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Keywords:Autoregressive distributed lag (ARDL) approach Economic growth Error correction model US air travel and freight demand a b s t r a c t This paper examines the short-and long-run effects of economic growth and market shocks (e.g., 9/11 terrorist attacks, Iraq war, SARS epidemic, and 2008 financial crisis) on air passenger and freight services using an autoregressive distributed lag (ARDL) approach to cointegration. Results show that, in the longrun, both air passenger and freight services tend to increase with economic growth. In the short-run, however, only air passenger service is responsive to economic growth. Finally, only the 9/11 terrorist attacks and the SARS have detrimental effects on air passenger demand both in the short-and long-run, and in the long-run, respectively. However, these market shocks are found to have little impact on air freight demand.

Cost‐effective disease control on the dairy farm can enhance productivity and subsequently profitability. Previous economic studies on animal disease have focused on production losses and evaluation of disease eradication programs and have provided little guidance on the optimal prevention action. This paper presents a theoretical model on the economics of livestock disease and develops an empirical model to determine the optimal set of control strategies for four production‐limiting cattle diseases: bovine viral diarrhea (BVD), enzootic bovine leukosis (EBL), Johne's Disease (JD) and neosporosis. Control functions indicating the prevalence of infection with each of the four diseases for each of the 10 strategies are estimated. The optimal strategies that minimize total disease cost (direct production losses and control expenditures) are provided for each disease on the basis of farm survey results from the maritime provinces. The results emphasize the importance of introduction checks before new animals enter the herd and adequate vaccination protection as cost‐effective control strategies. Lutter contre la maladie d'une manière rentable dans les élevages de bovins laitiers peut déboucher sur un meilleur rendement et des profits plus élevés. Les études économiques antérieures s'intéressant à cet aspect portaient essentiellement sur les pertes de production et l'évaluation des programmes d'éradication. Elles donnaient peu d'indications sur la solution idéale au niveau de la prévention. Cet article présente un modèle théorique de l'économique des maladies du bétail et aboutit à un modèle empirique permettant d'établir le jeu optimal de moyens pour lutter contre quatre maladies réduisant la production animale : la diarrhée à virus des bovins (DVB), la leucose bovine enzootique (LBE), la paratuberculose et la néosporose. Les auteurs estiment les fonctions qui indiquent la prévalence d'une infection pour chacune des quatre maladies retenues, dans le cadre des dix stratégies examinées. Ensuite, ils présentent les meilleures stratégies, à savoir celles qui minimisent le coût total de la maladie (pertes de production directes et dépenses associées à la lutte contre la maladie), pour chaque maladie en fonction des résultats d'un sondage auprès des éleveurs des provinces de l'Atlantique. Tout indique que les méthodes de lutte les plus rentables sont l'examen de l'animal avant son addition au troupeau et une vaccination qui protègera les bêtes de manière adéquate.

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A number of states in the United States have laws restricting drivers from using cellphones. Using state-level panel data, we examined the effect of cellphone laws on fatal crashes in the United States between 2000 and 2010. Our results show that there is insufficient power to detect a reduction in overall fatal crash rates scaled by vehicle miles and population estimates. Cellphone bans, however, have significantly reduced the fatal crash rates of drivers in certain age cohorts. The effect was most pronounced among drivers between 18 and 34 years of age. We did not find any significant effect among drivers in the 55 and older age cohorts.

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