A Panel Study of Zombie SMEs in Japan : Identification, Borrowing and Investment Behavior

* Revised：A Panel Study of ‘Zombie’ SMEs in Japan: Identification, Borrowing and Investment Behavior [13-16, 2013

Investigation of the Superconducting Gap Structure in SrFe2_2(As0.7_{0.7}P0.3_{0.3})2_2 by Magnetic Penetration Depth and Flux Flow Resistivity Analysis

We measured the microwave surface impedances and obtained the superfluid density and flux flow resistivity in single crystals of a phosphor-doped iron-based superconductor SrFe$_2$(As$_{1-x}$P$_{x}$)$_2$ single crystals ($x=0.30$, $T_c=25 \mathrm{K}$). At low temperatures, the superfluid density, $n_s (T)/n_s(0)$, obeys a power law, $n_s (T)/n_s (0)=1-C(T/T_c)^n$, with a fractional exponent of $n=1.5$-1.6. The flux flow resistivity was significantly enhanced at low magnetic fields. These features are consistent with the presences of both a gap with line nodes and nodeless gaps with a deep minimum. The remarkable difference observed in the superconducting gap structure between SrFe$_2$(As$_{1-x}$P$_{x}$)$_2$ and BaFe$_2$(As$_{1-x}$P$_{x}$)$_2$ in our experiments is important for clarifying the mechanism of iron-based superconductivity

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mediation: R package for causal mediation analysis

In this paper, we describe the R package mediation for conducting causal mediation analysis in applied empirical research. In many scientific disciplines, the goal of researchers is not only estimating causal effects of a treatment but also understanding the process in which the treatment causally affects the outcome. Causal mediation analysis is frequently used to assess potential causal mechanisms. The mediation package implements a comprehensive suite of statistical tools for conducting such an analysis. The package is organized into two distinct approaches. Using the model-based approach, researchers can estimate causal mediation effects and conduct sensitivity analysis under the standard research design. Furthermore, the design-based approach provides several analysis tools that are applicable under different experimental designs. This approach requires weaker assumptions than the model-based approach. We also implement a statistical method for dealing with multiple (causally dependent) mediators, which are often encountered in practice. Finally, the package also offers a methodology for assessing causal mediation in the presence of treatment noncompliance, a common problem in randomized trials

Frequency dispersion amplifies tsunamis caused by outer-rise normal faults

Although tsunamis are dispersive water waves, hazard maps for earthquake-generated tsunamis neglect dispersive effects because the spatial dimensions of tsunamis are much greater than the water depth, and dispersive effects are generally small. Furthermore, calculations that include non-dispersive effects tend to predict higher tsunamis than ones that include dispersive effects. Although non-dispersive models may overestimate the tsunami height, this conservative approach is acceptable in disaster management, where the goal is to save lives and protect property. However, we demonstrate that offshore frequency dispersion amplifies tsunamis caused by outer-rise earthquakes, which displace the ocean bottom downward in a narrow area, generating a dispersive short-wavelength and pulling-dominant (water withdrawn) tsunami. We compared observational evidence and calculations of tsunami for a 1933 Mw 8.3 outer-rise earthquake along the Japan Trench. Dispersive (Boussinesq) calculations predicted significant frequency dispersion in the 1933 tsunami. The dispersive tsunami deformation offshore produced tsunami inundation heights that were about 10% larger than those predicted by non-dispersive (long-wave) calculations. The dispersive tsunami calculations simulated the observed tsunami inundation heights better than did the non-dispersive tsunami calculations. Contrary to conventional practice, we conclude that dispersive calculations are essential when preparing deterministic hazard maps for outer-rise tsunamis

Modeling of a dispersive tsunami caused by a submarine landslide based on detailed bathymetry of the continental slope in the Nankai trough, southwest Japan

Tsunamis caused by submarine landslides are not accompanied by seismic waves and thus may appear at the coast without warning. In this study, detailed bathymetric surveys with a multi-narrow beam echo sounder were used to map submarine landslides on the continental shelf near Cape Muroto, in the Nankai trough off southwestern Japan. One of the surveyed submarine landslides was selected to supply dimensions for the simulation of a submarine mass movement by a two-layer flow model in which the upper and lower layers correspond to seawater and turbidity currents, respectively. The time series of seafloor deformation during this simulated landslide was used as the boundary condition to drive a tsunami simulation. The results showed strong directivity effects during tsunami generation in which pushing-dominant (positive) tsunami waves propagated seaward, in the direction of the submarine landslide, and pulling-dominant (negative) tsunami waves propagated landward. Both types of waves were strongly modified by frequency dispersion. For pulling-dominant waves, a tsunami simulation that included dispersion (Boussinesq) terms predicted greater maximum tsunami heights than a non-dispersive tsunami simulation. To avoid underestimation of tsunami heights, we recommend including dispersion terms when modeling tsunamis caused by submarine landslides for disaster planning purposes

Social Implementation of Tsunami Prediction System on Wakayama by Using DONET Information

High possibility of occurrence of earthquake with M9 or lager in the Nankai subduction zone was pointed out by Cabinet Office of Japanese government. Local governments along the area revised estimation of tsunami damages and attempt to reconstruct action plans for the disaster prevention. However, according to Cabinet office of Japanese government, the coastal area near the rupture zone receives huge tsunami within a few minutes after the earthquake happens. To take actions against the severe situation, we need a high-speed, and high-accurate tsunami prediction system. Baba et al. (2014) investigated the possibility for use of a concept of tsunami amplification in the early tsunami prediction. They computed tsunami waveforms at the twenty pressure gauges of dense ocean floor network system for earthquakes and tsunamis (DONET) and at prediction points near shore. They found clear correlations between them because tsunami height basically depends on the topography (bathymetry) during its propagation. In this study, an early tsunami prediction system using the concept of tsunami amplification was societally implemented in 6 regional areas in Wakayama Prefecture. We constructed a tsunami database that contains pre-computed tsunamis offshore and nearshore from 1506 earthquake scenarios may occur in the Nankai subduction zones. The new system detects first arrivals of earthquake and tsunami from DONET data in real time, and calculate average value of absolute observed pressure values among twenty DONET stations. The value is used to select an appropriate scenario from the tsunami database. Prediction accuracy of the system was also investigated by using cases of the 1944 Tonankai earthquake and the scenario earthquake provided by the Cabinet office. As a result, we found that predicted inundation area to be overestimated as the safety of the prediction.南海トラフの沈み込み帯において，M9クラス巨大地震とそれにともなう巨大津波の発生の可能性が内閣府により指摘されて久しい。この津波被害想定によると，地震域近傍の沿岸地域では地震発生から数分後に巨大な津波が到達してしまうため，津波防災に向けた行動計画の再構築や人的被害軽減のための迅速な対応策の検討が極めて重要になる。その対応策のひとつとして，高速かつ高精度な即時津波予測が有効と考えられる。本研究では，地震と津波観測に向けた稠密海底観測網(DONET)による沖合観測網を利用した即時津波予測システムを構築し，和歌山県沿岸6地域において実装を行い，その有効性の検討を行った。本システムにより，地震と津波の初動到達時間を即時評価できること，沿岸津波高や浸水域の即時予測が可能であることを示した。さらに，1944年昭和東南海地震の事例と内閣府のM9クラス巨大地震の波源シナリオを用いて本システムの予測精度を検証した。本システムで即時予測される沿岸津波高や浸水域面積はやや過大評価傾向にあるものの，おおむね安全側の予測結果となり，津波防災上有効なシステムであることを示した