1,559 research outputs found
Determining the physical conditions of extremely young Class 0 circumbinary disk around VLA1623A
We present detailed analysis of high-resolution C18O (2-1), SO (88-77), CO
(3-2) and DCO+ (3-2) data obtained by the Atacama Large
Millimeter/sub-millimeter Array (ALMA) towards a Class 0 Keplerian circumbinary
disk around VLA1623A, which represents one of the most complete analysis
towards a Class 0 source. From the dendrogram analysis, we identified several
accretion flows feeding the circumbinary disk in a highly anisotropic manner.
Stream-like SO emission around the circumbinary disk reveals the complicated
shocks caused by the interactions between the disk, accretion flows and
outflows. A wall-like structure is discovered south of VLA1623B. The discovery
of two outflow cavity walls at the same position traveling at different
velocities suggests the two outflows from both VLA1623A and VLA1623B overlays
on top of each other in the plane of sky. Our detailed flat and flared disk
modeling shows that Cycle 2 C18O J = 2-1 data is inconsistent with the combined
binary mass of 0.2 Msun as suggested by early Cycle 0 studies. The combined
binary mass for VLA1623A should be modified to 0.3 ~ 0.5 Msun.Comment: 26 pages, 20 figures, accepted by ApJ 2020.2.2
Rotating filament in Orion B: Do cores inherit their angular momentum from their parent filament?
Angular momentum is one of the most important physical quantities that govern
star formation. The initial angular momentum of a core may be responsible for
its fragmentation and can have an influence on the size of the protoplanetary
disk. To understand how cores obtain their initial angular momentum, it is
important to study the angular momentum of filaments where they form. While
theoretical studies on filament rotation have been explored, there exist very
few observational measurements of the specific angular momentum in star-forming
filaments. We present high-resolution N2D+ ALMA observations of the LBS 23
(HH24-HH26) region in Orion B, which provide one of the most reliable
measurements of the specific angular momentum in a star-forming filament. We
find the total specific angular momentum (), the
dependence of the specific angular momentum with radius (j(r) ), and the ratio of rotational energy to gravitational energy
() comparable to those observed in rotating cores with
sizes similar to our filament width ( 0.04 pc) in other star-forming
regions. Our filament angular momentum profile is consistent with rotation
acquired from ambient turbulence and with simulations that show cores and their
host filaments develop simultaneously due to the multi-scale growth of
nonlinear perturbation generated by turbulence.Comment: accepted by ApJ, 2020.12.
THE EFFECT OF FOOT POSITION ON KINETICS OF LOWER LIMBS DURING SQUAT
The purposes of this study were to evaluate the effects of the foot position on the joint forces and moments of lower limbs during squat. Eleven male weightlifters were recruited in this study to perform squat with different foot position (forward position and toe-out 20 degrees). The VICON motion analysis system and two KISTLER force platforms were used to record the kinematical and kinetic data during squat. The results showed that the ankle joint maximal shear force, maximal adduction moment, external rotation moment and knee external rotation moment during squat with foot forward position were significantly greater than the results in toe-out position. Squat with foot forward position could be suggested to improve the ankle stability in rehabilitative training
Higgs-pair Production and Decay in Simplest Little Higgs Model
In the framework of the simplest little Higgs model (SLHM), we study the
production of a pair of neutral CP-even Higgs bosons at the LHC. First, we
examine the production rate and find that it can be significantly larger than
the SM prediction. Then we investigate the decays of the Higgs-pair and find
that for a low Higgs mass their dominant decay mode is hh->\eta\eta\eta\eta
(\eta is a CP-odd scalar) while hh->b\bar{b}\eta\eta and hh->\eta\eta WW may
also have sizable ratios. Finally, we comparatively study the rates of pp-> hh
-> b\bar{b}\tau^+ \tau^-, pp->hh->b\bar{b}\gamma\gamma, and pp->hh->WWWW in the
SLHM and the littlest Higgs models (LHT). We find that for a light Higgs,
compared with the SM predictions, all the three rates can be sizably enhanced
in the LHT but severely suppressed in the SLHM; while for an intermediately
heavy Higgs, both the LHT and SLHM can enhance sizably the SM predictions.Comment: Version in Nucl. Phys.
Deranged Bioenergetics and Defective Redox Capacity in T Lymphocytes and Neutrophils Are Related to Cellular Dysfunction and Increased Oxidative Stress in Patients with Active Systemic Lupus Erythematosus
Urinary excretion of N-benzoyl-glycyl-Nε-(hexanonyl)lysine, a biomarker of oxidative stress, was higher in 26 patients with active systemic lupus erythematosus (SLE) than in 11 non-SLE patients with connective tissue diseases and in 14 healthy volunteers. We hypothesized that increased oxidative stress in active SLE might be attributable to deranged bioenergetics, defective reduction-oxidation (redox) capacity, or other factors. We demonstrated that, compared to normal cells, T lymphocytes (T) and polymorphonuclear neutrophils (PMN) of active SLE showed defective expression of facilitative glucose transporters GLUT-3 and GLUT-6, which led to increased intracellular basal lactate and decreased ATP production. In addition, the redox capacity, including intracellular GSH levels and the enzyme activity of glutathione peroxidase (GSH-Px) and γ-glutamyl-transpeptidase (GGT), was decreased in SLE-T. Compared to normal cells, SLE-PMN showed decreased intracellular GSH levels, and GGT enzyme activity was found in SLE-PMN and enhanced expression of CD53, a coprecipitating molecule for GGT. We conclude that deranged cellular bioenergetics and defective redox capacity in T and PMN are responsible for cellular immune dysfunction and are related to increased oxidative stress in active SLE patients
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