71 resultados para Specific Investments
Resumo:
According to the Taylor principle a central bank should adjust the nominal interest rate by more than one-for-one in response to changes in current inflation. Most of the existing literature supports the view that by following this simple recommendation a central bank can avoid being a source of unnecessary fluctuations in economic activity. The present paper shows that this conclusion is not robust with respect to the modelling of capital accumulation. We use our insights to discuss the desirability of alternative interest rate rules. Our results suggest a reinterpretation of monetary policy under Volcker and Greenspan: The empirically plausible characterization of monetary policy can explain the stabilization of macroeconomic outcomes observed in the early eighties for the US economy. The Taylor principle in itself cannot.
Resumo:
Revenue management practices often include overbooking capacity to account for customerswho make reservations but do not show up. In this paper, we consider the network revenuemanagement problem with no-shows and overbooking, where the show-up probabilities are specificto each product. No-show rates differ significantly by product (for instance, each itinerary andfare combination for an airline) as sale restrictions and the demand characteristics vary byproduct. However, models that consider no-show rates by each individual product are difficultto handle as the state-space in dynamic programming formulations (or the variable space inapproximations) increases significantly. In this paper, we propose a randomized linear program tojointly make the capacity control and overbooking decisions with product-specific no-shows. Weestablish that our formulation gives an upper bound on the optimal expected total profit andour upper bound is tighter than a deterministic linear programming upper bound that appearsin the existing literature. Furthermore, we show that our upper bound is asymptotically tightin a regime where the leg capacities and the expected demand is scaled linearly with the samerate. We also describe how the randomized linear program can be used to obtain a bid price controlpolicy. Computational experiments indicate that our approach is quite fast, able to scale to industrialproblems and can provide significant improvements over standard benchmarks.
Resumo:
According to the Taylor principle a central bank should adjust the nominal interest rate by more than one-for-one in response to changes in current inflation. Most of the existing literature supports the view that by following this simple recommendation a central bank can avoid being a source of unnecessary fluctuations in economic activity. The present paper shows that this conclusion is not robust with respect to the modelling of capital accumulation. We use our insights to discuss the desirability of alternative interest raterules. Our results suggest a reinterpretation of monetary policy under Volcker and Greenspan: The empirically plausible characterization of monetary policy can explain the stabilization of macroeconomic outcomes observed in the early eighties for the US economy. The Taylor principle in itself cannot.
Resumo:
Applying the competing--risks model to multi--cause mortality,this paper provides a theoretical and empirical investigation of the positive complementarities that occur between disease--specific policy interventions. We argue that since an individual cannot die twice, competing risks imply that individuals will not waste resources on causes that are not the most immediate, but will make health investments so as to equalize cause--specific mortality. However, equal mortality risk from a variety of diseases does not imply that disease--specific public health interventions are a waste. Rather, a cause--specific intervention produces spillovers to other disease risks, so that the overall reduction in mortality will generally be larger than the direct effect measured on the targeted disease. The assumption that mortality from non--targeted diseases remains the same after a cause--specific intervention under--estimates the true effect of such programs, since the background mortality is also altered as a result of intervention. Analyzing data from one of the most important public health programs ever introduced, the Expanded Program on Immunization (EPI) of the United Nations, we find evidence for the existence of such complementarities, involving causes that are not biomedically, but behaviorally, linked.
Resumo:
Individual-specific uncertainty may increase the chances of reform beingenacted and sustained. Reform may be more likely to be enacted because amajority of agents might end up losing little from reform and a minoritygaining a lot. Under certainty, reform would therefore be rejected, butit may be enacted with uncertainty because those who end up losing believethat they might be among the winners. Reform may be more likely to besustained because, in a realistic setting, reform will increase theincentives of agents to move into those economic activities that benefit.Agents who respond to these incentives will vote to sustain reform infuture elections, even if they would have rejected reform under certainty.These points are made using the trade-model of Fernandez and Rodrik (AER,1991).
Resumo:
The assessment of Latin American long term economic performance is in urgent need ofmobilizing more data to match the pressing demands of growth analysts. We present asystematic comparison of capital goods imports for 20 Latin American countries in 1925. It relies on both the foreign trade data of the importing countries and of the major exporting countries the industrialized economies of the time. The quality of foreign trade figures is tested; an homogeneous estimate of capital goods imported is derived, and its per capita ranking is discussed providing new light on Latin American development levels before import substitution.
Resumo:
In this paper we carefully link knowledge flows to and from a firm s innovation process with this firm s investment decisions. Three types of investments are considered: investments in applied research, investments in basic research, and investments in intellectual property protection. Only when basic research is performed, can the firm effectively access incoming knowledge flows and these incoming spillovers serve to increase the efficiency of own applied research. The firm can at the same time influence outgoing knowledge flows, improving appropriability of its innovations, by investing in protection. Our results indicate that firms with small budgets for innovation will not invest in basic research. This occurs in the short run, when the budget for know-how creation is restricted, or in the long-run, when market opportunities are low, when legal protection is not very important, or, when the pool of accessible and relevant external know-how is limited. The ratio of basic to applied research is non-decreasing in the size of the pool of accessible external know-how, the size and opportunity of the market, and, the effectiveness of intellectual property rights protection. This indicates the existence of economies of scale in basic research due to external market related factors. Empirical evidence from a sample of innovative manufacturing firms in Belgium confirms the economies of scale in basic research as a consequence of the firm s capacity to access external knowledge flows and to protectintellectual property, as well as the complementarity between legal and strategic investments.
Resumo:
We analyze a model where a multinational firm can use its superiortechnology in a foreign subsidiary only after appropriate trainingof local managers. Technological spillovers from foreign directinvestment arise when such managers are later hired by a localfirm. Benefits for the host economy may also take the form of therent that trained managers receive by the foreign affiliate toprevent them from moving to local competitors. We study conditionsunder which technological spillovers occur. We also show that undercertain circumstances the multinational firm might find it optimalto resort to export instead of foreign direct investment, to avoiddissipation of its intangible assets.
Resumo:
Precise estimation of propagation parameters inprecipitation media is of interest to improve the performanceof communications systems and in remote sensing applications.In this paper, we present maximum-likelihood estimators ofspecific attenuation and specific differential phase in rain. Themodel used for obtaining the cited estimators assumes coherentpropagation, reflection symmetry of the medium, and Gaussianstatistics of the scattering matrix measurements. No assumptionsabout the microphysical properties of the medium are needed.The performance of the estimators is evaluated through simulateddata. Results show negligible estimators bias and variances closeto Cramer–Rao bounds.
Resumo:
To better understand the biological controls that regulate sea urchin dynamics, we studied the effects of potential inter- and intra-specific competition for food on several biological variables of the main sea urchin in the Mediterranean (Paracentrotus lividus). We carried out a caging experiment in which we manipulated sea urchin density (natural vs. high density) and herbivorous fish (Sarpa salpa) accessibility (free access vs. exclusion) in a Posidonia oceanica meadow. No evidence of competition between fish and urchins was detected. Neither density-dependent mortality nor changes in the somatic variables were found; however, we detected that intra-specific competition affected the reproductive potential of P. lividus. The gonad index of urchins at high population densities was ca. 30% lower than that of urchins at natural densities. As a spawning event had just occurred when urchins were collected, these differences probably reflect differences in reserve content, which may compromise the following reproductive period and decrease survival in the long term, as the gonads are also used as storage organs. For the time period studied, mortality rates appeared to be independent of local densities. The results indicate that a long-term negative feedback mechanism appears to take place in P. lividus in response to increased population density.
Resumo:
Sarcoidosis is a multisystemic granulomatous disease of unknown etiology that usually presents with bilateral hiliar adenopathies, pulmonary infiltrations, and ocular and cutaneous lesions. The specific cutaneous lesions, or granulomatous, are produced in from 9% to 37% of patients with systemic sarcoidosis. Nevertheless, few patients have been described having specific lesions from sarcoidosis in the oral mucous membrane. We present 2 patients with systemic sarcoidosis who developed specific sarcoidosis lesions in the oral mucous membrane. The first patient presented a plaque on the tongue of a chronic nature associated with facial lupus pernio. The second patient presented a rapidly growing nodular lesion on the lower lip that was in fact the presentation sign of the disease. Although infrequent, oral lesions may constitute the first sign of systemic sarcoidosis. For this reason the oral mucous membrane needs to be explored when there is suspicion of sarcoidosis, and systemic sarcoidosis must be included in the differential diagnosis of oral granulomatous lesions.
Resumo:
In this paper, the expression for the cost of capital is derived when net and replacement investments exhibit differences in their effective prices due to a different fiscal treatment. It is shown that, contrary to previous results in the literature, the cost of capital should be constructed under an opportunity cost criterion rather than a historical one. This result has some important economic consequences, since the optimizing firm will take into account not only the effective price for the new investments but also consider the opportunity cost of replacing them.
Resumo:
[cat] Aquest article analitza la relació entre els ingressos dels pares i l’educació dels seus fills. En un context d’altruïsme perfecte, el model descriu les decisions dels pares sobre quant consumir i quant invertir en l’educació dels seus fills. El model prediu que els rendiments de l’educació en termes de sous haurien de ser lineals. Usant aquest model en una economia competitiva, es mostra com el resultat depèn dels subsidis o impostos del govern sobre l’educació. El compromís habitual igualtat-eficiència apareix en aquest context. Finalment, el model dóna intuïcions sobre la relació entre educació i productivitat.