With decreases in Arctic sea-ice extent in recent years, the Northern Sea Route (NSR) and Northwest Passage (NWP), which we collectively term the Arctic Sea Route (ASR), have become open for navigation more frequently. The ASR connects the Pacific and Atlantic Oceans, with the NSR following the Siberian coast, and the NWP following the north coast of North America. This study evaluated long-term ice concentrations along both routes using microwave data from the SMMR and SSM/I sensors, and analyzed details using data from the AMSR-E passive microwave sensor. The data were used to determine the number of navigable days according to various sea-ice concentrations. Analysis of SMMR and SSM/I data showed a remarkably large number of navigable days on the NSR since 1995. For the NWP, the low resolution of the SMMR and SSM/I data for the Canadian Arctic Archipelago made analysis difficult, but long-term change in the sea-ice distribution on the ASR was indicated. Analysis of the AMSR-E microwave sensor data revealed navigable days along the NSR in 2002 and from 2005 to 2009 (except 2007). For navigation purposes, the sea-ice decrease in specific regions is important, as well as the decrease across the Arctic Ocean as a whole. For the NWP, numerous navigable days were identified in the period 2006–08.

The seasonal duration of sea-ice cover in the region immediately north of Hokkaido in the Sea of Okhotsk was estimated from daily sea-ice concentration maps (1995–2009) produced by the Japanese Coast Guard. The results show that this period is generally well represented by the proxy record of sea-ice duration in the region of Utoro in the Shiretoko peninsula. Comparison of the duration of seasonal sea-ice cover along the coast of Hokkaido with meteorological conditions over the period of sea-ice mapping by the Japanese Coast Guard indicates that all sea ice will disappear from the coast of Hokkaido once air temperature is increased by 2–4˚C over present values by the effects of climate change.

Following an International Geophysical Year project, we conducted meteorological observations during 2004–07 around the Suntar–Khayata range in eastern Siberia, where a strong temperature inversion exists throughout the winter. The temperature on the flat plain around Oymyakon (~700ma.s.l.) was ~20°C lower than that in a glaciated area located at ~2000ma.s.l. The inversion remained stable from October to April due to the Siberian high. Snowfall was limited to the beginning and end of winter. The stable conditions prevented atmospheric disturbances and inhibited snowfall during midwinter. From 1945 to 2003, glaciers in the Suntar–Khayata range retreated, with an area reduction of 19.3%. To assess this retreat, we estimated the response of the glaciers to climate change. According to US National Centers for Environmental Prediction (NCEP) data, the temperature in this region increased by ~1.9°C over 60 years. By calculating snow accumulation and ablation, the sensitivity of the equilibrium-line altitude (ELA) to the temperature shift was evaluated. We estimated snow precipitation based on precipitation at <0°C and ablation using the degree-day method. By these estimates, the ELA of Glacier No. 31, assumed 2350 m at present, could rise ~150m if temperature rises an average of 1°C. Furthermore, a 1.8°C temperature rise could cause the ELA to rise to 2600ma.s.l., removing the accumulation zone. With no accumulation zone, the glacier body would decrease, roughly halving in volume after ~400 years.

We analyze sea-ice conditions along seven segments of the Northern Sea Route (NSR) over four time periods. We researched sea ice by segment, using data from the satellite microwave sensors SMMR, SSM/I and AMSR-E. The four analysis periods (periods I–IV: 1980–88, 1989–2001, 2002–06 and 2007–11, respectively) were determined based on changes in the extent of minimum sea ice throughout the Arctic Ocean. Sea ice showed a decreasing tendency from period I to period IV. For example, sea-ice area in period IV decreased compared to previous periods in the eastern East Siberian Sea and around Severnaya Zemlya, areas that had very high sea-ice concentrations in period I. Sea-ice area in the eastern East Siberian Sea decreased sharply during period III, whereas the Severnaya Zemlya area maintained a high ice concentration. In period IV, sea-ice coverage around Severnaya Zemlya was low, although it remained at 25% in the area east of Severnaya Zemlya, which is a key area for navigation. The proportion of multi-year (MY) ice drastically decreased after winter 2002, and only a small amount of MY ice existed in the winters of 2003–06. MY ice disappeared from the eastern East Siberian Sea after 2007. On the other hand, around Severnaya Zemlya the proportion of MY ice showed cyclic ups and downs between 1997 and 2008. Thus, the persistence of various types of sea ice varies according to region. The persistence of various types of sea ice around Severnaya Zemlya also varied each year.

Quite high amounts of evaporation observed on glaciers in dry Central Asia are one important component in the mass balance of glaciers. During glaciological research at West Kunlun Mountains on the northwestern Tibetan plateau in 1987, high evaporation of more than 2 mm of water per day was observed near the equilibrium line (5800–5900 m a.s.l.) in mid-summer due to dry and windy climate. Annual evaporation is estimated by a semi-empirical method using the full year meteorological data taken by an automatic meteorological station. This value shows that evaporation occupies quite a high percentage within the mass balance near the equilibrium line and on the whole glacier. Discussions will centre on comparison with evaporation data obtained on other glaciers and on the effect of such evaporation in the climate-glacier relation.

We measured the radiocarbon ages of 165 single-year tree rings from a Japanese Choukai Jindai cedar using accelerator mass spectrometry (AMS). By wiggle-matching the Choukai_AMS data set to the IntCal04 calibration data using OxCal v 3.10 and using the variation of the correlation coefficients between the Choukai_AMS and IntCal04 data sets, we precisely re-estimated that the 321 Choukai Jindai cedar tree rings range from 780 to 460 cal BC with an accuracy of 8 yr. The Choukai_AMS data set is older than the 3 raw data sets of European tree rings that comprise IntCal04. The Belfast and Seattle data sets are younger by −21.3 ± 5.5 and −22.7 ± 5.6 14C yr, respectively. The Choukai Jindai cedar is ∼22 14C yr older than the European tree rings, which is equivalent to an offset of −2.8‰ in 14C. In addition, the Choukai_AMS data set correlates well with the Belfast and Seattle data sets, with correlation coefficients of 0.89 and 0.68, respectively, between the temporal profiles. Hence, the temporal profile of the Choukai 14C ages shows a global variation.

Radiocarbon ages of Choukai Jindai cedar tree rings growing in the excess era of 14C concentrations during 2757–2437 cal BP were measured using 2 types of 14C measurement methods, i.e. liquid scintillation counting (LSC) and accelerator mass spectrometry (AMS). The difference between the 2 methods is 3.7 ± 5.2 14C yr on average for 61 single-year tree rings, indicating good agreement between the methods. The Choukai data sets show a small sharp bump with an average 14C age of 2497.1 ± 3.0 14C yr BP during 2650–2600 cal BP. Although the profile of the Choukai LSC data set compares well with that of IntCal04, having a 14C age difference of 4.6 ± 5.3 14C yr on average, the Choukai LSC 14C ages indicate variability against the smoothed profile of IntCal04.

We have measured the radiocarbon concentrations in single-yr tree rings of old wood by accelerated mass spectrometry (AMS) using a multicathode. The 14C concentrations of 10 single-yr tree rings were measured in 100 tree rings at intervals of 10. For each single-yr tree-ring sample, typically 80 measurements of the 14C concentrations were carried out using multicathodes. The sample standard deviations indicated that there are other fluctuations of typically 1.5%, in addition to the fluctuation of the Poisson counting statistics which is typically 3% for each measurement. The average 14C date of the tree rings was 22,130 ± 306 BP for all 624 data of single-yr tree-ring samples measured by the multicathodes. From the calibration data of Lake Suigetsu, the calendar dates of these 100 tree rings were located between 25,400 cal BP and 26,150 cal BP. The 14C dates changed between 21,979 BP and 22,272 BP, with an error of approximately 50 BP, corresponding to a precision of approximately 0.5%. There was a step with a change of approximately 144 BP for each 10 yr in the time profile.

We have measured the radiocarbon ages of 43 consecutive single-year tree rings using accelerator mass spectrometry (AMS) with a statistical accuracy of ∼2.3%. AMS 14C ages of the 36 viable samples are between 2708 and 2666 cal BP, a period in which the Δ14C of the IntCal04 curve (Reimer et al. 2004) shows an enhancement. The 14C ages of the samples are scattered with a Gaussian distribution around the interpolated IntCal04 calibration curve. The time profile of the deviations of the 36 14C ages from the interpolated IntCal04 calibration curve indicates a linear trend and a characteristic variability rather than a random fluctuation around the curve. The trend indicates a higher gradient than that of the interpolated IntCal04 calibration curve. The profile implies a periodic variation of approximately 11 yr and an amplitude of roughly 18 14C yr.

SIS receivers have higher sensitivity than Schottky diode receivers. The SIS mixer, however, must be cooled at 4 K level, and either a GM (Gifford-McMahon) + JT (Joule- Thomson) refrigerator or liquid helium is used. Therefore, SIS receivers are usually much larger and heavier than Schottky diode receivers which are usually cooled by a GM refrigerator only.

Kuriyama et al. developed a GM refrigerator using Er3Ni as a regenerator material which achieved to cool at 4 K level.

In this work, the SIS receiver was constructed and investigated, which was cooled below 4 K by the GM refrigerator with Er3Ni. It resulted in the SIS receiver which was about the same size and weight as a usual Schottky diode receiver.

Electron-beam-induced soft-X-ray emission spectroscopy (SXES) that uses a grating spectrometer has been introduced to a conventional scanning electron microscope (SEM) for characterizing desired specimen areas of bulk materials. The spectrometer was designed as a grazing incidence flat-field optics by using aberration corrected (varied line spacing) gratings and a multichannel plate detector combined with a charge-coupled device camera, which has already been applied to a transmission electron microscope. The best resolution was confirmed as 0.13 eV at Mg L-emission (50 eV), which is comparable with that of recent dedicated electron energy-loss spectroscopy instruments. This SXES-SEM instrument presents density of states of simple metals of bulk Mg and Li. Apparent band-structure effects have been observed in Si L-emission of Si wafer, P L-emission of GaP wafer, and Al L-emissions of intermetallic compounds of AlCo, AlPd, Al2Pt, and Al2Au.

We investigated the anisotropic g tensors of nine kinds of organic semiconductor molecules in the cationic state by density functional theory (DFT) calculations. Large anisotropy was obtained in sulfur-containing molecules because of the large spin-orbit coupling at the sulfur atoms. The calculated g values were validated by electron spin resonance (ESR) experiments for the cation radicals in solution.

Fetal lung maturity assessment in twin pregnancy has been discussed, but is still controversial. The purpose of this study is to predict the occurrence of respiratory distress syndrome (RDS) using lamellar body count (LBC) and analyze the validity of LBC for fetal lung maturity assessment in twin pregnancy. Three-hundred two amniotic fluid samples were obtained at cesarean section from 29 to 38 weeks of gestation. Samples were analyzed immediately with no centrifugation and the number of lamellar bodies was counted using a platelet channel on the Sysmex SF-3000. There were 18 neonates (6.0%) suffering from RDS. An LBC cut-off value of 2.95 × 104/μL resulted in 91.5% sensitivity and 83.3% specificity for predicting RDS. This cut-off value for predicting RDS was the same as that in singleton pregnancy. Moreover, the median LBC value in RDS cases was significantly lower than in non-RDS cases (1.50 ± 1.1 × 104/μL vs. 10.6 ± 7.5 × 104/μL; p < .001). This is the first report on the validity of LBC in twin pregnancy and also the largest study on fetal lung maturity assessment in twin pregnancy. An LBC value of >2.95 × 104/μL means reassuring findings for RDS even in twin pregnancy. We believe the data in this study provide valuable, new information for the management of twin pregnancies.

The efficiency of the energy conversion rate in the relativistic magnetic reconnection is investigated by means of Relativistic Resistive Magnetohydrodynamic (R2MHD) simulations. We confirmed that the simple Sweet-Parker type magnetic reconnection is a slow process for the energy conversion as theoretically predicted by Lyubarsky (2005). After the Sweet-Parker regime, we found a growth of the secondary tearing instability in the elongated current sheet. Then the energy conversion rate and the outflow velocity of reconnection jet increase rapidly. Such a rapid energy conversion would explain the time variations observed in many astrophysical flaring events.

To construct a more realistic model of relativistic reconnection, we extend our R2MHD code to R3MHD code by including the radiation effects (Relativistic Resistive Radiation Magnetohydrodynamics R3MHD). The radiation field is described by the 0th and 1st moments of the radiation intensity (Farris et al. 2008, Shibata et al. 2011). The code has already passed some one-dimensional and multi-dimensional numerical problems. We demonstrate the first results of magnetic reconnection in the radiation dominated current sheet.

We have carried out an angle-resolved photoemission study of double Ag nanofilm structures, composed of an outer Ag nanofilm / Cu barrier layer / inner Ag nanofilm / Cu(111) substrate. From these results, we discuss the electronic coupling between the quantized electronic states in the double Ag nanofilm structures with various configurations.