666 research outputs found
CSO and CARMA Observations of L1157. II. Chemical Complexity in the Shocked Outflow
L1157, a molecular dark cloud with an embedded Class 0 protostar possessing a
bipolar outflow, is an excellent source for studying shock chemistry, including
grain-surface chemistry prior to shocks, and post-shock, gas-phase processing.
The L1157-B1 and B2 positions experienced shocks at an estimated ~2000 and 4000
years ago, respectively. Prior to these shock events, temperatures were too low
for most complex organic molecules to undergo thermal desorption. Thus, the
shocks should have liberated these molecules from the ice grain-surfaces en
masse, evidenced by prior observations of SiO and multiple grain mantle species
commonly associated with shocks. Grain species, such as OCS, CH3OH, and HNCO,
all peak at different positions relative to species that are preferably formed
in higher velocity shocks or repeatedly-shocked material, such as SiO and HCN.
Here, we present high spatial resolution (~3") maps of CH3OH, HNCO, HCN, and
HCO+ in the southern portion of the outflow containing B1 and B2, as observed
with CARMA. The HNCO maps are the first interferometric observations of this
species in L1157. The maps show distinct differences in the chemistry within
the various shocked regions in L1157B. This is further supported through
constraints of the molecular abundances using the non-LTE code RADEX (Van der
Tak et al. 2007). We find the east/west chemical differentiation in C2 may be
explained by the contrast of the shock's interaction with either cold, pristine
material or warm, previously-shocked gas, as seen in enhanced HCN abundances.
In addition, the enhancement of the HNCO abundance toward the the older shock,
B2, suggests the importance of high-temperature O-chemistry in shocked regions.Comment: Accepted for publication in the Astrophysical Journa
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Deciphering the complex interplay between microbiota, HPV, inflammation and cancer through cervicovaginal metabolic profiling
Background: Dysbiotic vaginal microbiota have been implicated as contributors to persistent HPV-mediated cervical carcinogenesis and genital inflammation with mechanisms unknown. Given that cancer is a metabolic disease, metabolic profiling of the cervicovaginal microenvironment has the potential to reveal the functional interplay between the host and microbes in HPV persistence and progression to cancer. Methods: Our study design included HPV-negative/positive controls, women with low-grade and high-grade cervical dysplasia, or cervical cancer (n = 78). Metabolic fingerprints were profiled using liquid chromatography-mass spectrometry. Vaginal microbiota and genital inflammation were analysed using 16S rRNA gene sequencing and immunoassays, respectively. We used an integrative bioinformatic pipeline to reveal host and microbe contributions to the metabolome and to comprehensively assess the link between HPV, microbiota, inflammation and cervical disease. Findings: Metabolic analysis yielded 475 metabolites with known identities. Unique metabolic fingerprints discriminated patient groups from healthy controls. Three-hydroxybutyrate, eicosenoate, and oleate/vaccenate discriminated (with excellent capacity) between cancer patients versus the healthy participants. Sphingolipids, plasmalogens, and linoleate positively correlated with genital inflammation. Non-Lactobacillus dominant communities, particularly in high-grade dysplasia, perturbed amino acid and nucleotide metabolisms. Adenosine and cytosine correlated positively with Lactobacillus abundance and negatively with genital inflammation. Glycochenodeoxycholate and carnitine metabolisms connected non-Lactobacillus dominance to genital inflammation. Interpretation: Cervicovaginal metabolic profiles were driven by cancer followed by genital inflammation, HPV infection, and vaginal microbiota. This study provides evidence for metabolite-driven complex host-microbe interactions as hallmarks of cervical cancer with future translational potential. (C) 2019 The Authors. Published by Elsevier B.V.Flinn Foundation [1974]; Banner Foundation in Obstetrics and Gynecology Research; National Institutes of Health NCI [P30 CA023074]Open access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]
Non-commutative gauge theory on D-branes in Melvin Universes
Non-commutative gauge theory with a non-constant non-commutativity parameter
can be formulated as a decoupling limit of open strings ending on D3-branes
wrapping a Melvin universe. We construct the action explicitly and discuss
various physical features of this theory. The decoupled field theory is not
supersymmetric. Nonetheless, the Coulomb branch appears to remain flat at least
in the large N and large 't Hooft coupling limit. We also find the analogue of
Prasad-Sommerfield monopoles whose size scales with the non-commutativity
parameter and is therefore position dependent.Comment: 15 pages, 1 figure, reference adde
Spitzer Observations of Long-term Infrared Variability among Young Stellar Objects in Chamaeleon I
Infrared variability is common among young stellar objects, with surveys finding daily to weekly fluctuations of a few tenths of a magnitude. Space-based observations can produce highly sampled infrared light curves, but are often limited to total baselines of about 1 month due to the orientation of the spacecraft. Here we present observations of the Chameleon I cluster, whose low declination makes it observable by the Spitzer Space Telescope over a 200-day period. We observe 30 young stellar objects with a daily cadence to better sample variability on timescales of months. We find that such variability is common, occurring in ~80% of the detected cluster members. The change in [3.6]–[4.5] color over 200 days for many of the sources falls between that expected for extinction and fluctuations in disk emission. With our high cadence and long baseline we can derive power spectral density curves covering two orders of magnitude in frequency and find significant power at low frequencies, up to the boundaries of our 200-day survey. Such long timescales are difficult to explain with variations driven by the interaction between the disk and stellar magnetic field, which has a dynamical timescale of days to weeks. The most likely explanation is either structural or temperature fluctuations spread throughout the inner ~0.5 au of the disk, suggesting that the intrinsic dust structure is highly dynamic
Technical Considerations in Revision Anterior Cruciate Ligament Reconstruction for Operative Techniques in Orthopaedics
As the incidence of anterior cruciate ligament (ACL) reconstruction continues to increase, the rate of revision surgery continues to climb. Revision surgery has inherent challenges that must be addressed to achieve successful results. The cause of the primary ACL reconstruction failure should be determined and careful preoperative planning should be performed to address the cause(s) of failure. Each patient undergoing revision surgery should undergo a thorough history and physical examination, receive full-length alignment radiographs, lateral radiographs, 45° flexion weight-bearing posteroanterior radiographs, and patellofemoral radiographs. The 3-dimensional computed tomography scan should be performed to assess tunnel position and widening. Magnetic resonance imaging should be used to assess for intra-articular soft tissue pathology. Meniscal tears, meniscal deficiency, anterolateral capsule injuries, bony morphology, age, activity level, connective tissue diseases, infection, graft choice, and tunnel position can all affect the success of ACL reconstruction surgery. Meniscal lesions should be repaired, and in cases of persistent rotatory instability, extra-articular procedures may be indicated. Furthermore, osteotomies may be needed to correct malalignment or excess posterior tibial slope. Depending on the placement and condition of the original femoral and tibial tunnels, revision surgery may be performed in a single procedure or in a staged manner. In most cases, the surgery can be performed in one procedure. Regardless, the surgeon must communicate with the patient openly regarding the implications of revision ACL surgery, and the treatment plan should be developed in a shared fashion between the surgeon and the patient
Taking connected mobile-health diagnostics of infectious diseases to the field.
Mobile Health or mHealth - The application of mobile devices, their components and related technologies to healthcare is improving patients’ access to treatment and advice. Now, in combination with connected diagnostic devices it offers new possibilities to diagnose, track and control infectious diseases and improve health system efficiencies. In this context we look at these technologies and highlight their promise but also the challenges in realising their potential to increase patient access to testing, aid in their treatment and improve the capability of public health authorities to monitor outbreaks, implement responses, and assess the impact of interventions across the world
Fine Structure in the Circumstellar Environment of a Young, Solar-like Star: the Unique Eclipses of KH 15D
Results of an international campaign to photometrically monitor the unique
pre-main sequence eclipsing object KH 15D are reported. An updated ephemeris
for the eclipse is derived that incorporates a slightly revised period of 48.36
d. There is some evidence that the orbital period is actually twice that value,
with two eclipses occurring per cycle. The extraordinary depth (~3.5 mag) and
duration (~18 days) of the eclipse indicate that it is caused by circumstellar
matter, presumably the inner portion of a disk. The eclipse has continued to
lengthen with time and the central brightness reversals are not as extreme as
they once were. V-R and V-I colors indicate that the system is slightly bluer
near minimum light. Ingress and egress are remarkably well modeled by the
passage of a knife-edge across a limb-darkened star. Possible models for the
system are briefly discussed.Comment: 19 pages, 5 figure
High-fidelity transmission of entanglement over a high-loss freespace channel
Quantum entanglement enables tasks not possible in classical physics. Many
quantum communication protocols require the distribution of entangled states
between distant parties. Here we experimentally demonstrate the successful
transmission of an entangled photon pair over a 144 km free-space link. The
received entangled states have excellent, noise-limited fidelity, even though
they are exposed to extreme attenuation dominated by turbulent atmospheric
effects. The total channel loss of 64 dB corresponds to the estimated
attenuation regime for a two-photon satellite quantum communication scenario.
We confirm that the received two-photon states are still highly entangled by
violating the CHSH inequality by more than 5 standard deviations. From a
fundamental point of view, our results show that the photons are virtually not
subject to decoherence during their 0.5 ms long flight through air, which is
encouraging for future world-wide quantum communication scenarios.Comment: 5 pages, 3 figures, replaced paper with published version, added
journal referenc
Operation of a layer-oriented multiconjugate adaptive optics system in the partial illumination regime
Multiconjugate adaptive optics (MCAO) promises uniform wide-field atmospheric correction. However, partial illumination of the layers at which the deformable mirrors are conjugated results in incomplete information about the full turbulence field. We report on a working solution to this difficulty for layer-oriented MCAO, including laboratory and on-sky demonstration with the LINC-NIRVANA instrument at the Large Binocular Telescope. This approach has proven to be simple and stable
Quantum teleportation using active feed-forward between two Canary Islands
Quantum teleportation [1] is a quintessential prerequisite of many quantum
information processing protocols [2-4]. By using quantum teleportation, one can
circumvent the no-cloning theorem [5] and faithfully transfer unknown quantum
states to a party whose location is even unknown over arbitrary distances. Ever
since the first experimental demonstrations of quantum teleportation of
independent qubits [6] and of squeezed states [7], researchers have
progressively extended the communication distance in teleportation, usually
without active feed-forward of the classical Bell-state measurement result
which is an essential ingredient in future applications such as communication
between quantum computers. Here we report the first long-distance quantum
teleportation experiment with active feed-forward in real time. The experiment
employed two optical links, quantum and classical, over 143 km free space
between the two Canary Islands of La Palma and Tenerife. To achieve this, the
experiment had to employ novel techniques such as a frequency-uncorrelated
polarization-entangled photon pair source, ultra-low-noise single-photon
detectors, and entanglement-assisted clock synchronization. The average
teleported state fidelity was well beyond the classical limit of 2/3.
Furthermore, we confirmed the quality of the quantum teleportation procedure
(without feed-forward) by complete quantum process tomography. Our experiment
confirms the maturity and applicability of the involved technologies in
real-world scenarios, and is a milestone towards future satellite-based quantum
teleportation
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