209 research outputs found
Probing the ZZgamma and Zgammagamma Couplings Through the Process e+e- --> nu anti-nu gamma
We study the sensitivity for testing the anomalous triple gauge couplings
and via the process
at high energy linear colliders. For integrated luminosities of 500
and center of mass energies between 0.5 and 1.5 , we find that this
process can provide tests of the triple neutral gauge boson couplings of order
, one order of magnitude lower than the standard model prediction.Comment: 12 pages, 6 figure
The ALMA Early Science View of FUor/EXor objects. III. The Slow and Wide Outflow of V883 Ori
We present Atacama Large Millimeter/ sub-millimeter Array (ALMA) observations
of V883 Ori, an FU Ori object. We describe the molecular outflow and envelope
of the system based on the CO and CO emissions, which together
trace a bipolar molecular outflow. The CO emission traces the rotational
motion of the circumstellar disk. From the CO blue-shifted emission, we
estimate a wide opening angle of 150 for the outflow
cavities. Also, we find that the outflow is very slow (characteristic velocity
of only 0.65 km~s), which is unique for an FU Ori object. We calculate
the kinematic properties of the outflow in the standard manner using the
CO and CO emissions. In addition, we present a P Cygni profile
observed in the high-resolution optical spectrum, evidence of a wind driven by
the accretion and being the cause for the particular morphology of the
outflows. We discuss the implications of our findings and the rise of these
slow outflows during and/or after the formation of a rotationally supported
disk.Comment: 12 pages, 7 figures, 2 tables. Accepte
A census of Oph candidate members from Gaia DR2
The Ophiuchus cloud complex is one of the best laboratories to study the
earlier stages of the stellar and protoplanetary disc evolution. The wealth of
accurate astrometric measurements contained in the Gaia Data Release 2 can be
used to update the census of Ophiuchus member candidates. We seek to find
potential new members of Ophiuchus and identify those surrounded by a
circumstellar disc. We constructed a control sample composed of 188 bona fide
Ophiuchus members. Using this sample as a reference we applied three different
density-based machine learning clustering algorithms (DBSCAN, OPTICS, and
HDBSCAN) to a sample drawn from the Gaia catalogue centred on the Ophiuchus
cloud. The clustering analysis was applied in the five astrometric dimensions
defined by the three-dimensional Cartesian space and the proper motions in
right ascension and declination. The three clustering algorithms systematically
identify a similar set of candidate members in a main cluster with astrometric
properties consistent with those of the control sample. The increased
flexibility of the OPTICS and HDBSCAN algorithms enable these methods to
identify a secondary cluster. We constructed a common sample containing 391
member candidates including 166 new objects, which have not yet been discussed
in the literature. By combining the Gaia data with 2MASS and WISE photometry,
we built the spectral energy distributions from 0.5 to 22\microm for a subset
of 48 objects and found a total of 41 discs, including 11 Class II and 1 Class
III new discs. Density-based clustering algorithms are a promising tool to
identify candidate members of star forming regions in large astrometric
databases. If confirmed, the candidate members discussed in this work would
represent an increment of roughly 40% of the current census of Ophiuchus.Comment: A&A, Accepted. Abridged abstrac
Skeletal and dentoalveolar bilateral dimensions in unilateral palatally impacted canine using cone beam computed tomography
Abstract Background The aim of this investigation was to compare skeletal and dentoalveolar measurements of subject with unilateral palatally impacted canine versus the unaffected contralateral side on cone beam computed tomography (CBCT). Methods A cross-sectional study (split mouth design) that included 28 CBCTs (i.e., 56 sides) with unilaterally impacted maxillary canines was performed. After conducting a pilot test to gauge the researcher, heights and widths of skeletal and dentoalveolar variables obtained in the maxilla were measured using coronal and axial views. The angulations of incisors were also measured, and the side with impaction and the unaffected side were compared. Paired sample t test and Wilcoxon signed-rank test were used. Results Significant statistical differences (2 mm, pâ<â0.001) were found between the impacted and non-impacted side measurements from the mid-palatine raphe to the first premolar (proximal alveolar bone crest between the canine (deciduous or permanent) and first premolar); the distance were significantly lower (12.72â±â2.25 mm) than in the side without impaction (14.67â±â2.00 mm). Also, the central and lateral incisor angulations showed significant reductions; presenting disto-angulated incisors on the impacted canine side (86.14â±â7.70° and 74.75â±â12.67°, respectively) and mesial-angulated incisors on the non-impacted side (91.63â±â6.79° and 81.21â±â8.56° respectively). The other skeletal and dentoalveolar measurements showed no significant differences. Conclusions The width from the median raphe to the first premolar is lower in the side of maxillary palatal impacted canines than in the side without impaction. Lateral angulations of incisors were disto-angulated on the side of impacted canines. Both conditions have clinical implications in the orthodontic treatment
Scanning Electron Microscope Study of Wohlfahrtia magnifica (Schiner, 1862) (Diptera: Sarcophagidae) I. Structures with Parasitic and Possible Taxonomic Meaning
The larval development of Wohlfahrtia magnifica (the most important dipteran causing sheep myiasis in the Palearctic region) has been studied by means of scanning electron microscopy. The ultrastructure of mouth-hooks, oral ridges, labial lobes, body spines and anterior and posterior peritremes is described for the first time. Their possible adaptations to a parasitic lifeway are also discussed. Thus, the use of new structures in the Sarcophagidae taxonomy is proposed from the point of view of their ultrastructure and adaptative morphology
Direct identification of clinical pathogens from liquid culture media by MALDI-TOF MS analysis
Objectives: We propose using MALDI-TOF MS as a tool for identifying microorganisms directly from liquid cultures after enrichment of the clinical sample in the media, to obtain a rapid microbiological diagnosis and an adequate administration of the antibiotic therapy in a clinical setting.
Methods: To evaluate this approach, a series of quality control isolates were grown in thioglycollate (TG) broth and brain heart infusion (BHI) broth and extracted under four different protocols before finally being identified by MALDI-TOF MS. After establishing the best extraction protocol, we validated the method in a total of 300 liquid cultures (150 in TG broth and 150 in BHI broth) of different types of clinical samples obtained from two tertiary Spanish hospitals.
Results: The initial evaluation showed that the extraction protocol including a 5 minute sonication step yielded 100% valid identifications, with an average score value of 2.305. In the clinical validation of the procedure, 98% of the microorganisms identified from the TG broth were correctly identified relative to 97% of those identified from the BHI broth. In 24% of the samples analysed, growth by direct sowing was only successful in the liquid medium, and no growth was observed in the direct solid agar cultures.
Conclusions: Use of MALDI-TOF MS plus the sonication-based extraction method enabled direct and accurate identification of microorganisms in liquid culture media in 15 minutes, in contrast to the 24 hours of subculture required for conventional identification, allowing the administration of a targeted antimicrobial therapy
Limits on the Dipole Moments of the -Lepton via the Process $e^{+}e^{-}\to \tau^+ \tau^- \gamma in a Left-Right Symmetric Model
Limits on the anomalous magnetic moment and the electric dipole moment of the
lepton are calculated through the reaction at the -pole and in the framework of a left-right symmetric model.
The results are based on the recent data reported by the L3 Collaboration at
CERN LEP. Due to the stringent limit of the model mixing angle , the
effect of this angle on the dipole moments is quite small.Comment: 15 pages, 3 figure
The TWA 3 Young Triple System: Orbits, Disks, Evolution
We have characterized the spectroscopic orbit of the TWA 3A binary and
provide preliminary families of probable solutions for the TWA 3A visual orbit
as well as for the wide TWA 3A--B orbit. TWA 3 is a hierarchical triple located
at 34 pc in the 10 Myr old TW Hya association. The wide component
separation is 1."55; the close pair was first identified as a possible binary
almost 20 years ago. We initially identified the 35-day period orbital solution
using high-resolution infrared spectroscopy which angularly resolved the A and
B components. We then refined the preliminary orbit by combining the infrared
data with a re-analysis of our high-resolution optical spectroscopy. The
orbital period from the combined spectroscopic solution is 35 days, the
eccentricity is 0.63, and the mass ratio is 0.84; although this
high mass ratio would suggest that optical spectroscopy alone should be
sufficient to identify the orbital solution, the presence of the tertiary B
component likely introduced confusion in the blended optical spectra. Using
millimeter imaging from the literature, we also estimate the inclinations of
the stellar orbital planes with respect to the TWA 3A circumbinary disk
inclination and find that all three planes are likely misaligned by at least
30 degrees. The TWA 3A spectroscopic binary components have spectral
types of M4.0 and M4.5; TWA 3B is an M3. We speculate that the system formed as
a triple, is bound, and that its properties were shaped by dynamical
interactions between the inclined orbits and disk.Comment: Accepted to Ap
Alma Survey Of Circumstellar Disks In The Young Stellar Cluster IC 348
We present a 1.3 mm continuum survey of the young (2-3 Myr) stellar cluster
IC 348, which lies at a distance of 310 pc, and is dominated by low-mass stars
(M 0.1-0.6 M). We observed 136 Class II sources
(disks that are optically thick in the infrared) at 0.8 (200 au) resolution
with a 3 sensitivity of 0.45 mJy (M 1.3
M). We detect 40 of the targets and construct a mm-continuum
luminosity function. We compare the disk mass distribution in IC 348 to those
of younger and older regions, taking into account the dependence on stellar
mass. We find a clear evolution in disk masses from 1 to 5-10 Myr. The disk
masses in IC 348 are significantly lower than those in Taurus (1-3 Myr) and
Lupus (1-3 Myr), similar to those of Chamaleon~I, (2-3 Myr) and Ori
(3-5 Myr) and significantly higher than in Upper Scorpius (510 Myr). About
20 disks in our sample (5 of the cluster members) have estimated
masses (dust gas) 1 M and hence might be the precursors of
giant planets in the cluster. Some of the most massive disks include transition
objects with inner opacity holes based on their infrared SEDs. From a stacking
analysis of the 96 non-detections, we find that these disks have a typical dust
mass of just 0.4 M, even though the vast majority of
their infrared SEDs remain optically thick and show little signs of evolution.
Such low-mass disks may be the precursors of the small rocky planets found by
\emph{Kepler} around M-type stars.Comment: 19 pages, 12 figure
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