This paper studies the effect of station density on prices in the retail gasoline market in the Czech Republic. We estimate the impact of the number of competing stations in various driving-distance ranges around each station on prices. We find that station density has a negative effect on prices; the effect decreases with distance and is statistically significant up to six kilometers. This suggests that the retail gasoline market is local rather than national. 相似文献
This study explores the antecedents and consequences of marketing program standardization in subsidiaries of multinational corporations by contrasting the case of a lead market (Japan) and of an emerging market (Turkey). The findings show that: (1) marketing program standardization is positively related to performance in Japan and Turkey; (2) centralization of nonproduct decision is negatively related to performance in both markets; (3) customer similarity is positively related to marketing program standardization in both Japan and Turkey. Whereas, in Japan, marketing program standardization has a direct, positive relationship to performance, in Turkey, in addition to such a direct effect, there is also an indirect effect at work, through centralization of nonproduct decision. 相似文献
This paper deals with the problem of implementing the Walras correspondence via Nash equilibria, in exchange economies with infinitely many commodities and finitely many households with possibly non-ordered
preferences. We explicitly construct a feasible mechanism enjoying some features, which have natural economic meanings. Under
a fairly weak boundary condition, this game fully implements the Walras equilibria. If this condition is not fulfilled, our
mechanism nevertheless implements the constrained Walras equilibria.
Received: 11 December 2003, Accepted: 29 July 2005
JEL Classification:
D41, D43, D51
We thank (without implicating) Prof. Jean-Marc Bonnisseau and Cuong Le Van for helpful comments. The views expressed in this
paper reflect those of the authors and not necessarily those of Calyon. 相似文献
We study the local turnpike property for two classes of infinite-horizon discrete-time deterministic maximization problems
which have common applications, e.g., optimal growth theory. We follow a functional-analytic approach and rely on an implicit
function theorem for the space of the sequences which converge to zero. We shall assume the existence of an optimal path which
is not necessarily a steady-state. Relying on material developped in Blot and Crettez (Decis Econo Finance 27:1–34, 2004),
“On the smoothness of optimal paths” Decis Econ Finance, 21:1–34, 2004), we provide conditions under which a variation in
the initial conditions (i.e., capital stock and discount rate) yields an optimal solution which converges toward a reference
solution when time becomes infinite. We also provide new results on bounded solutions of difference equations.
We gratefully thank the editor, Silvano Holzer, and two anonymous referees for remarks and advices on a previous version of
this paper. 相似文献
In this paper we study a generalization of the dynamic Leontief input–output model. We extend the standard dynamic Leontief model with the balance equation of non-renewable resources. Obviously, the non-renewable stocks will decrease, exploiting primary resources. In this study we examine the controllability of this extended model by taking the consumption as the control parameter. Assuming balanced growth for both consumption and production, we investigate how long these scarce resources will cover the input needs of production and how the lifetime of the system depends on the balanced growth rate and on the consumption. In doing so, we apply classic results from control theory and on eigenvalue problems in linear algebra. 相似文献
The theory of fuzzy sets is applied to the output decisions of a price-taking firm facing imprecise information about expected future prices. Accepting risk resulting from the randomness of prices, the manager is interested in expected profits only. Since the set of possible expected-price vectors is fuzzy, a suitable defuzzification strategy is defined in analogy to the pessimism-optimism index proposed by L. Hurwicz. It depends on the manager's willingness to accept surprises resulting from a deviation of the true expected prices from the values that guided output decisions. Despite a linear cost function, well specified solutions to the optimization problem are possible without resorting to capacity constraints. 相似文献
Two experiments examined the effects of iterated polling and feedback on prediction accuracy for volatile world events using the Delphi paradigm. In both experiments, participants predicted rapidly changing geopolitical events. The first experiment occurred during the litigation surrounding the Clinton/Lewinsky affair in 1998. Results indicated that feedback improved individual and group accuracy for predictions of whether an event would occur. These types of predictions derived from group consensus were approximately 90% accurate, which was significantly higher than the average individual participant's accuracy. Neither polling nor feedback had much effect on time course predictions. The second experiment occurred during the American military action against the Taliban regime in Afghanistan in 2001. In Experiment 2, participants were polled three times to determine if increasing the number of iterated polls would improve Delphi accuracy. The results showed that accuracy improved from the first to the second poll but not from the second to the third. The groups predicted whether these scenarios would occur with approximately 75% accuracy, which was significantly higher than the accuracy of any individual participant. Once again, the Delphi procedure did not enhance time course predictions in Experiment 2. 相似文献
Aim: To assess the cost-effectiveness of nutrition education by dedicated dietitians (DD) for hyperphosphatemia management among hemodialysis patients.Materials and methods: This was a trial-based economic evaluation in 12 Lebanese hospital-based units. In total, 545 prevalent patients were cluster randomized to DD, trained hospital dietitian (THD), and existing practice (EP) groups. During Phase I (6 months), DD (n?=?116) received intensive education by DD trained on renal nutrition, THD (n?=?299) received care from trained hospital dietitians, and EP (n?=?130) received usual care from untrained hospital dietitians. Patients were followed-up during Phase II (6 months).Results: At baseline, EP had the lowest weekly hemodialysis time, and DD had the highest serum phosphorus and malnutrition-inflammation score. The additional costs of the intervention were low compared with the societal costs (DD: $76.7, $21,007.7; EP: $4.6, $18,675.4; THD: $17.4, $20,078.6, respectively). Between Phases I and II, DD showed the greatest decline in services use and societal costs (DD: –$2,364.0; EP: –$1,727.7; THD: –$1,105.7). At endline, DD experienced the highest decrease in adjusted serum phosphorus (DD: –0.32; EP: +0.16; THD: +0.04?mg/dL), no difference in quality-adjusted life-years (QALY), and the highest societal costs. DD had a cost-effectiveness ratio of $7,853.6 per 1?mg decrease in phosphorus, compared with EP; and was dominated by THD. Regarding QALY, DD was dominated by EP and THD. The results were sensitive to changes in key parameters.Limitations: The analysis depended on numerous assumptions. Interpreting the results is limited by the significant baseline differences in key parameters, suggestive of higher baseline societal costs in DD.Conclusions: DD yielded the greatest effectiveness and decrease in societal costs, but did not affect QALY. Regarding serum phosphorus, DD was likely to be cost-effective compared with EP, but had a low cost-effectiveness probability compared with THD. Regarding QALY, DD was not likely to be cost-effective. Assessing the long-term cost-effectiveness of DD, on similar groups, is recommended. 相似文献
The ease with which 3D CAD models may be modified and reused are two key aspects that improve the design-intent variable and that can significantly shorten the development timelines of a product. A set of rules are gathered from various authors that take different 3D modelling strategies into account. These rules are then applied to CAD strategic-knowledge learning methodology and included in 3D CAD modelling exercises for students following the degree in mechanical engineering at the University of Burgos (Spain). The experiment was conducted in two groups with a total of 75 students. The design-intent rules were introduced in the different exercises that the teacher explained in both the theoretical and the practical classes. In addition, a summary of the different design rules in each of the practical exercises was explained in the practical classes in only one of the groups. The experimental results, reported in this paper, tested the influence of these summaries on overall improvements in 3D modelling and on the design-intent variable, which is subdivided into four sections: skeleton, structures, alterations and constraints. The use of the summaries of the design intent rules led to statistically significant improvements in 3D modelling in the experimental group, in comparison with the group of students to whom those summaries were not explained. 相似文献
Aims: To model direct medical costs associated with reductions in cardiovascular disease (CVD) events in T2DM patients reported in the CANVAS and EMPA-REG trials, which assessed the cardiovascular safety of canagliflozin and empagliflozin, respectively.
Materials and methods: Costs were modeled from a US managed care organization (MCO) perspective for the CVD outcomes included in both trials: three-point major adverse cardiovascular event (MACE) and its components (cardiovascular-related death, nonfatal myocardial infarction, nonfatal stroke), as well as heart failure requiring hospitalization. The rate of CVD events averted (difference between study drug and placebo) was projected to the portion of an MCO T2DM population matching the respective trial’s inclusion criteria. A targeted literature search for paid amounts directly associated with each CVD event provided the unit costs, which were applied to the projected number of events averted, to calculate costs avoided per member per year (PMPY). One-way sensitivity analyses were performed on events averted, unit costs, and percentages of trial-applicable patients.
Results: Based on three-point MACE events averted, costs avoided PMPY of $6.17 (range: $1.27–$10.94) for CANVAS and $2.75 ($0.19–$4.83) for EMPA-REG were estimated. Costs avoided for individual components of MACE ranged from $0.77 to $3.84 PMPY for CANVAS and from -$0.97 (additional costs) to $1.54 for EMPA-REG. PMPY costs avoided for heart failure were $2.72 for CANVAS and $1.32 for EMPA-REG.
Limitations and conclusions: Models assumed independent, non-recurrent outcomes and were restricted to medical costs directly associated with the trial-reported events. The reductions in CVD events in T2DM patients reported for both CANVAS and EMPA-REG project to a positive cost avoidance for these events in an MCO population. The analysis did not include an assessment of the impact on total cost, as the costs associated with adverse events, drug utilization or other clinical outcomes were not examined. 相似文献