Accumulation Model Research Articles

Predictive modeling of patulin accumulation in apple lesions infected by Penicillium expansum using machine learning

Penicillium expansum causes blue mold in fruit, leading to the accumulation of patulin, a harmful toxin. Current detection methods for patulin are costly and complex, highlighting the need for a simplified approach. This study investigates the impact of P. expansum on ‘Golden Delicious’ and ‘Fuji’ apples, focusing on significant changes in lesion characteristics and fruit properties. Correlation analysis revealed strong positive associations between patulin content and lesion diameter, lesion depth, and fruit weight loss, while negative correlations were observed with apple firmness and flesh firmness. Of the four machine learning models used - Back Propagation Neural Network (BPNN), Random Forest (RF), Extreme Gradient Boosting (XGBoost) and Gradient Boosting Regression Tree (GBRT) - all showed good predictive performance without overfitting the data. BPNN outperformed the others in accurately predicting patulin accumulation (Golden Delicious: RMSE=0.72, MAE=0.217, R²=0.982; Fuji: RMSE=0.289, MAE=0.08, R²=0.994). Key features influencing patulin accumulation, identified using SHapley Additive exPlanation (SHAP) measures, included lesion diameter, lesion depth, and fruit weight loss. This research highlights the potential of machine learning to predict patulin accumulation based on these critical factors, providing a simplified detection method for postharvest fruit quality management.

Origin of ice in the Medusae Fossae Formation, equatorial Mars

We assess and test the recent radar-sounding findings of huge, kms-thick quantities of ice along the equatorial region of Mars covered by a thick protective cap (the Medusae Fossae Formation (MFF); Watters et al., 2024), using 1) atmospheric general circulation models (GCMs), 2) glacial ice accumulation and flow models, and 3) models for ice ablation-induced accumulation residues. Our results indicate that under Hesperian-era conditions, Mars at ∼40° spin-axis obliquity is predicted to accumulate snow/ice in excess of a km in less than a few million years in the MFF region, producing cold-based glaciers with basal melting over <7% of the deposit. We find that subsequent ablation of this ice deposit surface in the several billion year-long Amazonian during periods of episodic eolian stripping of MFF protective sublimation residues and dust/tephra deposits, provides a mechanism sufficient to form the thick capping layer. Similar, shorter-duration obliquity excursions during this period may have also contributed additional ice-sublation residue layers, consistent with the complex stratigraphy of the MFF. On the basis of the estimated non-ice component of the MFF ice deposit, we suggest that ablation alone could have formed the cap unit in a minimum of ∼350 million years, but was likely to have been episodic, operating in concert with periods of eolian surface lag removal over a much longer time period. The tripartite subdivision of MFF stratigraphy could indicate major periods of Amazonian obliquity excursions that deposited and removed thinner layers of ice and sublimation residue. The very high abundance of non-esker-like fluvial channels in part of the Lower Member of the MFF, combined with the paucity of ice-sheet basal melting in our analysis, suggests that ablation processes were sometimes dominated by top-down ice heating, melting and fluvial runoff. In summary, our three-part modeling approach supports the new findings, and offers new dimensions for the further analysis of the enigmatic MFF.

A highly sensitive and specific fluorescent probe for detecting ONOO– in liver-injured cells and tissues

The liver is a vital organ in the human body that performs important physiological functions. During the damage process, the liver produces a large amount of ONOO–, which is difficult to directly capture and detect in the physiological environment. Therefore, this work introduced the design and synthesis of HN-ONOO, a novel naphthylimide-based fluorescent probe, aiming to dynamically monitor the changes of ONOO– during liver damage. HN-ONOO demonstrated a stable response to ONOO–, achieving quantitative detection. Since the high biocompatibility of HN-ONOO, we observed different degrees of up-regulation of ONOO– in the liver inflammation damage, alcohol damage, drug damage, fat accumulation model, and mice drug-damaged livers. These results suggest that HN-ONOO can recognize and detect the liver injury marker ONOO–. In addition, HN-ONOO, as a powerful tool for early detection of liver damage and detoxification research, provides a new approach for related research.

Hitting probabilities for fast stochastic search *

Many physical phenomena are modeled as stochastic searchers looking for targets. In these models, the probability that a searcher finds a particular target, its so-called hitting probability, is often of considerable interest. In this work we determine hitting probabilities for stochastic search processes conditioned on being faster than a random short time. Such times have been used to model stochastic resetting or stochastic inactivation. These results apply to any search process, diffusive or otherwise, whose unconditional short-time behavior can be adequately approximated, which we characterize for broad classes of stochastic search. We illustrate these results in several examples and show that the conditional hitting probabilities depend predominantly on the relative geodesic lengths between the initial position of the searcher and the targets. Finally, we apply these results to a canonical evidence accumulation model for decision making.

Non-decision time: The Higgs Boson of decision.

Generative models of decision now permeate all subfields of psychology, cognitive, and clinical neuroscience. To successfully investigate decision mechanisms from behavior, it is necessary to assume the presence of delays prior and after the decision process itself. However, directly observing this "non-decision time (NDT)" from behavior long appeared beyond reach, the field mainly relying on models to estimate it. Here, we propose a biological definition of decision that includes perceptual discrimination and action selection, and in turn, explicitly equates NDT with the minimum sensorimotor delay, or "deadtime." We show how this delay is directly observable in behavioral data, without modeling assumptions, using the visual interference approach. We apply this approach to 11 novel and archival data sets from humans and monkeys gathered from multiple labs. We validate the method by showing that visual properties (brightness, color, size) consistently affect empirically measured visuomotor deadtime (VMDT), as predicted by neurophysiology. We then show that endogenous factors (strategic slowing, attention) do not affect VMDT. Therefore, VMDT consistently satisfies widespread selective influence assumptions, in contrast to NDT parameters from model fits. Last, contrasting empirically observed VMDT with NDT estimates from the EZ, drift diffusion, and linear ballistic accumulator models, we conclude that NDT parameters from these models are unlikely to consistently reflect visuomotor delays, neither at a group level nor for individual differences, in contrast to a widely held assumption. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Temperature optimization model to inhibit zero-order kinetic reactions

Abstract Originally, the Arrhenius parameters were used to estimate the rate of chemical reactions. This article aims to develop the optimal temperature to inhibit specific zero-order kinetic reactions. The model extends the use of the Arrhenius equation and heat capacity modeling to derive the optimal temperature solution. Specifically, the Arrhenius equation, which connects temperature to reaction rates, and the heat equation are formulated to create a comprehensive heat accumulation model. Analytical modeling is utilized through a derivative process to provide optimization. According to a case study of carotene oxidation, the derivative solution proposes −1.73 °C and can extend the reaction time by 206,160.29 days compared to a solution with no temperature change. The derivative solution also offers higher advantages in practical application than setting the lowest temperature limit due to the high initial energy requirement. The temperature derivative solution exhibits a global optimum property because of its high heat accumulation and slower kinetic reactions. These slower kinetic reactions can prevent reactant substances from deteriorating, making them valuable for maintaining a chemical’s shelf life. The temperature solutions offer valuable insights for devising an effective temperature strategy to inhibit specific chemical processes and verifying the relationship between temperature and heat accumulation with curvature.

Stress proliferation in ethnoracial disparities of mental health among U.S. sexual minority adults.

Non-White sexual minorities experience disproportionate adverse childhood experiences (ACEs) and adulthood discrimination, as compared to their White or heterosexual counterparts. These stressors lead to increased psychological distress and worsened clinical outcomes, including suicidality. Minority stress theory posits that systemic marginalization, as experienced by minoritized individuals, leads to distress. Intersectionality theory suggests that marginalization compounds over time for individuals with intersectional minority identities. Yet, the mechanisms underlying the stress proliferation process for individuals with intersectional minority identities remain largely unexamined. The present study used nationally representative data of sexual minority individuals (n = 1,518, Mage = 31 years, ethnoracial minority = 38.7%, female and gender minority = 50.6%) to investigate the relations among ethnoracial minoritization, ACEs, discrimination, distress, and self-injurious/suicidal outcomes. We proposed a novel integration of minority stress, intersectionality, and stress proliferation theories. Via longitudinal mediation, we tested models of stress persistence, stress accumulation, and stress sensitization. Our results confirmed disparities between White versus non-White sexual minorities on ACEs, discrimination experiences, and psychological distress. We found support for the stress persistence and the stress accumulation models, but not the stress sensitization model. Moreover, we found distress and discrimination were associated with future nonsuicidal self-injurious behaviors and suicidal outcomes, highlighting the deleterious consequences of intersectional minority stress proliferation. Our results support our proposed theory of intersectional minority stress proliferation where ethnoracial and sexual minoritization intersect and beget disproportionate ACEs, which in turn contribute to accumulation and persistence of psychological distress and discrimination experiences in adulthood. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Increased accuracy of service life prediction for fiber metal laminates by consideration of the manufacturing-induced residual stress state

Fiber metal laminates (FML) combine the high specific properties of fiber-reinforced polymers with the ductility and damage tolerance of metals. However, during the manufacturing process of FMLs, in-plane residual stresses arise in the single layers of the laminate. The stresses mainly originate from the different coefficients of thermal expansion of the two materials and lead to an inhomogeneous stress state in the thickness direction of the laminate. This work investigates the influence of such thermal residual stress (TRS) on the fatigue life in an FML by experimentally varying the TRS in identical layups using modified cure cycles. The experimental investigations show that the amount of TRS directly influences the fatigue performance of such laminates. Reducing the TRS, particularly the tensile residual stresses in the metal layers, slows the fatigue crack growth during cyclic loading. This leads to a significantly delayed crack initiation and slower crack propagation. Knowledge of material behavior is essential for utilizing the full potential of structural health monitoring (SHM) in component lifetime predictions. Predictive models require a set of input parameters to perform this task. Since the TRS in an FML significantly contributes to the component's fatigue life, its consideration in predictive approaches is inevitable. This finding is discussed based on a phenomenological damage accumulation model initially developed for composite materials.

Hydrogen-Rich Water (HRW) Reduces Fatty Acid-Induced Lipid Accumulation and Oxidative Stress Damage through Activating AMP-Activated Protein Kinase in HepG2 Cells.

Metabolic dysfunction-associated steatotic liver disease (MASLD) is characterized by excessive fat accumulation in the liver. Intracellular oxidative stress induced by lipid accumulation leads to various hepatocellular injuries including fibrosis. However, no effective method for mitigating MASLD without substantial side effects currently exists. Molecular hydrogen (H2) has garnered attention due to its efficiency in neutralizing harmful reactive oxygen species (ROS) and its ability to penetrate cell membranes. Some clinical evidence suggests that H2 may alleviate fatty liver disease, but the precise molecular mechanisms, particularly the regulation of lipid droplet (LD) metabolism, remain unclear. This study utilized an in vitro model of hepatocyte lipid accumulation induced by free fatty acids (FFAs) to replicate MASLD in HepG2 cells. The results demonstrated a significant increase in LD accumulation due to elevated FFA levels. However, the addition of hydrogen-rich water (HRW) effectively reduced LD accumulation. HRW decreased the diameter of LDs and reduced lipid peroxidation and FFA-induced oxidative stress by activating the AMPK/Nrf2/HO-1 pathway. Overall, our findings suggest that HRW has potential as an adjunctive supplement in managing fatty liver disease by reducing LD accumulation and enhancing antioxidant pathways, presenting a novel strategy for impeding MASLD progression.

Cold hardiness-informed budbreak reveals role of freezing temperatures and daily fluctuation in a chill accumulation model.

Fundamental questions in bud dormancy remain, including what temperatures fulfill dormancy requirements (i.e. chill accumulation). Recent studies demonstrate freezing temperatures promote chill accumulation and cold hardiness influences time to budbreak-the phenotype used for dormancy evaluations. Here we evaluated bud cold hardiness and budbreak responses of grapevines (Vitis hybrids) throughout chill accumulation under three treatments: constant (5 °C), fluctuating (-3.5 to 6.5 °C daily), and field conditions (Madison, WI, USA). Chill treatments experiencing lower temperatures promoted greater gains in cold hardiness (field>fluctuating>constant). All treatments decreased observed time to budbreak with increased chill accumulation. However, perceived treatment effectiveness changed when time to budbreak was adjusted to remove cold acclimation effects. Among three classic chill models (North Carolina, Utah, and Dynamic), none was able to correctly describe adjusted time to budbreak responses to chill accumulation. Thus, a new model is proposed that expands the range of chill accumulation temperatures to include freezing temperatures and enhances chill accumulation under fluctuating temperature conditions. Most importantly, our analysis demonstrates that adjustments for uneven acclimation change the perceived effectiveness of chill treatments. Therefore, future work in bud dormancy would benefit from simultaneously evaluating cold hardiness.

Microfinance Services and Household’s Income among Saving and Internal Lending Community Groups in Evurore Ward, Embu County, Kenya

The research established loans, savings and training services effect on the income of household’s income among saving and internal lending community groups in Evurore Ward of Embu County, Kenya. Greeman Bank model, Saving-Asset Accumulation model and Village Saving Model served as theoretical base of the study. Descriptive design was implemented following a population of 562 SILC practicing group members in Evurore Ward where proportionate sampling technique was applied to arrive at 291 respondents. Primary data was sourced employing the utilization of structured questionnaire. The outcome unveiled a significant positive effect of microfinance loans on household’s income; the effect of microfinance savings on household’s income among SILC groups was not statistically significant but positive; microfinance training had a significant positive effect on household’s income among SILC groups in Evurore Ward, Embu County, Kenya. The survey recommends that to further enhance the income-generating potential of SILC groups, it is necessary to promote increased access to microfinance loans. This can be achieved by collaborating with microfinance institutions, NGOs, and government agencies to expand the availability of microfinance loan programs tailored to the needs of SILC groups in the area. Keywords: Microfinance Services, Microfinance Lending, Microfinance Training, Microfinance Savings, Household Income

Melt pool control-assisted additive manufacturing of thin-walled parts

Thin-walled aerospace components manufactured by laser directed energy deposition are susceptible to thermal accumulation effects owing to their deposition path and efficiency, further leading to the edge collapse. The melt pool width, as the carrier of thermal input, is an important geometric factor reflecting the state of the melt pool. Therefore, an in-situ melt pool control technique was proposed. The melt pool width as the control target was monitored using a coaxial camera, and the laser power was adjusted in real time based on the proportional-integral-derivative algorithm. A thermal accumulation model in conventional mode and a thermal suppression model in control mode were derived. The surface roughness, porosity, microstructure, and tensile properties of AISI 316 L stainless steel were compared between two modes. The results demonstrated that the roughness and porosity of thin-walled parts were respectively reduced by 45.3% and 82.7% after control. The periodic evolution of interlayer columnar and equiaxed crystals, and the increase in deformation twins contributed to a simultaneous increase in tensile strength and toughness, with a maximum increase of 35.7% in elongation.

Dynamic evolution of residual stress upon manufacturing Al-based diesel engine diaphragm

Abstract As a thin-walled complex structure, the manufacturing of Al-based diesel engine diaphragms involves casting and heat treatment. Residual stress is introduced during the uneven temperature field in casting and heat treatment, as well as the plastic deformation and cutting heat during mechanical processing. This research investigates the evolution and accumulation models of residual stress in casting and heat treatment for Al-based diesel engine diaphragms using ProCAST and ABAQUS software, combining with the experimental tests. To mitigate residual stress, the optimal parameter combination for casting temperature, knockout temperature, and mold preheating temperature in casting process is explored. The results indicate that the knockout temperature has the most significant influence on casting residual stress, and mold preheating is beneficial for reducing residual stress. Despite improvements, some internal stress concentration areas persist on the knockout casting surface. Furthermore, T6 heat treatment proves to be effective in eliminating more than 50% of the residual stress.

1592-P: Evaluating TRIB1 as a Genetic Driver of Fatty Liver Disease in an In Vitro Model of Carbohydrate-Mediated Lipid Accumulation

1592-P: Evaluating TRIB1 as a Genetic Driver of Fatty Liver Disease in an In Vitro Model of Carbohydrate-Mediated Lipid Accumulation

Left and right: a tale of two tails of the wealth distribution

We study a model of wealth accumulation in altruistic lineages, in which households face uninsurable risk, investment indivisibilities and borrowing constraints. A thick upper tail of the stationary distribution of wealth is shown to emerge as a robust prediction, irrespective of (1) the presence of multidimensional (wealth and ability) heterogeneity and non-convexities in human capital formation, and (2) the nature of parental bequest motives (joy-of-giving vs. paternalism). Additionally, (3) we identify conditions under which the unique, ergodic wealth distribution exhibits a mass point at the bottom of its support, where credit market imperfections continue to affect, along the convergence process, the structure of wealth transitions at the lineage level. Motivated by these results, we then analyze the sensitivity of the left tail to various frictions and fiscal instruments that affect bequest strategies and the ensuing transmission of wealth across generations. In particular, capital income or bequest taxes with no redistribution may reinforce economic mechanisms underpinning mobility traps in the left tail, thereby increasing the persistence of households in the lowest tiers of the wealth distribution.

Preliminary analysis of the indicators and accumulation models of gas hydrates in the central Zhongjiannan Basin, western South China sea

The Zhongjiannan Basin is located in the western continental margin of the South China Sea (SCS). It was recently reported that there are geophysical indicators of gas hydrates in the northern Zhongjiannan Basin. However, due to the lack of in-depth studies, it remains unknown whether geophysical indicators of gas hydrates are also available in the central and southern Zhongjiannan Basin. Based on the latest geophysical data, we have identified the seismic anomaly features of gas hydrates and observed an obvious bottom simulating reflector (BSR) in the seismic section in the central Zhongjiannan Basin. Based on a comprehensive analysis of seismic characteristics, geological structures (e.g., faults, diapirs and pockmarks) and regional sedimentary conditions, we propose three accumulation models of gas hydrates in the central Zhongjiannan Basin. The first model is that gas develops in deep depression areas, migrates upwards from deep source rocks along vertical faults and forms reservoirs in shallow formations. The second model is that gas also forms in deep depression areas and rises along mud diapirs or gas chimneys from source rocks to shallow formations, with reservoirs formed above diapirs and/or mud volcanoes. The third model is that gas is mainly generated in slope areas where strata are relatively thin and fault structures are well developed; gas migrates upwards from source rocks along vertical faults, and reservoirs are formed beneath pockmarks. The geophysical indicators of gas hydrates are found for the first time in the central Zhongjiannan Basin of the SCS, yielding an important reference for further exploration and development.

Mercury Accumulation Pathways in a Model Marine Microalgae: Sorption, Uptake, and Partition Kinetics.

The accumulation of dissolved mercury (Hg) by phytoplankton is the largest concentration step along aquatic food chains. However, the cell uptake mechanisms remain unclear. In this study, the marine haptophyteTisochrysis lutea, a model phytoplankton species, was examined for its interactions with picomolar levels of dissolved inorganic divalent Hg (iHg) and monomethyl Hg (MMHg). For both these Hg species, the study observed their successive sorption and internalization over time, yielding Hg partition coefficients as well as sorption, uptake, and release rates. These results were integrated into a time-dependent, three-compartment model for marine cellular Hg accumulation that included exposure medium, phycosphere, and internalized mercury. Assuming equilibria and pseudo-first-order kinetics between compartments, this study obtained transfer rates of Hg between compartments. The results provide insight into the phycosphere as an intermediate compartment for Hg species accumulation and quantify its role in the internalization of Hg. Ultimately, the new model and its parametrization were successfully applied to literature data showing Hg cellular accumulation in different groups of marine phytoplankton, lending confidence in its robustness and potential contributions to help model the uptake of Hg in the aquatic food web.

Spatiotemporal Simulation of Soil Pb Accumulation Process in Urban-Rural Areas: A Case Study of a Large City in Central China

The high intensity of diverse human activities in urban-rural areas leads to complex soil Pb accumulation processes and high spatiotemporal heterogeneity, making it difficult to reveal the spatiotemporal characteristics of soil Pb accumulation in these areas. This study used a typical urban-rural area in a large city in Central China as the study area, constructed a soil Pb accumulation model, and established a spatiotemporal simulation method for soil Pb accumulation processes combining this model and land use classification and simulation results. Using this method, we simulated the soil Pb content in the study area from 2013 to 2040 and elucidated the future spatiotemporal variation characteristics of soil Pb content. The results showed that the average soil Pb content in the study area in 2013 was approximately 1.77 times the background value of the Pb content in the surface soil of the province where the city is located, indicating significant soil Pb pollution. The soil Pb content was predicted to continue increasing from 2013 to 2040, with relatively low increases (0.53-2.25 mg·kg-1) in the western, northern, and southern parts of the study area, accounting for 25.46 % of the total area, and relatively high increases (3.98-5.70 mg·kg-1) in the eastern part, accounting for 17.14 % of the total area. The increase in the area of forest land and the decrease in the area of water bodies and grassland in the eastern part of the study area led to a substantial rise in soil Pb content in this region; in addition, the spatial distribution of soil Pb content was highly correlated with the distribution of important factories and transportation facilities. This study overcomes the limitations of previous research that treated land use as unchanging and to a certain extent reflects the impact of regional land use changes on the heavy metal accumulation process. It provides a method for simulating the soil Pb accumulation process in urban-rural areas and a basis for controlling soil Pb pollution in the city's urban-rural areas.

Main controlling factors and exploration enlightenment of aluminous rock series gas reservoirs in Ordos Basin, NW China

Based on the data of outcrop, core, logging, gas testing, and experiments, the natural gas accumulation and aluminous rock mineralization integrated research was adopted to analyze the controlling factors of aluminous rock series effective reservoirs in the Ordos Basin, NW China, as well as the configuration of coal-measure source rocks and aluminous rock series reservoirs. A natural gas accumulation model was constructed to evaluate the gas exploration potential of aluminous rock series under coal seam in the basin. The effective reservoirs of aluminous rock series in the Ordos Basin are composed of honeycomb-shaped bauxites with porous residual pisolitic and detrital structures, with the diasporite content of greater than 80% and dissolved pores as the main storage space. The bauxite reservoirs are formed under a model that planation controls the material supply, karst paleogeomorphology controls diagenesis, and land surface leaching improves reservoir quality. The hot humid climate and sea level changes in the Late Carboniferous–Early Permian dominated the development of a typical coal-aluminum-iron three-stage stratigraphic structure. The natural gas generated by the extensive hydrocarbon generation of coal-measure source rocks was accumulated in aluminous rock series under the coal seam, indicating a model of hydrocarbon accumulation under the source. During the Upper Carboniferous–Lower Permian, the relatively low-lying area on the edge of an ancient land or island in the North China landmass was developed. The gas reservoirs of aluminous rock series, which are clustered at multiple points in lenticular shape, are important new natural gas exploration fields with great potential in the Upper Paleozoic of North China Craton.

Determination of Permanent Deformations of Non-Cohesive Soils in Pavement Structures under Repeated Traffic Load

One of the main types of distress in pavement structures is rutting, which may also reduce serviceability significantly. Most design methods typically attribute rutting to the asphalt layer alone, proposing that it can be managed by controlling vertical deformation or stress at the subgrade’s top. Furthermore, these methods frequently lack precise measurements for rut depth. On-site measurements show that the majority of permanent deformation occurs in the unbound layers beneath the asphalt; attention should be directed towards these layers. In recent literature, there are calculation methods that account for accumulating strains in soils. However, further investigation is needed regarding the effect of soil properties and the significance of the pavement cross-section. The literature is also somewhat contractionary regarding the origin of permanent deformations. In this research, the residual settlement of soils (base, subbase, and subgrade) under flexible pavement systems was analyzed due to the repeated traffic loads. Rut depths were calculated and analyzed using the High-Cycle Accumulation (HCA) model. The different behaviour in each course of the pavement system is discussed to reveal their contribution to total ruts. The effect of the grain size distribution of the subgrade was analyzed, and its significance on the rutting depths was demonstrated. Standardized pavement cross-sections with different asphalt thicknesses were evaluated, and the calculated settlements of the pavement originating from the ground during the design lifetime are also presented. It is shown that, with the same number of repetitions, the settlements calculated in each traffic load class are proportional to the thickness of the asphalt course. The contribution of the base, subbase, and subgrade courses to the total settlement is also presented for different subgrade types and traffic load classes.