This study investigates the labor market under increased automation of middle-skilled jobs wherein worker suitability for these jobs is considered. We examine two effects of increased automation on workers. The first effect is the possibility of replacement of middle-skilled workers by machines. The second effect is the diversity in job mismatch probabilities of workers. If machines perform a worker’s suitable jobs more (or less) than the worker’s unsuitable jobs, then the worker’s job mismatch probability rises (or declines). Because workers who have larger job mismatch probabilities remain job seekers, it is more difficult for a firm to find a suitable worker. Due to these two effects, underemployment rises.

A project was started in 1990 to rationalize the avalanche warning and evacuation system. The major items in the model project were: (1) zoning methods for dangerous areas; (2) establishment of a surveillance system; and (3) methods of determining a warning and evacuation standard. Since the scale of a snow avalanche cannot be predicted, areas with more than 30 KN m2 of impact are identified. Equipment for conducting automatic surveillance and data processing was developed to telemeter snow and weather data. Issuing warning or evacuation advice is the focus of the discussion. Judgment is based on information on current conditions obtained from a telemeter and from residents, and on information provided by forecasts of snowfall and temperatures until the following morning. Two methods of judgment are under consideration: one is to set out a standard value based on meteorological data obtained by observation, the other is based on a discriminant of danger level.

This study considers adult mortality and analyzes the effect of public health investment on economic development, whereby investment increases savings but decreases fertility through a decrease in adult mortality. As the labor force increases, investment temporarily decreases capital per unit of labor. However, the decrease in fertility increases capital per unit of labor in subsequent periods. By considering these two opposing effects of decreasing fertility, we clarify the conditions required for investment to improve economic development via increasing savings and decreasing fertility. We examine panel estimation and present some weak evidence for our model.

This paper considers differential fertility and analyzes how the fertility of people caught in poverty disturbs their escape from poverty. For escape from poverty, it is necessary that the average human capital stock exceed certain thresholds before the ratio of the number of poor to rich people increases more rapidly than the human capital level of rich people. Thus, the escape depends on a race between the accumulation of human capital by the rich and the accumulation of children by the poor. A high initial ratio of the number of poor to rich people would imply persistent poverty.

Engineering and manufacturing of thick and bio-functional tissue products is one of the big issues in tissue engineering. To produce such tissues, we need some innovative technologies, which enable us to build up thick, three-dimensional structures and to arrange multiple types of cells to make complicated tissue structures. Based on such considerations, we have developed a custom-made inkjet 3D bioprinter, which realized both of direct cell printing and 3D laminating printing with cells and hydrogel. Recently, it has been improved, and here we report recent progresses and our achievements with new version 3D bioprinter.

Image based printing mode and active Z-axis control system were added. As a useful structure, an image of multi-honeycomb pattern was designed in computer and next it was copied and finally in total 100 image data were prepared. Using those digital data, 3D image of thick multi-honeycomb structure was reconstructed in computer, and then, laminating printing was carried out using our new version 3D bioprinter with alginate hydrogel. The new version printer showed good performance of 3D laminating printing and finally complicated 3D multi-honeycomb hydrogel structures could be successfully fabricated. It is indicated that fabrication of cell containing 3D structures based on the computer aided designs is feasible and that such biofabrication technologies must contribute to further innovative advancement of tissue engineering.

We clarify the different effects of elementary and higher education on human capital accumulation and inequality. The productivity of elementary education plays a significant role in the widening of inequality regardless of the existence of multiple steady states. When the productivity of elementary education is low, the poor cannot afford higher education in the long run because the demand for education by the rich makes the price of education too high for the poor. However, the effect of its productivity on the attainable education level is ambiguous. A rise in the productivity of higher education always increases the education level.

In the trough silicon via (TSV) structure for 3-dimensional integration (3DI), large thermal-mechanical stress acts in the TSV caused by the mismatch in thermal expansion coefficient (CTE) of the TSV materials. In this study, the stress of multi-stacked thin silicon wafers composed of copper TSV and copper/low-k BEOL structure was analyzed by the finite element method (FEM), aiming to reduce the stress of TSV of 3D-IC. The results of sensitivity analysis using design of experiment (DOE) indicated that the thickness of the silicon and adhesive layer are the key factors for the structural integration of TSV design.

We consider endogenous changes of inputs from labor to capital in the production of intermediate goods, i.e., a form of mechanization. We derive complementary relationships between capital accumulation and mechanization by assuming a Cobb–Douglas production function for the production of final goods from intermediate goods. A constant-elasticity-of-substitution production function in which the elasticity of substitution exceeds unity can be endogenously derived as the envelope of Cobb–Douglas production functions when the efficiency of inputs is assumed in a specific form. The difficulty of mechanization represents the elasticity of substitution.

We investigated the copper grain size dependence on the interconnect line height using the EBSD (Electron Back Scattering Diffraction) pattern method. In our grain size measurements, we excluded the twin boundaries because of its small contribution to the electron scattering. Our experiments showed that the average grain size of a 70 nm-high line was about 24% smaller than for a 190 nm-high line.

We estimated the grain boundary scattering components by the Fuchs-Sondheimer (FS) and the Mayadas-Shatzkes (MS) models including the line height dependence of the grain size parameter (d). In order to evaluate precisely the influence of height dependence of grain size in the FS and MS models, we also determined the surface scattering coefficient of the Ta/Cu and SiC/Cu interfaces by an independent experiment.

From this, we found that grain boundary scattering components became approximately 32% larger for the 70 nm-wide line when the line height dependence of the grain size was taken into consideration.

The present study was conducted to examine the effects of three polyphenols (tannic acid, apigenin and quercetin) on hyaluronidase activity and in vitro fertilization (IVF) parameters. Among them, tannic acid showed by far the strongest potency for blocking hyaluronidase activity extracted from preincubated boar sperm, causing a dose-dependent inhibition over the range of 2–10 μg/ml. When cumulus-intact and cumulus-free oocytes were inseminated in IVF medium containing tannic acid, the penetration and the polyspermy rates were significantly decreased in the presence of 10 μg/ml tannic acid compared with those in the absence of tannic acid, and the addition of 5 μg/ml tannic acid significantly reduced the polyspermy rate (p < 0.05) compared with that of the control while maintaining the high penetration rate. However, apigenin and quercetin had no effect on the rate of polyspermy. Interestingly, the incidence of polyspermy was significantly reduced in oocytes inseminated with sperm pretreated with 5 μg/ml tannic acid (p < 0.05), although the pretreatment of oocytes had no effect against the polyspermy after insemination with untreated sperm. Treatment with tannic acid caused neither a protective proteolytic modification of the zona pellucida matrix before fertilization, nor a reduction of the proteolytic activity of acrosomal contents or the number of zona-bound spermatozoa. These data suggest that an appropriate concentration of tannic acid prevents polyspermy through the inhibition of sperm hyaluronidase activity during IVF of porcine oocytes.

Vortex shedding from flat plates with square leading and trailing edges having chord-to-thickness ratios 3–16 at Reynolds numbers (1–3) × 103 is investigated experimentally in low-speed wind tunnels. It is shown that vortex shedding from flat plates with square leading and trailing edges is characterized by the impinging-shear-layer instability where the separated shear layer becomes unstable in the presence of a sharp trailing edge corner. The Strouhal number which is based on the plate's chord is approximately constant and equal to 0.6 for chord-to-thickness ratios 3–5. With further increase in the ratio it increases stepwise to values that are approximately equal to integral multiples of 0.6.

This paper describes a numerical study of the flow around flat plates with square leading and trailing edges on the basis of a finite-difference analysis of the two-dimensional Navier—Stokes equations. The chord-to-thickness ratio of a plate, d/h, ranges from 3 to 9 and the value of the Reynolds number based on the plate's thickness is constant and equal to 103. The numerical computation confirms the finding obtained in our previous experiments that vortex shedding from flat plates with square leading and trailing edges is caused by the impinging-shear-layer instability. In particular, the Strouhal number based on the plate's chord increases stepwise with increasing d/h in agreement with the experiment. Numerical analyses also provide some crucial information on the complicated vortical flow occurring near the trailing edge in conjunction with the vortex shedding mechanism. Finally, the mechanism of the impinging-shear-layer instability is discussed in the light of the experimental and numerical findings.

We have investigated the magnetoelectric (ME) properties of the orthorhombic RMnO3 (R=mixed rare earth ions) crystals with and without the 4f magnetic moments, while keeping an average ionic size of R. In the presence of the magnetic contribution from the R ions ((Eu,Ho)MnO3), we have observed the ferroelectric polarization along the c axis (Pc) in a zero field, which arises from the bc spiral structure stabilized by the anisotropic exchange interaction between the R and Mn sublattices like TbMnO3. The Pc phase can be transferred to Pa by application of fields of ∼1.5 T parallel to the b axis. The observed decrease of transition field compared with TbMnO3 suggests that the magnetic contribution and the local distortion of the R ions are key factors for governing the ME properties.

This paper presents the variation of radiocarbon content in annual tree rings for the period AD 1413–1553, which includes the Spoerer Minimum period (AD 1415–1534). Since the variation of the production rate of 14C is strongly related to solar activity, the variation of 14C content in annual tree rings gives us information on the characteristics of variation of solar activity. We have studied solar activity during the grand solar minima, focusing especially on the stability of the 11-yr cycle. The minima are determined to have been almost free of sunspots. Our results, however, have revealed quite remarkably the existence of the 11-yr cycle for most of the time during the Spoerer Minimum. The 11-yr variation weakened around AD 1460–1510, suggesting that solar activity might have been strongly suppressed during these 50 yr.

For ultrafast material analyses, we constructed the time-resolved X-ray diffraction system utilizing ultrashort X-rays from laser-produced plasma generated by the 12-TW–50-fs laser at the Nuclear Engineering Research Laboratory. Ultrafast transient changes in laser-irradiated GaAs crystals were observed as X-ray diffraction patterns. Experimental results were compared with numerical analyses.

Melting and crystallization experiments of InGaSb were done under the reduced gravity condition (10–2G) in an airplane and at the normal gravity condition (1G) in the laboratory. Crystallized InGaSb was found to contain many needle crystals in both the cases. Reduced gravity condition was found to be more conducive for crystal growth than the normal gravity condition. Formation of spherical projections on the surface of InGaSb during its crystallization was in-situ observed using a high speed CCD camera in the drop experiment. Spherical projections showed dependence of gravity during its growth. Indium compositions in the spherical projections were found to vary depending on the temperature.

Seasonal variations of δ13C were analyzed for two Japanese cypress trees (Chamaecyparis obtusa), one buried and one living. Both trees were different in age but sampled in areas geographically close to each other in central Japan. A buried cypress with 394 annual rings was excavated from Old Fuji mudflow, the last glacial strata of the dormant Mt. Fuji volcano. The accelerator mass spectrometry (AMS) radiocarbon date of this glacial sample was 18,600 ± 120 BP (NUTA–4884). A living tree stem, which has 192 rings, was cut from the Izu Peninsula in 1986. In order to measure the seasonal δ13C fluctuation, the tree rings were divided equally into three earlywood and one or two latewood consecutive sections. The δ13C value within an annual ring generally increased from the first to the third or fourth sections then decreased in the last section. This pattern of the variation was similar in the glacial and modern samples. The δ13C value within an annual ring seems to be controlled by environmental factors (not plant physiological ones), since there was no isotopic shift in the seasonal δ13C variation at the earlywood-latewood boundary, which was controlled by plant physiology. The result suggests the potential to reconstruct the paleoenvironment within a year using the seasonal δ13C variation, though site-specific conditions such as soil characteristics would also affect to its fluctuation.