693 research outputs found
Towards Quantifying the Impact of Triaxiality on Optical Signatures of Galaxy Clusters: Weak Lensing and Galaxy Distributions
We present observational evidence of the impact of triaxiality on radial
profiles that extend to 40~Mpc from galaxy cluster centres in optical
measurements. We perform a stacked profile analysis from a sample of thousands
of nearly relaxed galaxy clusters from public data releases of the Dark Energy
Survey (DES) and the Dark Energy Camera Legacy Survey (DECaLS). Using the
central galaxy elliptical orientation angle as a proxy for galaxy cluster
orientation, we measure cluster weak lensing and excess galaxy density
axis-aligned profiles, extracted along the central galaxy's major or minor axes
on the plane-of-the-sky. Our measurements show a difference
per radial bin between the normalized axis-aligned profiles. The profile
difference between each axis-aligned profile and the azimuthally averaged
profile ( along major/minor axis) appears inside the clusters
( Mpc) and extends to the large-scale structure regime (
Mpc). The magnitude of the difference appears to be relatively insensitive to
cluster richness and redshift, and extends further out in the weak lensing
surface mass density than in the galaxy overdensity. Looking forward, this
measurement can easily be applied to other observational or simulation datasets
and can inform the systematics in cluster mass modeling related to triaxiality.
We expect imminent upcoming wide-area deep surveys, such as the Vera C. Rubin
Observatory's Legacy Survey of Space and Time (LSST), to improve our
quantification of optical signatures of cluster triaxiality.Comment: Submitted to MNRAS, minor differences because of recent comments,
comments are welcome and appreciate
Structured electrode additive manufacturing for lithium-ion batteries
A thick electrode with high areal capacity has been developed as a strategy
for high-energy-density lithium-ion batteries, but thick electrodes have
difficulties in manufacturing and limitations in ion transport. Here, we
reported a new manufacturing approach for ultra-thick electrode with aligned
structure, called structure electrode additive manufacturing or SEAM, which
aligns active materials to the through-thicknesses direction of electrodes
using shear flow and a designed printing path. The ultra-thick electrodes with
high loading of active materials, low tortuous structure, and good structure
stability resulting from a simple and scalable SEAM lead to rapid ion transport
and fast electrolyte infusion, delivering a higher areal capacity than
slurry-casted thick electrodes. SEAM shows strengths in design flexibility and
scalability, which allows the production of practical high energy/power density
structure electrodes
An Empirical Study on the Language Modal in Visual Question Answering
Generalization beyond in-domain experience to out-of-distribution data is of
paramount significance in the AI domain. Of late, state-of-the-art Visual
Question Answering (VQA) models have shown impressive performance on in-domain
data, partially due to the language priors bias which, however, hinders the
generalization ability in practice. This paper attempts to provide new insights
into the influence of language modality on VQA performance from an empirical
study perspective. To achieve this, we conducted a series of experiments on six
models. The results of these experiments revealed that, 1) apart from prior
bias caused by question types, there is a notable influence of postfix-related
bias in inducing biases, and 2) training VQA models with word-sequence-related
variant questions demonstrated improved performance on the out-of-distribution
benchmark, and the LXMERT even achieved a 10-point gain without adopting any
debiasing methods. We delved into the underlying reasons behind these
experimental results and put forward some simple proposals to reduce the
models' dependency on language priors. The experimental results demonstrated
the effectiveness of our proposed method in improving performance on the
out-of-distribution benchmark, VQA-CPv2. We hope this study can inspire novel
insights for future research on designing bias-reduction approaches.Comment: Accepted by IJCAI202
Seismic anisotropy and shear wave splitting associated with mantle plume-plate interaction
Geodynamic simulations of the development of lattice preferred orientation in the flowing mantle are used to characterize the seismic anisotropy and shear wave splitting (SWS) patterns expected for the interaction of mantle plumes and lithospheric plates. Models predict that in the deeper part of the plume layer ponding beneath the plate, olivine a axes tend to align perpendicular to the radially directed plume flow, forming a circular pattern reflecting circumferential stretching. In the shallower part of the plume layer, plate shear is more important and the a axes tend toward the direction of plate motion. Predicted SWS over intraplate plumes reflects the asymmetric influence of plate shear with fast S wave polarization directions forming a pattern of nested U shapes that open in the direction opposing both plate motion and the parabolic shape often used to describe the flow lines of the plume. Predictions explain SWS observations around the Eifel hot spot with an eastward, not westward, moving Eurasian plate, consistent with global studies that require relatively slow net (westward) rotation of all of the plates. SWS at the Hawaiian hot spot can be explained by the effects of plume-plate interaction, combined with fossil anisotropy in the Pacific lithosphere. In ridge-centered plume models, the fast polarization directions angle diagonally toward the ridge axis when the plume is simulated as having low viscosity beneath the thermal lithosphere. Such a model better explains SWS observations in northeast Iceland than a model that incorporates a high-viscosity layer due to dehydration of the shallow-most upper mantle
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Governance Policy Evaluation in the United States during the Pandemic: Nonpharmaceutical Interventions or Else?
Scientific evidence suggests that nonpharmaceutical interventions (NPIs) effectively curb the spread of COVID-19 before a pharmaceutical solution. Implementing these interventions also significantly affects regular socioeconomic activities and practices of social, racial, and political justice. Local governments often face conflicting goals during policymaking. Striking a balance among competing goals during a global pandemic is a fine science of governance. How well state governments consume the scientific evidence and maintain such a balance remains less understood. This study employs a set of Bayesian hierarchical models to evaluate how state governments in the United States use scientific evidence to balance the fighting against the spread of COVID-19 disease and socioeconomic, racial, social justice, and other demands. We modeled the relationships between five NPI strategies and COVID-19 caseload information and used the modeled result to perform a balanced governance evaluation. The results suggest that governmental attitude and guidance effectively guide the public to fight back against a global pandemic. The more detailed spatiotemporally varying coefficient process model produces 612,000 spatiotemporally varying coefficients, suggesting all measures sometimes work somewhere. Summarized results indicate that states emphasizing NPIs fared well in curbing the spread of COVID-19. With over 1 million deaths due to COVID-19 in the United States, we feel the balance scale likely needs to tip toward preserving human lives. Our evaluation of governance policies is hence based on such an argument. This study aims to provide decision support for policymaking during a national emergency
STAGE: Span Tagging and Greedy Inference Scheme for Aspect Sentiment Triplet Extraction
Aspect Sentiment Triplet Extraction (ASTE) has become an emerging task in
sentiment analysis research, aiming to extract triplets of the aspect term, its
corresponding opinion term, and its associated sentiment polarity from a given
sentence. Recently, many neural networks based models with different tagging
schemes have been proposed, but almost all of them have their limitations:
heavily relying on 1) prior assumption that each word is only associated with a
single role (e.g., aspect term, or opinion term, etc. ) and 2) word-level
interactions and treating each opinion/aspect as a set of independent words.
Hence, they perform poorly on the complex ASTE task, such as a word associated
with multiple roles or an aspect/opinion term with multiple words. Hence, we
propose a novel approach, Span TAgging and Greedy infErence (STAGE), to extract
sentiment triplets in span-level, where each span may consist of multiple words
and play different roles simultaneously. To this end, this paper formulates the
ASTE task as a multi-class span classification problem. Specifically, STAGE
generates more accurate aspect sentiment triplet extractions via exploring
span-level information and constraints, which consists of two components,
namely, span tagging scheme and greedy inference strategy. The former tag all
possible candidate spans based on a newly-defined tagging set. The latter
retrieves the aspect/opinion term with the maximum length from the candidate
sentiment snippet to output sentiment triplets. Furthermore, we propose a
simple but effective model based on the STAGE, which outperforms the
state-of-the-arts by a large margin on four widely-used datasets. Moreover, our
STAGE can be easily generalized to other pair/triplet extraction tasks, which
also demonstrates the superiority of the proposed scheme STAGE.Comment: Accepted by AAAI 202
Equivalence of Discrete Fracture Network and Porous Media Models by Hydraulic Tomography
Hydraulic tomography (HT) has emerged as a potentially viable method for mapping fractures in geologic media as demonstrated by recent studies. However, most of the studies adopted equivalent porous media (EPM) models to generate and invert hydraulic interference test data for HT. While these models assign significant different hydraulic properties to fractures and matrix, they may not fully capture the discrete nature of the fractures in the rocks. As a result, HT performance may have been overrated. To explore this issue, this study employed a discrete fracture network (DFN) model to simulate hydraulic interference tests. HT with the EPM model was then applied to estimate the distributions of hydraulic conductivity (K) and specific storage (S-s) of the DFN. Afterward, the estimated fields were used to predict the observed heads from DFN models, not used in the HT analysis (i.e., validation). Additionally, this study defined the spatial representative elementary volume (REV) of the fracture connectivity probability for the entire DFN dominant. The study showed that if this spatial REV exists, the DFN is deemed equivalent to EPM and vice versa. The hydraulic properties estimated by HT with an EPM model can then predict head fields satisfactorily over the entire DFN domain with limited monitoring wells. For a sparse DFN without this spatial REV, a dense observation network is needed. Nevertheless, HT is able to capture the dominant fractures.National Science and Technology Major Project of China [2017ZX05008-003-021]; Strategic Priority Research Program of the Chinese Academy of Sciences [XDB10030601]; Youth Innovation Promotion Association of the Chinese Academy of Sciences [2016063]; US Civilain Research and Development Foundation (CRDF) under the award: Hydraulic tomography in shallow alluvial sediments: Nile River Valley, Egypt [DAA2-15-61224-1]; Global Expert award through Tianjin Normal University from the Thousand Talents Plan of Tianjin City6 month embargo; published online: 23 April 2019This 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]
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