Positional isomer composition of monounsaturated fatty acids from a lacustrine sediment

From the surface sediment of a eutrophic lake (Japan), the double bond position in the monounsaturated fatty acids (C₁₅-C₂₆) has been determined by combined gas chromatography-mass spectrometry of the methoxylated derivatives. The relative abundance of 11-octadecenoic acid, suggested to be of bacterial origin, is higher in the chloroform-methanol extract than the extract by saponification.     

An attempt to separate Q from the Allende meteorite by physical methods

In order to characterize the planetary noble gas carrier Q, we separated a Q-rich floating fraction from the Allende meteorite into ten fractions by a combination of colloidal and density separations. All five noble gases in the separated fractions were analyzed by pyrolysis in 600 and 1600°C temperature steps. Half of Q in the floating fraction is concentrated in the fraction C1-8D with the density of 1.65 ± 0.04 g/cm³. All the separated fractions show similar isotopic ratios except for ⁴⁰Ar/³⁶Ar ratios. C1-8D has the lowest ³⁸Ar/³⁶Ar and ⁴⁰Ar/³⁶Ar ratios (0.18784 ± 0.00020 and 4.36 ± 0.15, respectively) in the 1600°C fraction, confirming that the fraction is enriched in Q. Most grains in C1-8D are carbonaceous with small amounts of F and O. These results imply either that the density of Q is 1.65 ± 0.04 g/cm³ or that Q preferentially sticks to matter of that density. All the separates have similar Q to diamond ratios, indicating that Q and diamond are closely associated.     

Long-period waves in the vicinity of Onagawa Bay (III)

Characteristics of seiches in Onagawa Bay are investigated on the basis of observations at the bay head, Konorihama, from May 1972 to May 1973 and at the outside of the bay, Enoshima during the same period. At Konorihama seiches with the double amplitude of 7 to 11 cm occurred most frequently (63 percent of the total samples) and the maximum reached 31 cm. Short-time spectral analyses indicate that the periods of the spectral peaks shift considerably with the lapse of time, and that the location of the nodal line near the bay mouth moves offshore and inshore of Enoshima. The cause of these phenomena seems to be attributed to the change of incident angle of waves coming from the open sea to excite seiches. Amplitudes of the fundamental and of the lateral modes of seiches increase or decrease alternately with time, suggesting the energy transfer between these modes. Bay oscillations induced by remarkable atmospheric pressure-waves were observed. However, the amplitudes of the oscillations were within a few centimeters and dissipated in a few hours.     

Skewed Occurrence Frequency of Water Temperature and Salinity in the Subarctic Regions

In a previous paper (Oguma and Nagata, 2002), it was shown that frequency distributions of temperature and salinity in the sea off Sanriku Coast, Japan are skewed, and sometimes observed values exceed m + 5σ (m = mean, σ = standard deviation). This means that, if we apply a 3σ criterion for a range check, many real data would be lost. We have expanded our analysis to the subarctic North Pacific, the subarctic North Atlantic and their surrounding areas, by computing the distributions of skewness and kurtosis. It is found that the region of high positive skewness extends in an east-north-east direction in the Mixed Water Region from off Sanriku, and reaches to about 155°E. A high negative skewness zone is recognized along the southern margin of the Kuroshio Extension. These are thought to be generated by the breaking of the meander of the Kuroshio Extension and subsequent ejection of warm and cold eddies to the north and south, respectively. Other high positive skewness areas are found to the south of Kuril Islands and in the Japan Sea. These are generated due to very sharp vertical gradients of temperature and salinity. The situation in the North Atlantic is very similar to the North Pacific, though the detailed nature is changed due to differences of oceanographic condition. The effect of grid size on the skewed nature of the distribution is also discussed. This revised version was published online in July 2006 with corrections to the Cover Date.     

Analysis software for upper atmospheric data developed by the IUGONET project and its application to polar science

To comprehensively understand the Arctic and Antarctic upper atmosphere, it is often crucial to analyze various data that are obtained from many regions. Infrastructure that promotes such interdisciplinary studies on the upper atmosphere has been developed by a Japanese inter-university project called the Inter-university Upper atmosphere Global Observation Network （1UGONET）. The objective of this paper is to describe the infrastructure and tools developed by IUGONET. We focus on the data analysis software. It is written in Interactive Data Language （IDL） and is a plug-in for the THEMIS Data Analysis Software suite （TDAS）, which is a set of IDL libraries used to visualize and analyze satellite- and ground-based data. We present plots of upper atmospheric data provided by IUGONET as examples of applications, and verify the usefulness of the software in the study of polar science. We discuss IUGONET＇s new and unique developments, i.e., an executable file of TDAS that can run on the IDL Virtual Machine, IDL routines to retrieve metadata from the IUGONET database, and an archive of 3-D simulation data that uses the Common Data Format so that it can easily be used with TDAS.     

Internal waves over the shelf in the western Bay of Bengal: a case study

Generation and propagation of internal waves (IWs) in the coastal waters of the extended shelf of the western Bay of Bengal are investigated for late winter by using the Massachusetts Institute of Technology General Circulation Model (MITgcm). The model is forced with astronomical tides and daily winds. Monthly climatological temperature and salinity fields are used as initial conditions. The simulations are compared with time series observations of temperature and currents from acoustic Doppler current profiler (ADCP) and conductivity-temperature-depth (CTD) moored at three locations south of Gopalpur: two at a local depth of 100 m and another at 400-m depth during 19–21 February 2012. The comparison of the spectral estimates for the time series of temperature from the model and observations are in reasonable agreement for the near-tidal frequency waves. The peak of temperature spectra is always found near the shelf break region which steadily lost its intensity over the continental shelf. The calculation of Richardson number reflected the presence of local mixing due to density overturning in the shelf region. To understand further the generation and propagation of internal tides in the region, energy flux and conversion of barotropic-to-baroclinic M₂ tidal energy are examined. The model simulations suggest that the internal tide is generated all along the shelf slope. The energy flux analysis shows that the internal tides propagate to either side of the generation sites.     

Noble gas study of the Saratov L4 chondrite

Abstract– We have determined the elemental abundances and the isotopic compositions of noble gases in a bulk sample and an HF/HCl residue of the Saratov (L4) chondrite using stepwise heating. The Ar, Kr, and Xe concentrations in the HF/HCl residue are two orders of magnitude higher than those in the bulk sample, while He and Ne concentrations from both are comparable. The residue contains only a portion of the trapped heavy noble gases in Saratov; 40 ± 9% for ³⁶Ar, 58 ± 12% for ⁸⁴Kr, and 48 ± 10% for ¹³²Xe, respectively. The heavy noble gas elemental pattern in the dissolved fraction is similar to that in the residue but has high release temperatures. Xenon isotopic ratios of the HF/HCl residue indicate that there is no Xe‐HL in Saratov, but Ne isotopic ratios in the HF/HCl residue lie on a straight line connecting the cosmogenic component and a composition between Ne‐Q and Ne‐HL. This implies that the Ne isotopic composition of Q has been changed by incorporating Ne‐HL (Huss et al. 1996) or by being mass fractionated during the thermal metamorphism. However, it is most likely that the Ne‐Q in Saratov is intrinsically different from this component in other meteorites. The evidence of this is a lack of correlation between the isotopic ratio of Ne‐Q and petrologic types of meteorites (Busemann et al. 2000). A neutron capture effect was observed in the Kr isotopes, and this process also affected the ¹²⁸Xe/¹³²Xe ratio. The ³He and ²¹Ne exposure ages for the bulk sample are 33 and 35 Ma, respectively.     

The effect of pyridine treatment on phase Q: Orgueil and Allende

Marrocchi et al. (2005) reported that low‐temperature fractions of heavy noble gases were largely removed upon pyridine treatment of the Orgueil CI meteorite. As pyridine is known to induce the swelling of the macromolecular network of organic matter, they concluded that the low‐temperature phase Q is macromolecular organic carbon. However, Busemann et al. (2008) showed that pyridine had no significant effect on the noble gas contents for other very primitive meteorites, such as CM and CR. Therefore, we prepared an HF–HCl residue and the pyridine‐treated residue of Orgueil, and re‐examined the results of Marrocchi et al. (2005) by analyzing all noble gases. We confirmed that heavy noble gases are surely removed by the pyridine treatment, but the degree of the loss of heavy noble gases is generally small, and is even smaller for the lighter noble gases. Furthermore, we could not observe the evidence of Xe isotopic ratios by removing only phase Q after the pyridine treatment. We further prepared the HF–HCl residue and the pyridine‐treated residue of the Allende CV3 meteorite and performed noble gas analyses. For Allende, there is no significant change in the elemental abundances after the pyridine treatment. These results suggest that only Orgueil is special, and it is likely that the gas loss of the Orgueil residue is due to the loss of some kind of organic matter that was formed and that adsorbed the fractionated Q and HL gases during the aqueous alteration within the parent body of Orgueil.     

Damped resonant appendages to increase inherent damping in buildings

It is demonstrated that the addition of a tuned mass-spring-dashpot system with a relatively small mass and a high damping ratio can be an effective way to increase the inherent damping characteristics of buildings and reduce, thus, their response to earthquake excitations. The demonstration is based on a theoretical formulation and on numerical and experimental studies that confirm this formulation. In the theoretical formulation, it is shown first that, if certain conditions are satisfied, the damping ratios in two of the modes of the system that is formed by a building and an appendage in resonance are approximately equal to the average of the corresponding damping ratios of the building and the appendage. Based on this finding, it is then shown that an attached appendage with a high damping ratio and tuned to the fundamental frequency of a building may increase the damping ratio in the fundamental mode of the building to a value close to half the damping ratio of the appendage. In the numerical study, the response of a ten-storey shear building is analysed under two different earthquake ground motions with and without the proposed resonant appendages. Appendages with damping ratios of 20 and 30 per cent are considered. In this study, it is found that under one of the ground motions the maximum displacement of the building's roof is reduced 30 per cent with the appendage with 20 per cent damping and 39 per cent with the one with 30 per cent damping. Similarly, with these two appendages the building's base shear is reduced 31 and 41 per cent, respectively. In the experimental study, a wooden three-storey structural model is tested in a shaking table with and without an appendage designed and constructed to have a damping ratio of 53-5 per cent. The test is conducted under random and sinusoidal base excitations. In the shaking table test under random excitation, the attached appendage reduces the response of the model 38-6 per cent, while in that under sinusoidal vibration 45-2 per cent.     

Toward Understanding the Formation of Molecular Clouds

Based on a comparison of similar colour indices we investigate the effects of luminosity and metallicity that influence the Strömgren and Vilnius photometric quantities for different spectral types. We notice significant differences for similar indices, apparently due to small deviations of central wavelengths and band-widths of the filters. For the G-K type stars of moderate luminosity we interpret the difference introduced by v and X pass-bands as an log g effect, reflecting the presence of H&;K Ca II stellar lines in these spectral types. We discuss a possible influence of the H&;K Ca II lines on the luminosities derived from the Vilnius classification diagrams.