Is Lavelle-McMullan transformation a really new symmetry in QED?

Lavelle-McMullan symmetry of QED is examined at classical and quantum levels. It is shown that Lavelle-McMullan symmetry does not give any new non-trivial information in QED by examining the Ward-Takahashi identities. Being inspired by the examination of Ward-Takahashi identity, we construct the generalized non-local and non-covariant symmetries of QED.Comment: LATEX, 9 pages, two figures generated by Feynma

CEO Career Concerns And Voluntary Disclosure

This paper investigates the relation between Chief Executive Officers (CEO) career concerns and voluntary disclosures using listed firm (KOSPI) data in Korea. Prior research suggests that explicit incentives in the form of CEO stock-based compensation or CEO’s equity ownership mitigate the agency problems of reluctance to make voluntary disclosure. In addition, implicit incentives arising from CEO career concerns are as important as explicit incentives for mitigating agency problems.The labor market assesses CEOs ability and CEO reputation in the market is a valuable asset that is associated with many long-term benefits, such as better future compensation, reappointment in the position, and greater managerial autonomy. CEOs are concerned about such an assessment and these concerns are referred to as career concerns. However, the market has incomplete information about CEOs’ ability especially when the CEOs have short tenures as a CEO position. Hence, CEOs with short tenures have more strong incentives to signal their ability to the labor market so that they can build proper reputation.Implicit incentives arising from CEO career concerns are measured by CEO tenure. I assume that short-tenured CEOs are more career-concerned than long-tenured CEOs. I find that CEOs with short tenures tend to more likely disclose management forecasts. I interpret this result that more career-concerned CEOs have strong incentives to signal their ability to the labor market in order to build their reputations which affect their future payoffs such as compensations and reappointment. In addition, management forecasts, means of voluntary disclosure, are used as effective mechanism. I also find that CEOs with short tenures tend to disclose more accurate management forecasts. This result implies that CEOs with more career concerns have more pressure to provide accurate forecasts because of their reliability in the labor market. Based on these empirical results, I infer that CEOs’ implicit incentives affect their voluntary disclosure decision.This study will contribute to academics and disclosure-related practitioners by documenting about CEOs’ career concerns and their voluntary disclosure decisions

Switching Controller Design for a Class of Markovian Jump Nonlinear Systems Using Stochastic Small-Gain Theorem

Switching controller design for a class of Markovian jump nonlinear systems with unmodeled dynamics is considered in this paper. Based on the differential equation and infinitesimal generator of jump systems, the concept of Jump Input-to-State practical Stability (JISpS) in probability and stochastic Lyapunov stability criterion are put forward. By using backsetpping technology and stochastic small-gain theorem, a switching controller is proposed which ensures JISpS in probability for the jump nonlinear system. A simulation example illustrates the validity of this design

Thermal performance of a scaled-up louvered fin heat exchanger with unequal louver pitch

We analyzed the thermal performance of louvered fin heat exchanger with equal and unequal louver pitch which continuously increased by 20% from air inlet area to the redirection region and difference of thermal performance of the louvered fin heat exchanger with unequal louver pitch was compared with that of equal louver pitch. The frost blocking of the spaces between louvers at front side of the louvered fin heat exchanger with unequal louver pitch was delayed and the time, the heat transfer rate of louvered fin heat exchanger reached 50% of the maximum heat transfer rate, of the unequal louver pitch louvered fin heat exchanger was also delayed than that of the equal louver pitch louvered fin heat exchanger. The operating time of louvered fin heat exchanger with unequal louver pitch was longer than that of equal louver pitch and the total heat transfer until reaching 50% of the maximum heat transfer rate increased at 18% than that of equal louver pitch.Papers presented to the 12th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Costa de Sol, Spain on 11-13 July 2016

Improvement of thermal efficiency of a radial heat sink with a surrounding structure

This study proposed a radial heat sink with a surrounding structure as a cooling system for light-emitting diode (LED) lighting with a circular base. The radial heat sink with long and middle fins was considered. Heat flow and radiative heat transfer were simulated numerically and the numerical model was validated experimentally. Natural convection heat transfer at the heat sink can be improved by controlling the air flow pattern. In this study, the surrounding structure increased the velocity of the inlet air around the heat sink due to the narrow air inlet surface, allowing the cooling air to move to the center of the heat sink. The effects of the material used to make the surrounding structure and the surface treatment of the heat sink were also analyzed. The results showed that the thermal efficiency of the radial heat sink was improved by up to 40% following installation of the chimney-shaped surrounding structure. The material used to make the surrounding structure did not influence the ability of the heat sink to dissipate heat. This research is expected to be helpful in the development of high-power LED lighting with a natural cooling system.Papers presented to the 12th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Costa de Sol, Spain on 11-13 July 2016

The Protective Effect of Apamin on LPS/Fat-Induced Atherosclerotic Mice

Apamin, a peptide component of bee venom (BV), has anti-inflammatory properties. However, the molecular mechanisms by which apamin prevents atherosclerosis are not fully understood. We examined the effect of apamin on atherosclerotic mice. Atherosclerotic mice received intraperitoneal (ip) injections of lipopolysaccharide (LPS, 2 mg/kg) to induce atherosclerotic change and were fed an atherogenic diet for 12 weeks. Apamin (0.05 mg/kg) was administered by ip injection. LPS-induced THP-1-derived macrophage inflammation treated with apamin reduced expression of tumor necrosis factor (TNF)-α, vascular cell adhesion molecule (VCAM)-1, and intracellular cell adhesion molecule (ICAM)-1, as well as the nuclear factor kappa B (NF-κB) signaling pathway. Apamin decreased the formation of atherosclerotic lesions as assessed by hematoxylin and elastic staining. Treatment with apamin reduced lipids, Ca2+ levels, and TNF-α in the serum from atherosclerotic mice. Further, apamin significantly attenuated expression of VCAM-1, ICAM-1, TGF-β1, and fibronectin in the descending aorta from atherosclerotic mice. These results indicate that apamin plays an important role in monocyte/macrophage inflammatory processing and may be of potential value for preventing atherosclerosis