549 research outputs found
Titus and the Queen: Julia Berenice and the Opposition to Titus\u27 Succession
The purpose of this paper is to demonstrate that one of the primary reasons for this apprehension towards Titus\u27 succession was his conspicuous love ofthe queen Berenice, to whom, they say, he even promised marriage. The affair of Titus and Berenice has not been given proper attention by modem scholars. Most ignore the affair or gloss over it as a novelty, yet this is an error. Those who do connect the relationship of Titus and Berenice to the political context of Flavian Rome, such as John Crook, mistakenly associate the delay in Berenice\u27s arrival to the influence of Licinius Mucianus. However, this paper will demonstrate that the relationship of Titus and Berenice is integral to understanding the opposition to the Flavian regime, and Titus\u27 succession in particular. It will examine how the history ofJulia Berenice before and after the start of her affair with Titus served as ammunition for the opposition against her and argue that their relationship became a focal point for the opposition to Titus\u27 succession led by Helvidius Priscus
Functions of cell surface galectin-glycoprotein lattices
Programmed remodeling of cell surface glycans by the sequential action of specific glycosyltransferases can control biological processes by generating or masking ligands for endogenous lectins. Galectins, a family of animal lectins with affinity for beta-galactosides, can form multivalent complexes with cell surface glycoconjugates and deliver a variety of intracellular signals to modulate cell activation, differentiation, and survival. Recent efforts involving genetic or biochemical manipulation of O-glycosylation and N-glycosylation pathways, as well as blockade of the synthesis of endogenous galectins, have illuminated essential roles for galectin-glycoprotein lattices in the control of biological processes including receptor turnover and endocytosis, host-pathogen interactions, and immune cell activation and homeostasis.Fil: Rabinovich, Gabriel Adrián. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Instituto de BiologÃa y Medicina Experimental. Fundación de Instituto de BiologÃa y Medicina Experimental. Instituto de BiologÃa y Medicina Experimental; Argentina. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de QuÃmica Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de QuÃmica Biológica de la Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Toscano, Marta Alicia. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Instituto de BiologÃa y Medicina Experimental. Fundación de Instituto de BiologÃa y Medicina Experimental. Instituto de BiologÃa y Medicina Experimental; ArgentinaFil: Jackson, Shawn S.. University of Maryland; Estados UnidosFil: Vasta, Gerardo R.. University of Maryland; Estados Unido
Broad N2H+ emission towards the protostellar shock L1157-B1
We present the first detection of N2H+ towards a low-mass protostellar
outflow, namely the L1157-B1 shock, at about 0.1 pc from the protostellar
cocoon. The detection was obtained with the IRAM 30-m antenna. We observed
emission at 93 GHz due to the J = 1-0 hyperfine lines. The analysis of the
emission coupled with the HIFI CHESS multiline CO observations leads to the
conclusion that the observed N2H+(1-0) line originates from the dense (> 10^5
cm-3) gas associated with the large (20-25 arcsec) cavities opened by the
protostellar wind. We find a N2H+ column density of few 10^12 cm-2
corresponding to an abundance of (2-8) 10^-9. The N2H+ abundance can be matched
by a model of quiescent gas evolved for more than 10^4 yr, i.e. for more than
the shock kinematical age (about 2000 yr). Modelling of C-shocks confirms that
the abundance of N2H+ is not increased by the passage of the shock. In summary,
N2H+ is a fossil record of the pre-shock gas, formed when the density of the
gas was around 10^4 cm-3, and then further compressed and accelerated by the
shock.Comment: ApJ, in pres
Testing PDR models against ISO fine structure line data for extragalactic sources
Far-infrared [C ii] 158-μm, [O i] 145-μm and [O i] 63-μm fine structure emission-line fluxes were measured from archival Infrared Space Observatory Long Wavelength Spectrometer spectra of 46 extragalactic sources, with 28 sources providing detections in all three lines. For 12 of the sources, the contribution to the [C ii] 158-μm line flux from H ii regions could be estimated from their detected [N ii] 122-μm line fluxes. The measured [C ii]/[O i] and [O i] 63/145-μm line flux ratios were compared with those from a grid of photodissociation region (PDR) models previously computed using the ucl_pdr code. Persistent offsets between the observed and modelled line ratios could be partly attributed to the effects of [O i] 63-μm self-absorption. Using the Spherical Multi-Mol (smmol) code, we calculated model [O i] line profiles and found that the strength of the [O i] 63-μm line was reduced by 20–80 per cent, depending on the PDR parameters. We conclude that high PDR densities and radiation field strengths, coupled with the effects of [O i] 63-μm self-absorption, are likely to provide the best match to the observed line flux ratios
A photodissociation region study of NGC 4038
We present a model of the photodissociation regions of NGC 4038, which is part of the Antennae galaxies. We have considered one-dimensional slabs of uniform density, all having a maximum AV = 10 mag, interacting with plane-parallel radiation. The density range in our simulations spans four orders of magnitude (100 ≤ n ≤ 106 cm−3) and the UV field strength spans more than three orders of magnitude (10 ≤ χ ≤ 104.5 multiples of the Draine field), from which we generated a grid of about 1400 simulations. We compare our results with Herschel SPIRE-FTS, CSO and ISO-LWS observations of eight CO transition lines (J = 1-0 to 8-7) and the [C I] 609 μm and [O I] 146 μm fine-structure lines. We find that the molecular and atomic emission lines trace different gas components of NGC 4038; thus, single emission models are insufficient to reproduce the observed values. In general, low-J CO transition lines correspond to either low-density regions interacting with low UV field strengths, or high-density regions interacting with high UV field strengths. Higher J CO transition lines are less dependent on the UV field strength and are fitted by gas with density n ∼ 104.5-105.2 cm− 3. We find that the observed fine-structure line ratio of [C I] 609 μm/[O I] 146 μm is reproduced by clouds subject to weaker UV fields compared to the CO lines. We make estimates of the XCO factor which relates the CO emission with the column density of molecular hydrogen, and find that it is less than the canonical Milky Way value
Ariel - Volume 4 Number 2
Editors
David A. Jacoby
Eugenia Miller
Tom Williams
Associate Editors
Paul Bialas
Terry Burt
Michael Leo
Gail Tenikat
Editor Emeritus and Business Manager
Richard J. Bonnano
Movie Editor
Robert Breckenridge
Staff
Richard Blutstein
Mary F. Buechler
Steve Glinks
Len Grasman
Alice M. Johnson
J. D. Kanofsky
Tom Lehman
Dave Mayer
Bernie Odd
A case of double cystic esophageal duplication in VACTERL syndrome: the first case report and a review of the literature
BackgroundAn esophageal duplication cyst (EDC) is a rare malformation resulting from the embryonic foregut. VACTERL syndrome is a genetic disorder affecting many systems of the human body. We report the first case of VACTERL syndrome associated to asymptomatic double EDC.Case reportA girl with anorectal malformation and rectovestibular fistula, kidney malformation, and various vertebral defects came to our attention at the time of birth. VACTERL disease was diagnosed. She underwent Peña anoplasty at 4 months of life without complications. MRI was conducted at the age of 2. It accidentally showed a double esophageal duplication (12 mm × 35 mm × 10 mm) at the D7–D9 level. We planned a thoracoscopy; previous intraoperative esophagogastroduodenoscopy showed an external compression of the native esophagus. Two duplicated esophageal lesions were removed. The patient made an uneventful recovery and was completely asymptomatic at long-term follow-up.ConclusionsVACTERL syndrome is still a not well-defined disease. Based on the current literature, this is the first case of a double esophageal duplication in a patient affected by VACTERL syndrome. According to us, the thoracoscopic approach of esophageal duplications can be followed by experts. Complete surgical excision is possible even if the cyst shares a common muscular wall with the esophagus. For this reason, we suggest to close the muscular wall by a simple interrupted suture
The Herschel HIFI water line survey in the low-mass proto-stellar outflow L1448
As part of the WISH (Water In Star-forming regions with Herschel) key
project, we report on the observations of several ortho- and para-H2O lines
performed with the HIFI instrument towards two bright shock spots (R4 and B2)
along the outflow driven by the L1448 low-mass proto-stellar system, located in
the Perseus cloud. These data are used to identify the physical conditions
giving rise to the H2O emission and infer any dependence with velocity. These
observations provide evidence that the observed water lines probe a warm
(T_kin~400-600 K) and very dense (n 10^6 - 10^7 cm^-3) gas, not traced by other
molecules, such as low-J CO and SiO, but rather traced by mid-IR H2 emission.
In particular, H2O shows strong differences with SiO in the excitation
conditions and in the line profiles in the two observed shocked positions,
pointing to chemical variations across the various velocity regimes and
chemical evolution in the different shock spots. Physical and kinematical
differences can be seen at the two shocked positions. At the R4 position, two
velocity components with different excitation can be distinguished, with the
component at higher velocity (R4-HV) being less extended and less dense than
the low velocity component (R4-LV). H2O column densities of about 2 10^13 and 4
10^14 cm^-2 have been derived for the R4-LV and the R4-HV components,
respectively. The conditions inferred for the B2 position are similar to those
of the R4-HV component, with H2O column density in the range 10^14 - 5 10^14
cm^-2, corresponding to H2O/H2 abundances in the range 0.5 - 1 10^-5. The
observed line ratios and the derived physical conditions seem to be more
consistent with excitation in a low velocity J-type shock with large
compression rather than in a stationary C-shock, although none of these
stationary models seems able to reproduce all the characteristics of the
observed emission.Comment: Accepted for publication in A&
Cyclic AMP-specific phosphodiesterase, PDE8A1, is activated by protein kinase A-mediated phosphorylation
The cyclic AMP-specific phosphodiesterase PDE8 has been shown to play a pivotal role in important processes such as steroidogenesis, T cell adhesion, regulation of heart beat and chemotaxis. However, no information exists on how the activity of this enzyme is regulated. We show that under elevated cAMP conditions, PKA acts to phosphorylate PDE8A on serine 359 and this action serves to enhance the activity of the enzyme. This is the first indication that PDE8 activity can be modulated by a kinase, and we propose that this mechanism forms a feedback loop that results in the restoration of basal cAMP levels. (C) 2012 Federation of European Biochemical Societies. Published by Elsevier B. V. All rights reserve
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