Search Results (5,917)

In dually flat manifolds, there is a deep connection between gradient flows and pregeodesics. This was one of the many important contributions of Amari to information geometry. In this paper, we extend the study of this relationship to general Riemannian manifolds. Our result does not impose conditions of flatness on the connection or symmetry on its non-metricity tensor, thus broadening the geometric setting beyond Hessian manifolds. Within this framework, we provide a criterion for comparing relaxation along two different gradient descent curves of a function, formulated in terms of the non-metricity tensor of a connection for which the gradient curves are pregeodesics. We use it to study Gaussian chains, whose relaxation trajectories coincide with gradient descent curves in the space of Gaussian distributions. Thus, we recover a recent result that establishes a universal asymmetry: warming up is faster than cooling down. Our work illustrates how geometric insights rooted in Amari’s legacy offer new perspectives for optimization problems and stochastic processes. Full article

The Yellow River Basin in Inner Mongolia (YRBIM) is a typical arid—semiarid ecological transition zone highly sensitive to climate change. Using long-term Normalized Difference Vegetation Index (NDVI) data together with meteorological and land cover data, this study applied the Sen+Mann–Kendall method and path coefficient analysis to quantify the direct and indirect effects of climatic factors on vegetation coverage. The YRBIM experienced a non-significant warm–wet trend from 1998 to 2019, characterized by slight increases in precipitation and temperature with asynchronous spatial patterns. Vegetation coverage generally improved, with high coverage areas expanding by 12.66% and low coverage areas decreasing by 10.04%. Improvement occurred mainly in eastern croplands and grasslands, while degradation in the northwest coincided with urban expansion and mining. Precipitation showed a highly significant positive correlation with the NDVI at 0.7510. The direct effect of precipitation was dominant at 0.7515, while the indirect effect was negligible at 0.0005. Temperature showed a weak inhibitory effect with a comprehensive effect of 0.0302, where the indirect inhibitory effect at 0.0400 slightly exceeded the direct promotional effect at 0.0098. These response patterns were consistent across most land cover types, except in rural settlements and unused land where temperature showed a weak positive influence. This study provides a scientific basis for ecological conservation and sustainable management in arid—semiarid transition zones. Full article

The circulation of the North Atlantic Ocean plays a vital role in the Earth’s climate system. Numerous studies, primarily through computer simulations, have examined the stability of the Atlantic Meridional Overturning Circulation (AMOC) in a warming climate. Some of these studies predict a potential collapse of the AMOC in the foreseeable future, which would require a significant influx of freshwater into the subpolar North Atlantic (NA) and Nordic Seas. Paleoreconstructions of NA circulation indicate a major shift in the position of the subpolar cold front, which either precedes or coincides with substantial changes in AMOC dynamics. These changes in the front position imply a significant alteration in circulation patterns, beginning with the noticeable restructuring of the subtropical and subpolar gyres. This would lead to modifications in the Gulf Stream system and the North Atlantic Current (NAC), affecting the thermohaline fields and the position and strength of these two current systems. Although some models predict a significant slowdown or even collapse of the AMOC, recent observational studies have offered a more cautious perspective. For instance, the Gulf Stream system exhibits high resilience to perturbations caused by ongoing sea surface warming. In this study, we analyzed the decadal variability of temperature and salinity from in situ observations, along with upper-ocean currents in the subpolar NA (SPNA). We found that the thermohaline pattern of the upper ocean layers in the SPNA and Nordic Seas has remained resilient for over 70 years. The deceleration of the AMOC is evident but relatively modest, with average velocities in the upper layers decreasing by less than 10–15% over 30 years. This deceleration was also inconsistent throughout the NAC region. Furthermore, the subpolar front migration over 70 years, as manifested in isotherm spatial variability, reached a maximum of 3° of latitude, with spatial variability of the yearly 10 °C isotherms being lower. Overall, the conclusion regarding the resilience of the NAC aligns well with that of the Gulf Stream, with no substantial changes in the position or intensity of the subpolar gyre. We conclude that while the AMOC is susceptible to some deceleration due to ongoing surface warming and/or high-latitude freshening, it may also be sufficiently resilient to withstand these changes. Although it cannot be entirely ruled out that the AMOC may reach its tipping point within this century, an analysis of data on decadal variability in the upper arm of the AMOC suggests that such a collapse is unlikely to occur. Full article

We analyze noise in a quantum-enhanced fiber optic gyroscope (FOG), focusing on one of the leading sources of phase uncertainty—uncorrelated photon saturation. Taking a squeezed state input as a source for N00N states, we compute the uncorrelated false coincidence counts at the optimal phase bias and determine an upper limit to the squeezed amplitude $\xi$ which allows for sub-shot noise precision. As examples, we apply parameters of present-day quantum FOG experiments and determine the maximum possible precision enhancement based on their respective $\xi$ and optimal phase bias points. With the aim of supporting future FOG setups with higher N00N state fluxes, our result highlights the need to transition to multimode states to bypass the $\xi$ limitation, such as photon pairs generated by the dynamical Casimir effect. Full article

The skin serves as a primary defensive barrier to protect the body from environmental contaminants, infections and trauma. Unfortunately, skin barrier’s structural and functional integrity can be compromised, disrupted or impaired due to a combination of internal and external factors, making it vulnerable and often leading to a wide range of skin conditions characterized by dryness, heightened sensitivity, and increased susceptibility to damage and infections. In addition, the integrity of the skin barrier tends to deteriorate progressively with age. As people age, their skin naturally changes and can also be compromised by a plethora of factors that reduce its strength and resilience. The aging skin becomes thinner and more sensitive, coinciding with a variety of structural–functional alterations, decreased levels of natural moisturizing factor (NMF), lipid content and hydration, increased transepidermal water loss (TEWL), altered skin surface pH (pHss) and microbiome diversity. All these age-related skin integrity alterations make the skin drier, flakier, itchy, and fragile, and more susceptible to damage and breakdown, thus diminishing its ability to effectively protect, repair and heal efficiently. Identifying skin integrity issues before they progress will foster positive outcomes through effective preventive measures. Hence, it is important to understand the impact of skincare formulations on skin integrity in compromised aging skin. A well-considered, evidence-based approach to skincare can provide cleansing, moisturizing and protective benefits, while aiding the reduction in skin integrity issues like dry and itchy skin, sensitive skin, bruising, skin tears, pressure injuries (PIs), lower leg ulcers and moisture-associated skin damage (MASD). Managing skin integrity in compromised aging skin begins with gentle skin cleansing, adequate moisturization and protective barrier care to ensure the skin’s function is maximized. Full article

In this paper, we introduce and systematically study the class of interpolative Geraghty-type contractive mappings within the framework of complete bicomplex-valued metric spaces (bi-CVMS). We prove seven new results: (i) a fixed point theorem for a single interpolative Geraghty contraction; (ii) a common fixed point theorem for a pair of such mappings; (iii) a fixed point theorem for interpolative Reich–Rus–Ćirić type contractions in bi-CVMS; (iv) a coincidence point and common fixed point theorem for weakly compatible maps; (v) a fixed point theorem for Jaggi-type hybrid contractions in bi-CVMS; (vi) a stability result for the Picard iteration associated with the main contraction; and (vii) an application theorem establishing the existence and uniqueness of solutions to a boundary value problem governed by a Caputo fractional differential equation. All results are furnished with complete proofs and non-trivial illustrative examples. Several well-known theorems—including those of Banach, Kannan, Reich, Geraghty, and their complex-valued analogues—follow as special cases. The paper significantly advances the fixed point theory in bicomplex-valued metric spaces. Full article

Primary succession following glacier retreat provides a natural system for testing whether soil development simply shifts fine roots along a single acquisitive–conservative axis orinstead changes the nutrient-acquisition pathway that dominates at the community level. We hypothesized a stage-dependent sequence, from substrate-limited exploration, to transient morphological capture, and finally to rhizosphere-mediated biochemical mobilization. To test this idea, we quantified fine-root morphology, absorptive-transport partitioning, anatomy, phosphatase activity, exudation, community-scale belowground structure, and soil and rhizosphere properties across woody communities representing approximately 20, 40, and 90 years since deglaciation in the Hailuogou Glacier foreland. Across succession stages, bulk density and pH declined, whereas field capacity, soil carbon, and soil nitrogen increased, indicating rapid development of the belowground resource environment. Fine-root strategies did not fall along a single acquisitive–conservative continuum. Instead, morphological nutrient capture peaked at intermediate succession: the 40-year stage had the highest specific root length, specific root area, absorptive-to-transport root length ratio, and root nitrogen concentration. In contrast, the 90-year stage showed lower specific root length but higher dry matter content, thicker cortex, greater standing fine-root biomass, larger rhizosphere volume, higher phosphatase activity, and greater area-based carbon exudation. This late-successional syndrome coincided with stronger extracellular enzyme activity, larger dissolved organic carbon and nitrogen pools, and higher microbial biomass, despite negative net nitrogen mineralization. Species-level analyses showed that biochemical-input traits were jointly shaped by successional stage, species identity, and their interaction. Together, these results show that primary succession did not simply increase or decrease root acquisitiveness. Instead, as soils developed, it changed the nutrient-acquisition pathway that dominated, with direct implications for nutrient cycling and vegetation dynamics in rapidly developing glacier-foreland ecosystems. Full article

Expansive clay slopes are vulnerable to progressive strength loss induced by repeated wetting and drying, a mechanism that drives shallow failure in active moisture zones. Reproducing this degradation experimentally is time-consuming and resource-intensive. This study evaluates whether Fully Softened Strength (FSS) can serve as a practical substitute for five wet–dry cycles in expansive clay slope stability assessment. Direct shear tests were conducted on wet–dry-cycled and reconstituted FSS specimens across fourteen experimental water contents. Strength parameters were incorporated into homogeneous and heterogeneous limit equilibrium slope models, considering degraded layer thicknesses of 1–5 m and suspended water table conditions. Equivalence was assessed using root mean square error (RMSE), prediction bias, and physical representativeness. Five wet–dry cycles produced a dominant cohesion reduction of 70.4% with minor changes in friction angle, reaching a quasi-stationary degraded state. FSS reproduced an equivalent system response through mechanical compensation between cohesion and friction—not through equality of strength parameters—under shallow failure conditions. The best statistical fit was obtained at w = 43.5% (RMSE = 0.314); however, w = 42.0%, coinciding with the liquid limit, provided a physically more robust interpretation with near-zero bias. Equivalence was found to be valid only for normal stresses ≤ 50 kPa, representative of shallow failure depths of 1–4 m. Full article

We developed an explainable machine learning framework combining 22 years (2003–2024) of multi-sensor satellite data (MODIS Aqua, CMEMS, C3S) with zone-specific SHAP attribution to quantify chlorophyll-a (Chl-a) mechanisms in the East China Sea. A geography-free XGBoost model achieved $R^2=0.802$ on 1.4 million pixel-month observations, and counterfactual experiments confirmed its superior environmental sensitivity over location-dependent models. Multi-strategy threshold detection identified two critical salinity boundaries—11.62 psu marking the turbidity-to-productivity transition (Cohen’s $d=-2.92$) and 34.03 psu at the Kuroshio Front ($d=-1.04$)—neither of which coincides with traditional physical definitions. Zone-specific SHAP analysis revealed that sea surface salinity (SSS) dominates Chl-a attribution across all zones but through fundamentally different mechanisms. We propose an “SSS Triple-Role Framework” in which salinity serves as turbidity proxy in estuarine waters, nutrient proxy in transitional waters, and dilution signal offshore, resolving the apparent contradiction of simultaneous positive and negative salinity effects. Non-additive interactions—including SSS × SST coupling (61% modulation) and SST × sea level amplification during Kuroshio intrusions—further demonstrate hierarchical controls missed by additive models. These findings provide quantitative benchmarks for ecosystem monitoring in river-dominated marginal seas. Full article

This article develops a simple model of the smartphone circular economy where the buy-back price offered to consumers is the main control variable. The model explicitly integrates refurbishment, recycling, and premature phone replacement encouraged by buy-back incentives. We distinguish three types of smartphones: premium, basic, and refurbished premium phones. Furthermore, consumers are segmented by buy-back sensitivity: sensitive users tend to return their phones and shorten their device lifespan, while non-sensitive users keep their phones longer. Additionally, refurbished consumers can buy new phones in case of insufficient supply. Our analysis reveals that with realistic parameters, there exists an optimal buy-back level that minimizes CO₂eq. emissions and waste, and this optimum coincides with the equilibrium between supply and demand on the refurbished market. However, depending on the system parameters, negative effects can be observed. For example, if most components are replaced during refurbishment, emissions increase with the buy-back. More generally, our results highlight the importance of eco-design. While the model is applied to smartphones, its structure is generic and can be adapted to other products with refurbishment and buy-back incentives. Full article

Religiously diverse societies are often portrayed as marked by tensions between exclusive worldviews and aspirations toward inclusive and cohesive social relations. These tensions are particularly salient in religious contexts, where deeply held convictions about truth and moral order may coexist uneasily with ideals of tolerance and mutual recognition. A central question emerging from this dilemma is how religious worldviews shape evaluations of religious others in increasingly diverse societies. Using cross-sectional survey data among religious Christians and Muslims in the Netherlands, we analyse associations between religious exclusivism, religious and national belonging, bonding and bridging social capital, and outgroup attitudes, combining bivariate correlations, multivariate regression, and regression-based serial mediation analyses. Results show that religious exclusivism is a robust independent predictor of colder outgroup evaluations. In contrast, religious belonging and both bonding and bridging social capital are associated with warmer outgroup evaluations: bonding shows the stronger association. Mediation analyses indicate that religious exclusivism is indirectly associated with warmer outgroup evaluations through religious belonging, whereas bonding social capital does not mediate exclusivism in the direction of outgroup negativity. The findings challenge the view of bonding as primarily closing and suggest that supportive in-group embeddedness can coincide with more positive evaluations of religious others. Full article

Cervical cancer (CC) is an alarming global health problem, with predominantly higher incidence, lethal progression, and mortality among women of African ancestry (AA) than women of European ancestry (EA). Although persistent high-risk human papillomavirus (HPV) integration and infection are the key etiological factors, currently available evidence implicates epigenetic reprogramming as a prime contributor to ancestry-associated differences in CC pathogenesis. To address these disparities, we performed genome-wide DNA methylation profiling of HPV-positive cervical intraepithelial neoplasia (CIN) lesions from AA (n = 15) and EA (n = 15) women. Differential methylation analysis identified a distinct epigenomic landscape in AA-CIN lesions, with widespread hypermethylation and hypomethylation at promoter-associated and regulatory CpG sites. Pathway enrichment analyses highlighted dysregulation of ECM-receptor interaction, focal adhesion, PI3K-Akt, MAPK, Ras, Rap1, and RUNX-dependent transcriptional networks. Comparative analysis across CIN grades (CIN1–CIN3) revealed progressive epigenetic reprogramming affecting cell cycles, cytoskeletal dynamics, signaling, and metabolic pathways. Among hypermethylated tumor suppressor genes, SH3GL2 and ARHGAP25 showed significantly higher methylation in AA lesions, accompanied by concomitant loss of their protein expression. MBD1, a methylation-binding regulator, was upregulated in AA-CIN lesions, coinciding with global loss of 5-hydroxymethylcytosine (5hmC), suggesting enhanced transcriptional repression. In contrast, EA lesions retained protein expression and 5hmC levels. Collectively, these findings indicate that early, ancestry-specific epigenetic modifications target tumor suppressor pathways and converge on oncogenic signaling, cytoskeletal remodeling, and cell–cell adhesion. Our study provides mechanistic insight into CC health disparities, identifying SH3GL2 and ARHGAP25 hypermethylation as potential biomarkers, and highlighting epigenetic regulation as a contributor to disparate CC progression in AA women. Full article

We present and discuss time-lapse gravity variations recorded by a large-scale absolute gravity network operating in Central Italy. The network comprises four stations distributed across the Lazio, Umbria, and Abruzzo regions, areas affected by the significant seismic activity of 2009 and 2016–2017. From 2018 to 2023, six campaigns were carefully conducted using an FG5 absolute gravimeter. We detected significant gravity decreases around 2020 reaching between −15 and −20 μGal in three sites and approximately −37 μGal at the fourth. The Sentinel-1 time series of permanent scatterers (PS) allowed us to exclude significant contribution from vertical deformations to the observed gravity changes. We analyzed both ground-based data (rainfall gauges and well water levels) and satellite-based observations (the Gravity Recovery and Climate Experiment-Follow-On, GRACE-FO, mission) together with the Global Land Data Assimilation System (GLDAS) and precipitation models. The results reveal a significant decrease in the regional groundwater content from 2018 to the end of 2020, which coincides temporally with the observed gravity decrease. We show that the absolute gravity variation trends observed at all stations are consistent with regional-scale hydrological processes, pointing to a significant decrease in terrestrial water storage (TWS) during the same time interval. At L’Aquila (AQUI), the gravity anomaly is larger than expected from regional hydrological products alone, suggesting an additional local component possibly related to the hydrogeological response of the fractured karst system undergoing significant post-seismic activity. Full article

In the Mediterranean principality of Thessaly, Greece, heat stress has become an environmental limitation on animal production and welfare. This study aims to quantify livestock heat stress using the temperature–humidity index (THI) and assess its spatial and temporal distribution across Thessaly during the warm seasons from 2020 to 2025, based on ERA5-Land reanalysis data. For selected livestock units, hourly air temperatures and dew point temperatures were used to generate and calculate maximum temperature fields and the THI under outdoor conditions, with no directly measured physiological responses in animals, but potential heat stress exposure was evaluated using THI derived from ERA5-Land data. The results reveal persistent thermal hotspots in the central and southeastern Thessalian plain, where maximum daily temperatures frequently exceeded 38–40 °C and locally surpassed 45 °C during August. THI values regularly exceeded 72, indicating productivity decline, and reached 82 during peak summer months, corresponding to high and severe stress categories. Mountainous regions were consistently 6–10 °C cooler and exhibited lower THI levels. Thermally stressful conditions extended from May through September, indicating sustained seasonal exposure rather than isolated heatwave events. The spatial coincidence between intensive livestock production and high-THI zones suggests structural vulnerability under current climate conditions. These findings offer a spatially explicit assessment of climate-driven thermal risk and support the development of targeted mitigation strategies and climate-resilient livestock management in Mediterranean agricultural regions. They also offer a data-driven foundation for integration into emerging Digital Twin frameworks for predictive livestock management. Full article

In this paper we study photon entanglement in the framework of Maxwell–Schwartz field theory. The ambient state space is the complex Maxwellian distribution space $W={\mathcal{S}}^{\prime }({\mathbb{M}}_4,{\mathbb{C}}^3)$, whose elements are fields of the form $F=\overrightarrow{E}+ic\overrightarrow{B}$. Polarization is realized as a two-dimensional complex subspace of W, generated by suitable linearly polarized Maxwellian solutions associated with opposite propagation directions. This yields canonical polarization sectors $P_A$ and $P_B$, each naturally isomorphic to ${\mathbb{C}}^2$. Within this setting, the Bell singlet state is represented by a non-factorizable tensorial Maxwellian field in $P_A\otimes P_B\subset W\otimes W$. By means of the induced rotated polarization bases, the standard joint probabilities of the photon polarization experiment are recovered exactly, and the correlation law $E(a,b)=-cos\left(2\right(a-b\left)\right)$ is obtained. Consequently, the usual CHSH value $2\sqrt{2}$ is reproduced in the Maxwell–Schwartz framework. To clarify the meaning of this violation, we first formulate the CHSH inequality in a purely measure-theoretic form, as a theorem about four correlators represented on a single probability space by bounded measurable functions. We then show that the correlators produced by the intrinsic Maxwellian Bell state do not admit such a common representation. The obstruction is structural: the ontic state is a global non-product field configuration, and the four correlations arise from different polarization resolutions of the same tensorial Maxwellian state. A second main result concerns the Born rule. For $L^2$ scalar quantum states in the domain of the Maxwellian correspondence, we prove that the squared Hilbert norm, times the constant ${\epsilon }_0$, coincides with the electromagnetic energy of the associated field. This leads to an energy interpretation of the Born rule: the Born probability density is identified with the normalized electromagnetic energy density up to an interference term depending on the chosen Maxwell–Schwartz isomorphism, which assumes the role of a quantum context. In the context of the Aspect and collaborators’ experiment, we prove that, on the other hand, the polarization probabilities become energy contributions of the corresponding field components. These results show that photon entanglement, Bell inequality violation, and the Born rule admit a coherent interpretation within Maxwell–Schwartz field theory, where the basic ontological objects are electromagnetic-like fields rather than abstract state vectors. Full article