On the Use of Border Taxes in Developing Countries

Contrary to what is implied by the so called “Wahsington consensus”, Stiglitz (2003) has argued that in the least developed countries border taxes are superior to VAT. However, supported by much respectable research, the IMF and World Bank’s recommend that developing countries substitute VAT for border taxes. The present paper provides an easy to implement parameterised general equilibrium model which may be used as the basis for empirical research, required to reach a consensus opinion within the profession on the issue. The model allows for the fact that different tax systems are associated with different administrative costs, and represents the informal sector as a parameterisation, the CES-UT, of a utility function with explicit representation of the use of time. By means of a quantitative example, it illustrates, on the one hand, that a large informal sector in itself does not justify the use of border taxes, but, on the other hand, when administrative costs of taxation are taken into account, that the size of the informal sector, as claimed as Stiglitz (2003), is indeed important for whether the use of border taxes is desirable or not.Optimal trade policy, VAT, tax-tariff reform, costs of tax administration, informal sector, developing countries

Welfare Effects of Tax and Price Changes Revisited

Dixit’s 1975 paper ‘Welfare Effects of Tax and Price Changes’ cosntitutes a seminal contribution to the theory of tax reform analysis within a second-best general equilibrium framework. The present paper clarifies ambiguities with respect to normalisation which have led to misinterpretation of some Dixit’s analytical results. It proves that a marginal tax reform starting from a proportional tax system will improve social welfare if it increases the supply of labour, whatever the rule of normalisation adopted, and shows that this result provides the key to understanding what determines the optimal system of commodity taxation as reflected in the Corlett and Hague analysis of optimal taxation in an economy with two produced commodities. Recasting work by Deaton (1981b), it generalises, using an alternative definition of the complementarity between consumption and leisure, to an economy with many commodities the insight that the optimal tax system is determined as a trade-off between two objectives : 1) to encourage the supply of labour to the market, and 2) to limit the distorsion of the pattern of consumption of produced commoditie. This insight cannot be illustrated by simulation studies using standard additive separable utility functions. However, extending work of Atkinson and Stern (1080,1981) the paper presents a parameterised utility function with explicit representation of the use of time, the CES-UT, which allows a flexible representation of the relationship between consumption and leisure. This functional form is used to provide a quantitative illustration of the trade-off which defines the optimal tax system and thus desirable directions of tax reform.Public economics, optimal taxation, tax reform, tax simulation, distance functions, CGE models

Constitutive parameter extraction for heated materials

The focus is the determination of the electrical constitutive paramaters of materials with general complex epsilon and mu values at elevated temperatures. Measurement fixtures and techniques are evaluated for frequencies between 8 and 12 GHz using a rectangular waveguide with the sample completely filling the fixture. Three different measurement techniques are evaluated to obtain the necessary measured quantities for parameter extraction. The most desirable technique used two reflection measurements from material samples of different thickness backed with a short. Temperatures up to 600 F were investigated

Household labor and marital quality : perceived partner responsiveness as a buffer for unfair divisions of labor

Perceptions of household labor divisions as unfair are associated with lower marital quality, particularly for women. However, perceived partner responsiveness -- individuals' beliefs about their partner as caring, validating, and understanding to one's core needs and values -- might buffer against the effects of unfair divisions of labor. This study examined perceived partner responsiveness as a moderator of the association between individual's perceptions of fairness of the division of household labor and global marital quality. The sample consisted of married or cohabiting adults from the third wave (2012) of the National Survey of Midlife Development in the United States (MIDUS) study (N = 1923). Hierarchical regression analyses suggested that perceived partner responsiveness did function as a moderator, such that at higher levels of PPR, perceptions of the division of labor as unfair were associated with higher marital quality and lower marital strain. Contrary to hypotheses, results did not differ by gender. These findings suggest the importance of positive relationship processes, such as perceptions of partner responsiveness, as buffers against the negative effects of unfair divisions of labor for couples.Includes bibliographical reference

Magnetic dipole moments in single and coupled split-ring resonators

We examine the role of magnetic dipoles in single and coupled pairs of metallic split-ring resonators by numerically computing their magnitude and examining their relative contributions to the scattering cross section. We demonstrate that magnetic dipoles can strongly influence the scattering cross section along particular directions. It is also found that the magnetic dipole parallel to the incident magnetic field and/or high-order multipoles may play a significant role in the linear response of coupled split-ring resonators.Comment: 7 pages, 3 figures, 1 tabl

Optimal transport: Fast probabilistic approximation with exact solvers.

We propose a simple subsampling scheme for fast randomized approximate computation of optimal transport distances on finite spaces. This scheme operates on a random subset of the full data and can use any exact algorithm as a black-box back-end, including state-of-the-art solvers and entropically penalized versions. It is based on averaging the exact distances between empirical measures generated from independent samples from the original measures and can easily be tuned towards higher accuracy or shorter computation times. To this end, we give non-asymptotic deviation bounds for its accuracy in the case of discrete optimal transport problems. In particular, we show that in many important instances, including images (2D-histograms), the approximation error is independent of the size of the full problem. We present numerical experiments that demonstrate that a very good approximation in typical applications can be obtained in a computation time that is several orders of magnitude smaller than what is required for exact computation of the full problem

Design, theory, and measurement of a polarization insensitive absorber for terahertz imaging

We present the theory, design, and realization of a polarization-insensitive metamaterial absorber for terahertz frequencies. We derive geometrical-independent conditions for effective medium absorbers in general, and for resonant metamaterials specically. Our fabricated design reaches and absorptivity of 78% at 1.145 ThzComment: 6 Pages, 5 figures; figures update

Multi‑physics bi‑directional evolutionary topology optimization on GPU‑architecture

Topology optimization has proven to be viable for use in the preliminary phases of real world design problems. Ultimately, the restricting factor is the computational expense since a multitude of designs need to be considered. This is especially imperative in such fields as aerospace, automotive and biomedical, where the problems involve multiple physical models, typically fluids and structures, requiring excessive computational calculations. One possible solution to this is to implement codes on massively parallel computer architectures, such as graphics processing units (GPUs). The present work investigates the feasibility of a GPU-implemented lattice Boltzmann method for multi-physics topology optimization for the first time. Noticeable differences between the GPU implementation and a central processing unit (CPU) version of the code are observed and the challenges associated with finding feasible solutions in a computational efficient manner are discussed and solved here, for the first time on a multi-physics topology optimization problem. The main goal of this paper is to speed up the topology optimization process for multi-physics problems without restricting the design domain, or sacrificing considerable performance in the objectives. Examples are compared with both standard CPU and various levels of numerical precision GPU codes to better illustrate the advantages and disadvantages of this implementation. A structural and fluid objective topology optimization problem is solved to vary the dependence of the algorithm on the GPU, extending on the previous literature that has only considered structural objectives of non-design dependent load problems. The results of this work indicate some discrepancies between GPU and CPU implementations that have not been seen before in the literature and are imperative to the speed-up of multi-physics topology optimization algorithms using GPUs

Ptychographic X-ray computed tomography of extended colloidal networks in food emulsions

As a main structural level in colloidal food materials, extended colloidal networks are important for texture and rheology. By obtaining the 3D microstructure of the network, macroscopic mechanical properties of the material can be inferred. However, this approach is hampered by the lack of suitable non-destructive 3D imaging techniques with submicron resolution. We present results of quantitative ptychographic X-ray computed tomography applied to a palm kernel oil based oil-in-water emulsion. The measurements were carried out at ambient pressure and temperature. The 3D structure of the extended colloidal network of fat globules was obtained with a resolution of around 300 nm. Through image analysis of the network structure, the fat globule size distribution was computed and compared to previous findings. In further support, the reconstructed electron density values were within 4% of reference values.Comment: 19 pages, 4 figures, to be published in Food Structur

An Unbiased Test for the Bioequivalence Problem

It is shown that the standard two one-sided tests procedure for bioequivalence is a biased test. Better tests exist. In this paper, an unbiased α-level test and other tests which are uniformly more powerful than the two one-sided tests procedure are constructed. Its power can be noticeably larger than that of the α-level two one-sided tests procedure