62 research outputs found
Three dimensional evolution of differentially rotating magnetized neutron stars
We construct a new three-dimensional general relativistic
magnetohydrodynamics code, in which a fixed mesh refinement technique is
implemented. To ensure the divergence-free condition as well as the magnetic
flux conservation, we employ the method by Balsara (2001). Using this new code,
we evolve differentially rotating magnetized neutron stars, and find that a
magnetically driven outflow is launched from the star exhibiting a kink
instability. The matter ejection rate and Poynting flux are still consistent
with our previous finding (Shibata et al., 2011) obtained in axisymmetric
simulations.Comment: 12 pages, 14 figures, accepted by PR
Reanalysis of the binary neutron star merger GW170817 using numerical-relativity calibrated waveform models
We reanalyze gravitational waves from a binary-neutron-star merger GW170817 using a numerical-relativity (NR) calibrated waveform model, the TF2+_KyotoTidal model. By imposing a uniform prior on the binary tidal deformability the symmetric credible interval of is estimated to be () for the case of (), where is the maximum frequency in the analysis. We also reanalyze the event with other waveform models: two post-Newtonian waveform models (TF2PNTidal and TF2+PNTidal), the TF2+NRTidal model that is another NR calibrated waveform model used in the LIGO-Virgo analysis, and its upgrade, the TF2+NRTidalv2 model. While estimates of parameters other than are broadly consistent among different waveform models, our results indicate that there is a difference in estimates of among three NR calibrated waveform models. The difference in the peak values of posterior probability density functions of between the NR calibrated waveform models: the TF2+KyotoTidal and TF2+NRTidalv2 models for is about 40 and is much smaller than the width of credible interval, which is about 700. The systematic error for the NR calibrated waveform models will be significant to measure in the case of GW170817-like signal for the planned third generation detectors's sensitivities
Constraint propagation equations of the 3+1 decomposition of f(R) gravity
Theories of gravity other than general relativity (GR) can explain the
observed cosmic acceleration without a cosmological constant. One such class of
theories of gravity is f(R). Metric f(R) theories have been proven to be
equivalent to Brans-Dicke (BD) scalar-tensor gravity without a kinetic term.
Using this equivalence and a 3+1 decomposition of the theory it has been shown
that metric f(R) gravity admits a well-posed initial value problem. However, it
has not been proven that the 3+1 evolution equations of metric f(R) gravity
preserve the (hamiltonian and momentum) constraints. In this paper we show that
this is indeed the case. In addition, we show that the mathematical form of the
constraint propagation equations in BD-equilavent f(R) gravity and in f(R)
gravity in both the Jordan and Einstein frames, is exactly the same as in the
standard ADM 3+1 decomposition of GR. Finally, we point out that current
numerical relativity codes can incorporate the 3+1 evolution equations of
metric f(R) gravity by modifying the stress-energy tensor and adding an
additional scalar field evolution equation. We hope that this work will serve
as a starting point for relativists to develop fully dynamical codes for valid
f(R) models.Comment: 25 pages, matches published version in CQG, references update
Conjugated docosahexaenoic acid suppresses KPL-1 human breast cancer cell growth in vitro and in vivo: potential mechanisms of action
Introduction The present study was conducted to examine the effect of conjugated docosahexaenoic acid (CDHA) on cell growth, cell cycle progression, mode of cell death, and expression of cell cycle regulatory and/or apoptosis-related proteins in KPL-1 human breast cancer cell line. This effect of CDHA was compared with that of docosahexaenoic acid (DHA).
Methods KPL-1 cell growth was assessed by colorimetric 3- (4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay; cell cycle progression and mode of cell death were examined by flow cytometry; and levels of expression of p53, p21Cip1/Waf1, cyclin D1, Bax, and Bcl-2 proteins were examined by Western blotting analysis. In vivo tumor growth was examined by injecting KPL-1 cells subcutaneously into the area of the right thoracic mammary fat pad of female athymic mice fed a CDHA diet.
Results CDHA inhibited KPL-1 cells more effectively than did DHA (50% inhibitory concentration for 72 hours: 97 μmol/l and 270 μmol/l, respectively). With both CDHA and DHA growth inhibition was due to apoptosis, as indicated by the appearance of a sub-G1 fraction. The apoptosis cascade involved downregulation of Bcl-2 protein; Bax expression was unchanged. Cell cycle progression was due to G0/G1 arrest, which involved increased expression of p53 and p21Cip1/Waf1, and decreased expression of cyclin D1. CDHA modulated cell cycle regulatory proteins and apoptosis-related proteins in a manner similar to that of parent DHA. In the athymic mouse system 1.0% dietary CDHA, but not 0.2%, significantly suppressed growth of KPL-1 tumor cells; CDHA tended to decrease regional lymph node metastasis in a dose dependent manner.
Conclusion CDHA inhibited growth of KPL-1 human breast cancer cells in vitro more effectively than did DHA. The mechanisms of action involved modulation of apoptosis cascade and cell cycle progression. Dietary CDHA at 1.0% suppressed KPL-1 cell growth in the athymic mouse system.</p
Cognitive and Psychological Reactions of the General Population Three Months After the 2011 Tohoku Earthquake and Tsunami
BACKGROUND: The largest earthquake on record in Japan (magnitude 9.0) occurred on March 11, 2011, and the subsequent tsunami devastated the Pacific coast of Northern Japan. These further triggered the Fukushima I nuclear power plant accidents. Such a hugely complex disaster inevitably has negative psychological effects on general populations as well as on the direct victims. While previous disaster studies enrolled descriptive approaches focusing on direct victims, the structure of the psychological adjustment process of people from the general population has remained uncertain. The current study attempted to establish a path model that sufficiently reflects the early psychological adaptation process of the general population to large-scale natural disasters. METHODS AND FINDINGS: Participants from the primary disaster area (n = 1083) and other areas (n = 2372) voluntarily participated in an online questionnaire study. By constructing path models using a structural equation model procedure (SEM), we examined the structural relationship among psychological constructs known related to disasters. As post-traumatic stress symptoms (PTS) were significantly more present in people in the primarily affected area than in those in secondary- or non-affected areas, the path models were constructed for the primary victims. The parsimoniously depicted model with the best fit was achieved for the psychological-adjustment centered model with quality of life (QoL) as a final outcome. CONCLUSION: The paths to QoL via negative routes (from negative cognitive appraisal, PTS, and general stress) were dominant, suggesting the importance of clinical intervention for reducing negative cognitive appraisal, and for caring for general stress and PTS to maintain QoL at an early stage of psychological adaptation to a disaster. The model also depicted the presence of a positive route where positive cognitive appraisal facilitates post-traumatic growth (PTG) to achieve a higher QoL, suggesting the potential importance of positive psychological preventive care for unexpected natural disasters
Fibrotic Myofibroblasts Manifest Genome-Wide Derangements of Translational Control
Background: As a group, fibroproliferative disorders of the lung, liver, kidney, heart, vasculature and integument are common, progressive and refractory to therapy. They can emerge following toxic insults, but are frequently idiopathic. Their enigmatic propensity to resist therapy and progress to organ failure has focused attention on the myofibroblast–the primary effector of the fibroproliferative response. We have recently shown that aberrant beta 1 integrin signaling in fibrotic fibroblasts results in defective PTEN function, unrestrained Akt signaling and subsequent activation of the translation initiation machinery. How this pathological integrin signaling alters the gene expression pathway has not been elucidated. Results: Using a systems approach to study this question in a prototype fibrotic disease, Idiopathic Pulmonary Fibrosis (IPF); here we show organized changes in the gene expression pathway of primary lung myofibroblasts that persist for up to 9 sub-cultivations in vitro. When comparing IPF and control myofibroblasts in a 3-dimensional type I collagen matrix, more genes differed at the level of ribosome recruitment than at the level of transcript abundance, indicating pathological translational control as a major characteristic of IPF myofibroblasts. To determine the effect of matrix state on translational control, myofibroblasts were permitted to contract the matrix. Ribosome recruitment in control myofibroblasts was relatively stable. In contrast, IPF cells manifested large alterations in the ribosome recruitment pattern. Pathological studies suggest an epithelial origin for IPF myofibroblasts through the epithelial to mesenchymal transition (EMT). In accord wit
The Einstein Toolkit: A Community Computational Infrastructure for Relativistic Astrophysics
We describe the Einstein Toolkit, a community-driven, freely accessible
computational infrastructure intended for use in numerical relativity,
relativistic astrophysics, and other applications. The Toolkit, developed by a
collaboration involving researchers from multiple institutions around the
world, combines a core set of components needed to simulate astrophysical
objects such as black holes, compact objects, and collapsing stars, as well as
a full suite of analysis tools. The Einstein Toolkit is currently based on the
Cactus Framework for high-performance computing and the Carpet adaptive mesh
refinement driver. It implements spacetime evolution via the BSSN evolution
system and general-relativistic hydrodynamics in a finite-volume
discretization. The toolkit is under continuous development and contains many
new code components that have been publicly released for the first time and are
described in this article. We discuss the motivation behind the release of the
toolkit, the philosophy underlying its development, and the goals of the
project. A summary of the implemented numerical techniques is included, as are
results of numerical test covering a variety of sample astrophysical problems.Comment: 62 pages, 20 figure
Relationship between salivary cortisol and depression in adolescent survivors of a major natural disaster
Loss of periostin/OSF-2 in ErbB2/Neu-driven tumors results in androgen receptor-positive molecular apocrine-like tumors with reduced Notch1 activity
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