3,315 research outputs found
Mining Circumgalactic Baryons in the Low-Redshift Universe
(Abridged) This paper presents an absorption-line study of the multiphase
circumgalactic medium (CGM) based on observations of Lya, CII, CIV, SiII,
SiIII, and SiIV absorption transitions in the vicinities of 195 galaxies at
redshift z<0.176. The galaxy sample is established based on a cross-comparison
between public galaxy and QSO survey data and is characterized by a median
redshift of =0.041, a median projected distance of =362 kpc to the
sightline of the background QSO, and a median stellar mass of log(M_star/M_sun)
= 9.7 \pm 1.1. Comparing the absorber features identified in the QSO apectra
with known galaxy properties has led to strong constraints for the CGM
absorption properties at z<~0.176. First, abundant hydrogen gas is observed out
to d~500 kpc, well beyond the dark matter halo radius Rh of individual
galaxies, with a mean covering fraction of ~60%. In contrast, no heavy elements
are detected at d>~0.7 Rh from either low-mass dwarfs or high-mass galaxies.
The lack of detected heavy elements in low- and high-ionization states suggests
that either there exists a chemical enrichment edge at d~0.7 Rh or gaseous
clumps giving rise to the observed absorption lines cannot survive at these
large distances. Considering all galaxies at d>Rh leads to a strict upper limit
for the covering fraction of heavy elements of ~3% (at a 95% confidence level)
over d=(1-9) Rh. At d<Rh, differential covering fraction between low- and
high-ionization gas is observed, suggesting that the CGM becomes progressively
more ionized from d<0.3 Rh to larger distances. Comparing CGM absorption
observations at low and high redshifts shows that at a fixed-fraction of Rh the
CGM exhibits stronger mean absorption at z=2.2 than at z~0. We discuss possible
pseudo-evolution of the CGM as a result of misrepresentation of halo radius.Comment: 25 pages, 13 figures; accepted for publication in MNRA
First R and I Lights and Their Photometric Analyses of GSC 02393-00680
We obtained complete and light curves of GSC 02393-00680 in 2008 and
analyzed them with the 2003 version of the W-D code. It is shown that GSC
02393-00680 is a W-type shallow contact binary system with a high mass ratio
and a degree of contact factor . It will be a good
example to check up on the TRO theory. A period investigation based on all
available data suggests that the system has a small-amplitude period
oscillation (; years). This may indicate it has a
moderate mass close third body, which is similar to XY Leo
MiAMix: Enhancing Image Classification through a Multi-stage Augmented Mixed Sample Data Augmentation Method
Despite substantial progress in the field of deep learning, overfitting
persists as a critical challenge, and data augmentation has emerged as a
particularly promising approach due to its capacity to enhance model
generalization in various computer vision tasks. While various strategies have
been proposed, Mixed Sample Data Augmentation (MSDA) has shown great potential
for enhancing model performance and generalization. We introduce a novel mixup
method called MiAMix, which stands for Multi-stage Augmented Mixup. MiAMix
integrates image augmentation into the mixup framework, utilizes multiple
diversified mixing methods concurrently, and improves the mixing method by
randomly selecting mixing mask augmentation methods. Recent methods utilize
saliency information and the MiAMix is designed for computational efficiency as
well, reducing additional overhead and offering easy integration into existing
training pipelines. We comprehensively evaluate MiaMix using four image
benchmarks and pitting it against current state-of-the-art mixed sample data
augmentation techniques to demonstrate that MIAMix improves performance without
heavy computational overhead
Cross-Attribute Matrix Factorization Model with Shared User Embedding
Over the past few years, deep learning has firmly established its prowess
across various domains, including computer vision, speech recognition, and
natural language processing. Motivated by its outstanding success, researchers
have been directing their efforts towards applying deep learning techniques to
recommender systems. Neural collaborative filtering (NCF) and Neural Matrix
Factorization (NeuMF) refreshes the traditional inner product in matrix
factorization with a neural architecture capable of learning complex and
data-driven functions. While these models effectively capture user-item
interactions, they overlook the specific attributes of both users and items.
This can lead to robustness issues, especially for items and users that belong
to the "long tail". Such challenges are commonly recognized in recommender
systems as a part of the cold-start problem. A direct and intuitive approach to
address this issue is by leveraging the features and attributes of the items
and users themselves. In this paper, we introduce a refined NeuMF model that
considers not only the interaction between users and items, but also acrossing
associated attributes. Moreover, our proposed architecture features a shared
user embedding, seamlessly integrating with user embeddings to imporve the
robustness and effectively address the cold-start problem. Rigorous experiments
on both the Movielens and Pinterest datasets demonstrate the superiority of our
Cross-Attribute Matrix Factorization model, particularly in scenarios
characterized by higher dataset sparsity
The Design of Nonlinear Chirp Based on the DSP Builder Technique
This paper, by analyzing the function Chirp, studies the software design and realization of the function. It offers a design plan based on the nonlinear Chirp signal of DSP Builder technique and designs the signal generator of the nonlinear Chirp based on the design flow of Matlab/Simulink/DSP Builder/Quartusll. It also conducts simulation verification using the development software Matlab/Simulink and Quartusll, proving that the design can well realize the signal source Chirp. The experiment proves that the DSP Builder technique can modify the starting frequency, bandwidth and the frequency resolution of linear frequency modulation signals by changing the programming parameters. The method is proved to be simple in designing, convenient in modification, low in cost and it doesn’t involve any programming; therefore, it is easy to realize
Optimal Acceleration-Velocity-Bounded Trajectory Planning in Dynamic Crowd Simulation
Creating complex and realistic crowd behaviors, such as pedestrian navigation behavior with dynamic obstacles, is a difficult and time consuming task. In this paper, we study one special type of crowd which is composed of urgent individuals, normal individuals, and normal groups. We use three steps to construct the crowd simulation in dynamic environment. The first one is that the urgent individuals move forward along a given path around dynamic obstacles and other crowd members. An optimal acceleration-velocity-bounded trajectory planning method is utilized to model their behaviors, which ensures that the durations of the generated trajectories are minimal and the urgent individuals are collision-free with dynamic obstacles (e.g., dynamic vehicles). In the second step, a pushing model is adopted to simulate the interactions between urgent members and normal ones, which ensures that the computational cost of the optimal trajectory planning is acceptable. The third step is obligated to imitate the interactions among normal members using collision avoidance behavior and flocking behavior. Various simulation results demonstrate that these three steps give realistic crowd phenomenon just like the real world
Macrophage migration inhibitory factor (MIF) family in arthropods : Cloning and expression analysis of two MIF and one D-dopachrome tautomerase (DDT) homologues in Mud crabs, Scylla paramamosain
Acknowledgements This research was supported by grants from the National Natural Science Foundation of China (Nos. 31172438 and U1205123), the Natural Science Foundation of Fujian Province (No. 2012J06008 and 201311180002) and the projects-sponsored by SRF. TW received funding from the MASTS pooling initiative (The Marine Alliance for Science and Technology for Scotland) funded by the Scottish Funding Council (grant reference HR09011) and contributing institutions.Peer reviewedPostprin
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