Trade and Inequality in Developing Countries: An Empirical Assessment

Developing and newly industrialized countries that have experienced the sharpest increases in wage inequality are those whose export shares have shifted towards more skill-intensive goods. We argue that this can be explained by technological catch-up. We develop this insight using a model that features both Ricardian and endowmentsbased comparative advantage. In this model Southern catch-up causes production of the least skill-intensive Northern goods to migrate South (where they become the most skill-intensive Southern goods). This raises wage inequality in both the South and the North. We provide empirical evidence that strongly supports this causal mechanism: Southern catch-up exacerbates Southern inequality by redirecting Southern export shares towards more skill-intensive goodsinternational trade, inequality, Southern catch-up

Twisted Alexander Invariants of Twisted Links

Let L be an oriented (d+1)-component link in the 3-sphere, and let L(q) be the d-component link in a homology 3-sphere that results from performing 1/q-surgery on the last component. Results about the Alexander polynomial and twisted Alexander polynomials of L(q) corresponding to finite-image representations are obtained. The behavior of the invariants as q increases without bound is described.Comment: 21 pages, 6 figure

Stability of levetiracetam oral solution repackaged in oral plastic syringes

Purpose The long-term stability of levetiracetam solution in oral syringes was investigated in order to define a suitable beyond-use date and demonstrate the feasibility of storing prepared syringes for extended periods as an alternative to commercial levetiracetam unit dose cups. Methods Levetiracetam oral solution (100 mg/mL) was drawn into 1- and 10-mL amber polypropylene oral syringes. Triplicate samples of the syringe preparations were stored at refrigeration (2–8 °C) or room temperature (20–25 °C) and evaluated at monthly intervals for up to six months. At each time point, the samples were visually inspected and levetiracetam stability was assessed via pH measurement and high-performance liquid chromatography (HPLC). A short-term forced degradation study was conducted to confirm that the HPLC assay method was stability indicating. Results Over the six-month storage period, there was no significant change in either the visual appearance or pH of any of the levetiracetam samples. The results of serial HPLC assessment indicated that at least 97% of the initial levetiracetam concentration was retained in all samples of 1- and 10-mL oral syringes at both refrigeration and room temperature. Although this study was conducted using a generic product, the stability data obtained may be applied in repackaging decisions regarding other generic formulations of levetiracetam with similar excipient compositions. Conclusion Commercial levetiracetam 100-mg/mL oral solution was stable for up to six months in amber polypropylene oral syringes stored at both refrigeration and room temperature conditions

Twisted Alexander Polynomials and Representation Shifts

For any knot, the following are equivalent. (1) The infinite cyclic cover has uncountably many finite covers; (2) there exists a finite-image representation of the knot group for which the twisted Alexander polynomial vanishes; (3) the knot group admits a finite-image representation such that the image of the fundamental group of an incompressible Seifert surface is a proper subgroup of the image of the commutator subgroup of the knot group.Comment: 7 pages, no figure