NATIONAl CHARACTER STUDIES OF JAPANESE

In this paper, I suggest that the national character studies of Japanese have largely been focused on cultural explanations. Thus, they share the weaknesses attributed to this approach. After a review of the literature on Japanese national character some possible future directions are suggested

Discovery of a short plateau phase in the early evolution of a gamma-ray burst afterglow

We report optical observations during the first hour of the gamma-ray burst (GRB) afterglow of GRB021004. Our observation revealed the existence of a short plateau phase, in which the afterglow remained at almost constant brightness, before an ordinary rapid fading phase. This plateau phase lasted for about 2 hours from 0.024 to 0.10 d after the burst, which corresponds to a missing blank of the early afterglow light curve of GRB990123. We propose that the plateau phase can be interpreted as the natural evolution of synchrotron emission from the forward shock region of a blast wave. The time when the typical frequency of the synchrotron emission passes through the optical range has been predicted to be about 0.1 d after the burst, which is consistent with the observed light curve. Our scenario hence implies that the observed feature in GRB021004 is a common nature of GRB afterglows.Comment: 3 pages, 1 figure, accepted for publication in PAS

Large-Amplitude 2.65-d Oscillation in the VY Scl-Type star V425 Cas

From long-term photometry of a VY Scl-type star, V425 Cas, between 1998 and 2000, we discovered a short-term, large-amplitude (up to 1.5 mag) variations. The variation was well represented by a single period of 2.65 d. The large amplitude and the profile of the folded light curve suggest that the dwarf nova-type disk instability is responsible for this variation. The shortness of the period is unprecedented in hydrogen-rich cataclysmic variables. Given the recent emerging evidence that the irradiation from white dwarfs in VY Scl-type systems affect their light behavior, we propose a possibility that this unique variation in V425 Cas can be explained by the combination of the dwarf nova-type disk instability and irradiation. Similar short-period "outbursts" have been known in X-ray transients (V518 Per), and helium cataclysmic variables (CR Boo and V803 Cen). We discuss the possibility that these phenomena have a common origin to the unique variation in V425 Cas.Comment: 6 pages, 5 figures, accepted for publication in Publ. Astron. Soc. Japa

Model-based analyses of trends over time in the age corresponding to the transition phase for Antarctic minke whales in the JARPA research area

This study applies a model-based approach similar to that of Thomson et al. (1999) to the transition phase data obtained from JARPA surveys to examine trends in the age at maturity for the I and P stocks of Antarctic minke whales. The results, which takes into account various potential biases related to examining trend in transition phase data (i.e. truncation and fringe effects, differences between readers, and readers learning over time) suggest that the age at maturity of Antarctic minke whales declined from about 11 years in the late 1940s to 7 years in the late 1960s for both stocks, and these declining trends are statistically significant at the 5% level. The analyses also suggest that the age at maturity increased slightly from the late 1960s to the late 1970s and has stabilized thereafter. These trends are consistent with the results obtained from VPA (Mori et al. 2006), which suggest that for both the I and P stocks, abundance increased from the 1940s to the late 1960s and thereafter has been stable or declined somewhat. This consistency enhances the confidence to be placed in estimates of parameters (such as natural mortality and MSYR) from such VPA analyses that may be of value for management purposes. It also serves to demonstrate the utility of age-at-maturity as an index to monitor stock status, and suggests that continued monitoring of this parameter is desirable both for this purpose and for contributing to the understanding of the dynamics of the Antarctic ecosystem

Rapid Optical Fluctuations in the Black Hole Binary, V4641 Sgr

We report on unprecedented short-term variations detected in the optical flux from the black hole binary system, V4641 Sgr. Amplitudes of the optical fluctuations were larger at longer time scales, and surprisingly reached ~60% around a period of ~10 min. The power spectra of fluctuations are characterized by a power law. It is the first case in black hole binaries that the optical emission was revealed to show short-term and large-amplitude variations given by such a power spectrum. The optical emission from black hole binaries is generally dominated by the emission from the outer portion of an accretion disc. The rapid optical fluctuations however indicate that the emission from an inner accretion region significantly contributes to the optical flux. In this case, cyclo-synchrotron emission associated with various scales of magnetic flares is the most promising mechanism for the violently variable optical emission.Comment: 5 pages, 2 figures, accepted for publication in PAS

Developmental morphology of ovules and seeds of Nymphaeales

金沢大学理工研究域自然システム学系Ovule and seed development in six species of Nymphaeales was examined. In the Cabombaceae the two species studied resemble some extant basal angiosperms by having a hood-shaped outer integument. A micropyle-hilum complex results when the outer integument and derived testa are lacking between the micropyle and the funiculus, thus the hood-shaped appearance. In the Nymphaeaceae the outer integument is annular at an early stage and then cup-shaped though it is semiannular at initiation in Nupar japonicum and Nymphaea alba. The micropyle and hilum are separated by an intervening testa. Developmental data on the formation of the outer integument, from semiannular to hood-shaped vs. from annular to cup-shaped, are useful for inferring the morphology of the outer integument from the relative position of the micropyle to the hilum in seed fossils. The oldest (early Cretaceous) probable nymphaealean seeds had the micropyle-hilum complex, suggesting that the hood-shaped outer integument may be primitive in the Nymphaeales. This needs to be tested by examination of this feature in other groups of basal angiosperms

AINTEGUMENTA homolog expression in Gnetum (gymnosperms) and implications for the evolution of ovulate axes in seed plants

金沢大学理工研究域自然システム学系The expression of GpANTL1, a homolog of AINTEGUMENTA (ANT) found in the gymnosperm Gnetum parvifolium, was analyzed by RT-PCR and in situ hybridization. GpANTL1 was expressed in the leaf primordia, root tips, and young ovules. In the ovulate axis, expression was detected as four distinct rings around the outer, middle, and inner envelope primordia as well as around the nucellar tip. This pattern of expression is similar to that of ANT in Arabidopsis thaliana. A comparison of the expression of GpANTL1 with that of PtANTL1 in the conifer Pinus thunbergii suggests that the integrated expression of PtANTL1 may have been caused by congenital fusion of the integument, ovuliferous scale, and bract. © 2008 The Author(s)

Photometric Studies of New Southern SU UMa-type dwarf novae, FL Triangulum Australe and CTCV J0549-4921

We report time-resolved optical CCD photometry on newly discovered SU UMa-type dwarf novae, FL TrA and CTCV J0549-4921. During the 2006 August outburst, we detected superhumps with a period of 0.59897(11) days for FL TrA, clarifying the SU UMa nature of the system. On the first night of our observations on FL TrA, the object showed no superhumps. This implies that it takes a few days for full development of superhumps. The superhump period variation diagram of FL TrA was similar to that observed in some WZ Sge stars and short period SU UMa-type stars. This indicates that the system is closely related to WZ Sge stars and SU UMa stars having short orbital periods. For CTCV J0549-4921, the candidates of the mean superhump period are 0.083249(10) days and 0.084257(8) days, respectively. Due to a lack of the observations, we cannot determine the true superhump period, but the latter period is favorable. Using the ASAS-3 archive, it turned out that the system shows only four outbursts over the past 6 years. The outburst amplitude of CTCV J0549-4921 was relatively small, with about 4.5 mag. One possibility is that mass evaporation may play a role during quiescence.Comment: 7 pages, 8 figures, published for PASJ vol.6

Discovery of a new dwarf nova, TSS J022216.4+412259.9: WZ Sge-type dwarf novae breaking the shortest superhump period record

We report on the time-resolved CCD photometry of a newly discovered variable star, TSS J022216.4+412259.9 during the outburst in 2005 November-December brightening. The obtained light curves unambiguously showed 0.2-0.3 mag modulations, which we confirmed to be the superhump observed among SU UMa-type dwarf novae. We also performed a period search for the data obtained during the outburst plateau phase, and revealed the existence of the two periodicities: 0.054868(98) days for the first two nights and 0.055544(26) days for the following plateau phase. This bi-periodicity is hardly observed in usual SU UMa-type dwarf novae, but characteristic of WZ Sge-type stars. We undoubtedly detected a rebrightening in the post-outburst stage, which is typical of short-period SU UMa-type dwarf novae including WZ Sge-type stars. These observations suggests that TSS J022216.4+412259.9 may be a new WZ Sge stars breaking the shortest superhump period of 0.05648 days for V592 Her among this class with a known superhump period so far.Comment: 5 pages, 6 figures, accepted for PASJ lette