226 research outputs found
-zips with additional structure on splitting models of Shimura varieties
We construct universal -zips on good reductions of the Pappas-Rapoport
splitting models for PEL-type Shimura varieties. We study the induced
Ekedahl-Oort stratification, which sheds new light on the mod geometry of
splitting models. Building on the work of Lan on arithmetic compatifications of
splitting models, we further extend these constructions to smooth toroidal
compactifications. Combined with the work of Goldring-Koskivirta on group
theoretical Hasse invariants, we get an application to Galois representations
associated to torsion classes in coherent cohomology in the ramified setting.Comment: 53 page
Responses of soil nitrogen mineralization to temperature and moisture in alpine ecosystems on the Tibetan Plateau
AbstractThe responses of soil net nitrogen (N) mineralization to temperature and moisture were investigated in four alpine ecosystems of forest, shrub, meadow and steppe by laboratory incubation method with undisturbed soil cores on the Tibetan Plateau. The results indicated the soil net N mineralization varies greatly between alpine ecosystems. The soil net N mineralization rate in three incubating moisture of forest ecosystem rose markedly, and that of meadow ecosystem rose gently from temperature of 5°C to 35°C, while that of shrub and steppe ecosystems increased from temperature of 5°C to 25°C and reduced from temperature of 25°C to 35°C. At the same incubating temperature, the soil net N mineralization of four alpine ecosystems increased in the middle moisture and deceased in the low or high moisture
Who is the Real Hero? Measuring Developer Contribution via Multi-dimensional Data Integration
Proper incentives are important for motivating developers in open-source
communities, which is crucial for maintaining the development of open-source
software healthy. To provide such incentives, an accurate and objective
developer contribution measurement method is needed. However, existing methods
rely heavily on manual peer review, lacking objectivity and transparency. The
metrics of some automated works about effort estimation use only syntax-level
or even text-level information, such as changed lines of code, which lack
robustness. Furthermore, some works about identifying core developers provide
only a qualitative understanding without a quantitative score or have some
project-specific parameters, which makes them not practical in real-world
projects. To this end, we propose CValue, a multidimensional information
fusion-based approach to measure developer contributions. CValue extracts both
syntax and semantic information from the source code changes in four
dimensions: modification amount, understandability, inter-function and
intra-function impact of modification. It fuses the information to produce the
contribution score for each of the commits in the projects. Experimental
results show that CValue outperforms other approaches by 19.59% on 10
real-world projects with manually labeled ground truth. We validated and proved
that the performance of CValue, which takes 83.39 seconds per commit, is
acceptable to be applied in real-world projects. Furthermore, we performed a
large-scale experiment on 174 projects and detected 2,282 developers having
inflated commits. Of these, 2,050 developers did not make any syntax
contribution; and 103 were identified as bots
Multi-step Temporal Modeling for UAV Tracking
In the realm of unmanned aerial vehicle (UAV) tracking, Siamese-based
approaches have gained traction due to their optimal balance between efficiency
and precision. However, UAV scenarios often present challenges such as
insufficient sampling resolution, fast motion and small objects with limited
feature information. As a result, temporal context in UAV tracking tasks plays
a pivotal role in target location, overshadowing the target's precise features.
In this paper, we introduce MT-Track, a streamlined and efficient multi-step
temporal modeling framework designed to harness the temporal context from
historical frames for enhanced UAV tracking. This temporal integration occurs
in two steps: correlation map generation and correlation map refinement.
Specifically, we unveil a unique temporal correlation module that dynamically
assesses the interplay between the template and search region features. This
module leverages temporal information to refresh the template feature, yielding
a more precise correlation map. Subsequently, we propose a mutual transformer
module to refine the correlation maps of historical and current frames by
modeling the temporal knowledge in the tracking sequence. This method
significantly trims computational demands compared to the raw transformer. The
compact yet potent nature of our tracking framework ensures commendable
tracking outcomes, particularly in extended tracking scenarios
GPTScan: Detecting Logic Vulnerabilities in Smart Contracts by Combining GPT with Program Analysis
Smart contracts are prone to various vulnerabilities, leading to substantial
financial losses over time. Current analysis tools mainly target
vulnerabilities with fixed control or data-flow patterns, such as re-entrancy
and integer overflow. However, a recent study on Web3 security bugs revealed
that about 80% of these bugs cannot be audited by existing tools due to the
lack of domain-specific property description and checking. Given recent
advances in Large Language Models (LLMs), it is worth exploring how Generative
Pre-training Transformer (GPT) could aid in detecting logicc vulnerabilities.
In this paper, we propose GPTScan, the first tool combining GPT with static
analysis for smart contract logic vulnerability detection. Instead of relying
solely on GPT to identify vulnerabilities, which can lead to high false
positives and is limited by GPT's pre-trained knowledge, we utilize GPT as a
versatile code understanding tool. By breaking down each logic vulnerability
type into scenarios and properties, GPTScan matches candidate vulnerabilities
with GPT. To enhance accuracy, GPTScan further instructs GPT to intelligently
recognize key variables and statements, which are then validated by static
confirmation. Evaluation on diverse datasets with around 400 contract projects
and 3K Solidity files shows that GPTScan achieves high precision (over 90%) for
token contracts and acceptable precision (57.14%) for large projects like
Web3Bugs. It effectively detects ground-truth logic vulnerabilities with a
recall of over 70%, including 9 new vulnerabilities missed by human auditors.
GPTScan is fast and cost-effective, taking an average of 14.39 seconds and 0.01
USD to scan per thousand lines of Solidity code. Moreover, static confirmation
helps GPTScan reduce two-thirds of false positives.Comment: Accepted by IEEE/ACM ICSE 202
Generative AI for Controllable Protein Sequence Design: A Survey
The design of novel protein sequences with targeted functionalities underpins
a central theme in protein engineering, impacting diverse fields such as drug
discovery and enzymatic engineering. However, navigating this vast
combinatorial search space remains a severe challenge due to time and financial
constraints. This scenario is rapidly evolving as the transformative
advancements in AI, particularly in the realm of generative models and
optimization algorithms, have been propelling the protein design field towards
an unprecedented revolution. In this survey, we systematically review recent
advances in generative AI for controllable protein sequence design. To set the
stage, we first outline the foundational tasks in protein sequence design in
terms of the constraints involved and present key generative models and
optimization algorithms. We then offer in-depth reviews of each design task and
discuss the pertinent applications. Finally, we identify the unresolved
challenges and highlight research opportunities that merit deeper exploration.Comment: 9 page
Weather Support for the 2008 Olympic and Paralympic Sailing Events
The Beijing 2008 Olympic and Paralympic Sailing Competitions (referred to as OPSC hereafter) were held at Qingdao during August 9–23 and September 7–13 2008, respectively. The Qingdao Meteorological Bureau was the official provider of weather support for the OPSC. Three-dimensional real-time information with high spatial-temporal resolution was obtained by the comprehensive observation system during the OPSC, which included weather radars, wind profile radars, buoys, automated weather stations, and other conventional observations. The refined forecasting system based on MM5, WRF, and statistical modules provided point-specific hourly wind forecasts for the five venues, and the severe weather monitoring and forecasting system was used in short-term forecasts and nowcasts for rainstorms, gales, and hailstones. Moreover, latest forecasting products, warnings, and weather information were communicated conveniently and timely through a synthetic, speedy, and digitalized network system to different customers. Daily weather information briefings, notice boards, websites, and community short messages were the main approaches for regatta organizers, athletes, and coaches to receive weather service products at 8:00 PM of each day and whenever new updates were available. During the period of OPSC, almost one hundred people were involved in the weather service with innovative service concept, and the weather support was found to be successful and helpful to the OPSC
Analysis of Factors Affecting the String Cross-Through Capability Within Long Horizontal Section in Shale Gas Drilling
Along with the further petroleum exploration and development, the conventional oil and gas resources cannot meet the needs of rapid economic development now. Shale gas energy as an important supplement to the existing traditional energy is one of the main successive energy in the future which has very important significance for our country to realize diversified energy security strategy. In the course of drilling and developing horizontal wells in shale gas reservoirs, when it comes to hole trajectory control technology based on guide screw drill in horizontal well drilling with long horizontal section, there are some problems that string extension ability will be limited through horizontal section and low drilling efficiency will happen in later period which is not good for economic and efficient development of shale gas. This article focused on the researches of limit mechanism of the influence factors such as assembly, drill string buckling, weight on bit, well depth profile, and slope, and finally the extension ability in horizontal section was effectively improved by optimizing the well bore profile design and optimizing drilling parameters
Evidence of strong and mode-selective electron–phonon coupling in the topological superconductor candidate 2M-WS 2
The interaction between lattice vibrations and electrons plays a key role in various aspects of condensed matter physics — including electron hydrodynamics, strange metal behavior, and high-temperature superconductivity. In this study, we present systematic investigations using Raman scattering and angle-resolved photoemission spectroscopy (ARPES) to examine the phononic and electronic subsystems of the topological superconductor candidate 2M-WS2. Raman scattering exhibits an anomalous nonmonotonic temperature dependence of phonon linewidths, indicative of strong phonon–electron scattering over phonon–phonon scattering. The ARPES results demonstrate pronounced dispersion anomalies (kinks) at multiple binding energies within both bulk and topological surface states, indicating a robust and mode-selective coupling between the electronic states and various phonon modes. These experimental findings align with previous calculations of the Eliashberg function, providing a deeper understanding of the highest superconducting transition temperature observed in 2M-WS2 (8.8 K) among all transition metal dichalcogenides as induced by electron–phonon coupling. Furthermore, our results may offer valuable insights into other properties of 2M-WS2 and guide the search for high-temperature topological superconductors
Protectin conjugates in tissue regeneration 1 alleviates sepsis-induced acute lung injury by inhibiting ferroptosis
Background: Acute lung injury (ALI) is a common and serious complication of sepsis with high mortality. Ferroptosis, categorized as programmed cell death, contributes to the development of lung injury. Protectin conjugates in tissue regeneration 1 (PCTR1) is an endogenous lipid mediator that exerts protective effects against multiorgan injury. However, the role of PCTR1 in the ferroptosis of sepsis-related ALI remains unknown. Methods: A pulmonary epithelial cell line and a mouse model of ALI stimulated with lipopolysaccharide (LPS) were established in vitro and in vivo. Ferroptosis biomarkers, including ferrous (Fe2+), glutathione (GSH), malondialdehyde (MDA) and 4-Hydroxynonenal (4-HNE), were assessed by relevant assay kits. Glutathione peroxidase 4 (GPX4) and prostaglandin-endoperoxide synthase 2 (PTGS2) protein levels were determined by western blotting. Lipid peroxides were examined by fluorescence microscopy and flow cytometry. Cell viability was determined by a CCK-8 assay kit. The ultrastructure of mitochondria was observed with transmission electron microscopy. Morphology and inflammatory cytokine levels predicted the severity of lung injury. Afterward, related inhibitors were used to explore the potential mechanism by which PCTR1 regulates ferroptosis. Results: PCTR1 treatment protected mice from LPS-induced lung injury, which was consistent with the effect of the ferroptosis inhibitor ferrostatin-1. PCTR1 treatment decreased Fe2+, PTGS2 and lipid reactive oxygen species (ROS) contents, increased GSH and GPX4 levels and ameliorated mitochondrial ultrastructural injury. Administration of LPS or the ferroptosis agonist RSL3 resulted in reduced cell viability, which was rescued by PCTR1. Mechanistically, inhibition of the PCTR1 receptor lipoxin A4 (ALX), protein kinase A (PKA) and transcription factor cAMP-response element binding protein (CREB) partly decreased PCTR1 upregulated GPX4 expression and a CREB inhibitor blocked the effects ofPCTR1 on ferroptosis inhibition and lung protection. Conclusion: This study suggests that PCTR1 suppresses LPS-induced ferroptosis via the ALX/PKA/CREB signaling pathway, which may offer promising therapeutic prospects in sepsis-related ALI
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