2,905 research outputs found
DialogBERT: Discourse-Aware Response Generation via Learning to Recover and Rank Utterances
Recent advances in pre-trained language models have significantly improved
neural response generation. However, existing methods usually view the dialogue
context as a linear sequence of tokens and learn to generate the next word
through token-level self-attention. Such token-level encoding hinders the
exploration of discourse-level coherence among utterances. This paper presents
DialogBERT, a novel conversational response generation model that enhances
previous PLM-based dialogue models. DialogBERT employs a hierarchical
Transformer architecture. To efficiently capture the discourse-level coherence
among utterances, we propose two training objectives, including masked
utterance regression and distributed utterance order ranking in analogy to the
original BERT training. Experiments on three multi-turn conversation datasets
show that our approach remarkably outperforms the baselines, such as BART and
DialoGPT, in terms of quantitative evaluation. The human evaluation suggests
that DialogBERT generates more coherent, informative, and human-like responses
than the baselines with significant margins.Comment: Published as a conference paper at AAAI 202
Enhanced photothermal therapy assisted with gold nanorods using a radially polarized beam
We report on the use of a radially polarized beam for photothermal therapy of cancer cells labeled with gold nanorods. Due to a three-dimensionally distributed electromagnetic field in the focal volume, the radially polarized beam is proven to be a highly efficient laser mode to excite gold nanorods randomly oriented in cancer cells. As a result, the energy fluence for effective cancer cell damage is reduced to one fifth of that required for a linearly polarized beam, which is only 9.3% of the medical safety level.<br /
Association Between Obstructive Sleep Apnea and Risk of Benign Vocal Fold Lesions: A Nationwide 9-Year Follow-Up Cohort Study
Since obstructive sleep apnea (OSA) affects various parts of the body, there has been little interest about the effect of OSA on voice. The objective of this study was to evaluate the risk of benign vocal fold lesions (BVFL) in OSA patients. This study used data from the National Health Insurance Service (NHIS) database. The study group was defined as the group diagnosed with OSA between 2008 and 2011. Non-OSA groups were selected based on propensity score (PS) matching. Incidence of BVFL among participants during the follow-up was analyzed. Cox proportional hazard regression analyses were performed to evaluate the association between OSA and incident BVFL. The HR value of the OSA group calculated by considering 8 variables indicates that the risk of developing BVFL is 79% higher than that of the control group. Further, among OSA patients, patients with a history of OP had a 35% lower risk of developing BVFL. The relationships between BVFL and 7 individual variables considered were as follows: For age, HR for the 40 to 59 years group was 1.20 (95%CI, 1.09-1.32). For sex, the HR in the female group was 1.22 (95%CI, 1.10-1.35). For residential areas, the HR values for Seoul 1.39 (95%CI, 1.23-1.59). In the high economic status group, the HR was 1.10 (95%CI, 1.01-1.21). This observational study indicated that OSA is associated with an increased incidence of BVFL. The incidence of BVFL increased with older age, female sex, and high SES
Isolation and characterization of the outer membrane of Escherichia coli with autodisplayed Z-domains
Abstract“Autodisplay technology” is an expression technique used to display the various recombinant proteins on the outer membrane (OM) of Escherichia coli. The resulting autodisplayed Z-domain has been used to improve the sensitivity of immunoassays. In this work, a facile isolation method of the OM fraction of E. coli with autodisplayed Z-domains was presented using (1) an enzyme reaction for the hydrolysis of the peptidoglycan layer and (2) short centrifugation steps. The purity of the isolated OM fraction was analyzed. For the estimation of contamination with bacterial proteins from other parts of E. coli, Western blots of marker proteins for the OM (OmpA), periplasm (β-lactamase), inner membrane (SecA), and cytoplasm (β-galactosidase) were performed. Additionally, assays of marker components or enzymes from each part of E. coli were carried out including the OM (KDO), inner membrane (NADH oxidase), periplasm (β-lactamase), and cytoplasm (β-galactosidase). The yield of OM isolation using this new method was determined to be 80% of the total OM amount, with less than 1% being contaminants from other parts of E. coli
An intrinsic link between long-term UV/optical variations and X-ray loudness in quasars
Observations have shown that UV/optical variation amplitude of quasars depend
on several physi- cal parameters including luminosity, Eddington ratio, and
likely also black hole mass. Identifying new factors which correlate with the
variation is essential to probe the underlying physical processes. Combining
~ten years long quasar light curves from SDSS stripe 82 and X-ray data from
Stripe 82X, we build a sample of X-ray detected quasars to investigate the
relation between UV/optical variation amplitude () and X-ray
loudness. We find that quasars with more intense X-ray radiation (com- pared to
bolometric luminosity) are more variable in UV/optical. Such correlation
remains highly significant after excluding the effect of other parameters
including luminosity, black hole mass, Ed- dington ratio, redshift, rest-frame
wavelength (i.e., through partial correlation analyses). We further find the
intrinsic link between X-ray loudness and UV/optical variation is gradually
more prominent on longer timescales (up to 10 years in the observed frame), but
tends to disappear at timescales < 100 days. This suggests a slow and long-term
underlying physical process. The X-ray reprocessing paradigm, in which
UV/optical variation is produced by a variable central X-ray emission
illuminating the accretion disk, is thus disfavored. The discovery points to an
interesting scheme that both the X-ray corona heating and UV/optical variation
is quasars are closely associated with magnetic disc turbulence, and the
innermost disc turbulence (where corona heating occurs) correlates with the
slow turbulence at larger radii (where UV/optical emission is produced).Comment: 9 pages, 4 figures, 1 table, accepted by Ap
Continuous Decomposition of Granularity for Neural Paraphrase Generation
While Transformers have had significant success in paragraph generation, they
treat sentences as linear sequences of tokens and often neglect their
hierarchical information. Prior work has shown that decomposing the levels of
granularity~(e.g., word, phrase, or sentence) for input tokens has produced
substantial improvements, suggesting the possibility of enhancing Transformers
via more fine-grained modeling of granularity. In this work, we propose a
continuous decomposition of granularity for neural paraphrase generation
(C-DNPG). In order to efficiently incorporate granularity into sentence
encoding, C-DNPG introduces a granularity-aware attention (GA-Attention)
mechanism which extends the multi-head self-attention with: 1) a granularity
head that automatically infers the hierarchical structure of a sentence by
neurally estimating the granularity level of each input token; and 2) two novel
attention masks, namely, granularity resonance and granularity scope, to
efficiently encode granularity into attention. Experiments on two benchmarks,
including Quora question pairs and Twitter URLs have shown that C-DNPG
outperforms baseline models by a remarkable margin and achieves
state-of-the-art results in terms of many metrics. Qualitative analysis reveals
that C-DNPG indeed captures fine-grained levels of granularity with
effectiveness.Comment: Accepted to be published in COLING 202
Precise Radial Velocities of Polaris: Detection of Amplitude Growth
We present a first results from a long-term program of a radial velocity
study of Cepheid Polaris (F7 Ib) aimed to find amplitude and period of
pulsations and nature of secondary periodicities. 264 new precise radial
velocity measurements were obtained during 2004-2007 with the fiber-fed echelle
spectrograph Bohyunsan Observatory Echelle Spectrograph (BOES) of 1.8m
telescope at Bohyunsan Optical Astronomy Observatory (BOAO) in Korea. We find a
pulsational radial velocity amplitude and period of Polaris for three seasons
of 2005.183, 2006.360, and 2007.349 as 2K = 2.210 +/- 0.048 km/s, 2K = 2.080
+/- 0.042 km/s, and 2K = 2.406 +/- 0.018 km/s respectively, indicating that the
pulsational amplitudes of Polaris that had decayed during the last century is
now increasing rapidly. The pulsational period was found to be increasing too.
This is the first detection of a historical turnaround of pulsational amplitude
change in Cepheids. We clearly find the presence of additional radial velocity
variations on a time scale of about 119 days and an amplitude of about +/- 138
m/s, that is quasi-periodic rather than strictly periodic. We do not confirm
the presence in our data the variation on a time scale 34-45 days found in
earlier radial velocity data obtained in 80's and 90's. We assume that both the
119 day quasi-periodic, noncoherent variations found in our data as well as
34-45 day variations found before can be caused by the 119 day rotation periods
of Polaris and by surface inhomogeneities such as single or multiple spot
configuration varying with the time.Comment: 15 pages, 7 figures, Accepted for publication in The Astronomical
Journa
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