3,271 research outputs found
The mystery of the 'Kite' radio source in Abell 2626: insights from new Chandra observations
We present the results of a new Chandra study of the galaxy cluster A2626.
The radio emission of the cluster shows a complex system of four symmetric arcs
without known correlations with the X-ray emission. The mirror symmetry of the
radio arcs toward the center and the presence of two optical cores in the
central galaxy suggested that they may be created by pairs of precessing radio
jets powered by dual AGNs inside the cD galaxy. However, previous observations
failed to observe the second jetted AGN and the spectral trend due to radiative
age along the radio arcs, thus challenging this interpretation. The new Chandra
observation had several scientific objectives, including the search for the
second AGN that would support the jet precession model. We focus here on the
detailed study of the local properties of the thermal and non-thermal emission
in the proximity of the radio arcs, in order to get more insights into their
origin. We performed a standard data reduction of the Chandra dataset deriving
the radial profiles of temperature, density, pressure and cooling time of the
intra-cluster medium. We further analyzed the 2D distribution of the gas
temperature, discovering that the south-western junction of the radio arcs
surrounds the cool core of the cluster. We studied the X-ray SB and spectral
profiles across the junction, finding a cold front spatially coincident with
the radio arcs. This may suggest a connection between the sloshing of the
thermal gas and the nature of the radio filaments, raising new scenarios for
their origin. A possibility is that the radio arcs trace the projection of a
complex surface connecting the sites where electrons are most efficiently
reaccelerated by the turbulence that is generated by the gas sloshing. In this
case, diffuse emission embedded by the arcs and with extremely steep spectrum
should be most visible at very low radio frequencies.Comment: 7 pages, 7 figures. Accepted for publication on A&
Detecting the point of release of virtual projectiles in AR/VR
Our aim is to detect the point of release of a thrown virtual projectile in VR/AR. We capture the full-body motion of 18 participants throwing virtual projectiles and extract motion features, such as position, velocity, rotation and rotational velocity for arm joints. Frame-level binary classifiers that estimate the point of release are trained and evaluated using a metric that prioritizes detection timing to obtain a ranking of joints and motion features. We find that wrist joint and rotation motion feature are most accurate, which can can help when placing simple motion tracking sensors for real-time throw detection
Purification and identification of secernin, a novel cytosolic protein that regulates exocytosis in mast cells
After permeabilization with the pore-forming toxin streptolysin-O mast cells can be triggered to secrete by addition of both calcium and a GTP analogue. If stimulation is delayed after permeabilization, there is a progressive decrease in the extent of secretion upon stimulation, eventually leading to a complete loss of the secretory response. This loss of secretory response can be retarded by the addition of cytosol from other secretory tissues, demonstrating that the response is dependent on a number of cytosolic proteins. We have used this as the basis of a bioassay to purify Secernin 1, a novel 50-kDa cytosolic protein that appears to be involved in the regulation of exocytosis from peritoneal mast cells. Secernin 1 increases both the extent of secretion and increases the sensitivity of mast cells to stimulation with calcium
Particle Impact Analysis of Bulk Powder During Pneumatic Conveyance
Fragmentation of powders during transportation is a common problem for manufacturers of food and pharmaceutical products. We illustrate that the primary cause of breakage is due to inter-particle collisions, rather than particle-wall impacts, and provide a statistical mechanics model giving the number of collisions resulting in fragmentation
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The pgip family in soybean and three other legume species: evidence for a birth-and-death model of evolution
Polygalacturonase-inhibiting proteins (PGIPs) are leucine-rich repeat (LRR) plant cell wall glycoproteins involved in plant immunity. They are typically encoded by gene families with a small number of gene copies whose evolutionary origin has been poorly investigated. Here we report the complete characterization of the full complement of the pgip family in soybean (Glycine max [L.] Merr.) and the characterization of the genomic region surrounding the pgip family in four legume species. Results: BAC clone and genome sequence analyses showed that the soybean genome contains two pgip loci. Each locus is composed of three clustered genes that are induced following infection with the fungal pathogen Sclerotinia sclerotiorum (Lib.) de Bary, and remnant sequences of pgip genes. The analyzed homeologous soybean genomic regions (about 126 Kb) that include the pgip loci are strongly conserved and this conservation extends also to the genomes of the legume species Phaseolus vulgaris L., Medicago truncatula Gaertn. and Cicer arietinum L., each containing a single pgip locus. Maximum likelihood-based gene trees suggest that the genes within the pgip clusters have independently undergone tandem duplication in each species. Conclusions: The paleopolyploid soybean genome contains two pgip loci comprised in large and highly conserved duplicated regions, which are also conserved in bean, M. truncatula and C. arietinum. The genomic features of these legume pgip families suggest that the forces driving the evolution of pgip genes follow the birth-and-death model, similar to that proposed for the evolution of resistance (R) genes of NBS-LRR-type
Untangling cosmic magnetic fields: Faraday tomography at metre wavelengths with LOFAR
14 pages, 6 figures. Accepted for publication in "The Power of Faraday Tomography" special issue of GalaxiesThe technique of Faraday tomography is a key tool for the study ofmagnetised plasmas in the new era of broadband radio-polarisation observations. In particular, observations at metre wavelengths provide significantly better Faraday depth accuracies compared to traditional centimetre-wavelength observations. However, the effect of Faraday depolarisationmakes the polarised signal very challenging to detect at metre wavelengths (MHz frequencies). In this work, Faraday tomography is used to characterise the Faraday rotation properties of polarised sources found in data from the LOFAR Two-Metre Sky Survey (LoTSS). Of the 76 extragalactic polarised sources analysed here, we find that all host a radio-loud AGN (Active Galactic Nucleus). The majority of the sources (~64%) are large FRII radio galaxies with a median projected linear size of 710 kpc and median radio luminosity at 144 MHz of 4 Ă— 10 26 W Hz -1 (with ~13% of all sources having a linear size > 1 Mpc). In several cases, both hotspots are detected in polarisation at an angular resolution of ~20'. One such case allowed a study of intergalactic magnetic fields on scales of 3.4 Mpc. Other detected source types include an FRI radio galaxy and at least eight blazars. Most sources display simple Faraday spectra, but we highlight one blazar that displays a complex Faraday spectrum, with two close peaks in the Faraday dispersion function.Peer reviewe
Canine dystocia in 50 UK first-opinion emergency-care veterinary practices: prevalence and risk factors
Dystocia can represent a major welfare issue for dogs of certain breeds and morphologies. First-opinion emergency-care veterinary caseloads represent a useful data resource for epidemiological research because dystocia can often result in emergency veterinary care. The study analysed a merged database of clinical records from 50 first-opinion emergency-care veterinary practices participating in the VetCompass Programme. Multivariable logistic regression modelling was used for risk factors analysis. There were 701 dystocia cases recorded among 18,758 entire female dogs, resulting in a dystocia prevalence of 3.7 per cent (95 per cent CI 3.5–4.0 per cent). Breeds with the highest odds of dystocia compared with crossbred bitches were French Bulldog (OR: 15.9, 95 per cent CI 9.3 to 27.2, P<0.001), Boston Terrier (OR: 12.9, 95 per cent CI 5.6 to 29.3, P<0.001), Chihuahua (OR: 10.4, 95 per cent CI 7.0 to 15.7, P<0.001) and Pug (OR: 11.3, 95 per cent CI 7.1 to 17.9, P<0.001). Bitches aged between 3.0 and 5.9 years had 3.1 (95 per cent CI 2.6 to 3.7, P<0.001) times the odds of dystocia compared with bitches aged under 3.0years. Certain breeds, including some brachycephalic and toy breeds, appeared at high risk of dystocia. Opportunities to improve this situation are discussed
The impact of homophobic bullying during sport and physical education participation on same-sex attracted and gender diverse young Australians’ depression and anxiety levels.
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