Economic Efficiency and Growth: Evidence from Brazil, China, and India

We compare economic efficiencies in Brazil, India, and China, where economic efficiency measures the gap between potential and actual output for a given input combination and technological factor. We use stochastic production frontier models to measure the contributions of factors of production and technology to growth and estimate non-positive error terms that capture production inefficiencies in each country. The results suggest that China and India had relatively inefficient production in the early 1980s but have since improved production efficiency substantially. In the same period, production efficiency in Brazil has declined somewhat from relatively high initial levels and the gap between production efficiency between these countries has narrowed substantially, supporting more rapid growth in China and India relative to Brazil.growth, trade, production

Transmission-Line Analysis of Epsilon-Near-Zero (ENZ)-Filled Narrow Channels

Following our recent interest in metamaterial-based devices supporting resonant tunneling, energy squeezing and supercoupling through narrow waveguide channels and bends, here we analyze the fundamental physical mechanisms behind this phenomenon using a transmission-line model. These theoretical findings extend our theory, allowing us to take fully into account frequency dispersion and losses and revealing the substantial differences between this unique tunneling phenomenon and higher-frequency Fabry-Perot resonances. Moreover, they represent the foundations for other possibilities to realize tunneling through arbitrary waveguide bends, both in E and H planes of polarization, waveguide connections and sharp abruptions and to obtain analogous effects with geometries arguably simpler to realize.Comment: 35 pages, 9 figure

A General Class of Metamaterial Transformation Slabs

In this paper, we apply transformation-based optics to the derivation of a general class of transparent metamaterial slabs. By means of analytical and numerical full-wave studies, we explore their image displacement/formation capabilities, and establish intriguing connections with configurations already known in the literature. Starting from these revisitations, we develop a number of nontrivial extensions, and illustrate their possible applications to the design of perfect radomes, anti-cloaking devices, and focusing devices based on double-positive (possibly nonmagnetic) media. These designs show that such anomalous features may be achieved without necessarily relying on negative-index or strongly resonant metamaterials, suggesting more practical venues for the realization of these devices.Comment: 25 pages, 13 figures; minor changes in the tex

Effect of Re-Wetting Treatment on the Dimensional Changes of Sugar Maple Wood

Air-dry wood samples are often simply re-wetted by direct immersion in order to raise the moisture content above the fiber saturation point. It is assumed that this treatment has no effect on the properties of wood and is equivalent to the green condition. A preliminary study was undertaken here to evaluate the influence of water re-saturation processes on the dimensional changes in sugar maple wood. Matched samples were subjected to three different full-water saturation treatments, from a four-step mild procedure to a one-step drastic procedure. Results showed that the re-wetting process had a significant effect on swelling and shrinkage of sugar maple wood

Effect of Knife Jointing on the Gluing Properties of Wood

Jointing is a common practice required to produce the same cutting circle for all knives mounted in a culterhead of a peripheral knife planer. This practice also is sometimes used wrongly to refresh slightly dulled knives. Initially the jointed land at the cutting edge has a 0 degree clearance angle, which becomes negative with the workpiece motion relative to the cutterhead and as the cutting edge wears. The jointing operation potentially could crush a thin layer of the planed board and affect the wood quality and performance. The gluing properties of sugar maple, red oak, and spruce woods were evaluated using four jointed land widths. A wider jointed land affected the surface quality and resulting gluing shear strength differently depending on anatomical differences of the specific woods. The effect of knife jointing was more pronounced where the moisture content of the samples had fluctuated

The Dutch version of the Child Posttraumatic Cognitions Inventory:validation in a clinical sample and a school sample

With the inclusion of trauma-related cognitions in the DSM-5 criteria for posttraumatic stress disorder (PTSD), the assessment of these cognitions has become essential. Therefore, valid tools for the assessment of these cognitions are warranted

Supralinear and Supramodal Integration of Visual and Tactile Signals in Rats: Psychophysics and Neuronal Mechanisms

To better understand how object recognition can be triggered independently of the sensory channel through which information is acquired, we devised a task in which rats judged the orientation of a raised, black and white grating. They learned to recognize two categories of orientation: 0° ± 45° ("horizontal") and 90° ± 45° ("vertical"). Each trial required a visual (V), a tactile (T), or a visual-tactile (VT) discrimination; VT performance was better than that predicted by optimal linear combination of V and T signals, indicating synergy between sensory channels. We examined posterior parietal cortex (PPC) and uncovered key neuronal correlates of the behavioral findings: PPC carried both graded information about object orientation and categorical information about the rat's upcoming choice; single neurons exhibited identical responses under the three modality conditions. Finally, a linear classifier of neuronal population firing replicated the behavioral findings. Taken together, these findings suggest that PPC is involved in the supramodal processing of shape. Knowledge about objects can be accessed through multiple sensory pathways. Nikbakht et al. find that rats judge object orientation by synergistically combining signals from vision and touch; posterior parietal cortex seems to be involved in the supramodal knowledge of orientation