Difference frequency generation by quasi-phase matching in periodically intermixed semiconductor superlattice waveguides

Wavelength conversion by difference frequency generation is demonstrated in domain-disordered quasi-phase-matched waveguides. The waveguide structure consisted of a GaAs/AlGaAs superlattice core that was periodically intermixed by ion implantation. For quasi-phase-matching periods of 3.0–3.8 μm, degeneracy pump wavelengths were found by second-harmonic generation experiments for fundamental wavelengths between 1520 and 1620 nm in both type-I and type-II configurations. In the difference frequency generation experiments, output powers up to 8.7 nW were generated for the type-I phase matching interaction and 1.9 nW for the type-II interaction. The conversion bandwidth was measured to be over 100 nm covering the C, L, and U optical communications bands, which agrees with predictions

Tur\'an Graphs, Stability Number, and Fibonacci Index

The Fibonacci index of a graph is the number of its stable sets. This parameter is widely studied and has applications in chemical graph theory. In this paper, we establish tight upper bounds for the Fibonacci index in terms of the stability number and the order of general graphs and connected graphs. Tur\'an graphs frequently appear in extremal graph theory. We show that Tur\'an graphs and a connected variant of them are also extremal for these particular problems.Comment: 11 pages, 3 figure

Macroeconomic impacts of Universal Health Coverage : Synthetic control evidence from Thailand

We study the impact of Universal Health Coverage (UHC) on various macroeconomic outcomes in Thailand using synthetic control methods. Thailand is compared to a weighted average of control countries in terms of aggregate health and economic performance over the period 1995 to 2012. Our results suggest that financial protection in Thailand has improved relative to its synthetic counterfactual. While out-of-pocket payments as a percentage of overall health expenditures decreased by 16.9 percentage points, annual government per capita health spending increased by $78. However, we detect no impact on total health spending per capita nor the share of the government budget allocated to health. We find positive health impacts as captured by reductions in infant and child mortality. The introduction of UHC has had no discernible impact on GDP per capita. Our results complement micro evidence based on within country variation. The counterfactual design implemented here may be used to inform other countries on the causal repercussions and benefits of UHC at the macroeconomic level

Universal health coverage at the macro level: Synthetic control evidence from Thailand

As more and more countries are moving towards Universal Health Coverage (UHC), it is important to understand the macro level or aggregate impacts of such a policy. We use synthetic control methods to study the impact of UHC, introduced in Thailand in 2001, on various macroeconomic and health outcomes. Thailand is compared to a weighted average of control countries in terms of aggregate health financing indicators, aggregate health outcomes and economic performance, over the period 1995 to 2012. Our results suggest that UHC helps alleviate the financial consequences of illnesses. The estimated treatment effect of UHC on out-of-pocket payments as a percentage of overall health expenditures is negative 13 percentage points and its effect on annual government per capita health spending is US$79. We detect a smaller effect of US$ 60.8 on total health spending per capita which appears with a lag. We document positive health effects as captured by reductions in infant and child mortality. We do not find any effect on GDP and the share of the government budget devoted to health. Overall, our results complement micro evidence based on within country variation. The counterfactual design implemented here may be used to inform other countries on the macro level repercussions of UHC

Are women better police officers? Evidence from survey experiments in Uganda

Can the feminization of public services improve quality and lower corruption? The underlying logic of such efforts is the belief that women have higher ethical standards than men. To answer this question, we examine the links between gender and policing practice using data from twelve vignette cases assessed by 600 Ugandan police officers. Our empirical strategy is based on a randomized framing experiment, which is designed to isolate the effect of gender from institutional factors and social norms. We find that the gender of the police officer depicted in the cases and victim gender are not related to the judgment of police malpractice, nor to suggested disciplinary measures. However, respondent gender matters for the reporting of misconduct and the perception of the official institutional policy of the police. Men are stricter when assessing cases along these dimensions. The results indicate that simply feminizing the police force is unlikely to enhance service quality

Adaptation and biomedical transition of people living with HIV to antiretroviral treatment in Burkina Faso

This article examines the adaptation and biomedical transition of people living with HIV (PLHIV) to antiretroviral treatment (ART) in Burkina Faso. The study employs a representat

Nucleation and growth of Pt atomic layer deposition on Al2O3 substrates using (methylcyclopentadienyl)-trimethyl platinum and O2 plasma

The nucleation and growth of Pt atomic layer deposition (ALD) on Al2O3 substrates was studied using (methylcyclopentadienyl)-trimethyl platinum (MeCpPtMe3) and O2 plasma as the reactants. The nucleation of Pt ALD was examined on Al2O3 ALD substrates at 300¿°C using a variety of techniques including spectroscopic ellipsometry, x-ray reflectivity, x-ray photoelectron spectroscopy, and scanning electron microscopy. These techniques revealed that Pt ALD does not nucleate and grow immediately on the Al2O3 ALD substrates. There was negligible Pt ALD during the first 38 ALD cycles. The Pt ALD growth rate then increased substantially during the next 12 ALD cycles. Subsequently, the Pt ALD growth rate reached a steady state linear growth regime for >50 ALD cycles. These measurements suggest that the Pt ALD first forms a number of nanoclusters that grow slowly during the first 38 ALD cycles. These islands then merge during the next 12 cycles and yield a steady state Pt ALD growth rate of ~0.05 nm/cycle for >50 ALD cycles. The Pt ALD film at the onset of the steady state linear growth regime was approximately 2–3 nm in thickness. However, the SEM images of these Pt ALD films appeared corrugated and wormlike. These films also had a density that was only 50–70% of bulk Pt. Film densities that were consistent with bulk Pt were not observed until after >100 ALD cycles when the Pt ALD films appeared much smoother and were 4–5 nm in thickness. The Pt ALD nucleation rate could be enhanced somewhat using different O2 plasma parameters

Agent-Based Simulations with Beliefs and SPARQL-Based Ask-Reply Communication

Abstract. We present the result of extending an agent-based simulation framework by adding a full-fledged model of beliefs and by supporting ask-reply communication with the help of the W3C RDF query language SPARQL. Beliefs are the core component of any cognitive agent archi-tecture. They are also the basis of ask-reply communication between agents, which allows social learning. Our approach supports the concep-tual distinctions between facts and beliefs, and between sincere answers and lies

Area-preserving dynamics of a long slender finger by curvature: a test case for the globally conserved phase ordering

A long and slender finger can serve as a simple ``test bed'' for different phase ordering models. In this work, the globally-conserved, interface-controlled dynamics of a long finger is investigated, analytically and numerically, in two dimensions. An important limit is considered when the finger dynamics are reducible to the area-preserving motion by curvature. A free boundary problem for the finger shape is formulated. An asymptotic perturbation theory is developed that uses the finger aspect ratio as a small parameter. The leading-order approximation is a modification of ``the Mullins finger" (a well-known analytic solution) which width is allowed to slowly vary with time. This time dependence is described, in the leading order, by an exponential law with the characteristic time proportional to the (constant) finger area. The subleading terms of the asymptotic theory are also calculated. Finally, the finger dynamics is investigated numerically, employing the Ginzburg-Landau equation with a global conservation law. The theory is in a very good agreement with the numerical solution.Comment: 8 pages, 4 figures, Latex; corrected typo

Fragment Isospin as a Probe of Heavy-Ion Collisions

Isotope ratios of fragments produced at mid-rapidity in peripheral and central collisions of 114Cd ions with 92Mo and 98Mo target nuclei at E/A = 50 MeV are compared. Neutron-rich isotopes are preferentially produced in central collisions as compared to peripheral collisions. The influence of the size (A), density, N/Z, E*/A, and Eflow/A of the emitting source on the measured isotope ratios was explored by comparison with a statistical model (SMM). The mid-rapidity region associated with peripheral collisions does not appear to be neutron-enriched relative to central collisions.Comment: 12 pages including figure