Quantifying the impact of technical barriers to trade : a framework for analysis

There has been increasing use of technical regulations as instruments of commercial policy in the context of multilateral, regional, and global trade. These nontariff barriers are of special concern to developing countries, which may bear additional costs in meeting mandatory standards. Many industrial and developing countries express frustration with regulations that vary across their export markets, require duplicative conformity procedures, and are continually revised to exclude imports. The authors provide a comprehensive overview of the policy debate and methodological issues surrounding product standards and technical barriers to trade. They begin with a review of the policy context driving demand for empirical analysis of standards in trade, then provide an analytical overview of the role of standards and their relationship to trade. They then review methodological approaches that have been used to analyze standards and theirimpact on trade. Their main interest lies in advancing techniques that are practical and may be fruitfully extended to the empirical analysis of regulations and trade. They discuss concrete steps that could be taken to move forward a practical, policy-relevant program of empirical research. Such steps would include: a) administering firm-level surveys in developing countries; b) devising methods for assessing how much standards restrict trade; and c) establishing econometric approaches that could be applied to survey and microeconomic data, to improve understanding of the role of standards in exports.Environmental Economics&Policies,Economic Theory&Research,TF054105-DONOR FUNDED OPERATION ADMINISTRATION FEE INCOME AND EXPENSE ACCOUNT,Trade and Services,Trade and Regional Integration

The cost of compliance with product standards for firms in developing countries: an econometric study

Standards and technical regulations exist to protect consumer safety or to achieve other goals, such as ensuring the interoperability of telecommunications systems, for example. Standards and technical regulations can, however, raise substantially both start-up and production costs for firms. Maskus, Otsuki, and Wilson develop econometric models to provide the first estimates of the incremental production costs for firms in developing nations in conforming to standards imposed by major importing countries. They use firm-level data generated from 16 developing countries in the World Bank Technical Barriers to Trade (TBT) Survey Database. Their findings indicate that standards do increase short-run production costs by requiring additional inputs of labor and capital. A 1 percent increase in investment to meet compliance costs in importing countries raises variable production costs by between 0.06 and 0.13 percent, a statistically significant increase. The authors also find that the fixed costs of compliance are nontrivial-approximately $425,000 per firm, or about 4.7 percent of value added on average. The results may be interpreted as one indication of the extent to which standards and technical regulations might constitute barriers to trade. While the relative impact on costs of compliance is relatively small, these costs can be decisive factors driving export success for companies. In this context, there is scope for considering that the costs associated with more limited exports to countries with import regulations may not conform to World Trade Organization rules encouraging harmonization of regulations to international standards, for example. Policy solutions then might be sought by identifying the extent to which subsidies or public support programs are needed to offset the cost disadvantage that arises from nonharmonized technical regulations.Environmental Economics&Policies,Economic Theory&Research,Health Economics&Finance,Administrative&Regulatory Law,Science Education

Self-Consistent Perturbation Theory for Thermodynamics of Magnetic Impurity Systems

Integral equations for thermodynamic quantities are derived in the framework of the non-crossing approximation (NCA). Entropy and specific heat of 4f contribution are calculated without numerical differentiations of thermodynamic potential. The formulation is applied to systems such as PrFe4P12 with singlet-triplet crystalline electric field (CEF) levels.Comment: 3 pages, 2 figures, proc. ASR-WYP-2005 (JAERI

Electronic Orders Induced by Kondo Effect in Non-Kramers f-Electron Systems

This paper clarifies the microscopic nature of the staggered scalar order, which is specific to even number of f electrons per site. In such systems, crystalline electric field (CEF) can make a singlet ground state. As exchange interaction with conduction electrons increases, the CEF singlet at each site gives way to Kondo singlets. The collective Kondo singlets are identified with itinerant states that form energy bands. Near the boundary of itinerant and localized states, a new type of electronic order appears with staggered Kondo and CEF singlets. We present a phenomenological three-state model that qualitatively reproduces the characteristic phase diagram, which have been obtained numerically with use of the continuous-time quantum Monte Carlo combined with the dynamical mean-field theory. The scalar order observed in PrFe_4P_{12} is ascribed to this staggered order accompanying charge density wave (CDW) of conduction electrons. Accurate photoemission and tunneling spectroscopy should be able to probe sharp peaks below and above the Fermi level in the ordered phase.Comment: 7 pages, 8 figure

Conservation in two-particle self-consistent extensions of dynamical-mean-field-theory

Extensions of dynamical-mean-field-theory (DMFT) make use of quantum impurity models as non-perturbative and exactly solvable reference systems which are essential to treat the strong electronic correlations. Through the introduction of retarded interactions on the impurity, these approximations can be made two-particle self-consistent. This is of interest for the Hubbard model, because it allows to suppress the antiferromagnetic phase transition in two-dimensions in accordance with the Mermin-Wagner theorem, and to include the effects of bosonic fluctuations. For a physically sound description of the latter, the approximation should be conserving. In this paper we show that the mutual requirements of two-particle self-consistency and conservation lead to fundamental problems. For an approximation that is two-particle self-consistent in the charge- and longitudinal spin channel, the double occupancy of the lattice and the impurity are no longer consistent when computed from single-particle properties. For the case of self-consistency in the charge- and longitudinal as well as transversal spin channels, these requirements are even mutually exclusive so that no conserving approximation can exist. We illustrate these findings for a two-particle self-consistent and conserving DMFT approximation.Comment: 17 pages, 9 figure

Microscopic Mechanism for Staggered Scalar Order in PrFe4P12

A microscopic model is proposed for the scalar order in PrFe4P12 where f2 crystalline electric field (CEF) singlet and triplet states interact with two conduction bands. By combining the dynamical mean-field theory and the continuous-time quantum Monte Carlo, we obtain an electronic order with staggered Kondo and CEF singlets with the total conduction number being unity per site. The ground state becomes semimetallic provided that the two conduction bands have different occupation numbers. This model naturally explains experimentally observed properties in the ordered phase of PrFe4P12 such as the scalar order parameter, temperature dependence of the resistivity, field-induced staggered moment, and inelastic features in neutron scattering. The Kondo effect plays an essential role for ordering, in strong contrast with ordinary magnetic orders by the RKKY interaction.Comment: 4 pages, 4figure

Electronic Order with Staggered Kondo and Crystalline Electric Field Singlets

Novel electronic order is found theoretically for a system where even number of localized electrons per site are coupled with conduction electrons. For precise quantitative study, a variant of the Kondo lattice model is taken with crystalline electric field (CEF) singlet and triplet states for each site. Using the dynamical mean-field theory combined with the continuous-time quantum Monte Carlo method, a staggered order with alternating Kondo and CEF singlets is identified for a case with one conduction electron per site being distributed in two conduction bands each of which is quarter-filled. This electronic order accompanies a charge density wave (CDW) of conduction electrons that accumulate more on Kondo-singlet sites than on CEF-singlet sites. Possible relevance of the present order to the scalar order in PrFe$_4$P$_{12}$ is discussed.Comment: 11 pages, 17 figure

A newly discovered neural stem cell population is generated by the optic lobe neuroepithelium during embryogenesis in Drosophila melanogaster.

Neural stem cells must balance symmetric and asymmetric cell divisions to generate a functioning brain of the correct size. In both the developing Drosophila visual system and mammalian cerebral cortex, symmetrically dividing neuroepithelial cells transform gradually into asymmetrically dividing progenitors that generate neurons and glia. As a result, it has been widely accepted that stem cells in these tissues switch from a symmetric, expansive phase of cell divisions to a later neurogenic phase of cell divisions. In the Drosophila optic lobe, this switch is thought to occur during larval development. However, we have found that neuroepithelial cells start to produce neuroblasts during embryonic development, demonstrating a much earlier role for neuroblasts in the developing visual system. These neuroblasts undergo neurogenic divisions, enter quiescence and are retained post-embryonically, together with neuroepithelial cells. Later in development, neuroepithelial cells undergo further cell divisions before transforming into larval neuroblasts. Our results demonstrate that the optic lobe neuroepithelium gives rise to neurons and glia over 60 h earlier than was thought previously.Royal Society Darwin Trust Research Professorship and 357 Wellcome Trust Senior Investigator Award 103792 to A.H.B. and Wellcome Trust PhD 358 Studentships 102454, to A.E.H., and 097423 to L.O. A.H.B acknowledges core funding to 359 The Gurdon Institute from the Wellcome Trust (092096) and CRUK (C6946/A14492

General relativistic effects on neutrino-driven wind from young, hot neutron star and the r-process nucleosynthesis

Neutrino-driven wind from young hot neutron star, which is formed by supernova explosion, is the most promising candidate site for r-process nucleosynthesis. We study general relativistic effects on this wind in Schwarzschild geometry in order to look for suitable conditions for a successful r-process nucleosynthesis. It is quantitatively discussed that the general relativistic effects play a significant role in increasing entropy and decreasing dynamic time scale of the neutrino-driven wind. Exploring wide parameter region which determines the expansion dynamics of the wind, we find interesting physical conditions which lead to successful r-process nucleosynthesis. The conditions which we found realize in the neutrino-driven wind with very short dynamic time scale $\tau_{\rm dyn} \sim 6$ ms and relatively low entropy $S \sim 140$. We carry out the $\alpha$-process and r-process nucleosynthesis calculation on these conditions by the use of our single network code including over 3000 isotopes, and confirm quantitatively that the second and third r-process abundance peaks are produced in the neutrino-driven wind.Comment: Accepted for publication in Ap