769 research outputs found
A General Heuristic Approach for Maximum Polygon Packing (CG Challenge)
No full textThis work proposes a general heuristic packing approach to address the Maximum Polygon Packing Problem introduced by the CG:SHOP 2024 Challenge. Our solver primarily consists of two steps: (1) Partitioning the container and polygons to form a series of small-scale subproblems; (2) For each subproblem, sequentially placing polygons into the container and attempting to eliminate overlaps
sj-pdf-1-avt-10.1177_13596535221082399 – Supplemental Material for Changes in blood lipids in patients with chronic hepatitis B after 48 weeks of tenofovir alafenamide treatment: A prospective real-world clinical study
No full textSupplemental Material, sj-pdf-1-avt-10.1177_13596535221082399 for Changes in blood lipids in patients with chronic hepatitis B after 48 weeks of tenofovir alafenamide treatment: A prospective real-world clinical study by Yeqiong Zhang, Zhipeng Li, Qiumin Luo, Wenxiong Xu, Lu Wang, Shu Zhu, Liang Peng and Chan Xie in Antiviral Therapy</p
An optimized entropy-based model for estimating river confluence hydrodynamics: Accounting for the effects of velocity dip
No full textThe entropy model has been successfully used to calculate the flow velocity profile of rivers according to the
measured surface-flow velocity. However, it has limitations in the large river where the obvious secondary flow and flow dip (i.e., the location of maximum flow velocity moves down from the surface) occur. The confluence of rivers is usually characterized by strong secondary circulations, posing great challenges for the accurate flow velocity and discharge estimation. This paper aims to assess the effectiveness of the previous entropy-based approach in velocity estimation of a large confluence and then propose an optimized method. The flow velocity data of the large confluence between the Yangtze River and the Poyang Lake under different discharge ratios were used. The performance of the previous entropy model got worse for the stronger secondary circulation survey. To better estimate the confluence hydrodynamics, a moving average method was introduced with its advantage of smoothing data and integrated into the framework of the entropic method for the better assessment of dip parameter, and hence the better estimation of flow velocity profiles. Furthermore, the maximum velocity was found to locate at one third of the total depth below the water surface. The range of entropic function 0.48 ~ 0.68 could provide a basis for the determination under various flow conditions in rivers. The value of entropic function and the dip parameter got larger as the discharge ratio decreased. This research has expanded the application for estimating hydrodynamics in large rivers
Strontium isotopes and rare earth elements in terrestrial hot-spring deposits: Characterization and geothermal implications
No full textIdentifying geothermal reservoir rock types is fundamental in geothermal exploration, but the absence of active surface geothermal manifestations (especially hot springs) in blind geothermal systems makes this identification difficult. Nevertheless, blind geothermal systems may develop early-formed hot-spring deposits. As (bio-) chemical precipitate, these deposits may retain geochemical signatures of spring waters and thus provide insights into reservoir rock types. To assess their geothermal implications, the 87Sr/86Sr and rare earth elements + yttrium (REE + Y) characteristics of hot-spring deposits in two geothermal systems were investigated and compared with those of their reservoir rocks. Results showed relatively uniform 87Sr/86Sr values in hotspring deposits within each system, but ocexogenous detritus input was also observed. The amount of detritus input relates to the potential for interaction with surrounding soils/rocks and is thus environmentally con trolled. Hot-spring deposits with high Sr concentrations showed greater 87 Sr/ 86 Sr contamination resistance than those with low Sr concentrations, revealing the influence of Sr concentration in hot-spring deposits on detrital 87 Sr/ 86 Sr contamination. The detritus input also influenced the REE + Y signatures of the hot-spring deposits, underscoring the necessity of contamination assessment before geochemical interpretation. Excluding samples with significant 87 Sr/ 86 Sr and/ or REE + Y contamination, the remaining samples closely mirrored their respective reservoir rocks in terms of 87 Sr/ 86 Sr, with partial overlap in REE + Y signatures. This suggests that the 87 Sr/ 86 Sr and REE + Y characteristics of hot-spring deposits provide valuable insights into reservoir rock types. However, variations in 87 Sr/ 86 Sr or REE + Y compositions between some hot-spring deposits and corresponding reservoir rocks indicate additional influencing factors beyond reservoir rock types. Therefore, a comprehensive understanding of reservoir rock types requires integrated geochemical characterization, probably including 87 Sr/ 86 Sr, REE + Y, and other parameters. These findings underscore the potential of geochemical characterization of hot-spring deposits for identifying geothermal reservoir rock types, and this geochemical approach can complement geological and geophysical data to improve exploration efficiency, especially in blind geothermal systems
Geochemical (δ13C, δ18O, 87Sr/86Sr, REEs) characterization of travertine in Tengchong, China: Insights into travertine origin and reservoir conditions
No full textGeochemical characterization is extensively employed in travertine research, yet few studies have explored the potential of travertine geochemistry for elucidating the subterranean details of spring systems. In this study, we systematically characterized the geochemical signatures (513C, 518O, 87Sr/86Sr, REEs, Zr, Th, Sr, Mn) of travertine from six spring systems in Tengchong (SW China) and compared them with those of potential reservoir rocks, aiming to understand travertine origin and assess reservoir conditions. Our results revealed substantial variations in the 513C and 518O of travertine among the examined systems, but the water temperature and parent CO2 assessments suggest a hot spring thermogene origin of the travertine. The 87Sr/86Sr of the studied travertine also varies significantly among the systems and overlaps with that of potential reservoir rocks. However, only the springs systems with reservoir temperatures exceeding 150 degrees C are likely to have precipitated travertine with 87Sr/86Sr resembling the whole-rock 87Sr/86Sr of the reservoir rocks. REE contamination by exogenous detritus and Fe-Mn (oxyhydr)oxides was noted, emphasizing the need for careful REE contamination evaluation in travertine research. The REE comparison reveals that the studied travertine does not fully replicate the REE signature of its potential reservoir rocks, but the REE pattern, (Eu/Eu*)SN, and (Ce/Ce*)SN characteristics of the travertine reveal informative reservoir conditions. In summary, this study shows that the geochemistry of the travertine offers valuable insights into its origin and reservoir conditions. These findings could assist in the geochemical interpretation of travertine and the exaction of hypogean reservoir conditions from travertine
Stock Options and Productivity: An empirical analysis of Japanese firms
Full text linkThis paper analyzes the relationship between the use of stock options and productivity by employing firm-level panel data from the Basic Survey of Japanese Business Structure and Activities. According to the analysis, the use of stock options has a positive impact on firm productivity. Productivity steadily increases after the adoption of stock options. In addition, we found suggestive evidence that R&D investment increases after the introduction of stock options. These results imply that the deregulation on the use of stock options in 1997 and the subsequent legal reforms have had positive contributions to the productivity performance of Japanese firms.
Towards a Local-Global Visual Feature-Based Framework for Recognition
No full textGeneral object and activity recognition is a fundamental problem in computer vision, which has been the subject of much research. Traditional approaches include model-based and appearance template-based methods. Recently, inspired by methods from the text retrieval literature, local visual feature-based models have shown a lot of success for recognition of objects or activities with large within-class geometric variability. There are several challenges in this approach, namely feature selection and target modeling using these features. This thesis proposes a local-global visual feature-based framework for general object and activity recognition with novel methods for these problems: 1) Combinatorial and statistical methods for selecting informative parts to build statistical models for part-based object recognition. First a combinatorial optimization formulation is used for clustering on a weighted multipartite graph. Second, a statistical method for selecting discriminative parts from positive images is used to localize objects. 2) An entropy based vocabulary selection method for “bag-of-words ” models for activity recognition. 3) Integrating both spatial and temporal information with appearance features for human activity recognition. This method models the human motions with the distribution of local motion features and their spatial-temporal arrangements. ii The effectiveness of the proposed methods is demonstrated by several object recognition and activity recognition data sets, which include human facial expressions and hand gestures, etc. This thesis also covers an interesting project regarding a framework of applying Discrete Fourier Transform to detect salient regions in images and video sequences. This framework generalizes the previous saliency detection methods and can be applied for saliency detection in the video sequences
Constructing tree decompositions of graphs with bounded gonality
No full textIn this paper, we give a constructive proof of the fact that the treewidth of a graph is at most its divisorial gonality. The proof gives a polynomial time algorithm to construct a tree decomposition of width at most k, when an effective divisor of degree k that reaches all vertices is given. We also give a similar result for two related notions: stable divisorial gonality and stable gonality.Accepted author manuscriptDiscrete Mathematics and Optimizatio
Neuronal alpha-synuclein-mediated autophagy drives lipid droplets accumulation in astrocytes and microglia and aggravates ischemic stroke
No full text501100007129 Natural Science Foundation of Shandong Province501100004479 Natural Science Foundation of Jiangxi Province501100001809 National Natural Science Foundation of Chin
Physical Activities and Parkinson's Disease Progression: A Two‐Sample Mendelian Randomization Study
No full textABSTRACT Aims To explore the causal relationship between physical activity (PA) and the progression of Parkinson's disease (PD), we conducted a two‐sample Mendelian randomization (MR) analysis. Methods Genetic variants were obtained from publicly available genome‐wide association study (GWAS) summary statistics for PA ( N = 377,000), age at onset ( N = 28,568), and PD progression ( N = 4093). Causal estimates were calculated using the inverse variance weighted (IVW) method, with MR‐Egger and weighted median analyses performed to assess the robustness of the results. Results Genetically predicted accelerometer‐based overall acceleration average (OAA) was associated with a reduced risk of constipation in PD progression (OR: 0.60, 95% CI: 0.42–0.86, p = 5.50 × 10 −3 ). Moderate‐to‐vigorous physical activity (MVPA) demonstrated a similar but stronger effect on constipation risk (OR: 0.03, 95% CI: 9.38 × 10 −4 –0.90, p = 0.043). Additionally, OAA showed a protective effect on motor experiences of daily living (OR: 0.84, 95% CI: 0.71–1.00, p = 0.046). No causal effects were identified for vigorous physical activity (VPA) or the fraction of accelerations exceeding 425 milligravities (FAA) on PD progression. Conclusion Our findings suggest a negative causal relationship between PA and PD progression, highlighting the potential role of physical activity in guiding therapeutic strategies for PD management
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