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Comparative experiments investigating the dissipation of four nursery-box-applied pesticides and three foliar-applied pesticides were conducted using lysimeters and in actual paddy fields. In the lysimeter experiments, there were test plots for submerged application for both application types. Analytical concentrations of the pesticides in paddy water were evaluated using appropriate kinetic models. The detection levels of pesticides in the paddy water for the nursery-box and foliar applications were 10–77% and 42–79% of the submerged application, respectively. The times required for 50% dissipation (DT(50)s) in case of the nursery-box and foliar applications were 0.8–10.4 days and 0.5–2.7 days, respectively. Although overall dissipations were affected by the physicochemical properties of the pesticide and the experimental design in the test plots, the initial detection levels in the lysimeters, governed by the runoff at transplanting and the deposition at spraying, were comparable with those in the actual paddy fields.

Antarctica is one of the most rapidly mass changing areas with poor ground observation data on Earth. Considering the dominant uncertainty in Glacial Isostatic Adjustment (GIA) effects for the Antarctic Ice Sheet (AIS) mass balance, we analyze mass change patterns of Antarctica qualitatively using a statistics-based blind source separation method named Independent Component Analysis (ICA). We extract the 6 leading independent components using gravimetric data derived from the Gravity Recovery and Climate Experiment (GRACE) mission and GRACE Follow-On (GRACE-FO) mission. The results show that the whole continental mass changes can be effectively separated into several spatial patterns that could be dominated by different physical processes. Although the hidden independent physical processes cannot be completely separated, some significant signals such as glacial melting components, snow accumulation components, periodic climatic components, and GIA effects could be determined without introducing any external information. We also found that the time period of the employed data sets has a direct impact on ICA results. This suggested that some impacts of extreme events, such as rapid increases of snowfall in the late 2000s might cause dramatic changes spatially and temporally. In general, ICA provides a special view for a better understanding of AIS mass changes and specific regional researches.

The 11th Symposium on Polar Science/Ordinary sessions: [OG] Polar Geosciences, Poster presentations, Mon. 16 Nov. - Fri. 18 Dec.

Three-year comprehensive experiments were conducted to compare the dissipation patterns of a total of 16 pesticides, including 3 metabolites, as granular formulations applied in lysimeters and paddy fields with two soil types. Analytical concentrations of the target pesticides in paddy water were analyzed using a granular kinetic model consisting of the following parameters: release rate, decrease rate, and dissolved concentration. Results of parameter grouping analyses of the kinetic models showed that 56% of data reproducibility (entire grouping) was obtained between replicates for the lysimeters. In comparisons between the lysimeters and paddy fields, 48% of decrease rates and 34% of release rates were grouped, although significant differences were observed with a nearly 90% difference for dissolved concentrations. These differences might be attributed to the hydrological components such as water management and meteorological covariates in paddy fields, the daily percolation in lysimeters and the adsorption-desorption kinetics between paddy water and soil.

The Ninth Symposium on Polar Science/Special session: [S] Antarctic ice-ocean interaction ～observation, reconstruction, and modeling～, Tue. 4 Dec. / Entrance Hall (1st floor) at National Institute of Polar Research

Previous studies have demonstrated multiple herbicide resistance in California populations of Echinochloa phyllopogon, a noxious weed in rice (Oryza sativa) fields. It was suggested that the resistance to two classes of acetolactate synthase-inhibiting herbicides, bensulfuron-methyl (BSM) and penoxsulam (PX), may be caused by enhanced activities of herbicide-metabolizing cytochrome P450. We investigated BSM metabolism in the resistant (R) and susceptible (S) lines of E. phyllopogon, which were originally collected from different areas in California. R plants metabolized BSM through O-demethylation more rapidly than S plants. Based on available information about BSM tolerance in rice, we isolated and analyzed P450 genes of the CYP81A subfamily in E. phyllopogon. Two genes, CYP81A12 and CYP81A21, were more actively transcribed in R plants compared with S plants. Transgenic Arabidopsis (Arabidopsis thaliana) expressing either of the two genes survived in media containing BSM or PX at levels at which the wild type stopped growing. Segregation of resistances in the F2 generation from crosses of R and S plants suggested that the resistance to BSM and PX were each under the control of a single regulatory element. In F6 recombinant inbred lines, BSM and PX resistances cosegregated with increased transcript levels of CYP81A12 and CYP81A21. Heterologously produced CYP81A12 and CYP81A21 proteins in yeast (Saccharomyces cerevisiae) metabolized BSM through O-demethylation. Our results suggest that overexpression of the two P450 genes confers resistance to two classes of acetolactate synthase inhibitors to E. phyllopogon. The overexpression of the two genes could be regulated simultaneously by a single trans-acting element in the R line of E. phyllopogon.

SUMMARY We have analysed the Ny-Alesund very long baseline interferometry (VLBI) data over the period 1994 August to 2004 May, and we obtain secular displacement rates relative to a NNR-NUVEL-1A reference frame of 0.2 ± 0.5 mm yr −1 , −1.7 ± 0.5 mm yr −1 and 4.8 ± 1.1 mm yr −1 for the north, east and vertical directions, respectively. The corresponding global positioning system (GPS) station displacement rates relative to the same reference frame for the north, east, and vertical directions are 0.2 ± 0.6 mm yr −1 , −2.3 ± 0.6 mm yr −1 , and 6.4 ± 1.5 mm yr −1 at NYA1 and -−0.1 ± 0.5 mm yr −1 , −1.6 ± 0.5 mm yr −1 , and 6.9 ± 0.9 mm yr −1 at NALL, where these GPS rates were derived from the ITRF2000 velocity solution of Heflin. From the comparison at 25 globally distributed collocated sites, we found that the difference in uplift rate between VLBI and GPS at Ny-Alesund is mainly due to a GPS reference frame scale rate error corresponding to 1.6 mm yr −1 in the GPS vertical rates. The uplift rate was estimated to be 5.2 ± 0.3 mm yr −1 from the analysis of the tide gauge data at Ny-Alesund. Hence the uplift rates obtained from three different kinds of data are very consistent each other. The absolute gravity (AG) measurements at Ny-Alesund, which were carried out four times (period: 1998‐2002) by three different FG5 absolute gravimeters, lead to a decreasing secular rate of −2.5 ± 0.9 μGal yr −1 (1 μGal = 10 −8 ms −2 ). In this analysis, the actual data obtained from a superconducting gravimeter at Ny-Alesund were used in the corrections for the gravity tide (including the ocean tide effect) and for the air pressure effect. We have

The remarkable interplay of chirality and magnetism in helical single-wall nanotubes of iron (FeSWNTs) is investigated using fully unconstrained spin-density-functional calculations. Spin-spiral waves exist and noncollinear helimagnetism appears only for the specific chirality of (6,3) and (5,3) FeSWNTs, whereas collinear ferromagnetism persists in other chiral FeSWNTs as unfolded monolayers, that is, chirality selectively involves the unusual helimagnetic phase transition (chiral selectivity). The emergence of quantum helimagnetism plays a variety of significant roles in (i) the stabilization of the chiral FeSWNTs as a long-lived “magic” structure in both freestanding and tip-suspended conditions, (ii) interference with quantum ballistic conductance by interband repulsion, and (iii) the involvement of chiral conductivity in which electric currents pass helically through the FeSWNTs. These chiral characteristics are a novel addition to the intriguing rich diversity of chirality-driven physics and phenomena.

We investigate the magnetic phase transition from collinear ferromagnetic (FM) ordering to noncollinear spin-spiral (SS) ordering in an Fe(110) monolayer under in-plane strain by performing fully unconstrained first-principles spin-density-functional calculations. The FM Fe(110) monolayer undergoes a FM-SS phase transition on the application of in-plane compression, whereas the application of tension keeps the system FM. The stability and wavelength of the excited SS state are further increased by compressive strains, especially along [$\overline{1}$10]. The FM-SS transition in the isotropically strained monolayer is dominated by competing exchange interactions between the ferromagnetically coupled first neighbor and the antiferromagnetically coupled second neighbor; the third neighbor also contributes to the transition under anisotropic strain. In addition, we demonstrate the stabilization mechanism of SS noncollinear magnetism from the electronic band structures: The noncollinear SS state is stabilized by a remarkable interband repulsion between the majority and minority spins, which occurs under in-plane compression.

We investigated a nanometer-sharp magnetic domain wall (DW) structure in a free-standing Fe(110) monolayer and studied the crucial role of in-plane strain using fully unconstrained noncollinear ab initio spin-density-functional theory calculations within the generalized gradient approximation. The DW width is calculated to be 0.86 nm. A precise vector-field description of the magnetization density revealed that a noncollinear character in the DW was spatially confined between atoms, whereas a collinear and high magnetization density was localized around each atom. In the rapid rotation of magnetic moments in the DW, we found an electron rearrangement from the d(zx) and d(x(2)-y(2)) states to the d(xy), d(yz) and d(z(2)) states due to a shift of band structures. Applied tensile and compressive in-plane strains both bring about narrower DWs in the monolayer except when the strain is small. The strain dependence of the DW width is discussed in terms of both exchange interaction and magnetocrystalline anisotropy.