21,150 research outputs found
VIMOS-VLT spectroscopy of the giant Ly-alpha nebulae associated with three z~2.5 radio galaxies
The morphological and spectroscopic properties of the giant (>60 kpc)
Ly-alpha nebulae associated with three radio galaxies at z~2.5 (MRC 1558-003,
MRC 2025-218 and MRC 0140-257) have been investigated using integral field
spectroscopic data obtained with VIMOS on VLT.
The morphologies are varied. The nebula of one source has a centrally peaked,
rounded appearance. In the other two objects, it consists of two spatial
components. The three nebulae are aligned with the radio axis within <30 deg.
The total Ly-alpha luminosities are in the range (0.3-3.4) x 1e44 erg s-1. The
Ly-alpha spectral profile shows strong variation through the nebulae, with FWHM
values in the range ~400-1500 km s-1 and velocity shifts V~120-600 km s-1.
We present an infall model which can explain successfully most Ly-alpha
morphological and spectroscopic properties of the nebula associated with MRC
1558-003. This adds further support to our previous conclusion that the
_quiescent_ giant nebulae associated with this and other high redshift powerful
radio galaxies are in infall. A problem for this model is the difficulty to
reproduce the large Ly-alpha FWHM values.
We have discovered a giant (~85 kpc) Ly-alpha nebula associated with the
radio galaxy MRC 0140-257 at z=2.64. It shows strikingly relaxed kinematics
(FWHM2) radio galaxies.Comment: 14 pages, 13 figures. Accepted for publication in MNRA
Discovery of a wide companion near the deuterium burning mass limit in the Upper Scorpius association
We present the discovery of a companion near the deuterium burning mass limit
located at a very wide distance, at an angular separation of 4.6+/-0.1 arcsec
(projected distance of ~ 670 AU) from UScoCTIO108, a brown dwarf of the very
young Upper Scorpius association. Optical and near-infrared photometry and
spectroscopy confirm the cool nature of both objects, with spectral types of M7
and M9.5, respectively, and that they are bona fide members of the association,
showing low gravity and features of youth. Their masses, estimated from the
comparison of their bolometric luminosities and theoretical models for the age
range of the association, are 60+/-20 and 14^{+2}_{-8} MJup, respectively. The
existence of this object around a brown dwarf at this wide orbit suggests that
the companion is unlikely to have formed in a disk based on current planet
formation models. Because this system is rather weakly bound, they did not
probably form through dynamical ejection of stellar embryos.Comment: 10 pages, including 4 figures and 2 table
Methods and Processes of Developing the Strengthening the Reporting of Observational Studies in Epidemiology â Veterinary (STROBE-Vet) Statement
BACKGROUND
Reporting of observational studies in veterinary research presents challenges that often are not addressed in published reporting guidelines.
OBJECTIVE
To develop an extension of the STROBE (Strengthening the Reporting of Observational Studies in Epidemiology) statement that addresses unique reporting requirements for observational studies in veterinary medicine related to health, production, welfare, and food safety.
DESIGN
Consensus meeting of experts.
SETTING
Mississauga, Canada.
PARTICIPANTS
Seventeen experts from North America, Europe, and Australia.
METHODS
Experts completed a pre-meeting survey about whether items in the STROBE statement should be modified or added to address unique issues related to observational studies in animal species with health, production, welfare, or food safety outcomes. During the meeting, each STROBE item was discussed to determine whether or not rewording was recommended and whether additions were warranted. Anonymous voting was used to determine consensus.
RESULTS
Six items required no modifications or additions. Modifications or additions were made to the STROBE items 1 (title and abstract), 3 (objectives), 5 (setting), 6 (participants), 7 (variables), 8 (data sources/measurement), 9 (bias), 10 (study size), 12 (statistical methods), 13 (participants), 14 (descriptive data), 15 (outcome data), 16 (main results), 17 (other analyses), 19 (limitations), and 22 (funding).
CONCLUSION
The methods and processes used were similar to those used for other extensions of the STROBE statement. The use of this STROBE statement extension should improve reporting of observational studies in veterinary research by recognizing unique features of observational studies involving food-producing and companion animals, products of animal origin, aquaculture, and wildlife
The constant-velocity highly collimated outflows of the planetary nebula He 2-90
We present high-dispersion echelle spectroscopic observations and a
narrow-band [N II] image of the remarkable jet-like features of He 2-90. They
are detected in the echelle spectra in the H-alpha and [N II] lines but not in
other nebular lines. The [N II]/H-alpha ratio is uniformly high, ~1. The
observed kinematics reveals bipolar collimated outflows in the jet-like
features and shows that the southeast (northwest) component expands towards
(away from) the observer at a remarkably constant line-of-sight velocity,
26.0+-0.5 km/s. The observed expansion velocity and the opening angle of the
jet-like features are used to estimate an inclination angle of ~5 degrees with
respect to the sky plane and a space expansion velocity of ~290 km/s. The
spectrum of the bright central nebula reveals a profusion of Fe lines and
extended wings of the H-alpha line, similar to those seen in symbiotic stars
and some young planetary nebulae that are presumed to host a mass-exchanging
binary system. If this is the case for He 2-90, the constant velocity and
direction of the jets require a very stable dynamic system against precession
and warping.Comment: 8 pages (emulate ApJ), 5 figure, 1 tabl
Effects of acute and repeated treatment with methocinnamox, a mu opioid receptor antagonist, on fentanyl self-administration in rhesus monkeys
Methocinnamox (MCAM), a mu opioid receptor antagonist with a long duration of action, attenuates heroin self-administration in rhesus monkeys, suggesting it could be an effective treatment for opioid use disorder (OUD). This study examined effects of acute and repeated MCAM administration on self-administration of the high-efficacy mu opioid receptor agonist fentanyl and characterized MCAM pharmacokinetics. Four rhesus monkeys self-administered i.v. infusions of fentanyl (0.00032âmg/kg/infusion) or cocaine (0.032âmg/kg/infusion). MCAM (0.1â0.32âmg/kg) or the opioid receptor antagonist naltrexone (0.001â0.032âmg/kg) was injected prior to test sessions to evaluate acute effects. On a separate occasion, 0.32âmg/kg MCAM was injected every 12 days for 5 total injections to evaluate the effectiveness of repeated treatment. Following acute injection, MCAM and naltrexone decreased fentanyl self-administration on the day of treatment, with attenuation lasting for up to 2 weeks after the larger MCAM dose and <1 day after naltrexone. Repeated MCAM administration decreased fentanyl self-administration for more than 2 months without altering cocaine self-administration. MCAM plasma concentrations peaked 15â45âmin after injection, with a half-life ranging from 13.7 to 199.8âmin, and decreased markedly 1 day after injection. MCAM selectively reduced opioid self-administration and remained effective with repeated administration. Moreover, MCAM was effective at times when plasma levels were very low, suggesting that pharmacodynamic (i.e., pseudoirreversible binding to mu opioid receptors) and not pharmacokinetic factors play a significant role in its long-lasting effects. Taken together with previous studies, these data indicate that MCAM could be a safe, effective, and long-acting treatment for OUD
Comparison of Bond Character in Hydrocarbons and Fullerenes
We present a comparison of the bond polarizabilities for carbon-carbon bonds
in hydrocarbons and fullerenes, using two different models for the fullerene
Raman spectrum and the results of Raman measurements on ethane and ethylene. We
find that the polarizabilities for single bonds in fullerenes and hydrocarbons
compare well, while the double bonds in fullerenes have greater polarizability
than in ethylene.Comment: 7 pages, no figures, uses RevTeX. (To appear in Phys. Rev. B.
A direct probe of cosmological power spectra of the peculiar velocity field and the gravitational lensing magnification from photometric redshift surveys
The cosmological peculiar velocity field (deviations from the pure Hubble
flow) of matter carries significant information on dark energy, dark matter and
the underlying theory of gravity on large scales. Peculiar motions of galaxies
introduce systematic deviations between the observed galaxy redshifts z and the
corresponding cosmological redshifts z_cos. A novel method for estimating the
angular power spectrum of the peculiar velocity field based on observations of
galaxy redshifts and apparent magnitudes m (or equivalently fluxes) is
presented. This method exploits the fact that a mean relation between z_cos and
m of galaxies can be derived from all galaxies in a redshift-magnitude survey.
Given a galaxy magnitude, it is shown that the z_cos(m) relation yields its
cosmological redshift with a 1-sigma error of sigma_z~0.3 for a survey like
Euclid (~10^9 galaxies at z<~2), and can be used to constrain the angular power
spectrum of z-z_cos(m) with a high signal-to-noise ratio. At large angular
separations corresponding to l<~15, we obtain significant constraints on the
power spectrum of the peculiar velocity field. At 15<~l<~60, magnitude shifts
in the z_cos(m) relation caused by gravitational lensing magnification
dominate, allowing us to probe the line-of-sight integral of the gravitational
potential. Effects related to the environmental dependence in the luminosity
function can easily be computed and their contamination removed from the
estimated power spectra. The amplitude of the combined velocity and lensing
power spectra at z~1 can be measured with <~5% accuracy.Comment: 22 pages, 3 figures; added a discussion of systematic errors,
accepted for publication in JCA
Measurements of a low temperature mechanical dissipation peak in a single layer of Ta2O5 doped with TiO2
Thermal noise arising from mechanical dissipation in oxide coatings is a
major limitation to many precision measurement systems, including optical
frequency standards, high resolution optical spectroscopy and interferometric
gravity wave detectors. Presented here are measurements of dissipation as a
function of temperature between 7 K and 290 K in ion-beam sputtered Ta2O5 doped
with TiO2, showing a loss peak at 20 K. Analysis of the peak provides the first
evidence of the source of dissipation in doped Ta2O5 coatings, leading to
possibilities for the reduction of thermal noise effects
Library of Seleno-Compounds as Novel Agents against Leishmania Species
The in vitro leishmanicidal activities of a series of 48 recently synthesized selenium derivatives against Leishmania infantum and Leishmania braziliensis parasites were tested using promastigotes and intracellular amastigote forms. The cytotoxicity of the tested compounds for J774.2 macrophage cells was also measured in order to establish their selectivity. Six of the tested compounds (compounds 8, 10, 11, 15, 45, and 48) showed selectivity indexes higher than those of the reference drug, meglumine antimonate (Glucantime), for both Leishmania species; in the case of L. braziliensis, compound 20 was also remarkably selective. Moreover, data on infection rates and amastigote numbers per macrophage showed that compounds 8, 10, 11, 15, 45, and 48 were the most active against both Leishmania species studied. The observed changes in the excretion product profile of parasites treated with these six compounds were also consistent with substantial cytoplasmic alterations. On the other hand, the most active compounds were potent inhibitors of Fe superoxide dismutase (Fe-SOD) in the two parasite species considered, whereas their impact on human CuZn-SOD was low. The high activity, low toxicity, stability, low cost of the starting materials, and straightforward synthesis make these compounds appropriate molecules for the development of affordable antileishmanicidal agents
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