926 research outputs found
Probing the Active Massive Black Hole Candidate in the Center of NGC 404 with VLBI
Recently Nyland et al. (2012) argued that the radio emission observed in the
center of the dwarf galaxy NGC 404 originates in a low-luminosity active
galactic nucleus (LLAGN) powered by a massive black hole (
M). High-resolution radio detections of MBHs are rare. Here we
present sensitive, contemporaneous Chandra X-ray, and very long baseline
interferometry (VLBI) radio observations with the European VLBI Network (EVN).
The source is detected in the X-rays, and shows no long-term variability. If
the hard X-ray source is powered by accretion, the apparent low accretion
efficiency would be consistent with a black hole in the hard state. Hard state
black holes are known to show radio emission compact on the milliarcsecond
scales. However, the central region of NGC 404 is resolved out on 10
milliarcsecond (0.15-1.5 pc) scales. Our VLBI non-detection of a compact,
partially self-absorbed radio core in NGC 404 implies that either the black
hole mass is smaller than M, or the source
does not follow the fundamental plane of black hole activity relation. An
alternative explanation is that the central black hole is not in the hard
state. The radio emission observed on arcsecond (tens of pc) scales may
originate in nuclear star formation or extended emission due to AGN activity,
although the latter would not be typical considering the structural properties
of low-ionization nuclear emission-line region galaxies (LINERs) with confirmed
nuclear activity.Comment: Accepted for publication in the Astrophysical Journal. 7 pages, 2
figures, 1 tabl
Relation between the phenomenological interactions of the algebraic cluster model and the effective two--nucleon forces
We determine the phenomenological cluster--cluster interactions of the
algebraic model corresponding to the most often used effective two--nucleon
forces for the O + system.Comment: Latex with Revtex, 1 figure available on reques
Characteristics of allergic colitis in breast-fed infants in the absence of cowâs milk allergy
AIM:
To investigate the characteristics of mucosal lesions and their relation to laboratory data and long-term follow up in breast-fed infants with allergic colitis.
METHODS:
In this study 31 breast-fed infants were prospectively evaluated (mean age, 17.4 wk) whose rectal bleeding had not ceased after a maternal elimination diet for cow's milk. Thirty-four age-matched and breast-fed infants (mean age, 16.9 wk) with no rectal bleeding were enrolled for laboratory testing as controls. Laboratory findings, colonoscopic and histological characteristics were prospectively evaluated in infants with rectal bleeding. Long-term follow-up with different nutritional regimes (L-amino-acid based formula or breastfeeding) was also included.
RESULTS:
Iron deficiency, peripheral eosinophilia and thrombocytosis were significantly higher in patients with allergic colitis in comparison to controls (8.4 ± 3.2 Όmol/L vs 13.7 ± 4.7 Όmol/L, P < 0.001; 0.67 ± 0.49 G/L vs 0.33 ± 0.17 G/L, P < 0.001; 474 ± 123 G/L vs 376 ± 89 G/L, P < 0.001, respectively). At colonoscopy, lymphonodular hyperplasia or aphthous ulceration were present in 83% of patients. Twenty-two patients were given L-amino acid-based formula and 8 continued the previous feeding. Time to cessation of rectal bleeding was shorter in the special formula feeding group (mean, 1.4 wk; range, 0.5-3 wk) when compared with the breast-feeding group (mean, 5.3 wk; range, 2-9 wk). Nevertheless, none of the patients exhibited rectal bleeding at the 3-mo visit irrespective of the type of feeding. Peripheral eosinophilia and cessation of rectal bleeding after administration of elemental formula correlated with a higher density of mucosal eosinophils.
CONCLUSION:
Infant hematochezia, after cow's milk allergy exclusion, is generally a benign and probably self-limiting disorder despite marked mucosal abnormality. Formula feeding results in shorter time to cessation of rectal bleeding; however, breast-feeding should not be discouraged in long-lasting hematochezia
A schematic model for QCD I: Low energy meson states
A simple model for QCD is presented, which is able to reproduce the meson
spectrum at low energy. The model is a Lipkin type model for quarks coupled to
gluons. The basic building blocks are pairs of quark-antiquarks coupled to a
definite flavor and spin. These pairs are coupled to pairs of gluons with spin
zero. The multiplicity problem, which dictates that a given experimental state
can be described in various manners, is removed when a particle-mixing
interaction is turned on. In this first paper of a series we concentrates on
the discussion of meson states at low energy, the so-called zero temperature
limit of the theory. The treatment of baryonic states is indicated, also.Comment: 29 pages, 6 figures. submitted to Phys. Rev.
Ovarian stimulation and ultrasound-guided oocyte retrieval in baboon (Papio cynocephalus anubis) during pituitary suppression with a GnRH agonist
The objective of this study was to investigate whether baboon females respond to an ovarian stimulation protocol incorporating pituitary suppression with a GnRH agonist (GnRHa) and either highly purified human FSH (hphFSH) or recombinant human FSH (rhFSH) with follicular development and oocyte maturation. A modified human ovulation induction protocol was applied to 5 adult female baboons with a history of regular menstrual cycles (33â34 days). A long-acting GnRHa implant containing goserelin acetate was placed subcutaneously (s.c.) on Days 22â24 of their menstrual cycle. Concentrations of serum oestradiol (E2), progesterone (P4) and human FSH were obtained by ELISA. Menses occurred ⌠10 days after GnRHa implantation. Daily hphFSH or rhFSH (75 IU i.m.) treatments were started ⌠10 days following menses. When the majority of follicles were â„ 5 mm in diameter and the E2 levels had reached a maximum, hCG (2000 IU i.m.) was administered to induce final maturation of oocytes and ovulation. Thirty to 34 h after hCG administration, transabdominal follicular aspiration was performed using a variable frequency transvaginal transducer with ultrasound. A total of 71 oocytes were collected from 4 animals (average: 17). The meiotic maturity of oocytes was evaluated 3 h after retrieval. Ninety-one percent of oocytes were in metaphase 2 and of grades I and II which are appropriate for in vitro insemination
The evolution of a jet ejection of the ultraluminous X-ray source Holmberg II X-1
We present quasi-simultaneous, multi-epoch radio and X-ray measurements of Holmberg II X-1 using the European VLBI Network (EVN), the Karl G. Jansky Very Large Array (VLA), and the Chandra and Swift X-ray telescopes. The X-ray data show apparently hard spectra with steady X-ray luminosities four months apart from each other. In the high-resolution EVN radio observations, we have detected an extended milliarcsecond scale source with unboosted radio emission. The source emits non-thermal, likely optically thin synchrotron emission, and its morphology is consistent with a jet ejection. The 9-GHz VLA data show an arcsecond-scale triple structure of Holmberg II X-1 similar to that seen at lower frequencies. However, we find that the central ejection has faded by at least a factor of 7.3 over 1.5 yr. We estimate the dynamical age of the ejection to be higher than 2.1 yr. We show that such a rapid cooling can be explained with simple adiabatic expansion losses. These properties of Holmberg II X-1 imply that ULX radio bubbles may be inflated by ejecta instead of self-absorbed compact jets
Identification of Arabidopsis mutants carrying T-DNA inserts in phosphoprotein phosphatase genes
Clusterization in the shape isomers of the 56Ni nucleus
The interrelation of the quadrupole deformation and clusterization is investigated in the example of the 56Ni nucleus. The shape isomers, including superdeformed and hyperdeformed states, are obtained as stability regions of the quasidynamical U(3) symmetry based on a Nilsson calculation. Their possible binary clusterizations are investigated by considering both the consequences of the Pauli exclusion principle and the energetic preference
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