304 research outputs found
The deflection of charged massive particles by a 4-Dimensional charged Einstein-Gauss-Bonnet black hole
Based on the Jacobi metric method, this paper studies the deflection of a
charged massive particle by a novel 4-dimensional charged Einstein-Gauss-Bonnet
black hole. We focus on the weak-filed approximation and consider the
deflection angle with finite-distance effects, i.e. the source and observer at
finite distances from the black hole. To this end, we use a geometric and
topological method, which is to apply the Gauss-Bonnet theorem to the
Jacobi-metric surface to calculate the deflection angle. We find that the
deflection angle contains a pure gravitational contribution , a pure
electrostatic one and a gravitational-electrostatic coupling term
. We also show that the electrostatic contribution can
also be computed by the Jacobi-metric method using the GB theorem to a charge
in a Minkowski flat spacetime background. We find that the deflection angle
increases(decreases) if the Gauss-Bonnet coupling constant is
negative(positive). Furthermore, the effects of the BH charge, the particle
charge-to-mass ratio and the particle velocity on the deflection angle are
analyzed.Comment: 11 pages, 5 Figures; conclusion part improved and reference adde
Deflection and gravitational lensing with finite distance effect in the strong deflection limit in stationary and axisymmetric spacetimes
We study the deflection and gravitational lensing (GL) of both timelike and
null signals in the equatorial plane of arbitrary stationary and axisymmetric
spacetimes in the strong deflection limit. Our approach employs a perturbative
method to show that both the deflection angle and the total travel time take
quasi-series forms , with the coefficients and incorporating the signal
velocity and finite distance effect of the source and detector. This new
deflection angle allows us to establish an accurate GL equation from which the
apparent angles of the relativistic images and their time delays are found.
These results are applied to the Kerr and the rotating Kalb-Ramond (KR)
spacetimes to investigate the effect of the spacetime spin in both spacetimes,
and the effective charge parameter and a transition parameter in the rotating
KR spacetime on various observables. Moreover, using our approach, the effect
of the signal velocity and the source angular position on these variables is
also studied.Comment: 15 pages, 10 figures; updated to publish versio
The Reconstruction of China's Regional Economic Pattern under the Background of "The Belt and Road" Strategy
The excessive development structure between China regions is generated in the process of industrialization and urbanization, and it is concentrated in an unequal spatial structure. The strategic concept of "The Belt and Road" provides an opportunity for the coordinated development of China's regional economy. On the one hand, it helps to promote economic transformation and upgrading in eastern China. On the other hand, it is helpful to realize the rising of central China and the opening of the western border zone, and optimize the regional development pattern. In this study, we propose that the regional coordination should be established by using "The Belt and Road" strategy. First of all, building a multi-center urban network to stimulate the economic development in the central and western regions; secondly, balancing the interests of different regions with a multi-level regional coordination mechanism and finally, forming a new pattern of coordinated regional development with institutionalized regional ecosystems. Keywords: The Belt and Road, regional imbalance, multi-center, regional coordination mechanism, institutio
Testing the cosmic curvature at high redshifts: the combination of LSST strong lensing systems and quasars as new standard candles
The cosmic curvature, a fundamental parameter for cosmology could hold deep
clues to inflation and cosmic origins. We propose an improved model-independent
method to constrain the cosmic curvature by combining the constructed Hubble
diagram of high-redshift quasars with galactic-scale strong lensing systems
expected to be seen by the forthcoming LSST survey. More specifically, the most
recent quasar data are used as a new type of standard candles in the range
, whose luminosity distances can be directly derived from the
non-linear relation between X-ray and UV luminosities. Compared with other
methods, the proposed one involving the quasar data achieves constraints with
higher precision () at high redshifts (). We also investigate the influence of lens mass distribution in the
framework of three types of lens models extensively used in strong lensing
studies (SIS model, power-law spherical model, and extended power-law lens
model), finding the strong correlation between the cosmic curvature and the
lens model parameters. When the power-law mass density profile is assumed, the
most stringent constraint on the cosmic curvature can be obtained.
Therefore, the issue of mass density profile in the early-type galaxies is
still a critical one that needs to be investigated further.Comment: 7 figures, 11 pages, accepted for publication in MNRA
Integrating Stock Features and Global Information via Large Language Models for Enhanced Stock Return Prediction
The remarkable achievements and rapid advancements of Large Language Models
(LLMs) such as ChatGPT and GPT-4 have showcased their immense potential in
quantitative investment. Traders can effectively leverage these LLMs to analyze
financial news and predict stock returns accurately. However, integrating LLMs
into existing quantitative models presents two primary challenges: the
insufficient utilization of semantic information embedded within LLMs and the
difficulties in aligning the latent information within LLMs with pre-existing
quantitative stock features. We propose a novel framework consisting of two
components to surmount these challenges. The first component, the Local-Global
(LG) model, introduces three distinct strategies for modeling global
information. These approaches are grounded respectively on stock features, the
capabilities of LLMs, and a hybrid method combining the two paradigms. The
second component, Self-Correlated Reinforcement Learning (SCRL), focuses on
aligning the embeddings of financial news generated by LLMs with stock features
within the same semantic space. By implementing our framework, we have
demonstrated superior performance in Rank Information Coefficient and returns,
particularly compared to models relying only on stock features in the China
A-share market.Comment: 8 pages, International Joint Conferences on Artificial Intelligenc
ReAct: Temporal Action Detection with Relational Queries
This work aims at advancing temporal action detection (TAD) using an
encoder-decoder framework with action queries, similar to DETR, which has shown
great success in object detection. However, the framework suffers from several
problems if directly applied to TAD: the insufficient exploration of
inter-query relation in the decoder, the inadequate classification training due
to a limited number of training samples, and the unreliable classification
scores at inference. To this end, we first propose a relational attention
mechanism in the decoder, which guides the attention among queries based on
their relations. Moreover, we propose two losses to facilitate and stabilize
the training of action classification. Lastly, we propose to predict the
localization quality of each action query at inference in order to distinguish
high-quality queries. The proposed method, named ReAct, achieves the
state-of-the-art performance on THUMOS14, with much lower computational costs
than previous methods. Besides, extensive ablation studies are conducted to
verify the effectiveness of each proposed component. The code is available at
https://github.com/sssste/React.Comment: ECCV202
New ages for the Upper Palaeolithic site of Xibaimaying in the Nihewan Basin, northern China: implications for small-tool and microblade industries in north-east Asia during Marine Isotope Stages 2 and 3
It has been suggested that the \u27small-tool\u27 and microblade Upper Palaeolithic industries coexisted in the Nihewan Basin of northern China for about 8-14 000 years during Marine Isotope Stage (MIS) 2. This inference was based on uranium-series ages of around 15 and 18 ka for bovid teeth recovered from the \u27latest\u27 small-tool site of Xibaimaying - the youngest occurrence of such tools in the region - and optically stimulated luminescence (OSL) dating of the earliest typical microblade site (Youfang: ∼26-29 ka). In this study, we re-dated the Xibaimaying site using single-grain OSL methods and the resulting ages indicate that the cultural layer was deposited 46 ± 3 ka ago, during MIS 3 - more than 20 millennia earlier than previously thought and older also than the so-called earliest \u27primitive\u27 and typical microblade tools found at Zhiyu (∼31-39 ka cal BP) and Youfang. These new ages for human occupation of Xibaimaying remove support for the parallel development of the small-tool and microblade industries in the Nihewan Basin during the Upper Palaeolithic, but reliable age estimates from additional sites are needed to confidently infer the nature of the chronological relationship between these two Upper Palaeolithic industries and the associated toolmakers
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