Agricultural tariff rate quotas implementation in the EU 1997-2002; Do developing countries enjoy quota rent?
Tariff rate quotas (TRQs) have been introduced and legitimised as a market access instrument in the Uruguay Round Agreement on Agriculture (URAA). TRQs combine both restriction of imports, and safeguard of current or preferential agricultural trade flows. By restricting the market access through high level tariff beyond the quota, one can imagine that exporters enjoying low level tariff would take share of quota rent. Do developing exporting countries benefit from EU TRQs? Do they enjoy quota rents or guaranteed market access? What should be their interest to defend about TRQs at WTO agricultural negotiations? This article aims to present an analysis of the 87 EU's agricultural TRQs implementation from 1997 to 2002, in order to bring to the fore the effects of such an import instrument for exporting countries in competition on the import market. Some theoretical elements of the economy of TRQs are first presented in order to introduce the empirical work. The database built is then used to interpret EU agricultural TRQs implementation during the period 1997-2002, and the global results in terms of potential total rent that one can theoretically expect from TRQs is detailed by products grouping and export country grouping. A first examination of the database shows that while preference margin is potentially high for TRQs as a whole, potential rent is not so high. Moreover, this potential rent seems to be concentrated on only bananas and sugar, because TRQs are actually binding for those two commodities. A focus on those products indicates that only few exporting countries are susceptible to enjoy this potential rent: Latin American for bananas and ACP for sugar. However that does not signify that TRQs may be eliminated without big losses for exporters: they actually procure guaranteed EU's market shares protected from foreign competition.
Approche graphique du fonctionnement des contingents tarifaires : effets sur l'accès au marché d'importation et le bien-être économique des exportateurs
[eng] This article studies the economics of tariff-rate quotas. We assume the existence of a large importing country and competition for the import market among several suppliers with different levels of competitiveness. We identify eleven theoretical situations according to the rules of quota allocation to exporters, the degree of constraint imposed by the quota, and the relative competitiveness of export supplies. We present a graphical analysis and discuss the effects of tariff-rate quotas on market access and welfare gains for exporters in the eleven cases. [fre] L’article etudie l’economie des contingents tarifaires sous l’hypothese d’un grand pays importateur et en considerant que plusieurs offres d’exportation, aux niveaux de competitivite distincts, se concurrencent sur le marche d’importation. Onze situations theoriques sont identifiees selon le niveau de contrainte impose par le contingent sur les importations, la facon dont le quota est alloue aux exportateurs potentiels et les competitivites relatives des offres en presence. Une representation graphique est developpee pour analyser chacune de ces situations et discuter des effets du contingent tarifaire en termes d’acces au marche d’importation, d’une part, et de bien-etre economique pour les exportateurs qui beneficient de cet instrument, d’autre part.
A bifunctional Cr/Yb/Tm:Ca3Ga2Ge3O12 phosphor with near-infrared long-lasting phosphorescence and upconversion luminescence.
Currently, upconversion nanocrystals and long-lasting phosphorescent particles have attracted extensive research interest for their possible applications as bioimaging probes. However, there are few reports concerning the achievement of both upconversion luminescence of lanthanide ions and long-lasting phosphorescence of transition metal ions in a sole host so far. Herein, we demonstrate a novel calcium gallium germanium garnet (Ca3Ga2Ge3O12) host where lanthanide ions such as Tm(3+)/Yb(3+) and transition metal ions such as Cr(3+) can be easily incorporated through substituting the Ca(2+) and Ga(3+) respectively. This Cr/Yb/Tm:Ca3Ga2Ge3O12 phosphor exhibits both broadband near-infrared long-lasting phosphorescence of Cr(3+) with an afterglow time of more than 7000 s and near-infrared to near-infrared upconversion luminescence of Tm(3+). Impressively, it is evidenced that the addition of Yb(3+)/Tm(3+) into Cr:Ca3Ga2Ge3O12 not only results in Tm(3+) upconversion luminescence but also greatly increases Cr(3+) afterglow time. Based on excitation/emission, three-dimensional thermoluminescence, and time-resolved luminescence spectra, the related long-lasting phosphorescence and upconversion luminescent mechanisms are systematically discussed as well.