426 research outputs found

    Regulating Advertisements: The Case of Smoking Cessation Products

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    In this paper we investigate how direct-to-consumer (DTC) advertising of pharmaceutical products in affected by regulations of the Food and Drug Administration and by market conditions. We focus on a relatively under-studied segment of the pharmaceutical market -- the market for smoking cessation products. Because of their proven effectiveness, these products could be the key to meeting public health goals to reduce smoking. However, in many ways, smoking cessation products have been more heavily regulated than cigarettes. Our empirical analysis uses data on advertising expenditures and data from an archive of print advertisements. The archive includes all smoking cessation product advertisements that appeared in over 13,000 issues of 28 magazines between January 1985 and May 2002. Our study period begins shortly atfer the first nicotine replacement product was introduced, and covers the evolution of the market as new products are introduced while some of the older products move from prescription to over-the-counter (OTC) status. OTC status eases the disclosure requirements imposed on advertisements of prescription pharmaceuticals, substantially reducing the costs of a print advertisement. Our results suggest that OTC status is associated with an increase in advertising expenditures and the number and pages of magazine advertisements. A current proposal to reduce disclosure requirements on all DTC advertisements of prescription drugs could have similar effects. Our results also suggest that advertising increase with the introduction of new products and with market competition.

    Youth Smoking, Cigarette Prices, and Anti-Smoking Sentiment

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    In this paper, we develop a new direct measure of state anti-smoking sentiment and merge it with micro data on youth smoking in 1992 and 2000. The empirical results from the cross-sectional models show two consistent patterns: after controlling for differences in state anti-smoking sentiment, the price of cigarettes has a weak and statistically insignificant influence on smoking participation; and state anti-smoking sentiment appears to be a potentially important influence on youth smoking participation. The cross-sectional results are corroborated by results from discrete time hazard models of smoking initiation that include state fixed effects. However, there is evidence of price-responsiveness in the conditional cigarette demand by youth and young adult smokers.

    Superparamagnetic magnetization equation in two dimensions

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    An equation for the dependence of magnetization on magnetic field in the case of two-dimensional (base plane) anisotropy has been derived. The resulting equation is expressed as an infinite series of modified Bessel functions, unlike the elementary function expressions that are applicable to the one-dimensional (axially anisotropic) and three-dimensional (isotropic) cases. Nevertheless, in the low-field limit, the series can be effectively truncated to give an approximate solution, while, in the high-field limit, an alternative expression has been derived which represents the limiting function as the field strength tends to infinity. The resulting expressions can be used to describe the superparamagnetic magnetization and susceptibility as a function of magnetic field in situations where the magnetic moments are constrained to lie in a plane, with no preferred direction within the plane. This can therefore be applied to two-dimensional structures, such as magnetic thin films, where magnetostatic energy confines the moments to the plane of the film, or to three-dimensional structures with planar magnetocrystalline anisotropy

    Normative resistance to responsibility to protect in times of emerging multipolarity: the cases of Brazil and Russia

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    This article assesses the normative resistance to Responsibility to Protect adopted by Brazil and Russia against the backdrop of their international identities and self-assigned roles in a changing global order. Drawing upon the framework of Bloomsfield's norm dynamics role spectrum, it argues that while the ambiguous Russian role regarding this principle represents an example of 'norm antipreneurship', particularities of Brazil's resistance are better grasped by a new category left unaccounted for by this model, which this study portrays as 'contesting entrepreneur'.- (undefined

    Remarks on 2+1 Self-dual Chern-Simons Gravity

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    We study 2+1 Chern-Simons gravity at the classical action level. In particular we rederive the linear combinations of the ``standard'' and ``exotic'' Einstein actions, from the (anti) self-duality of the ``internal'' Lorentzian indices. The relation to a genuine four-dimensional (anti)self-dual topological theory greatly facilitates the analysis and its relation to hyperbolic three-dimensional geometry. Finally a non-abelian vector field ``dual'' action is also obtained.Comment: 16+1 pages, LaTeX file, no figures, clarifications and comments added, typos corrected and one reference adde

    Diluted Networks of Nonlinear Resistors and Fractal Dimensions of Percolation Clusters

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    We study random networks of nonlinear resistors, which obey a generalized Ohm's law, VIrV\sim I^r. Our renormalized field theory, which thrives on an interpretation of the involved Feynman Diagrams as being resistor networks themselves, is presented in detail. By considering distinct values of the nonlinearity r, we calculate several fractal dimensions characterizing percolation clusters. For the dimension associated with the red bonds we show that dred=1/νd_{\scriptsize red} = 1/\nu at least to order {\sl O} (\epsilon^4), with ν\nu being the correlation length exponent, and ϵ=6d\epsilon = 6-d, where d denotes the spatial dimension. This result agrees with a rigorous one by Coniglio. Our result for the chemical distance, d_{\scriptsize min} = 2 - \epsilon /6 - [ 937/588 + 45/49 (\ln 2 -9/10 \ln 3)] (\epsilon /6)^2 + {\sl O} (\epsilon^3) verifies a previous calculation by one of us. For the backbone dimension we find D_B = 2 + \epsilon /21 - 172 \epsilon^2 /9261 + 2 (- 74639 + 22680 \zeta (3))\epsilon^3 /4084101 + {\sl O} (\epsilon^4), where ζ(3)=1.202057...\zeta (3) = 1.202057..., in agreement to second order in ϵ\epsilon with a two-loop calculation by Harris and Lubensky.Comment: 29 pages, 7 figure

    Microscale distribution patterns of terrestrial bryophytes in a subalpine forest: the use of logistic regression as an interpretive tool

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    This study investigated microhabitat relationships of terrestrial bryophytes in a subalpine forest of coastal British Columbia. Substratum affinities were characterized for dominant bryophytes. Logistic regression analysis was used to gain insight into the ecological determinants of fine scale (0.1 m2) bryophyte distribution by examining the predictive relationship between bryophyte species occurrence and localized environmental conditions, as well as the coverage of other bryophytes. The predictive relationships were compared to evaluate the relative importance of environmental factors versus interspecific interactions in structuring bryophyte communities. The results indicate that bryophytes show unique responses in their relationships to environmental conditions and other bryophytes. Positive feedback appears to be an important process among terrestrial bryophytes in subalpine forests

    Analysis with respect to instrumental variables for the exploration of microarray data structures

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    BACKGROUND: Evaluating the importance of the different sources of variations is essential in microarray data experiments. Complex experimental designs generally include various factors structuring the data which should be taken into account. The objective of these experiments is the exploration of some given factors while controlling other factors. RESULTS: We present here a family of methods, the analyses with respect to instrumental variables, which can be easily applied to the particular case of microarray data. An illustrative example of analysis with instrumental variables is given in the case of microarray data investigating the effect of beverage intake on peripheral blood gene expression. This approach is compared to an ANOVA-based gene-by-gene statistical method. CONCLUSION: Instrumental variables analyses provide a simple way to control several sources of variation in a multivariate analysis of microarray data. Due to their flexibility, these methods can be associated with a large range of ordination techniques combined with one or several qualitative and/or quantitative descriptive variables
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