4,410 research outputs found
Characterisation of a candidate dual AGN
We present Chandra and optical observations of a candidate dual AGN
discovered serendipitously while searching for recoiling black holes via a
cross-correlation between the serendipitous XMM source catalog (2XMMi) and
SDSS-DR7 galaxies with a separation no larger than ten times the sum of their
Petrosian radii. The system has a stellar mass ratio M/M. One of the galaxies (Source 1) shows clear evidence for AGN activity in
the form of hard X-ray emission and optical emission-line diagnostics typical
of AGN ionisation. The nucleus of the other galaxy (Source 2) has a soft X-ray
spectrum, bluer colours, and optical emission line ratios dominated by stellar
photoionisation with a "composite" signature, which might indicate the presence
of a weak AGN. When plotted on a diagram with X-ray luminosity vs [OIII]
luminosity both nuclei fall within the locus defined by local Seyfert galaxies.
From the optical spectrum we estimate the electron densities finding n e cm and n e cm. From a 2D
decomposition of the surface brightness distribution we infer that both
galaxies host rotationally supported bulges (Sersic index ). While the
active nature of Source 1 can be established with confidence, whether the
nucleus of Source 2 is active remains a matter of debate. Evidence that a faint
AGN might reside in its nucleus is, however, tantalising.Comment: 16 pages, 9 figures. Accepted for publication on MNRAS. Comments
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Enhanced propagation of motile bacteria on surfaces due to forward scattering
How motile bacteria move near a surface is a problem of fundamental
biophysical interest and is key to the emergence of several phenomena of
biological, ecological and medical relevance, including biofilm formation.
Solid boundaries can strongly influence a cell's propulsion mechanism, thus
leading many flagellated bacteria to describe long circular trajectories stably
entrapped by the surface. Experimental studies on near-surface bacterial
motility have, however, neglected the fact that real environments have typical
microstructures varying on the scale of the cells' motion. Here, we show that
micro-obstacles influence the propagation of peritrichously flagellated
bacteria on a flat surface in a non-monotonic way. Instead of hindering it, an
optimal, relatively low obstacle density can significantly enhance cells'
propagation on surfaces due to individual forward-scattering events. This
finding provides insight on the emerging dynamics of chiral active matter in
complex environments and inspires possible routes to control microbial ecology
in natural habitats
Attenuation of choroidal tickness in patients with Alzheimer disease: evidence from an Italian prospective study
INTRODUCTION: To compare the 12-month choroidal thickness (CT) change between
Alzheimer disease (AD) patients and normal subjects.
METHODS: In this prospective, observational study, 39 patients with a diagnosis
of mild to moderate AD and 39 age-matched control subjects were included. All the
subjects underwent neuropsychological (Mini Mental State Examination, Alzheimer
disease Assessment Scale-Cognitive Subscale, and the Clinical Dementia Rating
Scale) and ophthalmological evaluation, including spectral domain optical
coherence tomography, at baseline and after 12 months. CT was measured manually
using the caliper tool of the optical coherence tomography device.
RESULTS: After 12 months, AD patients had a greater reduction of CT than controls
(P≤0.05, adjusted for baseline CT, age, sex, axial length, and smoking).
DISCUSSION: CT in patients with AD showed a rate of thinning greater than what
could be expected during the natural course of aging
How do we treat life‐threatening anemia in a J ehovah's W itness patient?
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/109968/1/trf12888.pd
Outflows in the Narrow Line Region of Bright Seyfert Galaxies - I: GMOS-IFU Data
We present two-dimensional maps of emission-line fluxes and kinematics, as
well as of the stellar kinematics of the central few kpc of five bright nearby
Seyfert galaxies -- Mrk\,6, Mrk\,79, Mrk\,348, Mrk\,607 and Mrk\,1058 --
obtained from observations with the Gemini Multi-Object Spectrograph (GMOS)
Integral Field Unit (IFU) on the Gemini North Telescope. The data cover the
inner 3\farcs55\farcs0 -- corresponding to physical scales in the range
0.60.9 to 1.52.2\,kpc -- at a spatial resolution ranging
from 110 to 280 pc with a spectral coverage of 4300 -- 7100\,\AA\ and velocity
resolution of 90\,km\,s. The gas excitation is Seyfert like
everywhere but show excitation, but show excitation gradients that are
correlated with the gas kinematics, reddening and/or the gas density. The gas
kinematics show in all cases two components: a rotation one similar to that
observed in the stellar velocity field, and an outflow component. In the case
of Mrk607, the gas is counter-rotating relative to the stars. Enhanced gas
velocity dispersion is observed in association to the outflows according to two
patterns: at the locations of the highest outflow velocities along the
ionization axis or perpendicularly to it in a strip centered at the nucleus
that we attribute to an equatorial outflow. Bipolar outflows are observed in
Mrk\,348 and Mrk\,79, while in Mrk\,1058 only the blueshifted part is clearly
observed, while in the cases of Mrk\,6 and Mrk\,607 the geometry of the outflow
needs further constraints from modeling to be presented in a forthcoming study,
where the mass flow rate and powers will also be obtained.Comment: 20 pages, accepted by MNRA
An Overview of the Application of Blue Light-Emitting Diodes as a Non-Thermic Green Technology for Microbial Inactivation in the Food Sector
Blue light is an emerging technology used for the decontamination of food contact surfaces and products. It is based on the activation of photosensitizers by light, determining the release of reactive oxygen species (ROS). ROS causes damage to bacterial cells leading to cell death. Several types of microbes may be treated, such as bacteria, yeasts, moulds and viruses, in planktonic or biofilm form. Blue light technology is affected by several factors: light parameters (i.e., irradiance, dose, wavelength), microbial parameters (i.e., pH, temperature, initial inoculum, grade of biofilm maturation) and surface parameters (i.e., material, roughness, and optical properties). In addition, it may be used alone or coupled with other technologies. The use of blue light shows several advantages, such as safety for food operators, and a lower release of chemicals in the environment. Moreover, it seems unlikely for bacteria to develop resistance to the blue light application
Feeding and Feedback in the Inner Kiloparsec of the Active Galaxy NGC2110
We present two-dimensional gaseous kinematics of the inner 1.1 x 1.6kpc^2 of
the Seyfert 2 galaxy NGC2110, from optical spectra obtained with the GMOS
integral field spectrograph on the Gemini South telescope at a spatial
resolution of 100pc. Gas emission is observed over the whole field-of-view,
with complex - and frequently double - emission-line profiles. We have
identified four components in the emitting gas, according to their velocity
dispersion (sigma), which we refer to as: (1) warm gas disk (sigma =
100-220km/s); (2) cold gas disk (sigma = 60-90km/s); (3) nuclear component
(sigma = 220-600km/s); and (4) northern cloud (sigma = 60-80km/s). Both the
cold and warm disk components are dominated by rotation and have similar gas
densities, but the cold gas disk has lower velocity dispersions and reaches
higher rotation velocities. We attribute the warm gas disk to a thick gas layer
which encompasses the cold disk as observed in some edge-on spiral galaxies.
After subtraction of a rotation model from the cold disk velocity field, we
observe excess blueshifts of 50km/s in the far side of the galaxy as well as
similar excess redshifts in the near side. These residuals can be interpreted
as due to nuclear inflow in the cold gas, with an estimated ionized gas mass
inflow rate of 2.2 x 10^(-2)Msun/yr. We have also subtracted a rotating model
from the warm disk velocity field and found excess blueshifts of 100km/s to the
SW of the nucleus and excess redshifts of 40km/s to the NE, which we attribute
to gas disturbed by an interaction with a nuclear spherical outflow. This
nuclear outflow is the origin of the nuclear component observed within the
inner 300pc and it has a mass outflow rate of 0.9Msun/yr. In a region between
1" and 4" north of the nucleus we find a new low sigma component of ionized gas
which we attribute to a high latitude cloud photoionized by the nuclear source.Comment: 17 pages, 13 figures, 1 table; accepted for publication in MNRA
Processes controlling the vertical aerosol distribution in marine stratocumulus regions - a sensitivity study using the climate model NorESM1-M
The vertical distribution of aerosols plays an important role in determining the effective radiative forcing from aerosol–radiation and aerosol–cloud interactions. Here, a number of processes controlling the vertical distribution of aerosol in five subtropical marine stratocumulus regions in the climate model NorESM1-M are investigated, with a focus on the total aerosol extinction. A comparison with satellite lidar data (CALIOP, Cloud–Aerosol Lidar with Orthogonal Polarization) shows that the model underestimates aerosol extinction throughout the troposphere, especially elevated aerosol layers in the two regions where they are seen in observations. It is found that the shape of the vertical aerosol distribution is largely determined by the aerosol emission and removal processes in the model, primarily through the injection height, emitted particle size, and wet scavenging. In addition, the representation of vertical transport related to shallow convection and entrainment is found to be important, whereas alterations in aerosol optical properties and cloud microphysics parameterizations have smaller effects on the vertical aerosol extinction distribution. However, none of the alterations made are sufficient for reproducing the observed vertical distribution of aerosol extinction, neither in magnitude nor in shape. Interpolating the vertical levels of CALIOP to the corresponding model levels leads to better agreement in the boundary layer and highlights the importance of the vertical resolution
Necrotizing Pancreatitis: New Definitions and a New Era in Surgical Management
Background: Necrotizing pancreatitis is a challenging condition that requires surgical treatment commonly and is associated with substantial morbidity and mortality. Over the past decade, new definitions have been developed for standardization of severity of acute and necrotizing pancreatitis, and new management techniques have emerged based on prospective, randomized clinical trials. Methods: Review of English-language literature. Results: A new international classification of acute pancreatitis has been developed by PANCREA (Pancreatitis Across Nations Clinical Research and Education Alliance) to replace the Atlanta Classification. It is based on the actual local (whether pancreatic necrosis is present or not, whether it is sterile or infected) and systemic determinants (whether organ failure is present or not, whether it is transient or persistent) of severity. Early management requires goal-directed fluid resuscitation (with avoidance of over-resuscitation and abdominal compartment syndrome), assessment of severity of pancreatitis, diagnostic computed tomography (CT) imaging to assess for necrotizing pancreatitis, consideration of endoscopic retrograde cholangiopancreatography (ERCP) for biliary pancreatitis and early enteral nutrition support. Antibiotic prophylaxis is not recommended. Therapeutic antibiotics are required for treatment of documented infected pancreatic necrosis. The initial treatment of infected pancreatic necrosis is percutaneous catheter or endoscopic (transgastric/transduodenal) drainage with a second drain placement as required. Lack of clinical improvement after these initial procedures warrants consideration of minimally invasive techniques for pancreatic necrosectomy including video-assisted retroperitoneal debridement (VARD), minimally invasive retroperitoneal pancreatectomy (MIRP), or transluminal direct endoscopic necrosectomy (DEN). Open necrosectomy is associated with substantial morbidity, but to date no randomized trial has documented superiority of either minimally invasive or open surgical technique. Additional trials are underway to address this. Conclusions: Severe acute and necrotizing pancreatitis requires a multi-disciplinary treatment strategy that must be individualized for each patient. Optimal treatment of necrotizing pancreatitis now requires a staged, multi-disciplinary, minimally invasive ?step-up? approach that includes a team of interventional radiologists, therapeutic endoscopists, and surgeons.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/140218/1/sur.2014.123.pd
Text message communication in primary care research: a randomized controlled trial
Background. Text message communication is increasingly used in clinical practice but rarely in research. Particularly in young people, this method of participation in primary care research appears both feasible and acceptable. However, previous experience shows that text messaging for research may lead to lower response rates. Aim. To test the hypothesis that text message communication in primary care research does not lead to lower response rates compared to a paper-based method. Methods. This randomized controlled trial took place in 26 randomly selected practices in Victoria, Australia. Consecutive patients aged 16-24 years attending general practice appointments were recruited as part of a larger study on patients' perspectives. Patients owning a mobile phone were randomized to receive a question about satisfaction with the consultation either by text message or on a card completed before leaving the practice. Logistic regression was used to estimate the effect on the response rate of using text message rather than the card method, adjusting for clustering within practices and for differences in baseline characteristics among participants. Results. In total, 402 of 409 eligible young people agreed to participate and were randomized to either receive a text message (n = 193) or a card enquiry (n = 209). The response rate was 80.2% [95% confidence interval (CI): 73.3-87.1%] with text message and 85.6% (95% CI: 79.6-91.7%) with the card. The adjusted odds of responding (odds ratio: 0.62; 95% CI: 0.30-1.27) were not significantly lower in the group using text messaging compared to the group using the card response method. Conclusion. These findings offer new perspectives for use of text message communication to gather information from patients in primary care researc
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