72 research outputs found
Solar cycle variation of real CME latitudes
With the assumption of radial motion and uniform longitudinal distribution of
coronal mass ejections (CMEs), we propose a method to eliminate projection
effects from the apparent observed CME latitude distribution. This method has
been applied to SOHO LASCO data from 1996 January to 2006 December. As a
result, we find that the real CME latitude distribution had the following
characteristics: (1) High-latitude CMEs ( where is
the latitude) constituted 3% of all CMEs and mainly occurred during the time
when the polar magnetic fields reversed sign. The latitudinal drift of the
high-latitude CMEs was correlated with that of the heliospheric current sheet.
(2) 4% of all CMEs occurred in the range .
These mid-latitude CMEs occurred primarily in 2000, near the middle of 2002 and
in 2005, respectively, forming a prominent three-peak structure; (3) The
highest occurrence probability of low-latitude () CMEs was
at the minimum and during the declining phase of the solar cycle. However, the
highest occurrence rate of low-latitude CMEs was at the maximum and during the
declining phase of the solar cycle. The latitudinal evolution of low-latitude
CMEs did not follow the Sp\"{o}rer sunspot law, which suggests that many CMEs
originated outside of active regions.Comment: 4 pages, 4 figures, accepted by ApJ Lette
TrafficMOT: A Challenging Dataset for Multi-Object Tracking in Complex Traffic Scenarios
Multi-object tracking in traffic videos is a crucial research area, offering
immense potential for enhancing traffic monitoring accuracy and promoting road
safety measures through the utilisation of advanced machine learning
algorithms. However, existing datasets for multi-object tracking in traffic
videos often feature limited instances or focus on single classes, which cannot
well simulate the challenges encountered in complex traffic scenarios. To
address this gap, we introduce TrafficMOT, an extensive dataset designed to
encompass diverse traffic situations with complex scenarios. To validate the
complexity and challenges presented by TrafficMOT, we conducted comprehensive
empirical studies using three different settings: fully-supervised,
semi-supervised, and a recent powerful zero-shot foundation model Tracking
Anything Model (TAM). The experimental results highlight the inherent
complexity of this dataset, emphasising its value in driving advancements in
the field of traffic monitoring and multi-object tracking.Comment: 17 pages, 7 figure
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Periplasmic biomineralization for semi-artificial photosynthesis
Semiconductor-based biointerfaces are typically established either on the surface of the plasma membrane or within the cytoplasm. In Gram-negative bacteria, the periplasmic space, characterized by its confinement and the presence of numerous enzymes and peptidoglycans, offers additional opportunities for biomineralization, allowing for nongenetic modulation interfaces. We demonstrate semiconductor nanocluster precipitation containing single- and multiple-metal elements within the periplasm, as observed through various electron- and x-ray-based imaging techniques. The periplasmic semiconductors are metastable and display defect-dominant fluorescent properties. Unexpectedly, the defect-rich (i.e., the low-grade) semiconductor nanoclusters produced in situ can still increase adenosine triphosphate levels and malate production when coupled with photosensitization. We expand the sustainability levels of the biohybrid system to include reducing heavy metals at the primary level, building living bioreactors at the secondary level, and creating semi-artificial photosynthesis at the tertiary level. The biomineralization-enabled periplasmic biohybrids have the potential to serve as defect-tolerant platforms for diverse sustainable applications
Effect of carbon source on production, characterization and bioactivity of exopolysaccharide produced by Phellinus vaninii Ljup
Skywork: A More Open Bilingual Foundation Model
In this technical report, we present Skywork-13B, a family of large language
models (LLMs) trained on a corpus of over 3.2 trillion tokens drawn from both
English and Chinese texts. This bilingual foundation model is the most
extensively trained and openly published LLMs of comparable size to date. We
introduce a two-stage training methodology using a segmented corpus, targeting
general purpose training and then domain-specific enhancement training,
respectively. We show that our model not only excels on popular benchmarks, but
also achieves \emph{state of the art} performance in Chinese language modeling
on diverse domains. Furthermore, we propose a novel leakage detection method,
demonstrating that test data contamination is a pressing issue warranting
further investigation by the LLM community. To spur future research, we release
Skywork-13B along with checkpoints obtained during intermediate stages of the
training process. We are also releasing part of our SkyPile corpus, a
collection of over 150 billion tokens of web text, which is the largest high
quality open Chinese pre-training corpus to date. We hope Skywork-13B and our
open corpus will serve as a valuable open-source resource to democratize access
to high-quality LLMs
Search for Eccentric Black Hole Coalescences during the Third Observing Run of LIGO and Virgo
Despite the growing number of confident binary black hole coalescences
observed through gravitational waves so far, the astrophysical origin of these
binaries remains uncertain. Orbital eccentricity is one of the clearest tracers
of binary formation channels. Identifying binary eccentricity, however, remains
challenging due to the limited availability of gravitational waveforms that
include effects of eccentricity. Here, we present observational results for a
waveform-independent search sensitive to eccentric black hole coalescences,
covering the third observing run (O3) of the LIGO and Virgo detectors. We
identified no new high-significance candidates beyond those that were already
identified with searches focusing on quasi-circular binaries. We determine the
sensitivity of our search to high-mass (total mass ) binaries
covering eccentricities up to 0.3 at 15 Hz orbital frequency, and use this to
compare model predictions to search results. Assuming all detections are indeed
quasi-circular, for our fiducial population model, we place an upper limit for
the merger rate density of high-mass binaries with eccentricities at Gpc yr at 90\% confidence level.Comment: 24 pages, 5 figure
Impact Resistance Study of Three-Dimensional Orthogonal Carbon Fibers/BMI Resin Woven Composites
Three-dimensional woven composites have been reported to have superior fracture toughness, fatigue life and damage tolerance compared with laminated composites due to through-thickness reinforcement. These properties make them lighter replacements for traditional high-strength metals and laminated composites. This paper will present impact resistance research on three-dimensional orthogonal woven composites consisting of carbon fibers/bismaleimide resin (BMI). A series of impact tests were conducted using the gas gun technique with the impacted target of 150 mm × 150 mm × 8 mm (length × width × thickness) and the cylindrical titanium projectile. The projectile velocity ranged from 180 m/s to 280 m/s, generating different results from rebound to perforation. This paper also presents a multiscale modeling strategy to investigate the damage and failure behavior of three-dimensional woven composites. The microscale and mesoscale are identified to consider the fiber/matrix scale and the tow architecture scale respectively. The macroscale model was effective with homogenized feature. Then a combined meso-macroscale model was developed with the interface definitions for component analysis in the explicit dynamic software LS-DYNA. The presented results showed reliable interface connection and can be used to study localized composites damage at a relatively high efficiency
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