The interstellar medium:the key component in galactic evolution and modern cosmology     

Carl Heiles  Di Li  Naomi McClure-Griffiths  Lei Qian  Shu Liu 《天文和天体物理学研究(英文版)》2019,(2)

The gases of the interstellar medium(ISM) possess orders of magnitude more mass than those of all the stars combined and are thus the prime component of the baryonic Universe. With L-band surface sensitivity even better than the planned phase one of the Square Kilometre Array(SKA1), the Five-hundredmeter Aperture Spherical radio Telescope(FAST) promises unprecedented insights into two of the primary components of ISM, namely, atomic hydrogen(HI) and the hydroxyl molecule(OH). Here, we discuss the evolving landscape of our understanding of ISM, particularly, its complex phases, the magnetic fields within, the so-called dark molecular gas(DMG), high velocity clouds and the connection between local and distant ISM. We lay out, in broad strokes, several expected FAST projects, including an all northern-sky high-resolution HI survey(22 000 deg2, 3′FWHM beam, 0.2 km s~(-1)), targeted OH mapping, searching for absorption and maser signals, etc. Currently under commissioning, the commensal observing mode of FAST will be capable of simultaneously obtaining HI and pulsar data streams, making large-scale surveys in both science areas more efficient.  相似文献   

Changes in paleoseismic studies of active faults in Japan since the 1995 Kobe earthquake     

Yoko Ota 《Journal of Geodynamics》2000,29(3-5)

This paper discusses recent progress of onshore active faults studies in Japan, especially since the 1995 destructive Kobe earthquake, when the number of trenching studies, which are essential for the reconstruction of onshore paleoearthquakes, has rapidly increased. The timing and repeat interval of paleoearthquakes are here reviewed for the Miura Peninsula, south of Tokyo and the Awaji Island and Kobe-Osaka area, in central Japan, where trenching have been carried out very intensively in the last few years.  相似文献   

Developing best practice for using Marxan to locate Marine Protected Areas in European waters     

Smith  Robert J.; Eastwood  Paul D.; Ota  Yoshitaka; Rogers  Stuart I. 《ICES Journal of Marine Science》2009,66(1):188-194

  相似文献   

Fleet sizes,fishing effort and the ‘hidden’ factors behind statistics: An anthropological study of small-scale fisheries in UK     

Yoshitaka Ota  Roger Just 《Marine Policy》2008

The assessment of fishing effort is a vital part of fisheries management. However, assessing fishing effort by small-scale local fleets is often problematic, partly because of the complex socio-economic and cultural factors that govern the labour patterns of different fisheries employing different fishing practices. Often, official statistics produced by governmental agencies do not fully capture these factors, so a more holistic understanding of regional fisheries is required. Some contribution by social anthropologists is thus called for, in order to assess actual fishing effort and the trend of regional changes in fishing activities.  相似文献   

Evaluation of slope stability by finite element method using observed displacement of landslide   总被引：1，自引：0，他引：1  

Yasuo Ishii  Keiichi Ota  Senro Kuraoka  Ryosuke Tsunaki 《Landslides》2012,9(3):335-348

To monitor land deformation in detail, we ran a large-scale field test in which an artificial landslide was induced by the application of a load to a natural slope. The measured landslide displacement was reproduced numerically through the use of finite element model analysis with a two-dimensional elasto-viscoplastic model. The analysis suggested that the strength of the sliding surface decreased as the landslide mass moved. We propose a simple method for estimating safety factors. The method involves back-calculation of shear strength parameters through reproduction of observed landslide displacements and calculating the ratio of driving force to resisting force acting on the sliding surface as modeled by joint elements. This ratio, the “stability index”, shows the same trend as safety factors calculated by a two-dimensional limit equilibrium method and a shear strength reduction method that use back-calculated shear strength parameters estimated from the limit equilibrium state. The results indicate that the stability index may be applicable to the assessment of slope stability.  相似文献   

Impact of mesoscale eddies on particulate organic carbon flux in the western subarctic North Pacific     

Dobashi  Ryo  Ueno  Hiromichi  Matsudera  Nozomi  Fujita  Isao  Fujiki  Tetsuichi  Honda  Makio C.  Harada  Naomi 《Journal of Oceanography》2022,78(1):1-14

The mechanism that controls particulate organic carbon (POC) flux in the deep sea differs depending on the season and sea. The POC produced in the western subarctic North Pacific are known to be transported to the deep sea efficiently, but the direct relationship between the POC flux and physical processes is still unclear. In this study, we evaluated the effect of mesoscale eddies on POC flux in the western subarctic North Pacific. The seasonal and interannual variabilities of POC flux were investigated using data from a time-series sediment trap deployed at 4810 m at station K2 (47°N, 160°E) from 2005 to 2018. POC flux was high during May–November, appearing to reflect spring and fall blooms at the ocean surface. POC flux also showed interannual variability, with twelve peaks that were mostly affected by enhanced bloom just before the peak. Nine peaks of the twelve peaks were affected by mesoscale eddies, which enhanced bloom around K2 by extending the area with a high chlorophyll-a concentration along the coastal region into the offshore region, suggesting that mesoscale eddies strongly impact the interannual variability of POC flux at K2.

  相似文献   

Mammal remains at Rantis Cave,Israel, and Middle–Late Pleistocene human subsistence and ecology in the Southern Levant     

Ofer Marder  Reuven Yeshurun  Ronit Lupu  Guy Bar‐Oz  Miriam Belmaker  Naomi Porat  Hagai RON  Amos Frumkin 《第四纪科学杂志》2011,26(8):769-780

Rantis Cave is a recently discovered filled cave in central Israel, displaying a rich faunal accumulation of micromammals, ungulates and carnivores. U–Th dating assigns the beginning of accumulation to ca. 140 ka. The accumulation is culturally assigned to the late half of the Middle Paleolithic (MP) period. Single‐grain optically stimulated luminescence measurements attest to a complex sedimentological history. We present the cross‐disciplinary results of taphonomic and geomorphological analyses, which point to the cave serving as a natural pitfall trap for the large fauna, with little human or carnivore activity. The fauna is dominated by Dama among the ungulates and by Microtus among the micromammals. These data in conjunction with ungulate tooth mesowear analysis suggest a xeric Mediterranean environment on the eastern margin of the southern Levantine foothills. The relative taxonomic abundance of ungulate taxa shows some differences from anthropogenic MP sites, possibly reflecting the prey choice patterns of MP hunters. Overall, the natural accumulation scenario for Rantis Cave provides a rare paleoenvironmental and paleoeconomic reference to the rich anthropogenic MP faunas of the Southern Levant, enabling the reconstruction of a rich and diverse environmental setting for this important human dispersal route. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

Metaphors of warfare and the lessons of history: time to revisit a carbon tax?     

Naomi Oreskes 《Climatic change》2011,104(2):223-230

  相似文献   

On the “reality” and reality of anthropogenic climate change     

Naomi Oreskes 《Climatic change》2013,119(3-4):559-560

  相似文献   

Effects of ocean particles on the upwelling radiance and polarized radiance in the atmosphere-ocean system     

Chong Shi  Pucai Wang  Teruyuki Nakajima  Yoshifumi Ota  Saichun Tan  Guangyu Shi 《大气科学进展》2015,32(9):1186-1196

Based on a vector radiative transfer model of the atmosphere-ocean system, the influence of oceanic components on radiation processes, including polarization effects, was investigated in the wavelength region ranging from 0.380 to 0.865 μm. The components considered were phytoplankton, inorganic suspended material (sediment), and colored, dissolved organic matter. Due to their important roles in oceanic radiation processes, the sensitivity of the bidirectional reflectance to the rough ocean surface, represented by the wind velocity 10 m above the ocean surface, and aerosol, were taken into account. The results demonstrated that both radiance and polarized radiance just below the ocean surface were sensitive to the change of the concentrations of the considered components, while the dependence of polarized radiance on the observation geometry was more sensitive than radiance. Significant differences in the specular plane existed between the impacts of the phytoplankton and sediment on the degree of polarization just above the ocean surface at 670 nm. At the top of the atmosphere (TOA), polarization was relatively insensitive to changing concentrations of ocean particles at longer wavelengths. Furthermore, the radiance at the TOA in the solar plane was more sensitive to the aerosol optical thickness than wind velocity. In contrast, wind velocity strongly influenced the radiance at the TOA in the sun glint region, while the polarization degree showed less dependence in that region. Finally, a nonlinear optimal inversion method was proposed to simultaneously retrieve the aerosol and wind velocity using radiance measurement.  相似文献