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Hokkaido University Collection of Scholarly and Academic Papers (135.711 recursos)

HUSCAP (Hokkaido University Collection of Scholarly and Academic Papers) contains peer-reviewed journal articles, proceedings, educational resources and any kind of scholarly works of Hokkaido University.

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  1. Self-assembly of MoO3 needles in gas current for cubic formation pathway

    Ishizuka, Shinnosuke; Kimura, Yuki; Yokoi, Satoki; Yamazaki, Tomoya; Sato, Rikako; Hama, Tetsuya
    Nucleation and subsequent rapid growth are enigmatic due to the unrevealed pathways. Despite the relatively simpler mechanism compared to nucleation and growth in solution, that in vapor has received little attention. The largest hindrance to unveiling this process may be observing the rapid and mesoscopic-scale phenomena. To overcome this hindrance, we combine an experimental approach with in situ spatial scanning Fourier-transform infrared spectroscopy, which reveals the nucleating and growing nanoparticles in vapor. The nanoparticles are then collected at different evolutionary stages and analyzed by ex situ transmission electron microscopy (TEM). Needle-shaped molybdenum oxide (MoO3) nanoparticles were formed within similar to...

  2. Comparative analyses of whole-genome protein sequences from multiple organisms

    Yokono, Makio; Satoh, Soichirou; Tanaka, Ayumi
    Phylogenies based on entire genomes are a powerful tool for reconstructing the Tree of Life. Several methods have been proposed, most of which employ an alignment-free strategy. Average sequence similarity methods are different than most other whole-genome methods, because they are based on local alignments. However, previous average similarity methods fail to reconstruct a correct phylogeny when compared against other whole-genome trees. In this study, we developed a novel average sequence similarity method. Our method correctly reconstructs the phylogenetic tree of in silico evolved E. coli proteomes. We applied the method to reconstruct a whole-proteome phylogeny of 1,087 species from...

  3. Assembling interferometers and in-situ observation of ambient environments and solid-liquid interfaces

    Kimura, Yuki; Murayama, Kenta; Yamazaki, Tomoya; Maki, Takao
    The principle of interferometers and its applicability to our research on crystal growth can be understood through assembling interferometers. In particular, practical skills such as techniques for assembling interferometers and selecting optical components, which are not covered by general textbooks, can be learned.

  4. In-situ observation of crystal surfaces by optical microscopy

    Sazaki, Gen; Nagashima, Ken; Murata, Ken-ichiro; Furukawa, Yoshinori
    In this experimental course, attendees will learn how to obtain useful information about growth processes of crystals using ordinary optical microscopes, which are usually available in laboratories. We will demonstrate how thicknesses of crystals can be estimated from interference colors. We will also show in-situ observations of spiral steps and strain distributions by differential interference contrast microscopy and polarizing microscopy, respectively.

  5. Low ocean-floor rises regulate subpolar sea surface temperature by forming baroclinic jets

    Mitsudera, Humio; Miyama, T.; Nishigaki, H.; Nakanowatari, T.; Nishikawa, H.; Nakamura, Tomohiro; Wagawa, T.; Furue, R.; Fujii, Y.; Ito, S.
    Sea surface temperature (SST) fronts in mid-to high-latitude oceans have significant impacts on extratropical atmospheric circulations and climate. In the western subarctic Pacific, sharp SST fronts form between the cold subarctic water and the recently found quasi-stationary jets that advect warm waters originating in the Kuroshio northeastward. Here we present a new mechanism of the jet formation paying attention to the propagation of baroclinic Rossby waves that is deflected by eddy-driven barotropic flows over bottom rises, although their height is low (similar to 500 m) compared with the depth of the North Pacific Ocean (similar to 6000 m). Steered by...

  6. Seasonal-Scale Dating of a Shallow Ice Core From Greenland Using Oxygen Isotope Matching Between Data and Simulation

    Furukawa, Ryoto; Uemura, Ryu; Fujita, Koji; Sjolte, Jesper; Yoshimura, Kei; Matoba, Sumito; Iizuka, Yoshinori
    A precise age scale based on annual layer counting is essential for investigating pastenvironmental changes from ice core records. However, subannual scale dating is hampered by theirregular intraannual variabilities of oxygen isotope (δ18O) records. Here we propose a dating method basedon matching the δ18O variations between ice core records and records simulated by isotope-enabled climatemodels. We applied this method to a new δ18O record from an ice core obtained from a dome site insoutheast Greenland. The close similarity between the δ18O records from the ice core and models enablescorrelation and the production of a precise age scale, with an accuracy...

  7. Design and results of the ice sheet model initialisation experiments initMIP-Greenland: an ISMIP6 intercomparison

    Goelzer, Heiko; Nowicki, Sophie; Edwards, Tamsin; Beckley, Matthew; Abe-Ouchi, Ayako; Aschwanden, Andy; Calov, Reinhard; Gagliardini, Olivier; Gillet-Chaulet, Fabien; Golledge, Nicholas R.; Gregory, Jonathan; Greve, Ralf; Humbert, Angelika; Huybrechts, Philippe; Kennedy, Joseph H.; Larour, Eric; Lipscomb, William H.; Le clec'h, Sébastien; Lee, Victoria; Morlighem, Mathieu; Pattyn, Frank; Payne, Antony J.; Rodehacke, Christian; Rückamp, Martin; Saito, Fuyuki; Schlegel, Nicole; Seroussi, Helene; Shepherd, Andrew; Sun, Sainan; van de Wal, Roderik; Ziemen, Florian A.
    Earlier large-scale Greenland ice sheet sea-level projections (e.g. those run during the ice2sea and SeaRISE initiatives) have shown that ice sheet initial conditions have a large effect on the projections and give rise to important uncertainties. The goal of this initMIP-Greenland intercomparison exercise is to compare, evaluate, and improve the initialisation techniques used in the ice sheet modelling community and to estimate the associated uncertainties in modelled mass changes. initMIP-Greenland is the first in a series of ice sheet model intercomparison activities within ISMIP6 (the Ice Sheet Model Intercomparison Project for CMIP6), which is the primary activity within the Coupled...

  8. Sulfuritortus calidifontis gen. nov., sp nov., a sulfur oxidizer isolated from a hot spring microbial mat

    Kojima, Hisaya; Watanabe, Miho; Fukui, Manabu
    A novel sulfur-oxidizing autotrophic bacterium, strain J1A(T) was isolated from a hot spring microbial mat. The cells were Gram-stain-negative, catalase-negative and oxidase-positive. As sole electron donor for chemolithoautotrophic growth, strain J1A(T) utilized sulfide, thiosulfate, elemental sulfur, and tetrathionate. The G+C content of the genomic DNA was 66 mol%. Major cellular fatty acids (>40% of total) were C-16:0 and summed feature 3 (C-16:1 omega 7c and/or C-16:1 omega 6c). The predominant quinone was Q-8. Phylogenetic analysis of the 16S rRNA gene indicated that strain J1A(T) is a relative of species of the genus Thiobacillus, but shares only 93% or lower sequence...

  9. Stable carbon and nitrogen isotopic compositions of ambient aerosols collected from Okinawa Island in the western North Pacific Rim, an outflow region of Asian dusts and pollutants

    Kunwar, Bhagawati; Kawamura, Kimitaka; Zhu, Chunmao
    Stable carbon (delta C-13) and nitrogen (delta N-15) isotope ratios were measured for total carbon (TC) and nitrogen (TN), respectively, in aerosol (TSP) samples collected at Cape Hedo, Okinawa, an outflow region of Asian pollutants, during 2009-2010. The averaged delta C-13 and delta N-15 ratios are -22.2 parts per thousand and +12.5 parts per thousand, respectively. The delta C-13 values are similar in both spring (-22.5 parts per thousand) and winter (-22.5 parts per thousand), suggesting the similar sources and/or source regions. We found that delta C-13 from Okinawa aerosols are ca. 2 parts per thousand higher than those reported...

  10. Tracing atmospheric transport of soil microorganisms and higher plant waxes in the East Asian outflow to the North Pacific Rim by using hydroxy fatty acids: Year-round observations at Gosan, Jeju Island

    Tyagi, Poonam; Kawamura, Kimitaka; Kariya, Tadashi; Bikkina, Srinivas; Fu, Pingqing; Lee, Meehye
    Atmospheric transport of soil microorganisms and higher plant waxes in East Asia significantly influences the aerosol composition over the North Pacific. This study investigates the year-round atmospheric abundances of hydroxy fatty acids (FAs), tracers of soil microorganisms (-isomers), and plant waxes (- and -isomers), in total suspended particles collected at Gosan, Jeju Island, during April 2001 to March 2002. These hydroxy FAs showed a pronounced seasonality, higher concentrations in winter/spring and lower concentrations in summer/autumn, which are consistent with other tracers of soil microbes (trehalose), resuspended dust (nss-Ca2+), and stable carbon isotopic composition (C-13) of total carbon. The molecular distributions...

  11. Effects of chemical composition and mixing state on size-resolved hygroscopicity and cloud condensation nuclei activity of submicron aerosols at a suburban site in northern Japan in summer

    Müller, Astrid; Miyazaki, Yuzo; Aggarwal, Shankar G.; Kitamori, Yasuyuki; Boreddy, Suresh K. R.; Kawamura, Kimitaka
    Ambient hygroscopic properties, numbers of size-segregated cloud condensation nuclei (CCN) at different supersaturations (0.1%-0.8%), and the chemical composition of submicron particles were simultaneously measured at a suburban site in northern Japan in summer. Two distinct periods with different growth factors (GF), CCN activation diameters, and chemical compositions were observed. The data suggest that internally mixed sulfate aerosols dominated the accumulation size mode in relatively aged aerosols during the first period, whereas particles observed during the latter periods showed external mixing dominated by organics, which was linked to low hygroscopicity and CCN activity. In particular, the higher loading of water-soluble organic...

  12. Dissolved iron distribution in the western and central subarctic Pacific : HNLC water formation and biogeochemical processes

    Nishioka, Jun; Obata, Hajime
    It is well known that phytoplankton growth is broadly limited by iron (Fe) availability in the subarctic Pacific. To investigate which Fe sources control the amplitude of seasonal variation in biogeochemical parameters in the subarctic Pacific, we examined the spatial variation in the west-to-east distribution of dissolved Fe (DFe) across the western and central subarctic Pacific through the Japanese GEOTRACES program. The vertical section profile of the western subarctic Pacific gyre showed high dissolved Fe concentrations from the bottom of the surface mixed layer to as deep as approximately 3000 m, suggesting that Fe-rich intermediate water is transported laterally and...

  13. Thirteen years of observations on primary sugars and sugar alcohols over remote Chichijima Island in the western North Pacific

    Verma, Santosh Kumar; Kawamura, Kimitaka; Chen, Jing; Fu, Pingqing
    In order to understand the atmospheric transport of bioaerosols, we conducted long-term observations of primary sugars and sugar alcohols over remote Chichijima Island in the western North Pacific from 2001 to 2013. Our results showed that concentrations of total sugar compounds for 13 years ranged from 1.2 to 310 ngm(-3) (average of 46 +/- 49 ngm(-3)). We found that atmospheric circulations significantly affect the seasonal variations of bioaerosol distributions over the western North Pacific. The primary sugars (glucose and fructose) maximized in summer, possibly due to an increased emission of the vegetation products from local vascular plants in Chichijima. We...

  14. Long-term (2001-2012) trends of carbonaceous aerosols from a remote island in the western North Pacific: an outflow region of Asian pollutants

    Boreddy, Suresh K. R.; Haque, M. Mozammel; Kawamura, Kimitaka
    The present study reports on long-term trends of carbonaceous aerosols in total suspended particulate (TSP) samples collected at Chichijima in the western North Pacific during 2001-2012. Seasonal variations of elemental carbon (EC), organic carbon (OC), and water-soluble organic carbon (WSOC) concentrations showed maxima in winter to spring and minima in summer. These seasonal differences in the concentrations of carbonaceous aerosols were associated with the outflows of polluted air masses from East Asia, which are clearly distinguishable from pristine air masses from the central Pacific. The higher concentrations of carbonaceous aerosols during winter to spring are associated with long-range atmospheric transport...

  15. Processes of breaking of large-amplitude unsteady lee waves leading to turbulence

    Abe, S.; Nakamura, T.
    The transition to t urbulence after excitation of large-amplitude (~200 m) unsteady lee waves in Amchitka Pass, Alaska, is investigated using a nonhydrostatic vertically two-dimensional model with realistic topography. The model resolves motions two orders smaller than a large-amplitude unsteady lee wave, which is excited in the lee of the ridge, and shows that transition processes near the ridge top and downstream of the first trough of the unsteady lee wave are different. Near the ridge top, three stages of transition are identified. In the first stage, convection begins on the upstream sides (forward wave breaking) and downstream sides (backward...

  16. A survey of small terrestrial mammals in southern Sakhalin, conducted in 1994 and 1995

    Abe, Hisashi; Ohdachi, Satoshi; Maekawa, Koji
    We conducted a survey of small terrestria mammals by collecting samples from nine locations in southern Sakhalin, during the summer months of 1994 and 1995. Target animals included both murid and soricid species. "Panchu" kill traps and pitfall traps were used to capture animals. Most murid species captured were Apodemus peninsulae, Clethrionomry rutilus, and C. rufocanus. In addition, an individual of Myopus schisticolor was collected. Soricid species captured include Sorex gracillimus, S. unguiculatus, S. caecutiens, and S. daphaenodon.

  17. Correction for the misidentification of a shrew in Sakhalin by Abe et al. (1997) by analysis of the full nucleotide sequence of the mitochondrial cytochrome b gene

    Ohdachi, Satoshi
    One shrew specimen which is identified as Sorex unguiculatus in Abe et al. (1997) was reexamined. According to morphological characters and nucleotide sequences of the mitochondrial cytochrome b gene, it is reidentified as Sorex isodon.

  18. Changes in water properties and flow regime on the continental shelf off the Adelie/George V Land coast, East Antarctica, after glacier tongue calving

    Aoki, S.; Kobayashi, R.; Rintoul, S. R.; Tamura, T.; Kusahara, K.
    Oceanic changes before and after the relocation of iceberg B9B and calving of the Mertz Glacier Tongue (MGT) in February 2010 are examined on the continental shelf off the Adelie Land/George V Land coast, East Antarctica. Summer hydrographic observations, including stable oxygen isotope ratio (delta O-18), in 2001/2008 and 2011/2015 and results of a numerical model are used. Along the western flank of the MGT, temperature decreased between 2001 and 2015 for most of the water column in the Adelie Depression. delta O-18 generally decreased, especially at the MGT draft depths on the northern side. West of the MGT, temperature,...

  19. Evaluation of Marine Surface Wind Speed Observations From AMSR2 on GCOM-W Satellite

    Ebuchi, Naoto
    Observations of marine surface scalar wind speeds from the advanced microwave scanning radiometer 2 (AMSR2), onboard the global change observation mission-water satellite (GCOM-W), were evaluated by comparisons with offshore moored buoy measurements, output from the European Centre for Medium Range Weather Forecast Reanalysis Interim, and observations by the RapidScat (RSCAT) scatterometer onboard the International Space Station. In general, the AMSR2 wind speeds agreed well with the reference data. The root mean square difference between the AMSR2 and buoy measurements was 1.09 ms(-1), which is slightly larger than the mission goal of 1 ms(-1). Underestimation at low wind speeds (< 5ms(-1))...

  20. On the extraordinary snow on the sea ice off East Antarctica in late winter, 2012

    Toyota, Takenobu; Massom, Robert; Lecomte, Olivier; Nomura, Daiki; Heil, Petra; Tamura, Takeshi; Fraser, Alexander D.
    In late winter-early spring 2012, the second Sea Ice Physics and Ecosystems Experiment (SIPEX II) was conducted off Wilkes Land, East Antarctica, onboard R/V Aurora Australis. The sea-ice conditions were characterized by significantly thick first-year ice and snow, trapping the ship for about 10 days in the near coastal region. The deep snow cover was particularly remarkable, in that its average value of 0.45 m was almost three times that observed between 1992 and 2007 in the region. To reveal factors responsible, we used in situ observations and ERA-Interim reanalysis (1990-2012) to examine the relative contribution of the different components...

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