72 research outputs found
Equation of State in Numerical Relativistic Hydrodynamics
Relativistic temperature of gas raises the issue of the equation of state
(EoS) in relativistic hydrodynamics. We study the EoS for numerical
relativistic hydrodynamics, and propose a new EoS that is simple and yet
approximates very closely the EoS of the single-component perfect gas in
relativistic regime. We also discuss the calculation of primitive variables
from conservative ones for the EoS's considered in the paper, and present the
eigenstructure of relativistic hydrodynamics for a general EoS, in a way that
they can be used to build numerical codes. Tests with a code based on the Total
Variation Diminishing (TVD) scheme are presented to highlight the differences
induced by different EoS's.Comment: To appear in the ApJS September 2006, v166n1 issue. Pdf with full
resolution figures can be downloaded from
http://canopus.cnu.ac.kr/ryu/ryuetal.pd
The X-ray Pulse Profile of BG CMi
We present an analysis of the X-ray data of a magnetic cataclysmic variable,
BG CMi, obtained with ROSAT in March 1992 and with ASCA in April 1996. We show
that four peaks clearly exist in the X-ray pulse profile, unlike a single peak
found in the optical profile. The fluxes of two major pulses are
times larger than those of two minor pulses. The fraction of the total pulsed
flux increases from 51% to 85% with increasing energy in 0.1 2.0 keV,
whereas it decreases from 96% to 22% in 0.8 10 keV. We discuss the
implications of our findings for the origin of the pulse profile and its energy
dependence.Comment: To appear in New Astronom
The Distribution and Migration of 137Cs in Oak (Quercus serrata) and Cedar (Cryptomeria japonica) Forest Organic Fractions
To analyse the 137Cs distribution and migration under various fractions of organic matter layers, this study investigated easily recognizable, originally shaped organic L-fractions, and not easily recognizable, early fermented and fragmented organic F-fractions, of both oak (Quercus serrata) and cedar (Cryptomeria japonica) sampled from Osawa watershed sites at Nihonmatsu City, Fukushima Prefecture, Japan. The organic materials were put on top of soil columns from Field Museum (FM) Tamakyuryo in Hachioji City, Tokyo. The 137Cs vertical distribution in forest soil profiles was analyzed using the relaxation mass depth, ho (kg m−2). Soil columns with both L and F- organic layer fractions of both oak and cedar, labelled as Oak-L, Oak-F, Cedar-L and Cedar-F with four replications (n = 16), were set up by the laboratory column-based method and kept under five months’ incubation period. Soil columns after incubation were sampled at depths of 0–1 cm, 1–2 cm, 2–5 cm and 5–10 cm. Results of 137Cs inventory in the organic fractions showed that 86% (oak and cedar) of the total organic layer fractions 137Cs inventory accumulated within the F-layer, indicating that the transformation of litter is a huge source for potentially mobile 137Cs, especially the oak F-layer (67% 137Cs inventory) and further continuous transfer into the forest soil mineral layers. A higher ho in L treated soils (Oak-L and Cedar-L) compared to the F treatments implied that the low 137Cs amounts penetrated faster and deeper due to their water-soluble nature. Furthermore, Cedar-F showed a higher ho of 24.3 kg m−2 than Oak-F of ho, 14.0 kg m−2, and a significant positive relationship between 137Cs retention and total carbon (TC) (p < 0.05) suggested the influence of soil organic matter on 137Cs penetration and retention. The C/N (carbon nitrogen ratio) results revealed that organic matter fractions of high C/N including 137Cs, as observed in Cedar-F, in which decomposition does not advance, penetrates soil depths while the organic matter fraction of low C/N, observed in Oak-F, showed that decomposition advanced to release 137Cs which was held by adsorption unto the RIP (radiocesium interception potential) of soil surface. In addition, infiltration by water as a transportation process was suggested to largely influence the downward migration and retention of 137Cs at lower depths of Cedar-F.Japan Society for the Promotion of SciencePeer Reviewe
Leaf Longevity and Defense Characteristics in Trees of Betulaceae
北海道大学Foresty amd ForestProducts Research Institute(FFPRI)Hokkaido Research center, FFPRIProceedings : IUFRO Kanazawa 2003 "Forest Insect Population Dynamics and Host Influences"., Scedule:14-19 September 2003, Vemue: Kanazawa Citymonde Hotel, Kanazawa, Japan, Joint metting of IUFRO working groups : 7.01.02 Tree resistance to Insects | 7.03.06 Integrated management of forset defoloating insects | 7.03.07 Population dynamics of forest insects, Sponsored by: IUFRO-J | Ishikawa Prefecture | Kanazawa City | 21st-COE Program of Kanazawa University, Editors: Kamata, Naoto | Liebhold, Nadrew M. | Quiring, Dan T. | Clancy, Karen M
Hydrodynamic Interactions of Relativistic Extragalactic Jets with Dense Clouds
We have studied three-dimensional hydrodynamic interactions of relativistic
extragalactic jets with two-phase ambient media. These jets propagate through a
denser homogeneous gas and then impact clouds with densities 100 to 1000 times
higher than the initial beam density. The deflection angle of the jet is
influenced more by the density contrast of the cloud than by the beam Mach
number of the jet. A relativistic jet with low relativistic beam Mach number
can eventually be slightly bent after it crosses the dense cloud; however, we
have not seen permanently bent structures in the interaction of a high
relativistic beam Mach number jet with a cloud. The relativistic jet impacts on
dense clouds do not necessarily destroy the clouds completely, and much of the
cloud body can survive as a coherent blob. This enhancement of cloud durability
is partly due to the geometric influence of the off-axis collisions we consider
and also arises from the lower rate of cloud fragmentation through the
Kelvin-Helmholtz instability for relativistic jets. To compare our simulations
with observed extragalactic radio jets, we have computed the approximate
surface distributions of synchrotron emission at different viewing angles.
These surface intensity maps show relativistic jets interacting with clouds can
produce synchrotron emission knots similar to structures observed in many
VLBI-scale radio sources. We find that the synchrotron emission increases
steeply at the moment of impact and the emission peaks right before the jet
passes through the cloud.Comment: 32 pages, 7 figures, accepted for publication in Ap
Prognostic Role of TMED3 in Clear Cell Renal Cell Carcinoma: A Retrospective Multi-Cohort Analysis
Transmembrane p24 trafficking protein 3 (TMED3) is a metastatic suppressor in colon cancer and hepatocellular carcinoma. However, its function in the progression of clear cell renal cell carcinoma (ccRCC) is unknown. Here, we report that TMED3 could be a new prognostic marker for ccRCC. Patient data were extracted from cohorts in the Cancer Genome Atlas (TCGA) and the International Cancer Genome Consortium (ICGC). Differential expression of TMED3 was observed between the low stage (Stage I and II) and high stage (Stage III and IV) patients in the TCGA and ICGC cohorts and between the low grade (Grade I and II) and high grade (Grade III and IV) patients in the TCGA cohort. Further, we evaluated TMED3 expression as a prognostic gene using Kaplan-Meier survival analysis, multivariate analysis, the time-dependent area under the curve (AUC) of Uno’s C-index, and the AUC of the receiver operating characteristics at 5 years. The Kaplan-Meier analysis revealed that TMED3 overexpression was associated with poor prognosis for ccRCC patients. Analysis of the C-indices and area under the receiver operating characteristic curve further supported this. Multivariate analysis confirmed the prognostic significance of TMED3 expression levels (P = 0.005 and 0.006 for TCGA and ICGC, respectively). Taken together, these findings demonstrate that TMED3 is a potential prognostic factor for ccRCC
Tactile Avatar: Tactile Sensing System Mimicking Human Tactile Cognition
As a surrogate for human tactile cognition, an artificial tactile perception and cognition system are proposed to produce smooth/soft and rough tactile sensations by its user's tactile feeling; and named this system as “tactile avatar”. A piezoelectric tactile sensor is developed to record dynamically various physical information such as pressure, temperature, hardness, sliding velocity, and surface topography. For artificial tactile cognition, the tactile feeling of humans to various tactile materials ranging from smooth/soft to rough are assessed and found variation among participants. Because tactile responses vary among humans, a deep learning structure is designed to allow personalization through training based on individualized histograms of human tactile cognition and recording physical tactile information. The decision error in each avatar system is less than 2% when 42 materials are used to measure the tactile data with 100 trials for each material under 1.2N of contact force with 4cm s−1 of sliding velocity. As a tactile avatar, the machine categorizes newly experienced materials based on the tactile knowledge obtained from training data. The tactile sensation showed a high correlation with the specific user's tendency. This approach can be applied to electronic devices with tactile emotional exchange capabilities, as well as advanced digital experiences. © 2021 The Authors. Advanced Science published by Wiley-VCH GmbH1
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