Apoplastic diffusion barriers in Arabidopsis.

During the development of Arabidopsis and other land plants, diffusion barriers are formed in the apoplast of specialized tissues within a variety of plant organs. While the cuticle of the epidermis is the primary diffusion barrier in the shoot, the Casparian strips and suberin lamellae of the endodermis and the periderm represent the diffusion barriers in the root. Different classes of molecules contribute to the formation of extracellular diffusion barriers in an organ- and tissue-specific manner. Cutin and wax are the major components of the cuticle, lignin forms the early Casparian strip, and suberin is deposited in the stage II endodermis and the periderm. The current status of our understanding of the relationships between the chemical structure, ultrastructure and physiological functions of plant diffusion barriers is discussed. Specific aspects of the synthesis of diffusion barrier components and protocols that can be used for the assessment of barrier function and important barrier properties are also presented.

Technology diffusion and the spatial distribution of wages in the US

What explains the spatial distribution of wages across US counties? I find that two of the most important factors are spatial technology diffusion and externalities due to the aggregate scale of production. One empirical finding supporting the importance of spatial technology diffusion is that average wages in a county decrease with the average level of schooling in neighboring counties when employment in the county and average wages in neighboring counties are held constant. All empirical results are obtained using anovel instrument for (endogenous) employment at the county-leveland take into account other factors (e.g. productivity-differencesacross states, climate) that may determine wages.

Optimal monetary and fiscal policy in a currency union

We lay out a tractable model for fiscal and monetary policy analysis in a currency union, and study its implications for the optimal design of such policies. Monetary policy is conducted by a common central bank, which sets the interest rate for the union as a whole. Fiscal policy is implemented at the countrylevel, through the choice of government spending. The model incorporates country-specific shocks and nominal rigidities. Under our assumptions, the optimal cooperative policy arrangement requires that inflation be stabilized at the union level by the common central bank, while fiscal policy is used by each country for stabilization purposes. By contrast, when the fiscal authorities act in a non-coordinated way, their joint actions lead to a suboptimal outcome, and make the common central bank face a trade-off between inflation and output gap stabilization at the union level.

Promoção da língua portuguesa no mundo : hipótese de modelo estratégico

De successifs Gouvernements du Portugal, Organisations du Gouvernement Portugais et ses représentants légitimes, non mal de fois, s’affolent à associer la Langue Portugaise non seulement à l’identité Nationale mais aussi comme un moyen de reconnaissance internationale du pays, liée à une vision plus élargie reliée au concept géolinguistique et géopolitique de Lusophonie. Un concept particulièrement important et opératif qu’il est assimilé à l’image d’autres langues de présence globale ou, du moins, comme des langues de communication international intercontinental – comme les pays Anglophones, Spanophones et Francophones -. Le but, est celui de promouvoir l’usage international de la langue portugaise aussi que le développement économique et social des huit pays rassemblés à la Communauté des Pays de Langue Portugaise (CPLP). Cette étude, essaye de trouver les relations entre le discours officiel diffusé et les programmes de chaque Gouvernement depuis 1974. Une recherche sur la promotion, diffusion et/ou défense de la langue portugaise soit en temps que PLE (Portugais Langue Étrangère), soit en temps que dans le domaine de l’usage de la Langue Portugaise dans les différents Forums Internationaux dont le Portugal et les autres pays de langue portugaise font partie. Les discours et les documents officiels nous présentent toujours la promotion et diffusion de la langue comme une priorité, un impératif national, il est donc aussi impératif de confronter tous ces mots, dits et écrits, avec la réalité de l’action politique, voir, la politique de la langue effectivement mise en place, par les successifs gouvernements.

Introducing a first AIDS vaccine in Switzerland: a Policy Delphi analysis.

This preliminary exploration was limited by a number of factors. The format of the study has necessarily induced some form of selection bias of the panelists, because of the complexity of some questions, and the time required to complete the questionnaires. Several issues have not been addressed. One example could be the response to HIV infection occurring in a vaccinee. The study also did not address the difficulties related to the licensing of the vaccine. Indeed, the proposed scenario assumed that the vaccine had been registered as a starting point for the analysis. Finally, it has not been possible to conduct a sensitivity analysis, in order to evaluate how the responses would have been modified if some important characteristics of the vaccine had been modified.Very diverse evaluations were given in response to questions related with attitudes and perception of AIDS and AIDS vaccine. The possibility that vaccine availability or usage can be associated with an increased frequency in risky behaviors was spontaneously mentioned by half of the panelists. The estimation of the proportion of persons at highest risk who would choose to use this vaccine also indicated a high degree of uncertainty. This study offers important lessons. According to a broad and diverse panel of individuals, an incompletely effective AIDS vaccine would result in an additional level of complexity for the AIDS prevention strategy, rather than a simplification. The use of such a vaccine would have to be coupled with counselling. This implies a sustained emphasis on the recommendations which have been central to the STOP AIDS campaigns until now. In addition, consensual issues, as well as other issues more likely to be controversial have been identified. This should greatly help focusing the work of any committee designated to develop and implement a vaccination policy if an AIDS vaccine became available. Finally, our experience with the Policy Delphi indicates that this mode of structured communication could be usefully applied to other public health issues presenting a high visibility as well as a complex relationship with public perception.

Research joint ventures and optimal R&D policy with asymmetric information

When to allow Research Joint Ventures (RJVs) or not is an importantinstrument in the development of an optimal R&D policy. Theregulator, however, is unlikely to know all the relevant informationto regulate R&D optimally. The extent to which there existappropriability problems between the firms is one such variable thatis private information to the firms in the industry. In a duopolysetting we analyze the characteristics of a second-best R&D policywhere the government can either allow RJVs or not and give lump-sumsubsidies to the parties involved. The second-best R&D policy withoutsubsidies will either block some welfare improving RJVs or allow somewelfare reducing ones. With lump-sum subsidies, the second-best policytrades off the expected subsidy cost with allowing welfare decreasingRJVs or blocking welfare increasing ones.

Pharmaceutical generics, vertical product differentiation and public policy

This paper studies oligopolistic competition in off-patent pharmaceuticalmarkets using a vertical product differentiation model. This model canexplain the observation that countries with stronger regulations havesmaller generic market shares. It can also explain the differences inobserved regulatory regimes. Stronger regulation may be due to a higherproportion of production that is done by foreign firms. Finally, a closelyrelated model can account for the observed increase in prices by patentowners after entry of generic producers.

Endogenous policy leads to inefficient risk sharing

We analyze risk sharing and fiscal spending in a two-region model withcomplete markets. Fiscal policy determines tax rates for each state ofnature. When fiscal policy is decentralized, it can be used to affect prices of securities. To manipulate prices to their beneffit, regionschoose pro-cyclical fiscal spending. This leads to incomplete risk sharing,despite the existence of complete markets and the absence of aggregaterisk. When a fiscal union centralizes fiscal policy, securities pricescan no longer be manipulated and complete risk sharing ensues. If regionsare homogeneous, median income residents of both regions prefer the fiscalunion. If they are heterogeneous, the median resident of the rich regionprefers the decentralized setting.

Monetary policy shocks and transmission in Italy: A VAR analysis

This paper provides updated empirical evidence about the real and nominal effects of monetary policy in Italy, by using structural VAR analysis. We discuss different empirical approaches that have been used in order to identify monetary policy exogenous shocks. We argue that the data support the view that the Bank of Italy, at least in the recent past, has been targeting the rate on overnight interbank loans. Therefore, we interpret shocks to the overnight rate as purely exogenous monetary policy shocks and study how different macroeconomic variables react to such shocks.

Optimal bail out policy, conditionality and constructive ambiguity

This paper addresses the issue of the optimal behaviour of the Lender of Last Resort (LOLR) in its microeconomic role regarding individual financial institutions in distress. It has been argued that the LOLR should not intervene at the microeconomic level and let any defaulting institution face the market discipline, as it will be confronted with the consequences of the risks it has taken. By considering a simple costbenefit analysis we show that this position may lack a sufficient foundation. We establish that, instead, uder reasonable assumptions, the optimal policy has to be conditional on the amount of uninsured debt issued by the defaulting bank. Yet in equilibrium, because the rescue policy is costly, the LOLR will not rescue all the banks that fulfill the uninsured debt requirement condition, but will follow a mixed strategy. This we interpret as the confirmation of the "creative ambiguity" principle, perfectly in line with the central bankers claim that it is efficient for them to have discretion in lending to individual institutions. Alternatively, in other cases, when the social cost of a bank's bankruptcy is too high, it is optimal for the LOLR to bail out the insititution, and this gives support to the "too big to fail" policy.

Economic booms, trade deficits and economic policy

Many economic booms have been accompanied by realexchange rate appreciations, large trade defcits -whichhave sometimes persisted after the return to the initialexchange rate parity- and a deteriorating traded sector.Those circumstances have typically raised the questionof the de-sirability of some stabilization policy. We show that the dynamics induced by an expectedproductivity shock in an economy where the capital stockis non-mobile across sectors, match those circumstances.Furthermore, we obtain that credit market imperfectionstend to exacerbate trade deficits, and to cause aninefficient capacity reduction in the traded sector.Some stabilization policies are explored.

Monetary policy in the Euro area: Lessons from 5 years of ECB and implications for Turkey

We examine monetary policy in the Euro area from both theoretical and empirical perspectives. We discuss what theory tells us the strategy of Central banks should be and contrasts it with the one employed by the ECB. We review accomplishments (and failures) of monetary policy in the Euro area and suggest changes that would increase the correlation between words and actions; streamline the understanding that markets have of the policy process; and anchor expectation formation more strongly. We examine the transmission of monetary policy shocks in the Euro area and in some potential member countries and try to infer the likely effects occurring when Turkey joins the EU first and the Euro area later. Much of the analysis here warns against having too high expectations of the economic gains that membership to the EU and Euro club will produce.

The adverse effects of environmental policy in green markets

We model green markets in which purchasers, either firms orconsumers, have higher willingness-to-pay for lesspolluting goods. The effectiveness of pollution reductionpolicies is examined in a duopoly setting. We show thatduopolists' strategic behaviour may increase pollutionlevels. Maximum emission standards, commonly used in greenmarkets, improve the environmental features of products.Nonetheless, overall pollution levels will rise becausegovernment regulation also affects market shares and bootsfirms' sales. Consequently, social welfare may be reduced.We also explore the effects of technological subsidies andproduct charges, including differentiation of charges.