Aharanov-Bohm effect for the edge states of zigzag carbon nanotubes

Two delocalized states of metallic zigzag carbon nanotubes near the Dirac point can be localized by the Aharanov-Bohm magnetic field around 20 Tesla. The dependence of the localization on the length and diameter of the nanotubes shows that the localization-delocalization transition can be observed for 2 nm diameter tube. The mechanism of the localization is explained in terms of the deformation-induced gauge field, which shows a topological nature of the localization. The transition from the delocalized states to the localized states can be observed by scanning tunneling microscopy and spectroscopy. A similarity between the transition and the spin Hall effect is discussed.Comment: 7 pages, 4 figure

Effects of rat- prolactin 0n ingestive behavior and leptin levels in adult male rats

Previous studies have indicated that ovine- or bovine-prolactin stimulates ingestive behavior in female, but not in male rats; i.e., that prolactin has sex-specific effects on ingestive behavior. The question addressed here was whether ingestivebehavior in male rats would be induced by rat-prolactin. In a preliminary test male rats were allowed to ingest a 1 M solution of sucrose from a drinking spout. After daily intake of sucrose became stabilized, the males received rat-prolactin by pituitary grafting. The results showed that pituitary grafling both stimulates ingestive behavior and increases serum leptin levels in male rats. These findings coupled with previous findings suggest that proinctin has species-specific effects on ingestivc behavior

Four-electron shell structures and an interacting two-electron system in carbon nanotube quantum dots

Low-temperature transport measurements have been carried out on single-wall carbon nanotube quantum dots in a weakly coupled regime in magnetic fields up to 8 Tesla. Four-electron shell filling was observed, and the magnetic field evolution of each Coulomb peak was investigated, in which magnetic field induced spin flip and resulting spin polarization were observed. Excitation spectroscopy measurements have revealed Zeeman splitting of single particle states for one electron in the shell, and demonstrated singlet and triplet states with direct observation of the exchange splitting at zero-magnetic field for two electrons in the shell, the simplest example of the Hund's rule. The latter indicates the direct analogy to an artificial He atom.Comment: 4 pages, 3 figures, submitted to Physical Review Letter

Aquatic Biota in Winter Flooded Paddy Field with Organic Farming : Case Study in Field Science Center, Tohoku University, Japan

Poster Sessio

Responses of phytoplankton assemblages to iron availability and mixing water masses during the spring bloom in the Oyashio region, NW Pacific

Spring phytoplankton blooms play a major role in the carbon biogeochemical cycle of the Oyashio region, western subarctic Pacific, where the seasonal biological drawdown effect on seawater pCO 2 is one of the greatest among the world\u27s oceans. However, the bloom often terminates before depleting macronutrients, and the initiation and magnitude of the bloom is heterogeneous. We conducted a high resolution taxonomic and physiological assessment of phytoplankton in relation to the different physicochemical water masses of Coastal Oyashio Water (COW), Oyashio water (OYW), and modified Kuroshio water (MKW) in the Oyashio region from April to June 2007. Massive diatom blooms were found in April. Then, chlorophyll a concentration, cell abundance of diatom taxa, and the maximum photosystem II photochemical efficiency (F v /F m ) were positively correlated with the mixing ratios of COW, suggesting that the spring bloom in April was strongly affected by the intrusion of COW. In the OYW, intensive blooms occurred from the middle of May under low dissolved iron (DFe) concentration (\u3c 0.26 nM). Redundancy analysis showed that while diatom blooms accompanied by COW were related to DFe concentration, this was not the case in the OYW. These results indicated that diatoms in the OYW possess different iron adaptation strategies compared with diatoms in the water masses affected by COW. This led to the spatial heterogeneity of the Oyashio spring bloom. The results presented here demonstrate that water mass characterization with detailed assessments of phytoplankton taxonomy and physiological status can improve our understanding of marine ecosystems

Impact of harvest timing on 4-hydroxy-2,5-dimethyl-3(2H)-furanone concentration in 'Muscat Bailey A' grape berries

We analyzed the effect of harvest timing on the concentration of 4-hydroxy-2,5-dimethyl-3(2H)-furanone (furaneol) concentration in 'Muscat Bailey A' grape berries. 'Muscat Bailey A' is one of the wine produced most in Japan, and the furaneol concentration in these wines were much higher than those of wine made from other black Vitis vinifera grape varieties regardless of the growing region in Japan. The furaneol concentration in 'Muscat Bailey A' grape skin increased during the grape developmental period. Indeed, 'Muscat Bailey A' wines made from grape berries harvested at 9 weeks post-véraison contained a larger amount of furaneol than those made from grape berries harvested at 7 weeks post-véraison. These findings could contribute to improving viticultural and enological practices for the unique strawberry-like fruity aroma of 'Muscat Bailey A' wine.

Carbon K-shell photoelectron angular distribution from fixed-in-space CO2 molecules

Measurements of photoelectron angular distributions for carbon K-shell ionization of fixed-in-space CO2 molecules with the molecular axis oriented along, perpendicular and at 45 degrees to the electric vector of the light are reported. The major features of these measured spectra are fairly well reproduced by calculations employing a relaxed-core Hartree-Fock approach. In contrast to the angular distribution for K-shell ionization of N-2, which exhibits a rich structure dominated by the f-wave (l = 3) at the shape resonance, the angular distribution for carbon K-shell photoionization of CO2 is quite unstructured over the entire observed range across the shape resonance

Spatial variability in iron nutritional status of large diatoms in the Sea of Okhotsk with special reference to the Amur River discharge

The Sea of Okhotsk is known as one of the most biologically productive regions among the world's oceans, and its productivity is supported in part by the discharge of iron (Fe)-rich water from the Amur River. However, little is known about the effect of riverine-derived Fe input on the physiology of the large diatoms which often flourish in surface waters of the productive continental shelf region. We conducted diatom-specific immunochemical ferredoxin (Fd) and flavodoxin (Fld) assays in order to investigate the spatial variability of Fe nutritional status in the microplankton-sized (20–200 μm; hereafter micro-sized) diatoms. The Fd index, defined as the proportion of Fd to the sum of Fd plus Fld accumulations in the cells, was used to assess their Fe nutritional status. Additionally, active chlorophyll fluorescence measurements using pulse–amplitude-modulated (PAM) fluorometry were carried out to obtain the maximum photochemical quantum efficiency (<i>F</i>_v/<i>F</i>_m) of photosystem II for the total micro-sized phytoplankton assemblages including diatoms. During our observations in the summer of 2006, the micro-sized diatoms were relatively abundant (> 10 μg C L^&minus;1) in the neritic region, and formed a massive bloom in Sakhalin Bay near the mouth of the Amur River. Values of the Fd index and <i>F</i>_v/<i>F</i>_m were high (>0.9 and >0.65, respectively) near the river mouth, indicating that Fe was sufficient for growth of the diatoms. However, in oceanic waters of the Sea of Okhotsk, the diatom Fd index declined as cellular Fld accumulation increased. These results suggest that there was a distinct gradient in Fe nutritional status in the micro-sized diatoms from near the Amur River mouth to open waters in the Sea of Okhotsk. A significant correlation between dissolved Fe (D-Fe) concentration and the Fd index was found in waters off Sakhalin Island, indicating that D-Fe was a key factor for the photophysiology of this diatom size class. In the vicinity of the Kuril Islands between the Sea of Okhotsk and the Pacific Ocean, micro-sized diatoms only accumulated Fld (i.e., Fd index = 0), despite strong vertical mixing consistent with elevated surface D-Fe levels (>0.4 nM). Since higher Fe quotas are generally required for diatoms growing under low-light conditions, the micro-sized diatoms off the Kuril Islands possibly encountered Fe and light co-limitations. The differential expressions of Fd and Fld in micro-sized diatoms helped us to understand how these organisms respond to Fe availability in the Sea of Okhotsk in connection with the Amur River discharge

Molecular cloning and characterization of ABCG/PDR-type ABC transporter in grape berry skin

Grape (Vitis vinifera L.) skin contains the phenolic compound resveratrol which is important not only for resistance to biotic and abiotic stresses but also for human health. However, little is known about resveratrol transport in plant cells. ABC (ATP binding cassette) transporters are well-known transporters responsible for secondary metabolite accumulation in plants. Previous reports speculated that the full-size ABCG transporter pleiotropic drug-resistant (PDR) is involved in resveratrol transport in fungi and plants. In this paper, all full-size ABCG transporters found in the grape genome database are listed and focus is placed on VvABCG44/VvPDR14 as a candidate resveratrol transporter. The full-length cDNA of VvABCG44 was cloned by RT-PCR using mRNAs extracted from grape berry skin. VvABCG44 expression was induced by UV irradiation, and the expression pattern of VvABCG44 in various grape organs was similar to that of stilbene synthase (STS), a key enzyme in resveratrol synthesis. Resveratrol content in grape berry skin increased after UV irradiation. These results suggest that VvABCG44 functions as a resveratrol transporter in grape

Reduction of thermal fluctuations in a cryogenic laser interferometric gravitational wave detector

The thermal fluctuation of mirror surfaces is the fundamental limitation for interferometric gravitational wave (GW) detectors. Here, we experimentally demonstrate for the first time a reduction in a mirror's thermal fluctuation in a GW detector with sapphire mirrors from the Cryogenic Laser Interferometer Observatory at 17\,K and 18\,K. The detector sensitivity, which was limited by the mirror's thermal fluctuation at room temperature, was improved in the frequency range of 90\,Hz to 240\,Hz by cooling the mirrors. The improved sensitivity reached a maximum of $2.2 \times 10^{-19}\,\textrm{m}/\sqrt{\textrm{Hz}}$ at 165\,Hz.Comment: Accepted for publication in Physical Review Letters, 5 pages, 2 figure