11,634 research outputs found
Exploring the Dust Content of Galactic Winds with Herschel. I. NGC 4631
We present a detailed analysis of deep far-infrared observations of the
nearby edge-on star-forming galaxy NGC 4631 obtained with the Herschel Space
Observatory. Our PACS images at 70 and 160 um show a rich complex of filaments
and chimney-like features that extends up to a projected distance of 6 kpc
above the plane of the galaxy. The PACS features often match extraplanar
Halpha, radio-continuum, and soft X-ray features observed in this galaxy,
pointing to a tight disk-halo connection regulated by star formation. On the
other hand, the morphology of the colder dust component detected on larger
scale in the SPIRE 250, 350, and 500 um data matches the extraplanar H~I
streams previously reported in NGC 4631 and suggests a tidal origin. The PACS
70/160 ratios are elevated in the central ~3.0 kpc region above the nucleus of
this galaxy (the "superbubble"). A pixel-by-pixel analysis shows that dust in
this region has a higher temperature and/or an emissivity with a steeper
spectral index (beta > 2) than the dust in the disk, possibly the result of the
harsher environment in the superbubble. Star formation in the disk seems
energetically insufficient to lift the material out of the disk, unless it was
more active in the past or the dust-to-gas ratio in the superbubble region is
higher than the Galactic value. Some of the dust in the halo may also have been
tidally stripped from nearby companions or lifted from the disk by galaxy
interactions.Comment: Accepted for publication in The Astrophysical Journa
Broadband spin-controlled focusing via logarithmic-spiral nanoslits of varying width
This work presents analytical, numerical and experimental demonstrations of light diffracted through a logarithmic spiral (LS) nanoslit, which forms a type of switchable and focus-tunable structure. Owing to a strong dependence on the incident photon spin, the proposed LS-nanoslit converges incoming light of opposite handedness (to that of the LS-nanoslit) into a confined subwavelength spot, while it shapes light with similar chirality into a donut-like intensity profile. Benefitting from the varying width of the LS-nanoslit, different incident wavelengths interfere constructively at different positions, i.e., the focal length shifts from 7.5 ฮผm (at ฮป = 632.8 nm) to 10 ฮผm (at ฮป = 488 nm), which opens up new opportunities for tuning and spatially separating broadband light at the micrometer scale
Constructing Robust Emotional State-based Feature with a Novel Voting Scheme for Multi-modal Deception Detection in Videos
Deception detection is an important task that has been a hot research topic
due to its potential applications. It can be applied in many areas, from
national security (e.g., airport security, jurisprudence, and law enforcement)
to real-life applications (e.g., business and computer vision). However, some
critical problems still exist and are worth more investigation. One of the
significant challenges in the deception detection tasks is the data scarcity
problem. Until now, only one multi-modal benchmark open dataset for human
deception detection has been released, which contains 121 video clips for
deception detection (i.e., 61 for deceptive class and 60 for truthful class).
Such an amount of data is hard to drive deep neural network-based methods.
Hence, those existing models often suffer from overfitting problems and low
generalization ability. Moreover, the ground truth data contains some unusable
frames for many factors. However, most of the literature did not pay attention
to these problems. Therefore, in this paper, we design a series of data
preprocessing methods to deal with the aforementioned problem first. Then, we
propose a multi-modal deception detection framework to construct our novel
emotional state-based feature and use the open toolkit openSMILE to extract the
features from the audio modality. We also design a voting scheme to combine the
emotional states information obtained from visual and audio modalities.
Finally, we can determine the novel emotion state transformation feature with
our self-designed algorithms. In the experiment, we conduct the critical
analysis and comparison of the proposed methods with the state-of-the-art
multi-modal deception detection methods. The experimental results show that the
overall performance of multi-modal deception detection has a significant
improvement in the accuracy from 87.77% to 92.78% and the ROC-AUC from 0.9221
to 0.9265.Comment: 8 pages, for AAAI23 publicatio
Metabolism of ticagrelor in patients with acute coronary syndromes.
ยฉ The Author(s) 2018Ticagrelor is a state-of-the-art antiplatelet agent used for the treatment of patients with acute coronary syndromes (ACS). Unlike remaining oral P2Y12 receptor inhibitors ticagrelor does not require metabolic activation to exert its antiplatelet action. Still, ticagrelor is extensively metabolized by hepatic CYP3A enzymes, and AR-C124910XX is its only active metabolite. A post hoc analysis of patient-level (nโ=โ117) pharmacokinetic data pooled from two prospective studies was performed to identify clinical characteristics affecting the degree of AR-C124910XX formation during the first six hours after 180โmg ticagrelor loading dose in the setting of ACS. Both linear and multiple regression analyses indicated that ACS patients presenting with ST-elevation myocardial infarction or suffering from diabetes mellitus are more likely to have decreased rate of ticagrelor metabolism during the acute phase of ACS. Administration of morphine during ACS was found to negatively influence transformation of ticagrelor into AR-C124910XX when assessed with linear regression analysis, but not with multiple regression analysis. On the other hand, smoking appears to increase the degree of ticagrelor transformation in ACS patients. Mechanisms underlying our findings and their clinical significance warrant further research.Peer reviewedFinal Published versio
Chandra Observations of Galaxy Zoo Mergers: Frequency of Binary Active Nuclei in Massive Mergers
We present the results from a Chandra pilot study of 12 massive galaxy
mergers selected from Galaxy Zoo. The sample includes major mergers down to a
host galaxy mass of 10 that already have optical AGN
signatures in at least one of the progenitors. We find that the coincidences of
optically selected active nuclei with mildly obscured ( cm) X-ray nuclei are relatively common (8/12), but the
detections are too faint ( counts per nucleus; erg s cm) to reliably separate starburst and
nuclear activity as the origin of the X-ray emission. Only one merger is found
to have confirmed binary X-ray nuclei, though the X-ray emission from its
southern nucleus could be due solely to star formation. Thus, the occurrences
of binary AGN in these mergers are rare (0-8%), unless most merger-induced
active nuclei are very heavily obscured or Compton thick.Comment: 8 pages, including 5 figures and 1 table. Accepted by Ap
Experimental Quantum Communication without a Shared Reference Frame
We present an experimental realization of a robust quantum communication
scheme [Phys. Rev. Lett. 93, 220501 (2004)] using pairs of photons entangled in
polarization and time. Our method overcomes errors due to collective rotation
of the polarization modes (e.g., birefringence in optical fiber or
misalignment), is insensitive to the phase's fluctuation of the interferometer,
and does not require any shared reference frame including time reference,
except the need to label different photons. The practical robustness of the
scheme is further shown by implementing a variation of the Bennett-Brassard
1984 quantum key distribution protocol over 1 km optical fiber.Comment: 4 pages, 4 figure
Comparative bactericidal activities of daptomycin, glycopeptides, linezolid and tigecycline against blood isolates of Gram-positive bacteria in Taiwan
ABSTRACTIn-vitro MICs and minimum bactericidal concentrations (MBCs) of daptomycin, linezolid, tigecycline, vancomycin and teicoplanin against Gram-positive bacteria were determined using the broth microdilution method for ten blood isolates each of methicillin-susceptible Staphylococcus aureus (MSSA), methicillin-resistant S. aureus (MRSA), including two vancomycin-intermediate S. aureus (VISA), vancomycin-resistant Enterococcus faecium and Enterococcus faecalis. One strain of VISA was tested in a time-kill synergism assay of daptomycin combined with oxacillin, imipenem, rifampicin and isepamicin. Daptomycin showed excellent in-vitro bactericidal activity against all the isolates tested, with no tolerance or synergism effects when combined with other agents, except with rifampicin against VISA. Vancomycin had better bactericidal activity against MRSA and MSSA than did teicoplanin. Linezolid had the poorest bactericidal activity against the isolates tested, with 100% tolerance by the MSSA and VRE isolates, and 80% tolerance by the MRSA isolates. Tolerance towards tigecycline was exhibited by 40% of the MRSA isolates, 100% of the MSSA and vancomycin-resistant E. faecalis isolates, and 90% of the vancomycin-resistant E. faecium isolates
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