109 research outputs found
MHD Simulation of The Inner Galaxy with Radiative Cooling and Heating
We investigate the role of magnetic field on the gas dynamics in the Galactic
bulge region by three dimensional simulations with radiative cooling and
heating. While high-temperature corona with is formed in the
halo regions, the temperature near the Galactic plane is following the thermal equilibrium curve determined by the radiative cooling
and heating. Although the thermal energy of the interstellar gas is lost by
radiative cooling, the saturation level of the magnetic field strength does not
significantly depend on the radiative cooling and heating. The magnetic field
strength is amplified to on average, and reaches several
hundred locally. We find the formation of magnetically dominated
regions at mid-latitudes in the case with the radiative cooling and heating,
which is not seen in the case without radiative effect. The vertical thickness
of the mid-latitude regions is at the radial location of
from the Galactic center, which is comparable to the
observed vertical distribution of neutral atomic gas. When we take the average
of different components of energy density integrated over the Galactic bulge
region, the magnetic energy is comparable to the thermal energy. We conclude
that the magnetic field plays a substantial role in controlling the dynamical
and thermal properties of the Galactic bulge region.Comment: Submitted to ApJ; 21 pages, 18 figures 3 tables. Comment are welcom
Cosmic Ray Production of Li by Structure Formation Shocks in the Early Galaxy
We discuss the production of the element Li in the early Galaxy by cosmic
rays accelerated at structure formation shocks, driven by the hierarchical
merging of sub-Galactic halos during Galaxy formation. The salient features of
this scenario are discussed and compared with observations of Li in
metal-poor halo stars, including a recent Subaru HDS result on the star
HD140283. Some unique predictions of the model are clearly testable by future
observations and may also provide important insight into how the Galaxy formed.Comment: 4 pages, 1 figure; to appear in Nuc. Phys. A; talk at Nuclei in the
Cosmos 7, Fuji-Yoshida, Japan 200
International Competition on Graph Counting Algorithms 2023
This paper reports on the details of the International Competition on Graph
Counting Algorithms (ICGCA) held in 2023. The graph counting problem is to
count the subgraphs satisfying specified constraints on a given graph. The
problem belongs to #P-complete, a computationally tough class. Since many
essential systems in modern society, e.g., infrastructure networks, are often
represented as graphs, graph counting algorithms are a key technology to
efficiently scan all the subgraphs representing the feasible states of the
system. In the ICGCA, contestants were asked to count the paths on a graph
under a length constraint. The benchmark set included 150 challenging
instances, emphasizing graphs resembling infrastructure networks. Eleven
solvers were submitted and ranked by the number of benchmarks correctly solved
within a time limit. The winning solver, TLDC, was designed based on three
fundamental approaches: backtracking search, dynamic programming, and model
counting or #SAT (a counting version of Boolean satisfiability). Detailed
analyses show that each approach has its own strengths, and one approach is
unlikely to dominate the others. The codes and papers of the participating
solvers are available: https://afsa.jp/icgca/.Comment: https://afsa.jp/icgca
Cosmic Ray Production of Lithium-6 by Structure Formation Shocks in the Early Milky Way: A Fossil Record of Dissipative Processes during Galaxy Formation
While the abundances of Be and B observed in metal-poor halo stars are well
explained as resulting from spallation of CNO-enriched cosmic rays (CRs)
accelerated by supernova shocks, accounting for the observed Li in such
stars with supernova CRs is more problematic. Here we propose that
gravitational shocks induced by infalling and merging sub-Galactic clumps
during hierarchical structure formation of the Galaxy should dissipate enough
energy at early epochs, and CRs accelerated by such shocks can provide a
natural explanation of the observed Li. In clear constrast to supernovae,
structure formation shocks do not eject freshly synthesized CNO nor Fe, so that
the only effective production channel at low metallicity is
fusion, capable of generating sufficient Li with no accompanying Be or B
and no direct correspondence with Fe. Correlations between the Li abundance
and the kinematic properties of the halo stars may also be expected in this
scenario. Further, more extensive observations of Li in metal-poor halo
stars, e.g. by the Subaru HDS or VLT/UVES, may offer us an invaluable fossil
record of dissipative dynamical processes which occurred during the formation
of our Galaxy.Comment: Ap.J. in press; 6 pages, 1 figur
Bilateral Ovarian Tumors on MRI : How Should We Differentiate the Lesions?
Background: We investigated the distinguishing pathological features of bilateral ovarian tumors using magnetic resonance (MR) imaging. Methods: Eighty-six patients with bilateral ovarian tumors on MR imaging were evaluated. The pathological diagnosis was investigated, and the results were subjected to statistical analysis using Mann-Whitney U test, Fisher’s exact test, Chi-squared test and receiver operating characteristic (ROC) curve to determine the features useful for the differentiation of distinct types of lesions. Results: The diagnosis of bilateral ovarian tumors was confirmed in eighty-one patients and the majority of the lesions were further classified into serous carcinoma (n = 36), mature teratoma (n = 20) and metastasis (n = 12). We assessed the existence of factors useful for the MR imaging differentiation between metastasis and serous carcinoma or primary malignant ovarian tumors. Cancer antigen (CA) 125 serum level and maximum tumor diameter were significantly different between metastasis and serous carcinoma and similarly, between metastasis and primary malignant ovarian tumors. MR imaging morphology, ascites and peritoneal implants did not show any significant difference between the different types of lesions. Conclusion: Within our patient cohort, most bilateral ovarian tumor lesions were determined to be serous carcinoma, mature teratoma or metastasis. CA 125 serum level and maximum tumor diameter are useful markers for the differentiation between metastasis and serous carcinoma or primary malignant ovarian tumors
Ion Transport in Pendant and Backbone Polymerized Ionic Liquids
Polymerized ionic liquids (PILs) are single-ion conductors in which one of the ionic species is tethered to the polymer chain while the other is free to be transported. The ionic species can either be directly incorporated into the polymeric backbone (backbone PILs) or placed as pendant groups to the chain (pendant PILs). Here, we examined the morphology, conductivity, and rheology of imidazolium-based pendant and backbone PILs. We found that pendant PILs yielded higher ionic conductivity when scaled to Tg, but backbone PILs exhibited higher ionic conductivity on an absolute temperature scale, likely because of differences in the Tgs of the two systems. We also found that ion transport for backbone PILs was coupled to the segmental dynamics below Tg, where the decoupling of ionic conductivity from segmental relaxation was observed for pendant PILs. The results of this study will help the community to better understand the role of the PIL structure on conductivity to work toward the ultimate goal of designing high-performance solid polymer electrolytes
Loss of SOCS3 in T helper cells resulted in reduced immune responses and hyperproduction of interleukin 10 and transforming growth factor–β1
Suppressor of cytokine signaling (SOCS)3 is a major negative feedback regulator of signal transducer and activator of transcription (STAT)3-activating cytokines. Transgenic mouse studies indicate that high levels of SOCS3 in T cells result in type 2 T helper cell (Th2) skewing and lead to hypersensitivity to allergic diseases. To define the physiological roles of SOCS3 in T cells, we generated T cell–specific SOCS3 conditional knockout mice. We found that the mice lacking SOCS3 in T cells showed reduced immune responses not only to ovalbumin-induced airway hyperresponsiveness but also to Leishmania major infection. In vitro, SOCS3-deficient CD4+ T cells produced more transforming growth factor (TGF)-β1 and interleukin (IL)-10, but less IL-4 than control T cells, suggesting preferential Th3-like differentiation. We found that STAT3 positively regulates TGF-β1 promoter activity depending on the potential STAT3 binding sites. Furthermore, chromatin immunoprecipitation assay revealed that more STAT3 was recruited to the TGF-β1 promoter in SOCS3-deficient T cells than in control T cells. The activated STAT3 enhanced TGF-β1 and IL-10 expression in T cells, whereas the dominant-negative form of STAT3 suppressed these. From these findings, we propose that SOCS3 regulates the production of the immunoregulatory cytokines TGF-β1 and IL-10 through modulating STAT3 activation
Fast WDM provisioning with minimal probing: the first field experiments for DC exchanges
We propose an approach to estimate the end-to-end GSNR accurately in a short
time when a data center interconnect (DCI) network operator receives a service
request from users, not by measuring the GSNR at the operational route and
wavelength for the End-End optical path but by simply applying a QoT probe
channel link by link, at a convenient wavelength/modulation-format for
measurement. Assuming connections between coherent transceivers of various
frequency ranges, modulators, and modulation formats, we propose a new device
software architecture in which the DCI network operator optimizes the
transmission mode between user transceivers with high accuracy using only
standard parameters such as Bit Error Rate. In this paper, we first
experimentally built three different routes of 32 km/72 km/122 km in the C-band
to confirm the accuracy of this approach. For the operational end-to-end GSNR
measurements, the accuracy estimated from the sum of the measurements for each
link was 0.6 dB, and the wavelength-dependent error was about 0.2 dB. Then,
using field fibers deployed in the NSF COSMOS testbed (deployed in an urban
area), a Linux-based transmission device software architecture, and coherent
transceivers with different optical frequency ranges, modulators, and
modulation formats, the fast WDM provisioning of an optical path was completed
within 6 minutes (with a Q-factor error of about 0.7 dB).Comment: 9 pages, 11 figures, 3 table
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