3,187 research outputs found
Monthly 43 GHz VLBA Polarimetric Monitoring of 3C120 over 16 Epochs: Evidence for Trailing Shocks in a Relativistic Jet
We present a 16-month sequence of monthly polarimetric 43 GHz VLBA images of
the radio galaxy 3C 120. The images probe the inner regions of the radio jet of
this relatively nearby superluminal radio galaxy at a linear resolution of 0.07
pc ( km s Mpc). We follow the
motion of a number of features with apparent velocities between 4.010.08
and . A new superluminal knot, moving at , is observed to be ejected from the core at a time
coincident with the largest flare ever observed for this source at millimeter
wavelengths. Changes in the position angle of this component, as well as a
progressive rotation of its magnetic polarization vector, suggest the presence
of a twisted (resembling a helix in projection) configuration of the underlying
jet magnetic field and jet geometry. We identify several knots that appear in
the wake of the new superluminal component, moving at proper motions
times slower than any of the other moving knots observed in 3C 120. These
features have properties similar to those of the ``trailing'' shocks seen in
relativistic, time-dependent, hydrodynamical and emission simulations of
compact jets. Such trailing compressions are triggered by pinch-mode jet-body
instabilities caused by the propagation of a strong perturbation, which we
associate with the new strong superluminal component.Comment: 4 pages, 5 figures, accepted for publication in Astrophysical Journal
Letter
MAPCAT: Monitoring AGN with Polarimetry at the Calar Alto Telescopes
We introduce MAPCAT, a long-term observing program for "Monitoring of AGN
with Polarimetry at the Calar Alto Telescopes". Multi-spectral-range studies
are critical to understand some of the most relevant current problems of high
energy astrophysics of blazars such as their high energy emission mechanisms
and the location of their gamma-ray emission region through event associations
across the spectrum. Adding multi-spectral-range polarimetry allows for even
more reliable identification of polarized flares across the spectrum in these
kind of objects, as well as for more accurate modeling of their magnetic field.
As part of a major international effort to study the long term multi-spectral
range polarimetric behavior of blazars, MAPCAT uses -since mid 2007- CAFOS on
the 2.2m Telescope at the Calar Alto Observatory (Almeria, Spain) to obtain
monthly optical (R-band) photo-polarimetric measurements of a sample of 34 of
the brightest gamma-ray, optical, and radio-millimeter blazars accessible from
the northern hemisphere.Comment: To be published in the proceedings of High Energy Phenomena in
Relativistic Outflows III (HEPRO III, IJMPCS). 4 page
Systematic building of a distributed recursive algorithm : example : the shortest path algorithm
Projet PARADISDesigners of distributed algorithms must deal with a variety of issues including sequential algorithms design, communication protocols, fault tolerance. The distributed design must also include a proof step of the whole algorithm features. This paper gives a new scheme for the design of distributed algorithms. In this approach the design step is performed simultaneously with the proof step. Our distributed design method is mainly based upon parallel recursive schemes, but recursivity is used in a distributed environment so we use two existing and widely available tools : remote procedure call and the PAR instruction parallel execution of threads
3 mm GMVA Observations of Total and Polarized Emission from Blazar and Radio Galaxy Core Regions
We present total and linearly polarized 3 mm Global mm-VLBI Array images of a
sample of blazars and radio galaxies from the VLBA-BU-BLAZAR 7 mm monitoring
program designed to probe the innermost regions of active galactic nuclei (AGN)
jets and locate the sites of gamma-ray emission observed by the Fermi-LAT. The
lower opacity at 3 mm and improved angular resolution, on the order of 50
microarcseconds, allow us to distinguish features in the jet not visible in the
7 mm VLBA data. We also compare two different methods used for the calibration
of instrumental polarisation and we analyze the resulting images for some of
the sources in the sample.Comment: Polarised Emission from Astrophysical Jets, June 12-16, 2017,
Ierapetra, Greec
Empyema associated with Lemierre syndrome: case report and literature review
Postanginal septicemia, also called Lemierre syndrome, is a metastatic infection that can have multiple complications, including empyema. Therefore, the natural history of the disease begins with an infection of the oropharynx by microbiota from the digestive system, which causes a thrombophlebitis of the jugular vein with septic infiltrations, including into the lungs causing pneumonia, which in turn can generate parapneumonic effusions and/or empyemas. Furthermore, it is a syndrome that was thought to have been forgotten by the era of antibiotics, but with resistance to these antibiotics it has begun to re-emerge. Next, we will talk about a case of a 41-year-old man with no significant pathological history, who entered secondary to a peritonsillar abscess which turned into Lemierre syndrome with a treatment based on broad-spectrum antibiotics and then performed of lung decortication by thoracotomy. Empyema as a complication of Lemierre syndrome is rare and even more so in this post-antibiotic era, so health personnel should have a high clinical suspicion since adequate and timely treatment will help reduce the complications of this disease, as well as like his mortality
Inhibition of αvβ5 Integrin Attenuates Vascular Permeability and Protects against Renal Ischemia-Reperfusion Injury
Ischemia-reperfusion injury (IRI) is a leading cause of AKI. This common clinical complication lacks effective therapies and can lead to the development of CKD. The αvβ5 integrin may have an important role in acute injury, including septic shock and acute lung injury. To examine its function in AKI, we utilized a specific function-blocking antibody to inhibit αvβ5 in a rat model of renal IRI. Pretreatment with this anti-αvβ5 antibody significantly reduced serum creatinine levels, diminished renal damage detected by histopathologic evaluation, and decreased levels of injury biomarkers. Notably, therapeutic treatment with the αvβ5 antibody 8 hours after IRI also provided protection from injury. Global gene expression profiling of post-ischemic kidneys showed that αvβ5 inhibition affected established injury markers and induced pathway alterations previously shown to be protective. Intravital imaging of post-ischemic kidneys revealed reduced vascular leak with αvβ5 antibody treatment. Immunostaining for αvβ5 in the kidney detected evident expression in perivascular cells, with negligible expression in the endothelium. Studies in a three-dimensional microfluidics system identified a pericyte-dependent role for αvβ5 in modulating vascular leak. Additional studies showed αvβ5 functions in the adhesion and migration of kidney pericytes in vitro Initial studies monitoring renal blood flow after IRI did not find significant effects with αvβ5 inhibition; however, future studies should explore the contribution of vasomotor effects. These studies identify a role for αvβ5 in modulating injury-induced renal vascular leak, possibly through effects on pericyte adhesion and migration, and reveal αvβ5 inhibition as a promising therapeutic strategy for AKI
Deletion of inducible nitric-oxide synthase in leptin-deficient mice improves brown adipose tissue function
Abstract
Background: Leptin and nitric oxide (NO) on their own participate in the control of non-shivering thermogenesis. However,
the functional interplay between both factors in this process has not been explored so far. Therefore, the aim of the present
study was to analyze the impact of the absence of the inducible NO synthase (iNOS) gene in the regulation of energy
balance in ob/ob mice.
Methods and Findings: Double knockout (DBKO) mice simultaneously lacking the ob and iNOS genes were generated, and
the expression of molecules involved in the control of brown fat cell function was analyzed by real-time PCR, western-blot
and immunohistochemistry. Twelve week-old DBKO mice exhibited reduced body weight (p,0.05), decreased amounts of
total fat pads (p,0.05), lower food efficiency rates (p,0.05) and higher rectal temperature (p,0.05) than ob/ob mice.
Ablation of iNOS also improved the carbohydrate and lipid metabolism of ob/ob mice. DBKO showed a marked reduction in
the size of brown adipocytes compared to ob/ob mutants. In this sense, in comparison to ob/ob mice, DBKO rodents showed
an increase in the expression of PR domain containing 16 (Prdm16), a transcriptional regulator of brown adipogenesis.
Moreover, iNOS deletion enhanced the expression of mitochondria-related proteins, such as peroxisome proliferatoractivated
receptor c coactivator-1 a (Pgc-1a), sirtuin-1 (Sirt-1) and sirtuin-3 (Sirt-3). Accordingly, mitochondrial uncoupling
proteins 1 and 3 (Ucp-1 and Ucp-3) were upregulated in brown adipose tissue (BAT) of DBKO mice as compared to ob/ob
rodents.
Conclusion: Ablation of iNOS improved the energy balance of ob/ob mice by decreasing food efficiency through an increase
in thermogenesis. These effects may be mediated, in part, through the recovery of the BAT phenotype and brown fat cell
function improvement
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