3,317 research outputs found

    Sales Growth of New Pharmaceuticals Across the Globe: The Role of Regulatory Regimes

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    Prior marketing literature has overlooked the role of regulatory regimes in explaining international sales growth of new products. This paper addresses this gap in the context of new pharmaceuticals (15 new molecules in 34 countries) and sheds light on the effect regulatory regimes have on new drug sales across the globe. Based on a time-varying coefficient model, we find that differences in regulation substantially contribute to cross-country variation in sales. One of the regulatory constraints investigated, i.e. manufacturer price controls, has a positive effect on drug sales. The other forms of regulation such as restrictions of physician prescription budgets and the prohibition of direct-to-consumer advertising tend to hurt sales. The effect of manufacturer price controls is similar for newly launched and mature drugs. In contrast, regulations on physician prescription budget and direct-to-consumer advertising have a differential effect for newly launched and mature drugs. While the former hurts mature drugs more, the latter has a larger effect on newly launched drugs. In addition to these regulatory effects, we find that national culture, economic wealth, introduction timing, lagged sales and competition, also affect drug sales. Our findings may be used as input by managers for international launch and sales decisions. They may also be used by public policy administrators to compare drug sales in their country to other countries and to assess the role of regulatory regimes therein.economics;regulation;culture;drug;international new product growth;penalized splines;pharmaceutical;timevarying effects

    The design of digital-adaptive controllers for VTOL aircraft

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    Design procedures for VTOL automatic control systems have been developed and are presented. Using linear-optimal estimation and control techniques as a starting point, digital-adaptive control laws have been designed for the VALT Research Aircraft, a tandem-rotor helicopter which is equipped for fully automatic flight in terminal area operations. These control laws are designed to interface with velocity-command and attitude-command guidance logic, which could be used in short-haul VTOL operations. Developments reported here include new algorithms for designing non-zero-set-point digital regulators, design procedures for rate-limited systems, and algorithms for dynamic control trim setting

    Optimizing information flow in small genetic networks. I

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    In order to survive, reproduce and (in multicellular organisms) differentiate, cells must control the concentrations of the myriad different proteins that are encoded in the genome. The precision of this control is limited by the inevitable randomness of individual molecular events. Here we explore how cells can maximize their control power in the presence of these physical limits; formally, we solve the theoretical problem of maximizing the information transferred from inputs to outputs when the number of available molecules is held fixed. We start with the simplest version of the problem, in which a single transcription factor protein controls the readout of one or more genes by binding to DNA. We further simplify by assuming that this regulatory network operates in steady state, that the noise is small relative to the available dynamic range, and that the target genes do not interact. Even in this simple limit, we find a surprisingly rich set of optimal solutions. Importantly, for each locally optimal regulatory network, all parameters are determined once the physical constraints on the number of available molecules are specified. Although we are solving an over--simplified version of the problem facing real cells, we see parallels between the structure of these optimal solutions and the behavior of actual genetic regulatory networks. Subsequent papers will discuss more complete versions of the problem

    Sales Growth of New Pharmaceuticals Across the Globe: The Role of Regulatory Regimes

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    Prior marketing literature has overlooked the role of regulatory regimes in explaining international sales growth of new products. This paper addresses this gap in the context of new pharmaceuticals (15 new molecules in 34 countries) and sheds light on the effect regulatory regimes have on new drug sales across the globe. Based on a time-varying coefficient model, we find that differences in regulation substantially contribute to cross-country variation in sales. One of the regulatory constraints investigated, i.e. manufacturer price controls, has a positive effect on drug sales. The other forms of regulation such as restrictions of physician prescription budgets and the prohibition of direct-to-consumer advertising tend to hurt sales. The effect of manufacturer price controls is similar for newly launched and mature drugs. In contrast, regulations on physician prescription budget and direct-to-consumer advertising have a differential effect for newly launched and mature drugs. While the former hurts mature drugs more, the latter has a larger effect on newly launched drugs. In addition to these regulatory effects,

    NONQUADRATIC COST AND NONLINEAR FEEDBACK CONTROL

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/57832/1/BernsteinNonquadraticCost1993.pd

    An Evolutionary Reduction Principle for Mutation Rates at Multiple Loci

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    A model of mutation rate evolution for multiple loci under arbitrary selection is analyzed. Results are obtained using techniques from Karlin (1982) that overcome the weak selection constraints needed for tractability in prior studies of multilocus event models. A multivariate form of the reduction principle is found: reduction results at individual loci combine topologically to produce a surface of mutation rate alterations that are neutral for a new modifier allele. New mutation rates survive if and only if they fall below this surface - a generalization of the hyperplane found by Zhivotovsky et al. (1994) for a multilocus recombination modifier. Increases in mutation rates at some loci may evolve if compensated for by decreases at other loci. The strength of selection on the modifier scales in proportion to the number of germline cell divisions, and increases with the number of loci affected. Loci that do not make a difference to marginal fitnesses at equilibrium are not subject to the reduction principle, and under fine tuning of mutation rates would be expected to have higher mutation rates than loci in mutation-selection balance. Other results include the nonexistence of 'viability analogous, Hardy-Weinberg' modifier polymorphisms under multiplicative mutation, and the sufficiency of average transmission rates to encapsulate the effect of modifier polymorphisms on the transmission of loci under selection. A conjecture is offered regarding situations, like recombination in the presence of mutation, that exhibit departures from the reduction principle. Constraints for tractability are: tight linkage of all loci, initial fixation at the modifier locus, and mutation distributions comprising transition probabilities of reversible Markov chains.Comment: v3: Final corrections. v2: Revised title, reworked and expanded introductory and discussion sections, added corollaries, new results on modifier polymorphisms, minor corrections. 49 pages, 64 reference

    Bureaucratic institutional design. The case of the Italian NHS

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    We propose a model where a regional government’s choice of the number of bureaucratic agencies operating in a region depends upon the degree of substitutability and complementarity of the bureaucratic services being demanded. We show that, if the government perceives the citizens’ demand as a demand for substitutable services, it will choose provision by two independent agencies. If the government perceives the citizens’ demand as a demand for complementary services, it will choose provision by a single consolidated agency. Exogenous shocks to the number of citizens amplify these incentives. Evidence from the Italian National Health Service (NHS) supports this hypothesis. Results show a positive effect of proxies of substitutable services on the number of regional Local Health Authorities (LHAs) and a negative effect of proxies of complementary services. The major immigration amnesties, taken as shocks to the number of citizens entitled to the service, magnify these effects

    Optimal Feedback Control Rules Sensitive to Controlled Endogenous Risk-Aversion

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    The objective of this paper is to correct and improve the results obtained by Van der Ploeg (1984a, 1984b) and utilized in the literature related to feedback stochastic optimal control sensitive to constant exogenous risk-aversion (Karp 1987; Whittle 1989, 1990; Chow 1993, amongst others). More realistic, the proposed approach deals with endoge- nous risks that are under the control of the decision-maker. It has strong implications on the policy decisions adopted by the decision-maker during the entire planning horizon.Controlled stochastic environment, rational decision-maker, adaptive control, optimal path, feedback optimal strategy, endogenous risk-aversion, dynamic active learning.Controlled stochastic environment, rational decision-maker, adaptive control, optimal path, feedback optimal strategy, endogenous risk-aversion, dynamic active learning.
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