Which Osteotomy for Osteonecrosis of the Femoral Head and Which Patient for the Osteotomy?

Transtrochanteric curved varus osteotomy (TCVO) and transtrochanteric rotational osteotomy (TRO) are joint-preserving procedures for osteonecrosis of the femoral head. The purpose of this review is to provide up-to-date guidelines for the osteotomies. One retrospective comparison revealed that TCVO has shorter operation time, less bleeding, lower incidence of osteophyte formation, and lower rate of secondary collapse. To obtain successful results of the osteotomy, the patient should be younger than 40 years and should have a body mass index of less than 24 kg/m2. The osteotomy should be performed in early stages of femoral head osteonecrosis before marked collapse of the femoral head. The patient should have a medium-size lesion and an enough viable bone to restore the intact articular surface and subchondral bone in the weight-bearing area

Technical Efficiency in the Iron and Steel Industry: A Stochastic Frontier Approach

In this paper we examine the technical efficiency of firms in the iron and steel industry and try to identify the factors contributing to the industry's efficiency growth, using a time-varying stochastic frontier model. Based on our findings, which pertain to 52 iron and steel firms over the period of 1978-1997, POSCO and Nippon Steel were the most efficient firms, with their production, on average, exceeding 95 percent of their potential output. Our findings also shed light on possible sources of efficiency growth in the industry. If a firm is government-owned, its privatization is likely to improve its technical efficiency to a great extent. A firm's technical efficiency also tends to be positively related to its production level as measured by a share of the total world production of crude steel. Another important source of efficiency growth identified by our empirical findings is adoption of new technologies and equipment. Our findings clearly indicate that continued efforts to update technologies and equipment are critical in pursuit of efficiency in the iron and steel industry.

The United States - Korea Free Trade Agreement: Path to Common Economic Prosperity or False Promise?

The U.S.-Korea Free Trade Agreement, currently awaiting ratification in the legislatures of both countries, is known to be the most significant bilateral trade agreement for the United States since the conclusion of the North America Free Trade Agreement (NAFTA) in 1993 and for Korea since the initiation of the FTA drive in 2003. Both governments have promoted the U.S.-Korea FTA as the trade agreement that will enhance trade between the two countries and promote economic prosperity. The article critically reviews the inherent features of the U.S.-Korea FTA and examines whether the FTA is expected to promote the promised economic prosperity for both countries. The article also discusses prospects and impacts of the FTA on creating even larger free trade agreements between East Asia and North America and between East Asia and Europe

A Portrait of Emotion: Empowering Self-Expression through AI-Generated Art

We investigated the potential and limitations of generative artificial intelligence (AI) in reflecting the authors' cognitive processes through creative expression. The focus is on the AI-generated artwork's ability to understand human intent (alignment) and visually represent emotions based on criteria such as creativity, aesthetic, novelty, amusement, and depth. Results show a preference for images based on the descriptions of the authors' emotions over the main events. We also found that images that overrepresent specific elements or stereotypes negatively impact AI alignment. Our findings suggest that AI could facilitate creativity and the self-expression of emotions. Our research framework with generative AIs can help design AI-based interventions in related fields (e.g., mental health education, therapy, and counseling).Comment: Accepted CogSci 202

Two-dimensional heterogeneous photonic bandedge laser

We proposed and realized a two-dimensional (2D) photonic bandedge laser surrounded by the photonic bandgap. The heterogeneous photonic crystal structure consists of two triangular lattices of the same lattice constant with different air hole radii. The photonic crystal laser was realized by room-temperature optical pumping of air-bridge slabs of InGaAsP quantum wells emitting at 1.55 micrometer. The lasing mode was identified from its spectral positions and polarization directions. A low threshold incident pump power of 0.24mW was achieved. The measured characteristics of the photonic crystal lasers closely agree with the results of real space and Fourier space calculations based on the finite-difference time-domain method.Comment: 14 pages, 4 figure

New time-scale criteria for model simplification of bio-reaction systems

<p>Abstract</p> <p>Background</p> <p>Quasi-steady state approximation (QSSA) based on time-scale analysis is known to be an effective method for simplifying metabolic reaction system, but the conventional analysis becomes time-consuming and tedious when the system is large. Although there are automatic methods, they are based on eigenvalue calculations of the Jacobian matrix and on linear transformations, which have a high computation cost. A more efficient estimation approach is necessary for complex systems.</p> <p>Results</p> <p>This work derived new time-scale factor by focusing on the problem structure. By mathematically reasoning the balancing behavior of fast species, new time-scale criteria were derived with a simple expression that uses the Jacobian matrix directly. The algorithm requires no linear transformation or decomposition of the Jacobian matrix, which has been an essential part for previous automatic time-scaling methods. Furthermore, the proposed scale factor is estimated locally. Therefore, an iterative procedure was also developed to find the possible multiple boundary layers and to derive an appropriate reduced model.</p> <p>Conclusion</p> <p>By successive calculation of the newly derived time-scale criteria, it was possible to detect multiple boundary layers of full ordinary differential equation (ODE) models. Besides, the iterative procedure could derive the appropriate reduced differential algebraic equation (DAE) model with consistent initial values, which was tested with simple examples and a practical example.</p