612 research outputs found
The Black Hole Mass of Abell 1836-BCG and Abell 3565-BCG
Two brightest cluster galaxies (BCGs), namely Abell 1836-BCG and Abell
3565-BCG, were observed with the Advanced Camera for Surveys (ACS) and the
Space Telescope Imaging Spectrograph (STIS) on board the Hubble Space
Telescope. By modeling the available photometric and kinematic data, it
resulted that the mass of Abell 1836-BCG and Abell 3565-BCG are
M_bh=4.8(+0.8,-0.7)x10^9 M_sun and M_bh=1.3(+0.3,-0.4)x10^9 M_sun at 1 sigma
confidence level, respectively.Comment: 4 pages, 3 figures, Mem SAIt in press, Proceedings of the 51st Annual
Meeting of the Italian Astronomical Society, Florence, April 17-20, 200
Supermassive Black Holes in BCGs
We observed a sample of three Brightest Cluster Galaxies (BCGs), Abell
1836-BCG, Abell 2052-BCG, and Abell 3565-BCG, with the Advanced Camera for
Surveys (ACS) and the Imaging Spectrograph (STIS) on board the Space Telescope.
For each target galaxy we obtained high-resolution spectroscopy of the Halpha
and [NII]lambda6583 emission lines at three slit positions, to measure the
central ionized-gas kinematics. ACS images in three different filters (F435W,
F625W, and FR656N) have been used to determine the optical depth of the dust,
stellar mass distribution near the nucleus, and intensity map. We present
supermassive black hole (SBH) mass estimates for two galaxies which show
regular rotation curves and strong central velocity gradients, and an upper
limit on the SBH mass of the third one. For the SBHs of Abell 1836-BCG and
Abell 3565-BCG, we derived M_bh=4.8(-0.7,+0.8)10**9 M_sun and
M_bh=1.3(-0.4,+0.3)10**9 M_sun at 1 sigma confidence level, respectively. For
the SBH of Abell 2052-BCG, we found M_bh < 7.3 10**9 M_sun.Comment: 2 pages, 1 figure. To appear in the proceedings of "Black Holes: from
Stars to Galaxies", IAU Symp. No. 238, V. Karas & G. Matt (eds.), Cambridge
University Pres
Effects of carnitine and its congeners on eicosanoid discharge from rat cells: implications for release of TNFα
THE acyl carrier coenzyme A (CoA) is involved in fatty acid metabolism. The carnitine/CoA ratio is of particular importance in regulating the transport of long-chain fatty acids into mitochondria for oxidation. Also CoA has a role in the formation and breakdown of products from both the cyclooxygenase and lipoxygenase pathways of the precursor arachidonic acid. In the present study the effect of 4 days feeding of 300 mg/kg/day of L-carnitine, acetyl Lcarnitine and propionyl L-carnitine on the basal and calcium ionophore (A23187) stimulated release of arachidonic acid metabolites from rat carrageenin elicited peritoneal cells was investigated. There were two series of experiments carried out. In the first, the harvested peritoneal cell population consisted of less than 90% macrophages and additional polymorphonuclear (PMN) leucocytes. The basal release of prostaglandin E2 (PGE2), 6-ketoprostaglandin F1α (6-keto-PGF1α) and leukotriene B4 (LTB4) was stimulated by all treatments. The A23187 stimulated release of 6-keto-PGF1α and LTB4 was increased by all three compounds. The 6-keto-PGF1α:TxB2 and 6-keto-PGF1α:LTB4 ratios were increased by carnitine treatment. These results suggested that carnitine could modify the macrophage component of an inflammatory site in vivo. In the second series of experiments the harvested cell population was highly purified (>95% macrophages) and none of the compounds fed to the rats caused a change of either eicosanoid or TNFα formation. Moreover the 6-keto-PGF1α:TxB2 and 6-keto-PGF1α:LTB4 ratios were not enhanced by any of the compounds tested. It is conceivable that in the first series the increased ratios 6-keto-PGF1α:TxB2 and 6-keto-PGF1α:LTB4 reflected the effect of carnitine or its congeners on PMN leucocytes rather than on macrophages
Fundamental Planes, and the "barless" M-sigma relation, for supermassive black holes
The residuals about the standard M-sigma relation correlate with the
effective radius, absolute magnitude, and Sersic index of the host bulge -
although, it is noted here that the elliptical galaxies do not partake in such
correlations. Moreover, it is revealed that barred galaxies (with their
relatively small, faint, and low stellar concentration bulges) can deviate from
the M-sigma relation by delta(log M) = -0.5 to -1.0 dex (in the sense that
their sigma values are too large) and generate much of the aforementioned
correlations. Removal of the seven barred galaxies from the Tremaine et al. set
of 31 galaxies results in a ``barless M-sigma'' relation with an intrinsic
scatter of 0.17 dex (cf. 0.27 dex for the 31 galaxies) and a total scatter of
0.25 dex (cf. 0.34 dex for the 31 galaxies). The introduction of third
parameters does not reduce the scatter of the barless M-sigma relation.
Furthermore, removal of the barred galaxies, or all the disk galaxies, from an
expanded and updated set of 40 galaxies with reliable black hole mass
measurements gives a consistent result, such that log(M_bh/M_sun) =
(8.25+/-0.05) + (3.68+/-0.25)log [sigma/200].
The "barless" sigma-L relation for galaxies with black hole mass measurements
is found to be consistent with that from the SDSS sample of early-type
galaxies. In addition, the barless M-sigma relation, the M-L relation, and the
M-n relation are all shown to yield SMBH masses less than 2-4 x 10^9 M_sun.Comment: 16 pages. Originally submitted to ApJ on September 10, 200
On the relation between circular velocity and central velocity dispersion in high and low surface brightness galaxies
In order to investigate the correlation between the circular velocity Vc and
the central velocity dispersion of the spheroidal component sigma_c, we
analyzed these quantities for a sample of 40 high surface brightness disc
galaxies (hereafter HSB), 8 giant low surface brightness spiral galaxies
(hereafter LSB), and 24 elliptical galaxies characterized by flat rotation
curves. We find that the Vc-sigma_c relation is descri ed by a linear law out
to velocity dispersions as low as sigma_c~50km/s, while in previous works a
power law was adopted for galaxies with sigma_c>80k/ms.
Elliptical galaxies with Vc based on dynamical models or directly derived
from the HI rotation curves follow the same relation as the HSB galaxies in the
Vc-sigma_c plane. On the contrary, the LSB galaxies follow a different
relation, since most of them show either higher Vc (or lower sigma_c) with
respect to the HSB galaxies. This argues against the relevance of baryon
collapse in the radial density profile of the dark matter haloes of LSB
galaxies. (abridged)Comment: 18 pages, 4 figures, ApJ in pres
Singular charge fluctuations at a magnetic quantum critical point
Strange metal behavior is ubiquitous in correlated materials, ranging from cuprate superconductors to bilayer graphene, and may arise from physics beyond the quantum fluctuations of a Landau order parameter. In quantum-critical heavy-fermion antiferromagnets, such physics may be realized as critical Kondo entanglement of spin and charge and probed with optical conductivity. We present terahertz time-domain transmission spectroscopy on molecular beam epitaxyâgrown thin films of YbRh2Si2, a model strange-metal compound. We observed frequency over temperature scaling of the optical conductivity as a hallmark of beyond-Landau quantum criticality. Our discovery suggests that critical charge fluctuations play a central role in the strange metal behavior, elucidating one of the long-standing mysteries of correlated quantum matter.Financial support for this work was provided by the European Research Council (ERC Advanced Grant 227378), the U.S. Army Research Office (ARO W911NF-14-1-0496), the Austrian Science Fund (FWF W1243, P29279-N27, and P29296-N27), and the European Unionâs Horizon 2020 research and innovation programme (grant agreement No 824109 â EMP). X.L. and J.K. acknowledge financial support from the National Science Foundation (NSF MRSEC DMR-1720595) and the ARO (W911NF-17-1-0259). Q.S. acknowledges financial support from the NSF (DMR-1920740), the Robert A.Welch Foundation (C-1411), and the ARO (W911NF-14-1-0525), and hospitality of the University of California at Berkeley, the Aspen Center for Physics (NSF grant PHY-1607611), and the Los Alamos National Laboratory (via a Ulam Scholarship from the Center for Nonlinear Studies). This work has also been supported by an InterDisciplinary Excellence Award (IDEA) from Rice University (Q.S., E.R., J.K., S.P.)
Crossover Patient Outcomes for Targeted Lung Denervation in Moderate to Severe Chronic Obstructive Pulmonary Disease:AIRFLOW-2
BACKGROUND: Targeted Lung Denervation (TLD) is a potential new therapy for COPD. Radiofrequency energy is bronchoscopically delivered to the airways to disrupt pulmonary parasympathetic nerves, to reduce bronchoconstriction, mucus hypersecretion, and bronchial hyperreactivity. OBJECTIVES: This work assesses the effect of TLD on COPD exacerbations (AECOPD) in crossover subjects in the AIRFLOW-2 trial. METHOD: The AIRFLOW-2 trial is a multicentre, randomized, double-blind, sham-controlled crossover trial of TLD in COPD. Patients with symptomatic COPD on optimal medical therapy with an FEV1 of 30-60% predicted received either TLD or sham bronchoscopy in a 1:1 randomization. Those in the sham arm had the opportunity to cross into the treatment arm after 12 months. The primary end point was rate of respiratory adverse events. Secondary end points included adverse events, changes in lung function and health-related quality of life and symptom scores. RESULTS: Twenty patients were treated with TLD in the crossover phase and were subsequently followed up for 12 months (50% female, mean age 64.1 ± 6.9 years). After TLD, there was a trend towards a reduction in time to first AECOPD (hazard ratio 0.65, p = 0.28, not statistically significant) in comparison to sham follow-up period. There was also a reduction in time to first severe AECOPD in the crossover period (hazard ratio 0.38, p = 0.227, not statistically significant). Symptom scores and lung function showed stability. CONCLUSIONS: AIRFLOW-2 crossover data support that of the randomization phase, showing trends towards reduction in COPD exacerbations with TLD
Singular charge fluctuations at a magnetic quantum critical point
Strange metal behavior is ubiquitous in correlated materials, ranging from cuprate superconductors to bilayer graphene, and may arise from physics beyond the quantum fluctuations of a Landau order parameter. In quantum-critical heavy-fermion antiferromagnets, such physics may be realized as critical Kondo entanglement of spin and charge and probed with optical conductivity. We present terahertz time-domain transmission spectroscopy on molecular beam epitaxyâgrown thin films of YbRhâSiâ, a model strange-metal compound. We observed frequency over temperature scaling of the optical conductivity as a hallmark of beyond-Landau quantum criticality. Our discovery suggests that critical charge fluctuations play a central role in the strange metal behavior, elucidating one of the long-standing mysteries of correlated quantum matter
Bronchial Thermoplasty Induced Airway Smooth Muscle Reduction and Clinical Response in Severe Asthma:The TASMA Randomized Trial
RATIONALE: Bronchial Thermoplasty (BT) is a bronchoscopic treatment for severe asthma targeting airway smooth muscle (ASM). Observational studies have shown ASM mass reduction after BT but appropriate control groups are lacking. Furthermore, as treatment response is variable, identifying optimal candidates for BT treatment is important. AIMS: First, to assess the effect of BT on ASM mass and second, to identify patient characteristics that correlate with BT-response. METHODS: Severe asthma patients (n=40) were randomized to immediate (n=20) or delayed (n=20) BT-treatment. Prior to randomization, clinical, functional, blood and airway biopsy data were collected. In the delayed control group, re-assessment, including biopsies, was performed after 6 months of standard clinical care, followed by BT. In both groups, post-BT data including biopsies were obtained after 6 months. ASM mass (% positive desmin or α-smooth muscle actin area in the total biopsy) was calculated with automated digital analyses software. Associations between baseline characteristics and Asthma Control and Asthma Quality of Life Questionnaire (ACQ/AQLQ) improvement were explored. RESULTS: Median ASM mass decreased by >50% in the immediate BT group (n=17) versus no change in the delayed control group (n=19) (p=0.0004). In the immediate group ACQ scores improved with -0.79 (-1.61;0.02 IQR) compared to 0.09 (-0.25;1.17 IQR) in the delayed group (p=0.006). AQLQ scores improved with 0.83 (-0.15;1.69 IQR) versus -0.02 (-0.77;0.75 IQR) (p=0.04). Treatment response in the total group (n=35) was positively associated with serum IgE and eosinophils, but not with baseline ASM mass. CONCLUSION: ASM mass significantly decreases after BT when compared to a randomized non-BT treated control group. Treatment response was associated with serum IgE and eosinophil levels but not with ASM mass. Clinical trial registration available at www.clinicaltrials.gov, ID:NCT0222539
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