Search Results (6,221)

Digital resale platforms allow buyers to either purchase at a posted price or submit a lower offer subject to uncertain seller acceptance. This study develops a stylized finite-horizon dynamic program in which the buyer jointly chooses whether to bid and how much to offer while retaining a buy-now fallback. A savings transformation yields an exact participation boundary and a one-dimensional characterization of the optimal offer. The optimal discount increases with continuation saving; hence offers are less aggressive when more opportunities remain and rise after successive rejections. Each opportunity is modeled as a conditional exposure event to an exogenous seller pool; platform-specific visibility, matching, competing-buyer preemption, and strategic seller response are outside the baseline model. Numerical illustrations use assumed parameters and are internal model calculations, not statistical estimates or evidence of platform performance. Under the reference specification, the adaptive policy yields an expected payment of 283.34, only 0.13 units (4.42 basis points of buy-now) below the best fixed rule optimized for the same ten-opportunity horizon. A normalized sensitivity map shows that the model-implied gain increases with a wider feasible gap and lower opportunity cost but remains below 1% of buy-now in the stationary region examined. The contribution is a theoretical policy characterization, not a deployable buyer-facing tool; deployment would require estimating seller tolerance from accepted, rejected, and expired offer logs and testing the policy out of sample or in the field. Full article

ST-graph-based DP–QP speed planning may suffer from incomplete and discontinuous feasible-region boundaries due to discrete obstacle projection and coarse DP search. These boundary defects can degrade the feasibility and quality of subsequent QP speed optimization. To address this issue, this paper proposes a continuous bilateral ST feasible-region reconstruction method combined with bounded-slack QP speed planning. The method reconstructs the DP-derived feasible region into a finite, continuous, and bilaterally bounded longitudinal corridor. During reconstruction, the passing relationship determined by DP and the hard obstacle-safety constraints are preserved. Independent bounded slack variables are then introduced for the lower and upper corridor bounds to alleviate local near-infeasibility in the QP problem. Closed-loop CarSim–Simulink simulations in four representative scenarios show that the proposed method increases the valid bilateral-node ratio to 100% and reduces the average boundary variation by 54.5–57.7%. Across the tested scenarios, the resulting speed profiles improved travel efficiency while maintaining or improving longitudinal smoothness, and the maximum observed computation time remained below the 100 ms planning period. Full article

Background and Objectives: Proximal trunk and hip control during dynamic tasks is a key modifiable determinant of dynamic knee valgus (DKV) in soccer players. This study investigated the effects of adding dynamic core stability training (DCS) to the FIFA 11+ warm-up program compared with the FIFA 11+ on DKV, single-leg athletic stability, and isometric hip muscle strength in amateur soccer players. Methods: A single-blinded, parallel-group randomized controlled trial was conducted on 40 amateur soccer players (mean age 16.6 ± 3.1 years). Participants were randomly allocated to either DCS+FIFA 11+ training or FIFA 11+ alone, with both interventions performed three times per week for 8 weeks. DKV, single-leg athletic stability and isometric hip strength was assessed at the baseline, 4 weeks, and 8 weeks. Data were analyzed using linear mixed-effects models to examine Group, Time, and Group × Time effects, with participant included as a random effect. Benjamini–Hochberg false discovery rate adjustment was applied to the Group × Time comparisons. Results: Significant Time effects were observed for all outcomes. After Benjamini–Hochberg correction, significant Group × Time interactions were observed for left-leg athletic stability (adjusted p < 0.001; ηp² = 0.243), left hip abductor strength (adjusted p = 0.025; ηp² = 0.125), and right and left hip external rotator strength (adjusted p < 0.001 and <0.001; ηp² = 0.302 and 0.404 respectively), with greater improvements in the DCS+FIFA 11+ group. Both groups demonstrated reductions in right and left DKV over time; however, Group × Time interactions were not significant for either DKV measure. Conclusions: Adding dynamic core stability training to the FIFA 11+ was associated with greater longitudinal improvements in left-leg athletic stability and hip muscle strength outcomes, particularly left hip abductor and bilateral hip external rotator strength. Supplementing the FIFA 11+ with DCS training may provide additional benefits for selected aspects of lower-extremity movement control and proximal muscle strength in amateur soccer players. Full article

Hydrogeology is an important field in graduate programs in water and earth sciences due to its relevance for understanding and managing groundwater resources. However, although university faculty members generally possess strong scientific and technical expertise, they often have limited pedagogical preparation for teaching complex hydrogeological content. Therefore, the aim of this study was to analyze the importance that postgraduate faculty members in water and earth sciences from Central and North American countries attribute to the conceptual, procedural, and attitudinal components of Pedagogical Content Knowledge (PCK) in the teaching of groundwater dynamics, and to explore whether these perceptions differ according to pedagogical training, academic degree, and teaching experience. The study employed an exploratory, descriptive–comparative quantitative approach with a non-experimental cross-sectional design. The study included 41 faculty members recruited through non-probabilistic snowball sampling. Results indicated generally high valuations across the PCK components within the study sample, particularly logical, mathematical, and experimental skills. However, no statistically significant differences were found according to pedagogical training, teaching experience, or academic degree. Descriptively, participants attributed relatively greater importance to several scientific–technical PCK components, particularly logical, mathematical, and experimental skills. In conclusion, the findings suggest that specialized pedagogical training may be a potential curricular avenue for strengthening contextualized and meaningful teaching in postgraduate hydrogeology education. However, this implication is based on the descriptive findings and previous research rather than on evidence of an effect of pedagogical training in the present study. Full article

Background: Trail running is a sport characterized by taking place in natural environments and requiring constant adaptation to irregular terrain, making postural balance crucial for preventing falls and coping with the coordinative demands of these races. Objectives: This study aimed to analyze the acute effects of elevation on dynamic and static balance in young trained trail runners. Methods: Fifteen highly trained young athletes (eight females, seven males; age 16.8 ± 2.14 years) completed two similar training sessions except for elevation gain (1000 m vs. 15 m, flat). Static balance was evaluated using the Balance Error Scoring System (BESS), and dynamic balance was assessed with the Y Balance Test (YBT) before (pre) and after each session (post) using 2 × 2 (Time × Terrain) repeated-measures ANOVA. Results: BESS errors increased in both sessions but more after elevation (+3.33 vs. +1.20 errors; interaction p < 0.001; post-session 15.67 ± 1.23 vs. 12.67 ± 1.23). The YBT composite index showed no significant differences between elevation and flat sessions (83.32 ± 7.92 vs. 83.79 ± 7.59, p = 0.763) or in the interaction (p = 0.057). Conclusions: These findings highlight the need for specific strategies to preserve postural balance—especially static balance—during training and after trail races and support taking elevation gain into account when programming training load in young trail runners. Full article

The increasing penetration of non-conventional renewable energy sources poses operational flexibility challenges that motivate the coordination of distributed energy resources via active demand management. This study proposes an optimal operational strategy for a Virtual Power Plant (VPP) integrating conventional thermal generation, renewable sources, battery energy storage, main grid transactions, and active demand mechanisms. The optimization model is formulated as a Mixed-Integer Linear Programming (MILP) problem embedded within a receding horizon Model Predictive Control (MPC) framework. Active demand is represented through an aggregated shiftable load and distinct curtailable loads. Shiftable-load operation is regulated through power, ramping, and energy-balance constraints, whereas curtailable loads are governed by user discomfort penalties, economic incentives, and daily curtailment budgets. Renewable forecasting uncertainties are mitigated using a hybrid physical-LSBoost model that reduces prediction errors by up to $93.0\%$. Operational results demonstrate total operating cost reductions ranging from $2.08\%$ to $15.34\%$, alongside an $8.65\%$ peak demand reduction. A comprehensive sensitivity analysis reveals that active demand participation is governed by distinct qualitative mechanisms: strict budget bounds, a steep penalty threshold for curtailment activation, and a threshold-type saturation response to temporal price spreads for shiftable loads. Furthermore, high-resolution 5-min online operation confirms the real-time viability of the scheme, maintaining solver execution times under $1.69\mathrm{s}$ per iteration. It is concluded that coordinating active demand, storage, and MPC enhances both economic and technical VPP performance, though carbon emission abatement relies heavily on thermal dispatch dynamics, highlighting the need to explicitly balance economic and environmental trade-offs. Full article

Plants coordinate their growth and developmental programs through dynamic communication in the core of the nucleus, enabling them to adapt to persistently high-temperature environments. Upon heat stress, plants primarily perceive and transduce thermal signals between the nucleus and other organelles, a process defined as nuclear-organellar communication. The published research on plants in response to heat environments mainly focuses on sensing heat physical signals from the plasma membrane (PM)/cytosol to the nucleus, eliciting nuclear transcriptional reprogramming and decoding organelle-derived retrograde signals to the nucleus. Consequently, plants have evolved sophisticated systems to decode adverse temperature signals relying on efficient nuclear-organellar coordination. This review summarizes how plants maintain cellular homeostasis via nuclear crosstalk. Heat signals are initially perceived, which triggers the production of secondary messengers including phosphatidic acid (PA), calcium ions (Ca²⁺) and reactive oxygen species (ROS). In addition, proteins also deliver thermal signals to the nucleus. As the central signaling hub, the nucleus orchestrates global transcriptional reprogramming predominantly through the Heat Shock Transcriptional Factors (HSFs)–heat shock proteins (HSPs) regulatory module, and sends instructions to the endoplasmic reticulum (ER), chloroplasts and mitochondria. Conversely, organelle-derived retrograde signals coordinate stress adaptation: the unfolded protein response relieves ER stress, and heat stress activates ROS-mediated chloroplast-to-nucleus and mitochondria-to-nucleus feedback pathways. We further outline candidate thermosensing proteins residing in different organelles, and highlight major unsolved issues. Critical knowledge gaps include the intrinsic thermosensing capacity of chloroplasts and mitochondria, inter-organellar coordination of second-messenger dynamics, specific organelle functions, and the biological roles of membrane contact sites. Further mechanistic insights will facilitate the application of genome editing, synthetic biology and artificial-intelligence-aided design to breed heat-tolerant crops without yield penalties. Full article

Efficient tractor coverage planning requires suitable swath orientations and kinematically feasible connections. In two-pass diagonal harrowing, sequential boustrophedon planning treats the two swath families independently and may introduce avoidable connection travel. This study proposes a Field-Geometry-Aware Bidirectional Coverage and Connection Path Co-Optimization algorithm (FG-BCO) for a single tractor operating in convex, obstacle-free polygonal fields. FG-BCO clips two parallel swath families to the field boundary, constructs feasible cross-pass links between oriented endpoints, assembles alternating route paths, and applies subset dynamic programming to optimize their visiting order and traversal orientation. The resulting route is converted into a forward-only trajectory and checked against boundary-containment and minimum-turning-radius constraints. FG-BCO was compared with Sequential Boustrophedon Coverage Path Planning (SB-CPP) in rectangular, regular pentagonal, regular hexagonal, and irregular fields using 648 matched angle pairs per field. When the minimum path length of each algorithm was selected independently from the tested angle pairs, FG-BCO achieved reductions of 18.65%, 9.65%, 15.20%, and 17.11% in the four fields, respectively. However, FG-BCO produced shorter routes in only 57.87%, 41.82%, 40.43%, and 40.59% of the matched cases. The corresponding mean paired saving rates were 0.646%, −0.484%, −0.144%, and −0.833%, with medians of 0.939%, −1.060%, −0.923%, and −1.094%. These results distinguish the potential reduction obtainable through angle selection from performance under an arbitrary prescribed angle pair. FG-BCO is advantageous when the two swath families produce favorable endpoint proximity, heading compatibility, and turning space, but its improvement is not universal. Preliminary evaluation of the working-angle pair in relation to the target field geometry is therefore recommended before application. Full article

Sodium-ion batteries are generally considered a promising alternative to lithium-ion batteries due to the abundance and low cost of sodium. However, their main limitation is the lack of an appropriate anode, since the usual graphite electrode used in lithium batteries is incompatible with the larger ionic radius of sodium. In this work, the theoretical behavior of pillared graphene as a possible anode is analyzed via computational simulations based on Density Functional Theory (DFT) using the FIREBALL program. The structural relaxation results reveal that staggered pillars are more stable than the aligned alternative. The adsorption energy of sodium is shown to be significantly higher than for graphite, with a maximum value of $-2.23$ eV, leading to an important energetic benefit. The diffusion analysis shows high mobility for sodium, with migration barriers comparable to those of lithium ions both in the flat regions of the structure and close to the nanotubes. The values are comparable to those of the standard graphite used in current batteries. Finally, the charge analysis confirms significant electronic transfer from both sodium and lithium to the lattice. These data indicate that pillared graphene can be a good candidate for the optimization of charge dynamics in sodium-ion batteries. Full article

Olive reproductive phenology depends on the balance between winter chilling and subsequent heat accumulation, yet multi-environment Mediterranean observations to assess this dynamic across thermal regimes remain scarce. We monitored Full Budburst (FB) and Full Flowering (FF) during 2021–2024 in 670 cultivars across five germplasm banks in Greece, Italy, Morocco, Spain, and Türkiye. Median dates, periods, dispersion, and phenological stage overlap were related to bioclimatic factors and chilling and heat accumulation. The influence of the germplasm-bank environment, year, and their interaction on the timing of both stages was assessed. The Median Full Budburst (FB₅₀) and Median Full Flowering date (FF₅₀) were strongly correlated. Likewise, budburst dispersion (ID_bb) was positively associated with flowering dispersion (ID_ff), serving as descriptive indicators of phenological synchrony under varying thermal regimes. Warmer conditions between FB₅₀ and FF₅₀ were associated with a shorter transition to flowering. Conversely, warmer pre-budburst conditions and lower chilling accumulation were associated with greater budburst and flowering dispersion and reduced synchrony. These findings indicate that budburst provides an important temporal reference for flowering. Integrating budburst and flowering dispersion with transition gap (T_gap) metrics offers a quantitative framework for characterizing population-level phenological responses under contrasting thermal regimes and enhancing future olive breeding programs. Full article

Background: Carcinogenesis has traditionally been attributed to the accumulation of somatic mutations in nuclear genes regulating cell proliferation, survival, and apoptosis. Although hereditary genetic predispositions account for less than 10% of cases, the extensive heterogeneity of the somatic mechanisms driving tumorigenesis—including subsets of neoplasms lacking canonical nuclear mutations—suggests that non-mutational mechanisms and organelle dynamics significantly influence tumor onset. Emerging evidence increasingly supports the concept that mitochondrial dysfunction and metabolic reprogramming are essential factors in tumor development, rather than merely downstream consequences of nuclear genetic alterations. While current literature establishes mitochondrial alterations as crucial co-initiators and facilitators of early transformation, defining whether metabolic failures may eventually act as primary trigger remains an ongoing area of investigation. Within this perspective, the “Endosymbiotic/Evolutionary Theory” provides a useful heuristic model, since it conceptualizes metabolic rewiring not as a literal genetic reversal, but as an adaptive shift toward ancestral, highly glycolytic survival programs when oxidative microenvironments are compromised. Methods: We conducted a comprehensive theoretical and comparative analysis of mitochondrial biology, interrogating the structural, functional, and evolutionary parallels between mitochondria, intracellular bacteria, and viruses within the conceptual context of the endosymbiotic theory. Particular attention was given to mitochondrial proteins associated with organellogenesis, bioenergetic control, and molecular mechanisms facilitating mitochondrial–nuclear communication, including the integration of mitochondrial DNA (mtDNA) into nuclear DNA (nDNA) as nuclear mitochondrial DNA segments (NUMTs). Results: Under sustained bioenergetic stress, mitochondrial retrograde signaling can achieve regulatory dominance over the nucleus, driving a functional dissociation between organellar metabolic state and nuclear control. While not autonomous in a strict sense, this shift echoes the evolutionary legacy described by the endosymbiotic theory, whereby mitochondria act as semi-independent bioenergetic systems capable of imposing profound effects on nuclear gene expression and cellular fate. The resulting state is characterized by metabolic reconfiguration, loss of differentiation fidelity, and the acquisition of cancer stem cell–like properties. This process may unfold through a sequence of interrelated events: (1) persistent endogenous or exogenous stressors that challenge cellular homeostasis; (2) establishment of a chronic inflammatory state and sustained redox imbalance; (3) progressive disruption of the cellular microenvironment and inter-organelle communication; (4) emergence of a permissive pre-neoplastic niche characterized by impaired oxidative phosphorylation (OXPHOS), altered mitochondrial dynamics, and sustained retrograde signaling; (5) activation of adaptive survival pathways and escape from canonical cell death and checkpoint controls; and (6) progression toward a dedifferentiated, stem-like cellular phenotype associated with metabolic plasticity and increased resilience. Conclusions: We recommend that cancer be reframed as a dedifferentiated cellular state primarily driven by mitochondria-derived signaling, reflecting the organelle’s ancestral autonomy and the reactivation of evolutionarily conserved mechanisms involving transposons, retrotransposons, Long Interspersed Nuclear Element-1 (L1), transposable elements (TEs), reactive oxygen species (ROS), and mtDNA–nDNA crosstalk, including the generation of nuclear mitochondrial DNA segments (NUMTs). This perspective extends the canonical view of predominantly nuclear-driven oncogenesis by reframing carcinogenesis as a bioenergetic and bio-evolutionary process, thereby highlighting mtDNA–nDNA interactions and mitochondrial signaling as central targets for cancer prevention, diagnosis, and therapy. Full article

Airborne pollen is a major public health concern due to its allergenic properties. Understanding long-term changes in pollen dynamics is essential for evaluating shifts in exposure to airborne allergens and enhancing allergy risk management. In this study we examine long-term trends in airborne pollen in the urban area of Bolzano, the capital city of the Autonomous Province of Bolzano—South Tyrol (Northern Italy), over a 30-year period (1995–2024), with a focus on changes in pollen taxa composition, abundance and the phenological descriptors of the pollen season. Pollen was collected using a Hirst-type volumetric sampler, operated as part of the continuous aerobiological monitoring program of the Agency for Environment and Climate Protection of the Autonomous Province of Bolzano—South Tyrol, and analysed following European standard protocols. Thirty-one taxa dominated the pollen spectrum and were investigated using two different statistical approaches. First, we used generalised linear models (GLMs) to calculate the relative annual change in Annual Pollen Integral (Δ_APIn), and then we analysed the overall trends of the main pollen season (MPS) descriptors: timing, duration and total amount of airborne pollen recorded over an entire year for a given taxon. Although no overall trend in Annual Pollen Integral (APIn) was detected, marked taxon-specific heterogeneity emerged. The strongest positive estimated trends occurred in allergenic taxa such as Morus (+4.56% Yr⁻¹), Olea (+3.76% Yr⁻¹), and Cupressaceae (+2.46% Yr⁻¹), whereas negative estimated trends were seen in taxa such as Poaceae (−0.75%Yr⁻¹), Urticaceae (−0.79%Yr⁻¹), and native Artemisia taxa (−4.89%Yr⁻¹). When taxa were grouped according to their ecological categories, arboreal and non-native pollen increased significantly by 1.44 and 2.12%Yr⁻¹ respectively. Several taxa also exhibited earlier season onset and longer pollen seasons, notably Poaceae and Urticaceae. These findings provide evidence of taxon-specific changes in pollen seasons and airborne pollen concentrations in Bolzano, highlighting their relevance for allergy risk assessment. Full article

Renewable power plants with co-located battery energy storage systems (BESSs) coordinate forecast-deviation control, renewable-surplus management, electricity-price arbitrage, and ancillary-service commitments through the shared power and energy capability of the battery. This study develops a layered framework for scenario-based intraday multi-service co-optimization and grid-value assessment. The plant-level mixed-integer linear programming (MILP) model operates at 15 min resolution and represents piecewise deviation penalties, time-varying export limits, battery dynamics, a terminal state-of-charge condition, throughput-based degradation costs, and the opportunity cost of reserving regulation headroom. Its scenario-contingent formulation evaluates expected intraday operating value across ten representative photovoltaic trajectories under a perfect-information structure. A complementary service map assigns fast dynamic and system-level indicators to the control, power-flow, and dispatch models appropriate to their time scales. The numerical study considers an 80 MW photovoltaic plant with a 10 MW/20 MWh BESS, evaluates four regulation-compensation cases, and records a complete C4 run time of 209.421893 s on an Intel Core i7-10710U computer with 16 GB RAM. Energy-oriented service stacking increases expected daily plant benefit in the case study, while regulation reservation becomes attractive when compensation exceeds the opportunity cost of battery power and energy headroom. The framework provides a consistent basis for interpreting service interactions, decision timing, data provenance, and plant- and system-level value. Full article

The global power sector is undergoing a profound transformation driven by the rapid expansion of variable renewable energy sources, supported by climate commitments and increasingly competitive technologies. This shift heightens the need for operational flexibility. Hydropower plants with storage play a central role in enabling renewable integration and ensuring that the system can balance the supply; however, their flexibility is often limited by environmental constraints and competing water uses. This study assesses strategies to enhance renewable integration through improved operational flexibility in hydropower plants. The analysis combines Stochastic Dual Dynamic Programming (SDDP) with hourly operational simulations to represent system operation under uncertain inflows and variable renewable energy (VRE) in Brazil’s Northeast region—an area marked by a high share of hydropower and VRE. The methodology incorporates critical hydrological conditions and evaluates how relaxing selected operational constraints, commonly imposed for environmental purposes, influences energy and capacity supply. Results show that hydropower can provide substantial generation modulation to offset renewable variability. Enhanced coordination between hydropower and renewables also reduces thermal dispatch, lowering associated emissions and costs. The findings reinforce that hydropower remains essential in low-carbon power systems and suggest that adapting operational rules and regulatory frameworks is necessary to unlock its full flexibility potential while meeting power-system requirements. Full article

Metabolic dysfunction-associated steatotic liver disease (MASLD) is the most common chronic liver disease and is closely associated with obesity, insulin resistance, and the recently conceptualized cardiovascular–kidney–metabolic syndrome. For decades, the pathogenesis of steatosis has been viewed primarily through the lens of insulin and the canonical transcriptional programs it regulates—sterol regulatory element-binding protein 1c, carbohydrate response element-binding protein, peroxisome proliferator-activated receptors, and AMP-activated protein kinase. At the same time, recent data point to the existence of a complex network of non-canonical regulators that, independently of insulin, significantly modulate hepatic lipid metabolism. This review systematizes information on the fibroblast growth factors FGF21 and FGF19, adipokines (adiponectin, leptin), apolipoprotein C-III, as well as the monoamine neurotransmitters serotonin and dopamine. These molecules act within the interorgan axes “liver–adipose tissue,” “gut–liver,” “brain–liver,” and “liver–spleen,” coordinating lipolysis, gluconeogenesis, very-low-density lipoprotein secretion, inflammation, and fibrogenesis. Disruption of the dynamic balance between canonical and non-canonical regulators is central to the progression from simple steatosis to steatohepatitis and fibrosis. The clinical translation of this concept has already begun: the thyroid hormone receptor β agonist resmetirom and the glucagon-like peptide-1 (GLP-1) receptor agonist semaglutide have received regulatory approval for specific categories of patients with noncirrhotic metabolic dysfunction-associated steatohepatitis and fibrosis, while FGF21 and FGF19 analogs, the dual glucose-dependent insulinotropic polypeptide (GIP)/GLP-1 agonist tirzepatide, and agents targeting apolipoprotein C-III are at various stages of clinical development or are being used for related metabolic indications. Expanding the insulin-centric paradigm to include non-canonical axes opens up new diagnostic and therapeutic possibilities for MASLD. Full article