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16 pages, 1205 KB  
Article
Trajectories of Proactive Health Behaviors Among Chinese Middle-Aged and Older Adults with Multimorbidity: A Cohort Study Using Group-Based Trajectory Modeling
by Jiaxuan Wang, Ziqi Wang, Fan Du, Jiaojiao Lv, Jiulong Kou, Jieting Chen and Mingxia Jing
Eur. J. Investig. Health Psychol. Educ. 2026, 16(3), 38; https://doi.org/10.3390/ejihpe16030038 - 6 Mar 2026
Viewed by 541
Abstract
(1) Background: Proactive health behaviors are key to reducing their burden and supporting healthy aging. (2) Methods: We analyzed five waves (2011–2020) of CHARLS data from 1343 middle-aged and older adults (≥45 years) with multimorbidity. An entropy weight method was used to create [...] Read more.
(1) Background: Proactive health behaviors are key to reducing their burden and supporting healthy aging. (2) Methods: We analyzed five waves (2011–2020) of CHARLS data from 1343 middle-aged and older adults (≥45 years) with multimorbidity. An entropy weight method was used to create a composite score for proactive health behaviors, and group-based trajectory modeling identified behavioral trajectories. Multivariate logistic regression and Shapley value decomposition assessed determinants and their relative contributions. Generalized structural equation modeling and latent class analysis were applied to estimate direct and indirect effects across the full sample and key multimorbidity subgroups. (3) Results: Two trajectories emerged: a “declining group” (91.44%) and an “improving group” (8.56%). The improving group was more likely to include younger, urban individuals with higher education, retired status, smaller family size, and lower depression levels. Education (40.67%) and depressive symptoms (31.22%) were the strongest determinants of trajectory. Path analysis showed that higher education and retirement indirectly supported sustained proactive health behaviors by reducing depression. The direct and indirect effects varied across subgroups. (4) Conclusion: The proactive health behaviors of middle-aged and elderly patients with multimorbidity exhibit a declining trend. Future health policies and interventions should prioritize mental health. Full article
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19 pages, 7020 KB  
Article
Monitoring Public Bird Roosts with Saliency-Constrained Multi-Peak Doppler Spectra from Weather Radar
by Zujing Yan, Kai Cui, Xuan Liu, Ke Xu, Zhongbo Liu, Xichao Dong, Rui Wang and Cheng Hu
Remote Sens. 2026, 18(5), 725; https://doi.org/10.3390/rs18050725 - 28 Feb 2026
Viewed by 283
Abstract
Monitoring bird activity at public roosts is essential for understanding stopover behavior during migration, assessing ecological change, and supporting conservation strategies. Existing weather radar-based roost detection methods primarily rely on high-reflectivity ring-shaped echoes, which can lead to missed detections when roost-related echo structures [...] Read more.
Monitoring bird activity at public roosts is essential for understanding stopover behavior during migration, assessing ecological change, and supporting conservation strategies. Existing weather radar-based roost detection methods primarily rely on high-reflectivity ring-shaped echoes, which can lead to missed detections when roost-related echo structures are weak or indistinct. To address this limitation, this study proposes a saliency-constrained multi-peak spectral approach for monitoring and identifying public bird roosts using weather radar. At the radar resolution-cell scale, a saliency-constrained multi-peak Doppler spectrum decomposition and classification method is developed. Mixed Doppler power spectra are decomposed into multiple independent subpeaks through spectral peak saliency detection, and spectral polarimetric features are utilized to identify bird-related subpeaks, yielding a set of bird motion subgroups within each resolution cell. On this basis, a Bird Roost Index (BRI) is introduced, which couples the number of bird subgroups with their radial velocity dispersion to quantitatively characterize the complexity of bird motion modes in local airspace. Finally, the proposed method is applied to operational S-band weather radar observations collected over the Dongting Lake Basin roosts region during the spring season. The results demonstrate that the BRI exhibits strong spatial consistency and coherent temporal evolution, enabling robust characterization of communal roosting activity. This confirms the robustness of the proposed approach and highlights its potential for operational monitoring of migratory bird communal roosts using weather radar spectral data. Full article
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16 pages, 1057 KB  
Article
Linking Cancer Pain Features and Biosignals for Automatic Pain Assessment
by Marco Cascella, Francesco Perri, Alessandro Ottaiano, Mariachiara Santorsola, Maria Luisa Marciano, Fabiana Raffaella Rampetta, Monica Pontone, Anna Crispo, Francesco Sabbatino, Gianluigi Franci, Walter Esposito, Gennaro Cisale, Maria Romano, Francesco Amato, Amalia Scuotto, Vittorio Santoriello and Alfonso Maria Ponsiglione
Cancers 2026, 18(4), 646; https://doi.org/10.3390/cancers18040646 - 16 Feb 2026
Cited by 1 | Viewed by 513
Abstract
Background: Pain remains one of the most debilitating and prevalent symptoms in cancer patients. However, assessment based solely on subjective self-report tools is limited by cognitive impairment and the heterogeneous nature of cancer pain. Since evidence on the ability of physiological biosignals to [...] Read more.
Background: Pain remains one of the most debilitating and prevalent symptoms in cancer patients. However, assessment based solely on subjective self-report tools is limited by cognitive impairment and the heterogeneous nature of cancer pain. Since evidence on the ability of physiological biosignals to discriminate cancer pain intensity and pain phenotypes in real clinical settings remains limited, this study explored the potential of biosignals to discriminate between pain intensity and pain type. Methods: Electrodermal activity (EDA) and electrocardiogram (ECG) signals were recorded in cancer patients using the BITalino (r)evolution board (sampling frequency 1000 Hz). EDA was processed to extract skin conductance responses (SCRs) using continuous decomposition analysis (CDA) and trough-to-peak (TTP) methods. Heart rate variability (HRV) features were extracted in both time and frequency domains, including low frequency (LF), high frequency (HF), and the LF/HF ratio. Non-parametric Kruskal–Wallis tests were performed to compare biosignal parameters across pain intensity (Numeric Rating Scale, NRS: low 1–3; medium 4–6; and high 7–10) and pain types (nociceptive, neuropathic, mixed, and breakthrough cancer pain—BTCP). Results: Data from 61 patients were analyzed. For EDA, the maximum skin conductance response amplitude (MaxCDA) significantly differed across intensity groups (p = 0.037). Post hoc analysis showed a significant difference between the low- and high-intensity groups (p = 0.015), with the low-intensity group exhibiting a higher mean MaxCDA (0.063 µS) than the high-intensity group (0.024 µS). Several EDA parameters were significantly associated with pain type. The number of SCRs (TTP) (p = 0.015) and maximum SCR amplitude (TTP) (p = 0.040) were significantly lower in the mixed pain group compared with the nociceptive and neuropathic groups. No HRV parameters showed significant associations with pain intensity or pain type. BTCP did not significantly affect any biosignal parameters. Subgroup analyses showed that EDA features discriminating mixed pain were preserved in patients without bone metastases, BTCP, or high opioid burden, whereas no clinical variable modified the association between biosignals and pain intensity and type. Conclusions: In this investigation, selected EDA parameters were associated with cancer pain intensity and pain type, whereas heart rate variability measures did not show significant discrimination under the present methodological conditions. These findings suggest that EDA may provide complementary information on pain-related autonomic alterations in oncology patients. However, biosignals should not be considered standalone indicators of pain, and their interpretation requires integration with clinical variables and pharmacological context. Further studies adopting multimodal and longitudinal approaches are needed to clarify their role in automatic pain assessment in cancer care. Full article
(This article belongs to the Special Issue Palliative Care and Pain Management in Cancer)
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31 pages, 469 KB  
Article
Weyl-Type Symmetry and Subalgebra Rigidity in von Neumann Algebras
by Saeed Hashemi Sababe and Mostafa Hassanlou
Mathematics 2026, 14(3), 505; https://doi.org/10.3390/math14030505 - 30 Jan 2026
Viewed by 329
Abstract
We propose and develop a unified framework for Weyl-type symmetry in von Neumann algebras. Motivated by recent automorphism-rigidity phenomena that identify finite Weyl groups inside automorphism groups of crossed products arising from lattice actions on homogeneous spaces, we introduce the Weyl group of [...] Read more.
We propose and develop a unified framework for Weyl-type symmetry in von Neumann algebras. Motivated by recent automorphism-rigidity phenomena that identify finite Weyl groups inside automorphism groups of crossed products arising from lattice actions on homogeneous spaces, we introduce the Weyl group of an inclusion W(M;B):=AutB(M)/InnB(M), for a unital inclusion BM of von Neumann algebras, and investigate its structure across several rigidity regimes. Our main results (1) prove finiteness or triviality of W(M;B) for large classes of nonamenable crossed products, including hyperbolic and product-type actions with spectral gap and malleability; (2) establish a subgroup-normalizer rigidity principle for inclusions L(Λ)L(Γ) that identifies AutL(Λ)(L(Γ)) with a discrete group controlled by NΓ(Λ); (3) show that permutation-type symmetry for product/tensor decompositions is the only possible nontrivial symmetry of the underlying group subalgebras; and (4) extend the analysis to type III factors via Maharam extensions and unique-Cartan phenomena, proving that W(M;B) is discrete and often trivial, leaving only modular flows as outer symmetries. Consequences include new computations of outer automorphism groups, constraints on intermediate subalgebras, and classification consequences for crossed products and amalgamated free products. The methods combine Popa’s intertwining-by-bimodules, spectral-gap and s-malleable deformations, boundary/ucp-map rigidity, and groupoid/Cartan techniques. Full article
32 pages, 4940 KB  
Article
Seasonality and Development Trends of Seasonal Lifestyle Tourism on Tropical Islands: A Case Study of Hainan, China
by Chenyang Wang, Wenzheng Yu, Xin Yao, Caixia Liu and Furqan Asif
Sustainability 2026, 18(3), 1263; https://doi.org/10.3390/su18031263 - 27 Jan 2026
Viewed by 563
Abstract
The rise in seasonal lifestyle tourism, characterized by winter-escape health and wellness stays and long-term leisure residence, has intensified peak–off-peak imbalances and pressures on the allocation of tourism service supply in tropical island destinations. However, existing research lacks a systematic comparison of seasonal [...] Read more.
The rise in seasonal lifestyle tourism, characterized by winter-escape health and wellness stays and long-term leisure residence, has intensified peak–off-peak imbalances and pressures on the allocation of tourism service supply in tropical island destinations. However, existing research lacks a systematic comparison of seasonal fluctuations and long-term evolution for this subgroup at the city/county level. Therefore, this study aims to characterize the seasonal pattern, long-term trend features, and typological differentiation of seasonal lifestyle tourism at the county level, and to compare differences across types. Using monthly data on seasonal lifestyle tourism for 18 cities/counties in Hainan from 2021 to 2024, we apply TRAMO/SEATS decomposition to identify seasonal structures and measure seasonal amplitude and employ the Hodrick–Prescott (HP) filter to extract trend components and determine their directions of change. We further construct five development types by integrating trend categories and changes in seasonal amplitude and test between-type differences using one-way analysis of variance (ANOVA). Results show that Hainan exhibits a stable “winter–spring peak and summer–autumn trough” pattern (peaks concentrated in January–March and December, with the off-season typically spanning May–October), with strong seasonality and pronounced spatial heterogeneity. The four-year mean seasonal range at the county level is 215.01, with high values clustered in southern Hainan; Haikou remains relatively low, while Wenchang shows an upward trend. Long-term trends are clearly differentiated: 13 counties show sustained growth, 2 show decline, and 3 display a U-shaped recovery (decline followed by rebound). Growth rates also vary substantially, with Qionghai increasing at roughly 27 times the rate of Qiongzhong. Integrating seasonal and trend characteristics yields five types, of which the Robust Development type accounts for the largest share (50%). Between-type differences are mainly reflected in tourism service supply capacity: the number of star-rated hotels (p = 0.033, η2 = 0.530) and overnight visitors (p = 0.004, η2 = 0.676) differ significantly across types, whereas differences in natural-environment conditions are not significant. This study provides a scientific basis for zoning management and optimizing low-season strategies in Hainan. Full article
(This article belongs to the Section Economic and Business Aspects of Sustainability)
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14 pages, 1055 KB  
Article
Rotating Night Shifts and Physical Well-Being in Nurses: Cross-Sectional Associations Consistent with a Sleep Quality Pathway
by Andreja Kolarić, Azeem Majeed, Mate Car and Ivan Miskulin
Nurs. Rep. 2026, 16(1), 19; https://doi.org/10.3390/nursrep16010019 - 8 Jan 2026
Viewed by 873
Abstract
Background: Rotating and night-including shifts disrupt circadian alignment, impair sleep, and may reduce nurses’ physiological recovery. Objectives: This study aimed (1) to compare sleep quality and physical well-being across four shift schedules among hospital nurses and (2) to examine whether the [...] Read more.
Background: Rotating and night-including shifts disrupt circadian alignment, impair sleep, and may reduce nurses’ physiological recovery. Objectives: This study aimed (1) to compare sleep quality and physical well-being across four shift schedules among hospital nurses and (2) to examine whether the association between rotating shifts and physical well-being was statistically consistent with an indirect association via sleep quality. Methods: In this cross-sectional study, 173 nurses from a tertiary hospital in Zagreb, Croatia, completed validated measures of sleep quality and physical well-being. Four shift patterns were analyzed—fixed morning, morning–afternoon, extended 12-h, and rotating three-shift—using Welch ANOVA and regression models. A bootstrapped mediation analysis (10,000 resamples; BCa method), interpreted as a statistical decomposition, estimated an indirect association consistent with sleep quality. Results: Rotating-shift nurses reported the poorest sleep (PSQI = 10.2 ± 2.6; p = 0.003). Physical well-being did not differ significantly across shift types (p = 0.08), although rotating-shift nurses had the lowest mean physical scores (24.3 ± 4.4). The rotating-shift subgroup was small (n = 16), limiting precision. The mediation analysis was statistically consistent with an indirect association between rotating shifts and physical well-being via sleep quality (ACME = −1.85, 95% CI −3.05 to −0.88; p < 0.001), while the proportion of the total association was imprecisely estimated. Conclusions: In this single-site cross-sectional sample, rotating night shifts were associated with poorer sleep and, on average, lower physical well-being; patterns were statistically consistent with an indirect association via sleep quality. Because exposure, mediator, and outcome were measured concurrently, these findings are hypothesis-generating and do not establish causality. Full article
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19 pages, 1922 KB  
Article
Validated Transfer Learning Peters–Belson Methods for Survival Analysis: Ensemble Machine Learning Approaches with Overfitting Controls for Health Disparity Decomposition
by Menglu Liang and Yan Li
Stats 2025, 8(4), 114; https://doi.org/10.3390/stats8040114 - 10 Dec 2025
Viewed by 691
Abstract
Background: Health disparities research increasingly relies on complex survey data to understand survival differences between population subgroups. While Peters–Belson decomposition provides a principled framework for distinguishing disparities explained by measured covariates from unexplained residual differences, traditional approaches face challenges with complex data patterns [...] Read more.
Background: Health disparities research increasingly relies on complex survey data to understand survival differences between population subgroups. While Peters–Belson decomposition provides a principled framework for distinguishing disparities explained by measured covariates from unexplained residual differences, traditional approaches face challenges with complex data patterns and model validation for counterfactual estimation. Objective: To develop validated Peters–Belson decomposition methods for survival analysis that integrate ensemble machine learning with transfer learning while ensuring logical validity of counterfactual estimates through comprehensive model validation. Methods: We extend the traditional Peters–Belson framework through ensemble machine learning that combines Cox proportional hazards models, cross-validated random survival forests, and regularized gradient boosting approaches. Our framework incorporates a transfer learning component via principal component analysis (PCA) to discover shared latent factors between majority and minority groups. We note that this “transfer learning” differs from the standard machine learning definition (pre-trained models or domain adaptation); here, we use the term in its statistical sense to describe the transfer of covariate structure information from the pooled population to identify group-level latent factors. We develop a comprehensive validation framework that ensures Peters–Belson logical bounds compliance, preventing mathematical violations in counterfactual estimates. The approach is evaluated through simulation studies across five realistic health disparity scenarios using stratified complex survey designs. Results: Simulation studies demonstrate that validated ensemble methods achieve superior performance compared to individual models (proportion explained: 0.352 vs. 0.310 for individual Cox, 0.325 for individual random forests), with validation framework reducing logical violations from 34.7% to 2.1% of cases. Transfer learning provides additional 16.1% average improvement in explanation of unexplained disparity when significant unmeasured confounding exists, with 90.1% overall validation success rate. The validation framework ensures explanation proportions remain within realistic bounds while maintaining computational efficiency with 31% overhead for validation procedures. Conclusions: Validated ensemble machine learning provides substantial advantages for Peters–Belson decomposition when combined with proper model validation. Transfer learning offers conditional benefits for capturing unmeasured group-level factors while preventing mathematical violations common in standard approaches. The framework demonstrates that realistic health disparity patterns show 25–35% of differences explained by measured factors, providing actionable targets for reducing health inequities. Full article
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45 pages, 507 KB  
Article
Cohomological Structure of Principal SO(3)-Bundles over Real Curves with Applications to Robot Orientation Control
by Álvaro Antón-Sancho
Mathematics 2025, 13(19), 3119; https://doi.org/10.3390/math13193119 - 29 Sep 2025
Viewed by 1462
Abstract
This paper provides advances in the study of principal SO(3)-bundles over smooth projective real curves, with applications to robot manipulation orientation. The work introduces a novel specific classification of these bundles, establishing a bijection between isomorphism classes and specific [...] Read more.
This paper provides advances in the study of principal SO(3)-bundles over smooth projective real curves, with applications to robot manipulation orientation. The work introduces a novel specific classification of these bundles, establishing a bijection between isomorphism classes and specific direct sums of cyclic groups. The explicit computation of the cohomology ring H*(P,Z) for a principal SO(3)-bundle P over a real curve X, revealing its complete structure and torsion subgroups, is a major contribution of the paper. This paper further demonstrates that the equivariant cohomology HSO(3)*(P,Z) is isomorphic to H*(X,Z)H*(BSO(3),Z), with implications for connections and curvature. These results are then applied to robotics, showing that for manipulators with revolute joints, a principal SO(3)-bundle encoding end-effector orientation whose second Stiefel–Whitney class characterizes the obstruction to continuous orientation control exists. For robots with spherical wrists, the configuration space factors as a product, allowing for the decomposition of connections with control implications. Finally, a mechanical connection is constructed that minimizes kinetic energy, with its curvature identifying configurations where small perturbations cause large orientation changes. Full article
(This article belongs to the Special Issue Real Algebraic Geometry and Its Applications)
18 pages, 320 KB  
Article
Symmetric Spaces of Qubits and Gaussian Modes
by Antonio de Jesús Castillo Moctezuma, José Luis Lucio and Alan Josué Sierra-Torres
Symmetry 2025, 17(2), 292; https://doi.org/10.3390/sym17020292 - 14 Feb 2025
Viewed by 1446
Abstract
The understanding of the properties of multipartite systems is a long-standing challenge in quantum theory that signals the need for new ideas and alternative frameworks that can shed light on the intricacies of quantum behavior. In this work, we argue that symmetric spaces [...] Read more.
The understanding of the properties of multipartite systems is a long-standing challenge in quantum theory that signals the need for new ideas and alternative frameworks that can shed light on the intricacies of quantum behavior. In this work, we argue that symmetric spaces provide a common language to describe two-qubit and two-mode Gaussian systems. Our approach relies on the use of equivalence classes that are defined by a subgroup of the maximal symmetry group of the system and involves an involution which enables the Cartan decomposition of the group elements. We work out the symmetric spaces of two qubits and two modes to identify classes which include an equal degree of mixing states, product states, and X states, among others. For three qubits and three modes, we point out how the framework can be generalized and report partial results about the physical interpretations of the symmetric spaces. Full article
(This article belongs to the Section Physics)
19 pages, 5748 KB  
Article
Microbial Community Structure, Diversity, and Succession During Decomposition of Kiwifruit Litters with Different Qualities
by Yupeng Lu, Zhu Gao, Yulin Zhu, Dongliang Yao and Xiaoling Wang
Microorganisms 2024, 12(12), 2498; https://doi.org/10.3390/microorganisms12122498 - 4 Dec 2024
Cited by 6 | Viewed by 2081
Abstract
There are differences in the litter quality and decomposition rate of kiwifruit varieties, but it is not clear whether these differences are related to microbial communities. The leaf litters of two kiwifruit varieties (A. chinensis cv ‘Hongyang’ and A. chinensis cv ‘Jinyan’) [...] Read more.
There are differences in the litter quality and decomposition rate of kiwifruit varieties, but it is not clear whether these differences are related to microbial communities. The leaf litters of two kiwifruit varieties (A. chinensis cv ‘Hongyang’ and A. chinensis cv ‘Jinyan’) were taken as objects, and the structure, diversity, and succession of the soil microbial communities were analyzed using an in situ decomposition experiment. Moreover, the contents of C, N, P, and K in the litters during decomposition were analyzed. The results show that there were variety differences in community structure at the generic level. Lophotrichus, Acaulium, and Fusarium were relatively more abundant in the microbial community of the ‘Hongyang’ kiwifruit litter, and Humicola and Tausonia were relatively more abundant in the microbial community of the ‘Jinyan’ kiwifruit litter. Subgroup_6 and Sphingomonas were the dominant bacteria. The bacterial community diversity of ‘Jinyan’ kiwifruit was higher than that of the ‘Hongyang’ kiwifruit litter. The community diversity was higher in the middle and later periods. The contents of C and N in the litters were the main factors affecting microbial communities. The abundances of Humicola and Apiotrichum were negatively correlated with the contents of C and N, and the abundances of Sphingomonas and SC-I-84 were positively correlated with the content of C. There were variety differences in the microbial communities corresponding to the decomposition processes of the ‘Hongyang’ and ‘Jinyan’ kiwifruit litters. The mechanisms of the variety differences were related to litter quality and the initial soil microbial community. Full article
(This article belongs to the Section Plant Microbe Interactions)
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14 pages, 841 KB  
Article
A Closed-Form Analytical Conversion between Zernike and Gatinel–Malet Basis Polynomials to Present Relevant Aberrations in Ophthalmology and Refractive Surgery
by Masoud Mehrjoo, Damien Gatinel, Jacques Malet and Samuel Arba Mosquera
Photonics 2024, 11(9), 883; https://doi.org/10.3390/photonics11090883 - 20 Sep 2024
Cited by 3 | Viewed by 2418
Abstract
The Zernike representation of wavefronts interlinks low- and high-order aberrations, which may result in imprecise clinical estimates. Recently, the Gatinel–Malet wavefront representation has been introduced to resolve this problem by deriving a new, unlinked basis originating from Zernike polynomials. This new basis preserves [...] Read more.
The Zernike representation of wavefronts interlinks low- and high-order aberrations, which may result in imprecise clinical estimates. Recently, the Gatinel–Malet wavefront representation has been introduced to resolve this problem by deriving a new, unlinked basis originating from Zernike polynomials. This new basis preserves the classical low and high aberration subgroups’ structure, as well as the orthogonality within each subgroup, but not the orthogonality between low and high aberrations. This feature has led to conversions relying on separate wavefront reconstructions for each subgroup, which may increase the associated numerical errors. This study proposes a robust, minimised-error (lossless) analytical approach for conversion between the Zernike and Gatinel–Malet spaces. This method analytically reformulates the conversion as a nonhomogeneous system of linear equations and computationally solves it using matrix factorisation and decomposition techniques with high-level accuracy. This work fundamentally demonstrates the lossless expression of complex wavefronts in a format that is more clinically interpretable, with potential applications in various areas of ophthalmology, such as refractive surgery. Full article
(This article belongs to the Special Issue Visual Optics)
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29 pages, 2079 KB  
Article
The Impact of Access to Intermediate Inputs on Export Margins: Firm-Level Evidence from the Regression Decomposition Approach
by Mohammad Rayhan Miah and Masaru Ichihashi
Sustainability 2024, 16(10), 4196; https://doi.org/10.3390/su16104196 - 16 May 2024
Cited by 2 | Viewed by 2963
Abstract
This paper analyzes how export margins responded to an intermediate input supply shock caused by the 2020 lockdown in China. We use regression decomposition with triple and quadruple difference-in-differences models to identify causal impacts and mitigate potential heterogeneity in transaction-level customs data from [...] Read more.
This paper analyzes how export margins responded to an intermediate input supply shock caused by the 2020 lockdown in China. We use regression decomposition with triple and quadruple difference-in-differences models to identify causal impacts and mitigate potential heterogeneity in transaction-level customs data from the Bangladesh apparel manufacturing industry. The triple difference estimate shows that the average export value per firm–product–destination combination declined by approximately 65%, leading to a decrease in overall exports of woven apparel from Bangladesh. The input supply shock also adversely affected the subgroups of firms across various firm-level characteristics along the intensive margin. Moreover, the export market share decomposition reveals that the shock significantly affected intensive margins by decreasing incumbents’ market allocation by 9%. An equivalent increase in extensive margins led to a readjustment in the market allocation, leading to fewer market leavers and slightly more new market entrants. Our results indicate that Bangladesh’s exports mostly decreased due to the smaller quantities of products exported rather than there being fewer firms, destinations, or products involved in export trade. There were significant market share reallocations that occurred after the Chinese input supply shock. An appropriate policy stance is required for sustainable export sector growth strategies, which will enhance the country’s defense against potential future shocks and foster the achievement of sustainable development goals (SDGs) in Bangladesh. Full article
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14 pages, 4510 KB  
Article
Enhanced Cathode Performance in Pr0.5Sr0.5FeO3−δ of Perovskite Catalytic Materials via Doping with VB Subgroup Elements (V, Nb, and Ta)
by Hongfei Chen, Zhe Lü and Yujie Wu
Materials 2024, 17(7), 1635; https://doi.org/10.3390/ma17071635 - 3 Apr 2024
Cited by 1 | Viewed by 1771
Abstract
Perovskite-style materials are cathode systems known for their stability in solid oxide fuel cells (SOFCs). Pr0.5Sr0.5FeO3−δ (PSF) exhibits excellent electrode performance in perovskite cathode systems at high temperatures. Via VB subgroup metals (V, Nb, and Ta) modifying the [...] Read more.
Perovskite-style materials are cathode systems known for their stability in solid oxide fuel cells (SOFCs). Pr0.5Sr0.5FeO3−δ (PSF) exhibits excellent electrode performance in perovskite cathode systems at high temperatures. Via VB subgroup metals (V, Nb, and Ta) modifying the B-site, the oxidation and spin states of iron elements can be adjusted, thereby ultimately adjusting the cathode’s physicochemical properties. Theoretical predictions indicate that PSF has poor stability, but the relative arrangement of the three elements on the B-site can significantly improve this material’s properties. The modification of Nb has a large effect on the stability of PSF cathode materials, reaching a level of −2.746 eV. The surface structure of PSF becomes slightly more stable with an increase in the percentage of oxygen vacancy structures, but the structural instability persists. Furthermore, the differential charge density distribution and adsorption state density of the three modified cathode materials validate our adsorption energy prediction results. The initial and final states of the VB subgroup metal-doped PSF indicate that PSFN is more likely to complete the cathode surface adsorption reaction. Interestingly, XRD and EDX characterization are performed on the synthesized pure and Nb-doped PSF material, which show the orthorhombic crystal system of the composite theoretical model structure and subsequent experimental components. Although PSF exhibits strong catalytic activity, it is highly prone to decomposition and instability at high temperatures. Furthermore, PSFN, with the introduction of Nb, shows greater stability and can maintain its activity for the ORR. EIS testing clearly indicates that Nb most significantly improves the cathode. The consistency between the theoretical predictions and experimental validations indicates that Nb-doped PSF is a stable and highly active cathode electrode material with excellent catalytic activity. Full article
(This article belongs to the Section Catalytic Materials)
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17 pages, 550 KB  
Article
Spontaneous Emergence of a Causal Time Axis in Euclidean Space from a Gauged Rotational Symmetry Theory
by Michael Luke Walker
Symmetry 2024, 16(1), 4; https://doi.org/10.3390/sym16010004 - 19 Dec 2023
Viewed by 2255
Abstract
We demonstrate the emergence of an effective “time” axis in the ground state of a gauged rotational symmetry theory in four-dimensional Euclidean space. In so doing, we remove the necessity of Wick rotation to Lorentz spacetime, an arbitrary and sometimes ill-defined procedure, especially [...] Read more.
We demonstrate the emergence of an effective “time” axis in the ground state of a gauged rotational symmetry theory in four-dimensional Euclidean space. In so doing, we remove the necessity of Wick rotation to Lorentz spacetime, an arbitrary and sometimes ill-defined procedure, especially for gravity-related theories. We begin by adapting the Cho-Duan-Ge decomposition to the gauge theory of the four-dimensional rotational symmetry group SO(4), where it identifies the maximal Abelian subgroup SO(2)SO(2) in a gauge covariant manner. We then find the one-loop effective theory to have a stable condensate of monopoles corresponding to the reduction of SO(4) symmetry to SO(2)SO(2). The construction of the condensate ensures that the four-dimensional spatial direction of its field strength must coincide with that of this embedding, and that a magnetic potential must be worked against to divert a trajectory away from this direction. Indeed, movement along this direction represents minimal potential energy. We take it to be the time direction. The gauge-dependent nature of the condensate is such that different gauge choices may lead to different time axes and we show on very general grounds that these different coordinate systems must be relatable by transformations of Lorentz form. Full article
(This article belongs to the Special Issue Physics and Symmetry Section: Feature Papers 2023)
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14 pages, 579 KB  
Article
Demographic Change and Inequality in the Korean Farm Income
by Sunhyung Min
Agriculture 2023, 13(9), 1832; https://doi.org/10.3390/agriculture13091832 - 18 Sep 2023
Cited by 5 | Viewed by 3008
Abstract
This study examines the impact of demographic shifts on income inequality among farm households over an 18-year period, from 2003 to 2021. Our principal aim is to determine whether changes in income inequality are driven more by intra-group changes in age/household size groups [...] Read more.
This study examines the impact of demographic shifts on income inequality among farm households over an 18-year period, from 2003 to 2021. Our principal aim is to determine whether changes in income inequality are driven more by intra-group changes in age/household size groups or by changes between these groups. Furthermore, the study aims to understand which age/household size groups are associated with changes in income inequality. The methodology of this study involves using the generalized entropy (GE) index, which allows for the decomposition of inequality within and between population subgroups. The study divides the total population into subgroups based on age and household size and analyzes both static and dynamic inequality. Results show that (i) the within-group effect for static farm income inequality is more significant than the between-group effect. (ii) On the other hand, for changes in inequality (dynamic inequality), the between-group effect in the case of age and the within-group effect in the case of household size are important. (iii) Changes in income inequality are more related to structural changes in the age group of farmers than to the size of household. Full article
(This article belongs to the Section Agricultural Economics, Policies and Rural Management)
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