Electronic structure of an electron on the gyroid surface, a helical labyrinth

Previously reported formulation for electrons on curved periodic surfaces is used to analyze the band structure of an electron bound on the gyroid surface (the only triply-periodic minimal surface that has screw axes). We find that an effect of the helical structure appears as the bands multiply sticking together on the Brillouin zone boundaries. We elaborate how the band sticking is lifted when the helical and inversion symmetries of the structure are degraded. We find from this that the symmetries give rise to prominent peaks in the density of states.Comment: RevTeX, 4 pages, 6 figure

Recessions and Financial Disruptions in Emerging Markets: A Bird´s Eye View.

This paper provides an overview of the implications of recession and financial disruption episodes in emerging markets. We report three major findings. First, compared to advanced countries, recessions and financial disruptions in emerging markets are often more costly. Second, recessions associated with financial disruption episodes, such as credit crunches, equity price busts and financial crises, tend to be deeper than other recessions in emerging markets. Third, the temporal dynamics of macroeconomic and financial variables around these episodes in emerging markets are different than those in advanced countries. In light of these broad observations, the paper provides a review of recessions and financial market disruptions in Chile

Does Openness to International Financial Flows Contribute to Productivity Growth?

Economic theory has identified a number of channels through which openness to international financial flows could raise productivity growth. However, while there is a vast empirical literature analyzing the impact of financial openness on output growth, far less attention has been paid to its effects on productivity growth. This paper provides a comprehensive analysis of the relationship between financial openness and total factor productivity (TFP) growth using an extensive dataset that includes various measures of productivity and financial openness for a large sample of countries. We find that de jure capital account openness has a robust positive effect on TFP growth. The effect of de facto financial integration on TFP growth is less clear, but this masks an important and novel result. We find strong evidence that FDI and portfolio equity liabilities boost TFP growth while external debt is actually negatively correlated with TFP growth. The negative relationship between external debt liabilities and TFP growth is attenuated in economies with higher levels of financial development and better institutions.foreign direct investment, external assets and liabilities, capital flows, capital account liberalization, financial openness, portfolio equity, debt, total factor productivity

Using media to improve the informed consent process for youth undergoing pediatric endoscopy and their parents.

Background and study aims Youth undergoing pediatric endoscopic procedures and their parents demonstrate suboptimal comprehension of the informed consent (IC) process. We developed informational videos discussing key IC elements for pediatric endoscopy and evaluated their effects on youth and parental comprehension of the IC process. Patients and methods A randomized controlled trial of the video intervention was performed among youth undergoing endoscopy and their parents at an academic children's hospital. Randomization occurred at the time of enrollment using permutated blocks. Following the IC process with the proceduralist, subjects underwent structured interviews to assess IC comprehension. An Informed Consent Overall Score (ICOS: range 0 - 4) for comprehension was calculated. Results Seventy-seven pairs of children and their parents participated. Intervention recipients (N = 37 pairs) demonstrated higher ICOS scores as compared to control counterparts (mean (standard deviation): 3.6 (0.7) v. 2.9 (0.9), intervention v. control parents, P < 0.0001 and 2.7 (1.1) v. 1.7 (1.1), intervention v. control youth, P < 0.0001). Conclusions A media intervention addressing key elements of the IC process for pediatric endoscopy was effective in improving comprehension of IC for youth undergoing endoscopic procedures and their parents

Growth and Volatility in an Era of Globalization

We extend the analysis in Kose, Prasad, and Terrones (2005) to provide a comprehensive examination of the cross-sectional relationship between growth and macroeconomic volatility over the past four decades. We also document that while there has generally been a negative relationship between volatility and growth during this period, the nature of this relationship has been changing over time and across different country groups. In particular, we detect major shifts in this relationship after trade and financial liberalizations. In addition, our results show that volatility stemming from the main components of domestic demand is negatively associated with economic growth. Copyright 2005, International Monetary Fund

Electronic properties of curved graphene sheets

A model is proposed to study the electronic structure of slightly curved graphene sheets with an arbitrary number of pentagon-heptagon pairs and Stone-Wales defects based on a cosmological analogy. The disorder induced by curvature produces characteristic patterns in the local density of states that can be observed in scanning tunnel and transmission electron microscopy.Comment: Corrected versio

Electron orbital valves made of multiply connected armchair carbon nanotubes with mirror-reflection symmetry: tight-binding study

Using the tight-binding method and the Landauer-B\"{u}ttiker conductance formalism, we demonstrate that a multiply connected armchair carbon nanotube with a mirror-reflection symmetry can sustain an electron current of the $\pi$-bonding orbital while suppress that of the $\pi$-antibonding orbital over a certain energy range. Accordingly, the system behaves like an electron orbital valve and may be used as a scanning tunneling microscope to probe pairing symmetry in d-wave superconductors or even orbital ordering in solids which is believed to occur in some transition-metal oxides.Comment: 4 figures, 12 page

Intrinsic carrier mobility of multi-layered MoS2_2 field-effect transistors on SiO2_2

By fabricating and characterizing multi-layered MoS$_2$-based field-effect transistors (FETs) in a four terminal configuration, we demonstrate that the two terminal-configurations tend to underestimate the carrier mobility $\mu$ due to the Schottky barriers at the contacts. For a back-gated two-terminal configuration we observe mobilities as high as 125 cm$^2$V$^{-1}$s$^{-1}$ which is considerably smaller than 306.5 cm$^2$V$^{-1}$s$^{-1}$ as extracted from the same device when using a four-terminal configuration. This indicates that the intrinsic mobility of MoS$_2$ on SiO$_2$ is significantly larger than the values previously reported, and provides a quantitative method to evaluate the charge transport through the contacts.Comment: 8 pages, 5 figures, typos fixed, and references update

How does financial globalization affect risk sharing? Patterns and channels

In theory, one of the main benefits of financial globalization is that it should allow for more efficient international risk sharing. In this paper, we provide a comprehensive empirical evaluation of the patterns of risk sharing among different groups of countries and examine how international financial integration has affected the evolution of risk sharing patterns. Using a variety of empirical techniques, we conclude that there is at best a modest degree of international risk sharing, and certainly nowhere near the levels predicted by theory. In addition, only industrial countries have attained better risk sharing outcomes during the recent period of globalization. Developing countries have, by and large, been shut out of this benefit. The most interesting result is that even emerging market economies, which have witnessed large increases in cross-border capital flows, have seen little change in their ability to share risk. We find that the composition of flows may help explain why emerging markets have not been able to realize this presumed benefit of financial globalization. In particular, our results suggest that portfolio debt, which has dominated the external liability stocks of most emerging markets until recently, is not conducive to risk sharing