Collider probes of singlet fermionic dark matter scenarios for the Fermi gamma-ray excess

We investigate the collider signatures of the three benchmark points in the singlet fermionic dark matter model. The benchmark points, which were introduced previously to explain the Fermi gamma-ray excess by dark matter (DM) pair annihilation at the Galactic center, have definite predictions for future collider experiments such as the International Linear Collider and the High-Luminosity LHC. We consider four collider observables: (1) Higgs signal strength (essentially $hZZ$ coupling), (2) triple Higgs coupling, (3) exotic Higgs decay, and (4) direct production of a new scalar particle. The benchmark points are classified by the final states of the DM annihilation process: a pair of $b$ quarks, SM-like Higgs bosons, and new scalar particles. Each benchmark scenario has detectable new physics signals for the above collider observables that can be well tested in the future lepton and hadron colliders.Comment: 14 pages, 1 figure, 1 tabl

Russias Place in the Changing Strategic Triangle in the Post-Cold War Northeast Asia: From an Outcast to a Strategic Player?

This paper is an attempt to analyze Russias regional political place and power in Northeast Asia through the US-China-Russia triangularity and to forecast the future of Russias place in the region by applying the basic logic and concepts of social network theory such as social capital and structural hole. From Russias perspective, the structural hole that formulated as a result of its own de-link strategy in the 1990s has developed into a determining factor in disabling Russia from regaining its position and influence in the Northeast Asian region. To overcome this obstacle, Russia has continuously developed its diplomatic strategies and reviewed the potential for cooperating with the US. Nonetheless, the US-Russian rivalry and competition at the global level is severely damaging an opportunity for the coming of a stable and cooperative order in Northeast Asia. However, the works of the US utilizing Russia without excluding China, and establishment of a vision for a regional order in the context of fostering stability and cooperation will become an utmost important factor in developing peace and co-prosperity in Northeast Asia. A sort of a semi-triangulairty among the US-China-Russia seems more beneficial for regional stability and cooperation

Russian Nonproliferation Policy and the Korean Peninsula

Efforts to resolve the threat posed to Northeast Asia\u27s security by North Korea\u27s nuclear proliferation through six-party negotiations are proceeding with great difficulty. As in any multilateral process, a major problem is understanding the goals and perspectives of each of the participants. This monograph focuses upon Moscow’s perspectives with regard to North Korea’s nuclear program and Russia’s own standing in Northeast Asia, as well as of the other participants in those negotiations, since their views unfortunately are not well-known or readily available in the United States.https://press.armywarcollege.edu/monographs/1701/thumbnail.jp

Micro-nano hybrid structures with manipulated wettability using a two-step silicon etching on a large area

Nanoscale surface manipulation technique to control the surface roughness and the wettability is a challenging field for performance enhancement in boiling heat transfer. In this study, micro-nano hybrid structures (MNHS) with hierarchical geometries that lead to maximizing of surface area, roughness, and wettability are developed for the boiling applications. MNHS structures consist of micropillars or microcavities along with nanowires having the length to diameter ratio of about 100:1. MNHS is fabricated by a two-step silicon etching process, which are dry etching for micropattern and electroless silicon wet etching for nanowire synthesis. The fabrication process is readily capable of producing MNHS covering a wafer-scale area. By controlling the removal of polymeric passivation layers deposited during silicon dry etching (Bosch process), we can control the geometries for the hierarchical structure with or without the thin hydrophobic barriers that affect surface wettability. MNHS without sidewalls exhibit superhydrophilic behavior with a contact angle under 10°, whereas those with sidewalls preserved by the passivation layer display more hydrophobic characteristics with a contact angle near 60°

Force correlations in molecular and stochastic dynamics

A molecular gas system in three dimensions is numerically studied by the energy conserving molecular dynamics (MD). The autocorrelation functions for the velocity and the force are computed and the friction coefficient is estimated. From the comparison with the stochastic dynamics (SD) of a Brownian particle, it is shown that the force correlation function in MD is different from the delta-function force correlation in SD in short time scale. However, as the measurement time scale is increased further, the ensemble equivalence between the microcanonical MD and the canonical SD is restored. We also discuss the practical implication of the result.Comment: 9 pages, 4 figures and Computer Physics Communcations (in press

Optical properties of iron-based superconductor LiFeAs single crystal

We have measured the reflectivity spectra of the iron based superconductor LiFeAs (Tc = 17.6 K) in the temperature range from 4 to 300 K. In the superconducting state (T < Tc), the clear opening of the optical absorption gap was observed below 25 cm-1, indicating an isotropic full gap formation. In the normal state (T > Tc), the optical conductivity spectra display a typical metallic behavior with the Drude type spectra at low frequencies, but we found that the introduction of the two Drude components best fits the data, indicating the multiband nature of this superconductor. A theoretical analysis of the low temperature data (T=4K < Tc) also suggests that two superconducting gaps best fit the data and their values were estimated as {\Delta}1 = 1.59 meV and {\Delta}2 = 3.15 meV, respectively. Using the Ferrell-Glover-Tinkham (FGT) sum rule and dielectric function {\epsilon}1({\omega}), the superconducting plasma frequency ({\omega}ps) is consistently estimated to be 6,665 cm-1, implying that about 59 % of the free carriers in the normal state condenses into the SC condensate. To investigate the various interband transition processes (for {\omega} > 200 cm-1), we have also performed the local-density approximation (LDA) band calculation and calculated the optical spectra of the interband transitions. The theoretical results provided a qualitative agreement with the experimental data below 4000 cm-1Comment: 19 pages, 5 figures. This paper has been accepted for publication in New Journal of Physic

Location Tracking of Moving Crew Members for Effective Damage Control in an Emergency

In an emergency, the commanding officer may have limited information, and crew members may behave differently compared to how they behaved during training. In an emergency situation, if the commanding officer is aware of each crew member's location and role in that situation, he can disseminate orders expeditiously and precisely. To realise a faster and more precise dissemination of orders through better awareness of each crew member's location and role, real-time crew member tracking is needed. The technical feasibility of a real time crew-tracking system based on a wireless sensor network has been studied, with the intent to improve effective commanding in an emergency. Herein, location tracking was achieved using instrumentation consisting of ZigBee tags, routers, and gateways, which were used to record the location and role data of moving crew members on a full-scale ship.Defence Science Journal, 2011, 61(1), pp.57-61, DOI:http://dx.doi.org/10.14429/dsj.61.50

Effects of strobe light stimulation on postnatal developing rat retina

The nature and intensity of visual stimuli have changed in recent years because of television and other dynamic light sources. Although light stimuli accompanied by contrast and strength changes are thought to have an influence on visual system development, little information is available on the effects of dynamic light stimuli such as a strobe light on visual system development. Thus, this study was designed to evaluate changes caused by dynamic light stimuli during retinal development. This study used 80 Sprague-Dawley rats. From eye opening (postnatal day 14), half of the rats were maintained on a daily 12-h light/dark cycle (control group) and the remaining animals were raised under a 12-h strobe light (2 Hz)/dark cycle (strobe light-reared group). Morphological analyses and electroretinogram (ERG) were performed at postnatal weeks 3, 4, 6, 8, and 10. Among retinal neurons, tyrosine hydroxylase-immunoreactive (TH-IR, dopaminergic amacrine cells) cells showed marked plastic changes, such as variations in numbers and soma sizes. In whole-mount preparations at 6, 8, and 10 weeks, type I TH-IR cells showed a decreased number and larger somata, while type II TH-IR cells showed an increased number in strobe-reared animals. Functional assessment by scotopic ERG showed that a-wave and b-wave amplitudes increased at 6 and 8 weeks in strobe-reared animals. These results show that exposure to a strobe light during development causes changes in TH-IR cell number and morphology, leading to a disturbance in normal visual functions