141 research outputs found
T-duality to Scattering Amplitude and Wilson Loop in Non-commutative Super Yang-Mills Theory
We first perform bosonic T-duality transformation on one of the marginal TsT
(T-duality, shift, T-duality)-deformed spacetime, which
corresponds to 4D non-commutative super Yang-Mills theory
(NCSYM). We then construct the solution to killing spinor equations of the
resulting background, and perform the fermionic T-duality transformation. The
final dual geometry becomes the usual but with the constant
NS-NS B-field depending on the non-commutative parameter. As applications, we
study the gluon scattering amplitude and open string (Wilson loop) solution in
the TsT-deformed spacetime, which are dual to the null
polygon Wilson loop and the folded string solution respectively in the final
dual geometry.Comment: 24 pages, latex, references added, published versio
Correlation Functions in the TsT/ Correspondence
We investigate the proposed holographic duality between the TsT
transformation of IIB string theory on AdS with NS-NS flux
and a single-trace deformation of the symmetric orbifold CFT. We
present a non-perturbative calculation of two-point correlation functions using
string theory and demonstrate their consistency with those of the
deformation. The two-point correlation function of the deformed theory on the
plane, written in momentum space, is obtained from that of the undeformed
theory by replacing with , where is
the spacetime conformal weight, is a deformation parameter,
and are the momenta, and labels the twisted sectors in the
deformed symmetric product. At , the non-perturbative result satisfies the
Callan-Symanzik equation for double-trace deformed CFT derived in
\cite{Cardy:2019qao}. We also perform conformal perturbations on both the
worldsheet CFT and the symmetric orbifold CFT as a sanity check. The
perturbative and non-perturbative matching between results on the two sides
provides further evidence of the conjectured TsT/ correspondence.Comment: 35 page
Uncertainty Sentence Sampling by Virtual Adversarial Perturbation
Active learning for sentence understanding attempts to reduce the annotation
cost by identifying the most informative examples. Common methods for active
learning use either uncertainty or diversity sampling in the pool-based
scenario. In this work, to incorporate both predictive uncertainty and sample
diversity, we propose Virtual Adversarial Perturbation for Active Learning
(VAPAL) , an uncertainty-diversity combination framework, using virtual
adversarial perturbation (Miyato et al., 2019) as model uncertainty
representation. VAPAL consistently performs equally well or even better than
the strong baselines on four sentence understanding datasets: AGNEWS, IMDB,
PUBMED, and SST-2, offering a potential option for active learning on sentence
understanding tasks
Generic Intent Representation in Web Search
This paper presents GEneric iNtent Encoder (GEN Encoder) which learns a
distributed representation space for user intent in search. Leveraging large
scale user clicks from Bing search logs as weak supervision of user intent, GEN
Encoder learns to map queries with shared clicks into similar embeddings
end-to-end and then finetunes on multiple paraphrase tasks. Experimental
results on an intrinsic evaluation task - query intent similarity modeling -
demonstrate GEN Encoder's robust and significant advantages over previous
representation methods. Ablation studies reveal the crucial role of learning
from implicit user feedback in representing user intent and the contributions
of multi-task learning in representation generality. We also demonstrate that
GEN Encoder alleviates the sparsity of tail search traffic and cuts down half
of the unseen queries by using an efficient approximate nearest neighbor search
to effectively identify previous queries with the same search intent. Finally,
we demonstrate distances between GEN encodings reflect certain information
seeking behaviors in search sessions
Mendelian randomization analysis identified tumor necrosis factor as being associated with severe COVID-19
Background: Observational studies have shown that anti-tumor necrosis factor (TNF) therapy may be beneficial for patients with coronavirus disease 2019 (COVID-19). Nevertheless, because of the methodological restrictions of traditional observational studies, it is a challenge to make causal inferences. This study involved a two-sample Mendelian randomization analysis to investigate the causal link between nine TNFs and COVID-19 severity using publicly released genome-wide association study summary statistics.Methods: Summary statistics for nine TNFs (21,758 cases) were obtained from a large-scale genome-wide association study. Correlation data between single-nucleotide polymorphisms and severe COVID-19 (18,152 cases vs. 1,145,546 controls) were collected from the COVID-19 host genetics initiative. The causal estimate was calculated by inverse variance-weighted (IVW), MR–Egger, and weighted median methods. Sensitivity tests were conducted to assess the validity of the causal relationship.Results: Genetically predicted TNF receptor superfamily member 6 (FAS) positively correlated with the severity of COVID-19 (IVW, odds ratio = 1.10, 95% confidence interval = 1.01–1.19, p = 0.026), whereas TNF receptor superfamily member 5 (CD40) was protective against severe COVID-19 (IVW, odds ratio = 0.92, 95% confidence interval = 0.87–0.97, p = 0.002).Conclusion: Genetic evidence from this study supports that the increased expression of FAS is associated with the risk of severe COVID-19 and that CD40 may have a potential protective effect against COVID-19
PSR J1926-0652: A Pulsar with Interesting Emission Properties Discovered at FAST
We describe PSR J1926-0652, a pulsar recently discovered with the
Five-hundred-meter Aperture Spherical radio Telescope (FAST). Using sensitive
single-pulse detections from FAST and long-term timing observations from the
Parkes 64-m radio telescope, we probed phenomena on both long and short time
scales. The FAST observations covered a wide frequency range from 270 to 800
MHz, enabling individual pulses to be studied in detail. The pulsar exhibits at
least four profile components, short-term nulling lasting from 4 to 450 pulses,
complex subpulse drifting behaviours and intermittency on scales of tens of
minutes. While the average band spacing P3 is relatively constant across
different bursts and components, significant variations in the separation of
adjacent bands are seen, especially near the beginning and end of a burst. Band
shapes and slopes are quite variable, especially for the trailing components
and for the shorter bursts. We show that for each burst the last detectable
pulse prior to emission ceasing has different properties compared to other
pulses. These complexities pose challenges for the classic carousel-type
models.Comment: 13pages with 12 figure
A global experiment on motivating social distancing during the COVID-19 pandemic
Finding communication strategies that effectively motivate social distancing continues to be a global public health priority during the COVID-19 pandemic. This cross-country, preregistered experiment (n = 25,718 from 89 countries) tested hypotheses concerning generalizable positive and negative outcomes of social distancing messages that promoted personal agency and reflective choices (i.e., an autonomy-supportive message) or were restrictive and shaming (i.e., a controlling message) compared with no message at all. Results partially supported experimental hypotheses in that the controlling message increased controlled motivation (a poorly internalized form of motivation relying on shame, guilt, and fear of social consequences) relative to no message. On the other hand, the autonomy-supportive message lowered feelings of defiance compared with the controlling message, but the controlling message did not differ from receiving no message at all. Unexpectedly, messages did not influence autonomous motivation (a highly internalized form of motivation relying on one’s core values) or behavioral intentions. Results supported hypothesized associations between people’s existing autonomous and controlled motivations and self-reported behavioral intentions to engage in social distancing. Controlled motivation was associated with more defiance and less long-term behavioral intention to engage in social distancing, whereas autonomous motivation was associated with less defiance and more short- and long-term intentions to social distance. Overall, this work highlights the potential harm of using shaming and pressuring language in public health communication, with implications for the current and future global health challenges
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