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The experimental setup is devised to simulate the presence of vertical cracks with varying widths within concrete structures. Co-polarimetric ground-penetrating radar (GPR) surveys are carried out to acquire the “VV” and “HH” polarization data. The time-varying centroid frequency attribute is employed to describe the vertical variation in the center frequency of the radar wave, unveiling a gradual vertical decay in the centroid frequency at the locations of vertical cracks. An improved time-varying centroid frequency attribute based on the adaptive sparse S-transform (ASST) is proposed and tested by a finite-difference time-domain model and co-polarimetric GPR data, which can offer better resolution compared to that of the conventional S-transform. By analyzing the waveform and centroid frequency properties of the two polarizations, we conclude that the “VV” polarization is relatively sensitive to centimeter scale cracks, while the “HH” polarization is more sensitive to millimeter scale cracks.

This study focuses on the application of ground-penetrating radar (GPR) in conducting field surveys and data processing at the northern campus of Jilin Jianzhu University. The research site’s geographical location and overall conditions are described. A detailed layout of the survey lines for 3D surveys is presented. The collected data undergo basic processing and interpretation, identifying multiple target bodies and their associated electromagnetic responses. Advanced analyses such as 3D imaging, common attribute analysis, and time-varying centroid frequency attribute analysis are employed to investigate underground features and potential pipe networks. The case study in this research demonstrates that the integration of 3D GPR surveys and time-varying centroid frequency analysis can effectively assess the attenuation characteristics of subsurface media and structures, thereby enhancing the overall prospecting and data interpretation capabilities of GPR.

Abstract Ground-penetrating radar (GPR) has emerged as a powerful geophysical tool for subsurface characterization. However, conventional fixed-offset systems often lack the capability to fully resolve complex dielectric properties. This study presents an enhanced amplitude and phase variation with offset (APVO) analytical framework for co-polarized GPR systems, which significantly improves the detection of subsurface anomalies through comprehensive characterization of electromagnetic responses. We systematically investigate both vertical–vertical (VV) and horizontal–horizontal (HH) polarization modes, and address key limitations in existing approaches by focusing on the amplitude variations caused by the first reflection. For VV polarization, we develop an optimized exponential gain compensation method that demonstrates superior performance in correcting signal attenuation and preserving true amplitude relationships compared to conventional power-law approaches. In HH polarization analysis, we experimentally validate the remarkable stability of Brewster angle detection across varying target geometries, confirming its dependence on dielectric contrast. Our phase-tracking methodology achieves excellent agreement with theoretical predictions, enabling accurate determination of subsurface dielectric properties. The proposed framework combines amplitude and phase response patterns to differentiate various subsurface anomalies, including cavities, light non-aqueous phase liquids contaminated zones, and saturated layers. These advancements offer significant improvements over conventional single-offset GPR measurements and have practical applications in environmental monitoring, archaeological surveys, and infrastructure inspection.

AimTo investigate the association between multimorbidity and disability and impaired physical performance, and to further evaluate the mediating effect of physical pain in this association.Methods1321 community-dwelling older adults, who were over 60 years old in southern China, were regarded as participants in this cross-sectional study. Subjects completed a multi-instrument questionnaire including essential characteristics and physical function assessments. Physical function was assessed by activities of daily living (ADL), instrumental activities of daily living (IADL), index of mobility scale (NAGI), index of basic physical activities scale (RB), and short physical performance battery (SPPB). Multimorbidity was defined as the simultaneous presence of two or more chronic conditions. Multivariable regression and mediation analyses were conducted and gender differences were explored.ResultsThe prevalence of multimorbidity was 44.6% in our study. In gender stratification analysis, multimorbidity was significantly associated with ADL disability (OR = 2.16), IADL disability (OR = 1.97), NAGI disability (OR = 2.84), RB disability (OR = 2.65) and lower SPPB score (β = − 0.83) in women. The rate of pain increased with the number of chronic diseases and the multimorbidity patients with higher pain prevalence. Moreover, the presence of pain was also significantly associated with disability and impaired physical performance. Mediation analysis illustrated that pain was accounted for 16.5% to 22.1% of the adverse effects of multimorbidity on disability and impaired physical performance in women.ConclusionsMultimorbidity was significantly associated with disability and impaired physical performance, and pain might be a mediating factor for adverse effects of multimorbidity on disability and impaired physical performance in women.

PurposeThe aim of this study was to explore associations between objectively assessed physical fitness levels and sleep quality in community-dwelling elderly people in South China.MethodsOne thousand one hundred thirty-six (504 males and 632 females) community-dwelling adults aged ≥ 50 years old in Dongguan City, South China, were included in the cross-sectional study. All the participants were asked to complete all prepared multi-instrument questionnaire, including the Pittsburgh Sleep Quality Index (Chinese version), for the assessment of the sleep quality and information regarding socio-demographic characteristics, lifestyle, and physical health data. Physical fitness was measured by grip strength, one-leg standing test (OLST) with eyes open, back scratch test, and the forced vital capacity (FVC).ResultsThe percentage of poor sleep quality among elderly people (≥ 50 years old) was up to 18.2%. Lower FVC was associated with the poorer sleep quality (adjusted OR = 0.74 per SD increase; P = 0.009), and participants with lower performance in back scratch test were more likely to suffer poor sleep quality (adjusted OR = 1.17 per SD increase; P = 0.035). The independent contribution of physical fitness tests results on the risk of poor sleep quality was 22.1%.ConclusionsOur results indicated that sleep quality was strongly associated with physical fitness among community-dwelling elderly people; the lower of the physical fitness predicted poorer sleep quality.

An ecofriendly process has been successfully developed to synthesize the polycrystalline silver nanopolyhedrons with a high yield at large scale. By using tannic acid in the presence of poly (vinyl pyrrolidone) (PVP), high quality silver nanopolyhedrons were obtained in an aqueous one-pot reaction without any templates or auxiliaries. The film made from the silver nanostructures exhibits an electrical conductivity higher than 104 S/cm on both rigid and flexible substrates. The supreme mechanical strength of this silver film recommends its wide application in printing and flexible electronics.

In this paper, we introduce PolyMath, a multilingual mathematical reasoning benchmark covering 18 languages and 4 easy-to-hard difficulty levels. Our benchmark ensures difficulty comprehensiveness, language diversity, and high-quality translation, making it a highly discriminative multilingual mathematical benchmark in the era of reasoning LLMs. We conduct a comprehensive evaluation for advanced LLMs and find that even Qwen-3-235B-A22B-Thinking and Gemini-2.5-pro, achieve only 54.6 and 52.2 benchmark scores, with about 40% accuracy under the highest level From a language perspective, our benchmark reveals several key challenges of LLMs in multilingual reasoning: (1) Reasoning performance varies widely across languages for current LLMs; (2) Input-output language consistency is low in reasoning LLMs and may be correlated with performance; (3) The thinking length differs significantly by language for current LLMs. Additionally, we demonstrate that controlling the output language in the instructions has the potential to affect reasoning performance, especially for some low-resource languages, suggesting a promising direction for improving multilingual capabilities in LLMs.