Did International Trade Become Dirtier in Developing Countries? On the Composition Effect of International Trade on the Environment

Utilizing the world panel dataset for the pollution emission embedded in international trade for the period between 1988 and 2009, we investigated whether the composition of international trade of a country moved away from pollution-intensive industries as its income level rises. The empirical evidence suggests that the income levels of countries are negatively related to export pollution intensity, but we also find that income is negatively related to import pollution intensity. Thus, the composition effect of international trade on the environment is only consistent with the pollution haven hypothesis on the export side, which predicts that developing countries export more of dirtier industries and import more of cleaner industries after trade liberalization. Further investigation reveals that the lower-middle income countries experienced an increase in the pollution emission of exports and a decrease in the pollution emission of imports, whereas the countries in the lowest income group experienced increases in the pollution emission embodied in both exports and imports.Composition effect; Environment; International trade; Pollution emission; Pollution haven hypothesis.

Two-dimensional crystal melting and D4-D2-D0 on toric Calabi-Yau singularities

We construct a two-dimensional crystal melting model which reproduces the BPS index of D2-D0 states bound to a non-compact D4-brane on an arbitrary toric Calabi-Yau singularity. The crystalline structure depends on the toric divisor wrapped by the D4-brane. The molten crystals are in one-to-one correspondence with the torus fixed points of the moduli space of the quiver gauge theory on D-branes. The F- and D-term constraints of the gauge theory are regarded as a generalization of the ADHM constraints on instantons. We also show in several examples that our model is consistent with the wall-crossing formula for the BPS index.Comment: 72 pages, 44 figure

Image-based Basic Verb Learning through Learner-centred and Teacher-centred Approaches —A Case Study on Japanese EFL Junior High School Students

This pilot study made comparisons on image-based basic verb learning through learner and teacher-centred approaches. To this purpose, 121 Japanese EFL junior high school students participated. In a learner-centred activity, they just engaged in a card game in which they were able to pay attention to relationships between situational images and forms of the targeted basic verbs. In a teacher-centred instruction, the participants were explicitly taught how given definitions of another basic verb were motivated semantically from situational-images. Immediately after each treatment, post-tests were administered. A week after each immediate post-test, delayed post-tests were given. Analysis of the results found that only high proficiency learners were capable of image-based basic verb learning through either the card game activity or the explicit instruction alone. Considering the results and a SLA model, the authors concluded that image-based basic verb learning should be implemented through learner-centred activity first, followed by teacher-centred explicit instruction