in the above reaction.
Isolation of Tribromoacetamide from an Okinawan Alga and Biological Activities of Its Analogs
Authors: Kigoshi Hideo , Ichino Takao , Takada Noboru , Suenaga Kiyotake , Yamada Akihiro , Yamada Kaoru , Uemura Daisuke 
Published: December 2003

Abstract
Tribromoacetamide was isolated from the Okinawan alga Wrangelia species, and the biological activities of this compound and its analogs were investigated.
The Online TSP Against Fair Adversaries
Authors: Blom Michiel , Krumke Sven O. , de Paepe Willem E. , Stougie Leen 
Published: December 2003

In the online traveling salesman problem, requests for visits to cities (points in a metric space) arrive online while the salesman is traveling. The salesman moves at no more than unit speed and starts and ends his work at a designated origin. The objective is to find a routing for the salesman that finishes as early as possible. Performance of algorithms is measured through their competitive ratio, comparing the outcome of the algorithms with that of an adversary who provides the problem instance and therefore is able to achieve the optimal offline solution. Objections against such omnipotent adversaries have lead us to devise an adversary that is in a natural way, in the context of routing problems, more restricted in power. For the exposition we consider the online traveling salesman problem on the metric space given by ℝ0+, the non-negative part of the real line. We show that a very natural strategy is 3/2-competitive against the conventional adversary, which matches the lower-bound on competitive ratios achievable for algorithms for this problem. Against the more “fair adversary”, that we propose, we show that there exists an algorithm with competitive ratio (1 + √17)/4 ≈ 1.28 and provide a matching lower bound. We also show competitiveness results for a special class of algorithms (called zealous algorithms) that do not allow waiting time for the server as long as there are requests unserved.
Non-Approximability Results for Scheduling Problems with Minsum Criteria
Authors: Hoogeveen Han , Schuurman Petra , Woeginger Gerhard J. 
Published: December 2003

We provide several non-approximability results for deterministic scheduling problems whose objective is to minimize the total job completion time. Unless 𝒫 =𝒩𝒫, none of the problems under consideration can be approximated in polynomial time within arbitrarily good precision. Most of our results are derived by APX-hardness proofs. We show that, whereas scheduling on unrelated machines with unit weights is polynomially solvable, the problem becomes APX-hard if release dates or weights are added. We further show APX-hardness for scheduling in flow shops, job shops, and open shops. We also investigate the problems of scheduling on parallel machines with precedence constraints and unit processing times, and two variants of the latter problem with unit communication delays; for these problems we provide lower bounds on the worst-case behavior of any polynomial-time approximation algorithm through the gap-reduction technique.
Sorting Permutations by Reversals Through Branch-and-Price
Authors: Caprara Alberto , Lancia Giuseppe , Ng See-Kiong 
Published: December 2003

We describe an exact algorithm for the problem of sorting a permutation by the minimum number of reversals, originating from evolutionary studies in molecular biology. Our approach is based on an integer linear programming formulation of a graph-theoretic relaxation of the problem, calling for a decomposition of the edge set of a bicolored graph into the maximum number of alternating cycles. The formulation has one variable for each alternating cycle, and the associated linear programming relaxation is solved by column generation. A major advantage with respect to previous approaches is that the subproblem to face in the column-generation phase no longer requires the solution of min-cost general matching problems, but of min-cost bipartite matching problems. Experiments show that there is a tremendous speed-up in going from general matching to bipartite matching, although the best-known algorithms for the two problems have the same theoretical worst-case complexity. We also show the worst-case ratio between the lower bound value obtained by our new method and previous ones. We illustrate the effectiveness of our approach through extensive computational experiments. In particular, we can solve to proven optimality the largest real-world instances from the literature in a few seconds, and the other (smaller) real-world instances within a few milliseconds on a workstation. Moreover, we can solve to optimality random instances with n + 100 within 3 seconds, and with n + 200 within 15 minutes, where n is the size of the permutation, whereas the size of the instances solvable by previous approaches was at most 100. We also describe a polynomial-time heuristic algorithm that consistently finds solutions within 2% of the optimum for random instances with n up to 1000.
Solving the Generalized Assignment Problem: An Optimizing and Heuristic Approach
Authors: Nauss Robert M. 
Published: December 2003

The classical generalized assignment problem (GAP) may be stated as finding a minimum-cost assignment of tasks to agents such that each task is assigned to exactly one agent and such that each agent's resource capacity is honored. This NP-hard problem has applications that include job scheduling, routing, loading for flexible manufacturing systems, and facility location. Due to the difficulty in solving “hard” GAPs to optimality, most recent papers either describe heuristic methods for generating “good” solutions or, in the case of optimizing methods, computational results are limited to 500 to 1,000 binary variables. In this paper we describe a special purpose branch-and-bound algorithm that utilizes linear programming cuts, feasible-solution generators, Lagrangean relaxation, and subgradient optimization. We present computational results for solving “hard” problems with up to 3,000 binary variables. An unanticipated benefit of the algorithm is its ability to generate good feasible solutions early in the process whose solution quality generally dominates the solutions generated by two recently published heuristics. Furthermore, the computation time required is often less than the time taken by the heuristics. Thus, we have an optimizing algorithm that can be used quite effectively as a heuristic when proof of optimality is not an absolute requirement.
Book Reviews
Authors: Lev Benjamin 
Published: December 2003

The range of books reviewed is wide, covering theory and applications in operations research, statistics, management science, econometrics, mathematics, computers, and information systems (no software is reviewed). In addition, we include books in other fields that emphasize technical applications. Publishers who wish to have their books reviewed should send them to Professor Benjamin Lev. We list the books received; not all books received can be reviewed because space is limited. Those who would like to review books are urged to send me their names, addresses, and specific areas of expertise. We commission all reviews and do not accept unsolicited book reviews. Readers are encouraged to suggest books that might be reviewed or to ask publishers to send me copies of such books. The authors or editors of the books reviewed in this issue are Jacek Blazewicz, Klaus H. Ecker, Erwin Pesch, Guenter Schmidt, Jan Weglarz, Eric V. Denardo, Zbigniew Michalewicz, David B. Fogel, Tan Miller, Christoph Schneeweiss, Dileep R. Sule, Stanislav Uryasev, and Panos M. Pardalos.
An Evaluation of Self-Organizing Map Networks as a Robust Alternative to Factor Analysis in Data Mining Applications
Authors: Kiang Melody Y. , Kumar Ajith 
Published: December 2003

Kohonen's self-organizing map (SOM) network is one of the most important network architectures developed during the 1980s. The main function of SOM networks is to map the input data from an n-dimensional space to a lower dimensional (usually one- or two-dimensional) plot while maintaining the original topological relations. Therefore, it can be viewed as an analog of factor analysis. In this research, we evaluate the feasibility of using SOM networks as a robust alternative to factor analysis and clustering for data mining applications. Specifically, we compare SOM network solutions to factor analytic and K-Means clustering solutions on simulated data sets with known underlying factor and cluster structures. The comparisons indicate that the SOM networks provide solutions superior to unrotated factor solutions in general and provide more accurate recovery of underlying cluster structures when the input data are skewed. Our findings suggest that SOM networks can provide robust alternatives to traditional factor analysis and clustering techniques in data mining applications.
Should Optional Properties Be Used in Conceptual Modelling? A Theory and Three Empirical Tests
Authors: Bodart François , Patel Arvind , Sim Marc , Weber Ron 
Published: December 2003

An important feature of some conceptual modelling grammars is the features they provide to allow database designers to show real-world things may or may not possess a particular attribute or relationship. In the entity-relationship model, for example, the fact that a thing may not possess an attribute can be represented by using a special symbol to indicate that the attribute is optional. Similarly, the fact that a thing may or may not be involved in a relationship can be represented by showing the minimum cardinality of the relationship as zero. Whether these practices should be followed, however, is a contentious issue. An alternative approach is to eliminate optional attributes and relationships from conceptual schema diagrams by using subtypes that have only mandatory attributes and relationships. In this paper, we first present a theory that led us to predict that optional attributes and relationships should be used in conceptual schema diagrams only when users of the diagrams require a surface-level understanding of the domain being represented by the diagrams. When users require a deep-level understanding, however, optional attributes and relationships should not be used because they undermine users' abilities to grasp important domain semantics. We describe three experiments which we then undertook to test our predictions. The results of the experiments support our predictions.
Measuring Information Technology Payoff: A Meta-Analysis of Structural Variables in Firm-Level Empirical Research
Authors: Kohli Rajiv , Devaraj Sarv 
Published: December 2003

Payoffs from information technology (IT) continue to generate interest and debate both among academicians and practitioners. The extant literature cites inadequate sample size, lack of process orientation, and analysis methods among the reasons some studies have shown mixed results in establishing a relationship between IT investment and firm performance.In this paper we examine the structural variables that affect IT payoff through a meta analysis of 66 firm-level empirical studies between 1990 and 2000. Employing logistic regression and discriminant analyses, we present statistical evidence of the characteristics that discriminate between IT payoff studies that observed a positive effect and those that did not. In addition, we conduct ordinary least squares (OLS) regression on a continuous measure of IT payoff to examine the influence of structural variables on the result of IT payoff studies.The results indicate that the sample size, data source (firm-level or secondary), and industry in which the study is conducted influence the likelihood of the study finding greater improvements on firm performance. The choice of the dependent variable(s) also appears to influence the outcome (although we did not find support for process-oriented measurement), the type of statistical analysis conducted, and whether the study adopted a cross-sectional or longitudinal design. Finally, we present implications of the findings and recommendations for future research.
The Impact of Experience and Time on the Use of Data Quality Information in Decision Making
Authors: Fisher Craig W. , Chengalur-Smith InduShobha , Ballou Donald P. 
Published: December 2003

Data Quality Information (DQI) is metadata that can be included with data to provide the user with information regarding the quality of that data. As users are increasingly removed from any personal experience with data, knowledge that would be beneficial in judging the appropriateness of the data for the decision to be made has been lost. Data tags could provide this missing information. However, it would be expensive in general to generate and maintain such information. Doing so would be worthwhile only if DQI is used and affects the decision made. This work focuses on how the experience of the decision maker and the available processing time influence the use of DQI in decision making. It also explores other potential issues regarding use of DQI, such as task complexity and demographic characteristics. Our results indicate increasing use of DQI when experience levels progress through the stages from novice to professional. The overall conclusion is that DQI should be made available to managers without domain-specific experience. From this it would follow that DQI should be incorporated into data warehouses used on an ad hoc basis by managers.
Delegating Pricing Decisions
Authors: Bhardwaj Pradeep 
Published: December 2003

An outstanding problem in marketing is why some firms in a competitive market delegate pricing decisions to agents and other firms do not. This paper analyzes the impact of competition on the delegation decision and, in turn, the impact of delegation on prices and incentives. The theory builds on the simplest framework of competition in two dimensions: prices and (sales agents') effort. Specifically, we are interested in answering the following questions: (1) Does competition affect the price-delegation decision and, if yes, why? (2) How do prices vary under price-delegation and no-price-delegation scenarios? (3) Do the incentives to the sales representatives vary under the delegation and no-delegation scenarios? To address these issues, we build a game-theoretic model that consists of two firms selling through their sales representatives. These representatives are company employees. Sales are a function of prices and selling efforts. The risk-neutral firms decide whether or not to delegate the pricing decision to risk-averse sales representatives. The wages to the sales representatives consist of salary plus a commission on gross margins. The commission on gross margins can be adjusted, either through communicated marginal cost of production, which we call “virtual” marginal cost, or directly. The firm and the sales representative are assumed to have the same information about the market, that is, there is no information asymmetry. With competition in two dimensions, the strategic nature of decision variable price depends on the relative intensity of competition. With unobservable contracts and risk-averse sales representatives, firms delegate the pricing decision when price competition is intense. Part of the uncertainty in demand is absorbed by the firm by keeping “virtual” marginal cost greater than the marginal cost of production. The competing firm infers this through the risk aversion of the sales representatives. Under price delegation the sales representatives' wages are higher, and they set a price that is higher than what the firms would have set themselves. This leads to softening of price competition that is to the advantage of both firms. When the effort competition is dominant, however, the firms prefer to make the pricing decision themselves, because this reduces the intensity of effort competition among agents. A single-instrument commission structure in which the firms adjust the “virtual” marginal cost is compared to a two-instrument commission structure in which the firms can adjust the commission rate, as well the “virtual” marginal cost. Under no price delegation, the two incentive schemes are the same. However, under price delegation the risk premium with the two-instrument scheme is lower. However, the prices and efforts are higher with the single-instrument scheme. When price competition is intense, the increase in risk premium with the single instrument scheme is more than compensated for by the increase in profits. This is the benefit of softening price competition through higher prices.
Creating Win–Win Trade Promotions: Theory and Empirical Analysis of Scan-Back Trade Deals
Authors: Drèze Xavier , Bell David R. 
Published: December 2003

Manufacturer trade promotion spending is second only to cost of goods sold as a profit-and-loss item, yet manufacturers often lose money on these deals as a result of forward-buying by retailers. The search for more effective forms of trade promotion and the availability of scanners at cash registers has led to the emergence of a new type of trade deal—the scan-back—that gives retailers a discount on unitssoldduring the promotion rather than on unitsbought. We develop a theory to compare retailer pricing decisions and profitability under scan-back and traditional off-invoice trade deals. We show that, when the terms of the trade deal are identical, retailers prefer off-invoice trade deals and manufacturers prefer scan-backs. Manufacturers can, however, redesign the scan-back to leave the retailer weakly better off and leave themselves strictly better off. Using proprietary data from the beverage category, we conduct an empirical analysis and find that during the promotion period scan-back trade deals, relative to off-invoice deals: (1) Do not cause excess ordering and (2) generate higher retail sales through lower retail prices. Implications for researchers and managers are discussed.