Effect of Irregular Worker Protection Law on Welfare Benefits Payment

Since the 1997 Asian financial crisis, the polarization of wages and welfare benefits by the type of employment contract in the Korean labor market has intensified. The Korean government enacted the Irregular Worker Protection Law (hereafter denoted as IWPL), which focuses on non-discrimination in 2007. From the characteristics of personnel management in Korea, a hypothetical mechanism can be proposed that companies ensure long-term and stable employment in the internal labor market by suppressing the expenditure of welfare benefits, a type of quasi-fixed labor cost, in response to IWPL. To test this hypothesis, we construct the treatment group with similar characteristics to the comparison group through propensity score matching (hereafter denoted as PSM). Then, the difference in difference (hereafter denoted as DID) is performed on two matched groups. As a result of the analysis, IWPL is confirmed to have a negative effect on welfare benefits payment, and this reduction effect gradually increases with the passage of time. Finding shows the possibility that companies have minimized the negative employment effect of IWPL and protected the internal labor market by adopting personnel management that reduces quasi-fixed labor costs such as welfare benefits

AMC with predicted CQI in packet-based wireless systems

In a packet based wireless system, an adaptive modulation and coding (AMC) scheme is often employed with the use of channel quality information (CQI). However, the AMC can be operated improperly due to delayed CQI, causing performance degradation. In this paper, we consider the use of predicted CQI for the AMC considering the feedback delay and channel characteristics. We also consider the use of a hybrid automatic repeat request scheme with the proposed AMC for further improvement in high mobility environments.the Ministry of Information & Communications, Korea, under the Information Technology Research Center (ITRC) Progra

Effective SNR Based MIMO Switching in Mobile WiMAX Systems

The mobile WiMAX system considers the use of (2×2) multiple-input multiple-output (MIMO) schemes for performance improvement. It is required for mobile stations to appropriately switch the MIMO mode; space– time block code (STBC) or vertical spatial multiplexing (VSM). In this paper we consider a novel switching scheme for the MIMO mode based on effective signal-tonoise ratio. Assuming the use of a minimum mean square error (MMSE) receiver for the VSM and a maximum ratio combining receiver for the STBC, the threshold for the mode switching is analytically derived in a closed form. Simulation results show that the proposed switching scheme outperforms conventional switching schemes in terms of the capacity and outage probability

Coupled surface plasmon–phonon polariton nanocavity arrays for enhanced mid-infrared absorption

Resonant optical cavities are essential components in mid-infrared applications. However, typical film-type cavities require multilayer stacks with a micronthick spacer due to mid-infrared wavelengths, and their performance is limited by narrow frequency tunability and angular sensitivity. We propose and experimentally demonstrate the subwavelength-scale (≈0/150) resonant nanocavity arrays that enhance the absorption spectrum of the device in the mid-infrared (10–12 microns) via excitation of coupled surface plasmon–phonon polaritons. The proposed metal–insulator–polar dielectric (gold–silicon–silicon carbide) structure supports a guided mode of the coupled surface polaritons in the lateral direction while vertically confining the mid-infrared wav

Spontaneous Symmetry Breaking of Population between Two Dynamic Attractors in a Driven Atomic Trap: Ising-class Phase Transition

We have observed spontaneous symmetry breaking of atomic populations in the dynamic phase-space double-potential system, which is produced in the parametrically driven magneto-optical trap of atoms. We find that the system exhibits similar characteristics of the Ising-class phase transition and the critical value of the control parameter, which is the total atomic number, can be calculated. In particular, the collective effect of the laser shadow becomes dominant at large atomic number, which is responsible for the population asymmetry of the dynamic two-state system. This study may be useful for investigation of dynamic phase transition and temporal behaviour of critical phenomena.Comment: 4 pages, 4 figure

Towards optimization of P3HT:bisPCBM composites for highly efficient polymer solar cells

The optimization of the polymer solar cells based on regioregular poly(3-hexylthiophene) (P3HT) and the bisadduct of phenyl C(61)-butyric acid methyl ester (bisPCBM) is studied thoroughly as a role of solvent-annealing effect as well as different concentration of bisPCBM. In the case of P3HT: bisPCBM of 1 : 0.8 w/w, more balanced electron and hole mobilities are observed, resulting in better performance of the solar cells. Under the best balance conditions such as P3HT: bisPCBM of 1 : 0.8 w/w, the solvent annealing is employed to further clarify the optimization of the devices. Such a treatment leads to the formation of crystalline P3HT domains in the blend films, which is determined by X-ray diffraction, UV-vis spectroscopy, and atomic force microscopy. From our experiment, one can conclude that the best power conversion efficiency of 3.75% is achieved in a layered structure of P3HT: bisPCBM of 1 : 0.8 w/w for a solvent-annealing time of 24 h.close201

Spatiotemporally and Sequentially-Controlled Drug Release from Polymer Gatekeeper-Hollow Silica Nanoparticles

Combination chemotherapy has become the primary strategy against cancer multidrug resistance; however, accomplishing optimal pharmacokinetic delivery of multiple drugs is still challenging. Herein, we report a sequential combination drug delivery strategy exploiting a pH-triggerable and redox switch to release cargos from hollow silica nanoparticles in a spatiotemporal manner. This versatile system further enables a large loading efficiency for both hydrophobic and hydrophilic drugs inside the nanoparticles, followed by self-crosslinking with disulfide and diisopropylamine-functionalized polymers. In acidic tumour environments, the positive charge generated by the protonation of the diisopropylamine moiety facilitated the cellular uptake of the particles. Upon internalization, the acidic endosomal pH condition and intracellular glutathione regulated the sequential release of the drugs in a time-dependent manner, providing a promising therapeutic approach to overcoming drug resistance during cancer treatment.ope

High efficiency near diffraction-limited mid-infrared flat lenses based on metasurface reflectarrays

A limiting factor in the development of mid-infrared optics is the lack of abundant materials that are transparent, low cost, lightweight, and easy to machine. In this paper, we demonstrate a metasurface device that circumvents these limitations. A flat lens based on antenna reflectarrays was designed to achieve near diffraction-limited focusing with a high efficiency (experiment: 80%, simulation: 83%) at 45(o) incidence angle at {\lambda} = 4.6 {\mu}m. This geometry considerably simplifies the experimental arrangement compared to the common geometry of normal incidence which requires beam splitters. Simulations show that the effect of comatic aberrations is small compared to parabolic mirrors. The use of single-step photolithography allows large scale fabrication.Comment: 9 page

Replenishment of microRNA-188-5p restores the synaptic and cognitive deficits in 5XFAD Mouse Model of Alzheimer’s Disease

MicroRNAs have emerged as key factors in development, neurogenesis and synaptic functions in the central nervous system. In the present study, we investigated a pathophysiological significance of microRNA-188-5p (miR-188-5p) in Alzheimer’s disease (AD). We found that oligomeric Aβ(1-42) treatment diminished miR-188-5p expression in primary hippocampal neuron cultures and that miR-188-5p rescued the Aβ(1-42)-mediated synapse elimination and synaptic dysfunctions. Moreover, the impairments in cognitive function and synaptic transmission observed in 7-month-old five familial AD (5XFAD) transgenic mice, were ameliorated via viral-mediated expression of miR-188-5p. miR-188-5p expression was down-regulated in the brain tissues from AD patients and 5XFAD mice. The addition of miR-188-5p rescued the reduction in dendritic spine density in the primary hippocampal neurons treated with oligomeric Aβ(1-42) and cultured from 5XFAD mice. The reduction in the frequency of mEPSCs was also restored by addition of miR-188-5p. The impairments in basal fEPSPs and cognition observed in 7-month-old 5XFAD mice were ameliorated via the viral-mediated expression of miR-188-5p in the hippocampus. Furthermore, we found that miR-188 expression is CREB-dependent. Taken together, our results suggest that dysregulation of miR-188-5p expression contributes to the pathogenesis of AD by inducing synaptic dysfunction and cognitive deficits associated with Aβ-mediated pathophysiology in the disease