Competitive Model Research Articles

Improving biodegradability of dissolved organic matter (DOM) in old landfill leachate by electrochemical pretreatment: The effect mechanism of polarity

Enhancing the biodegradability of old landfill leachate is vital for the efficient treatment or resource utilization of municipal solid waste. Electrochemical pretreatment emerges as a promising technology for transformation of refractory dissolved organic matter (DOM). However, the specific impact of polarity on improving biodegradability of DOM remains unclear. In this study, a divided electrolyzer was used to explore the changes in the biodegradability of DOM in old landfill leachate during electrolysis. Meanwhile, the correlation mechanism between BOD5 variation and DOM evolution was explored by spectroscopy and Maldi-TOF-MS analysis. Results shown that different polarities all have positive effect on enhancing the biodegradability of DOM, while the structural changes related with BOD5 are depending on the polarity. In the anode chamber, electrochemical oxidation (EO) generates and eliminates carboxyl groups. Additionally, EO concurrently eliminates humic-like substances, which are challenging for microorganisms to degrade, and protein-like substances, which are easily degradable by microorganisms. This creates a competitive mechanism that coexist the promotion and inhibition for biodegradability. In the cathode chamber, electrochemical reduction (ER) transforms DOM components, accumulating easily useable protein components for microorganisms. Kinetic studies show that EO related BOD5 changes are aptly described by a competition model, considering both generation and removal of bioavailable components. ER related BOD5 changes suit a pseudo-first-order kinetic model. These insights into the transformation of old leachate DOM support the development of methods predicting BOD5 evolution, crucial for future process optimization.

Effect of radiation after surgery on the prognosis of children with Wilms tumor

Background To explore the association between radiation after surgery and the 5-year overall survival (OS) and 5-year cancer-specific survival (CSS) in patients with Wilms tumor. Methods In this cohort study, 1564 participants were identified from the Surveillance, Epidemiology, and End Results (SEER) database. The univariate and multivariable COX proportional risk model as well as competitive risk model were used to explore the covariates associated with 5-year OS and 5-year CSS of patients with Wilms tumor and the correlation between radiation after surgery and 5-year OS or 5-year CSS of patients with Wilms tumor, respectively. The Kaplan-Meier curves of participants were plotted. Results The median follow-up was 126.00 (84.00, 178.00) months. Patients receiving surgery had higher 5-year survival probability than those not receiving surgery, while participants receiving radiation after surgery showed poor 5-year survival than those not. After adjusting for covariates including age and SEER stage, increased risk of 5-year overall mortality in patients with Wilms tumor [hazard ratio (HR) = 1.62, 95% confidence interval (CI): 1.10–2.41). After the adjustment for confounding factors including age, SEER stage and ethnicity, increased risk of 5-year cancer-specific mortality of patients with Wilms tumor was observed in those receiving radiation after surgery (HR = 1.77, 95%CI: 1.13–2.79). Conclusion Radiation after surgery was associated with poor prognosis of patients with Wilms tumor, which indicated that the clinicians should assess whether the patient was suitable for using radiation after surgery.

Local Wisdom and Product Competition Model of MSMEs Rambutan Tangkue Based on Intellectual Property In Curugbitung Sub-District, Lebak District

Local wisdom is a view of life and also knowledge in which there are various life strategies which have a form of activity carried out by local communities which certainly helps to answer various problems, especially in meeting community needs. This research aims to determine the competition model in selling products for micro, small and medium enterprises in rambutan tangkue fruit, as well as to determine the concept of developing local wisdom (local wisdom), especially in micro, small and medium enterprise products for rambutan tangkue in Curugbitung District, Lebak Regency. This research uses qualitative methods with an empirical juridical approach. The data used includes primary data, secondary data and tertiary data. This research shows that the competition model for MSMEs rambutan tangkue products in Curugbitung District usually prioritizes cooperation with each other in achieving profits and superiority of rambutan tangkue fruit and the concept of developing local wisdom of rambutan tangkue fruit using the concept of production response, innovation-friendly processes and marketing strategies creative one.

Global attractor and its 1D and 2D structures of Beverton–Holt Ricker competition model

Beverton–Holt Ricker competition model is a planar difference system that describes intraspecific competition among individuals and interspecific competition. Known works investigated the stability of equilibria in some cases, showed the existence of stable 2-periodic points when there are no interior equilibria, and found numerically an attractor with riddled basin of attraction for some appropriate parameters. In this paper, we prove the existence of the global attractor, and give a complete description on qualitative properties and bifurcations of all equilibria except for some cases of high degeneracy. Moreover, we obtain different kinds of 1-dimensional or 2-dimensional structures of the global attractor, which were not considered in the known work.

Free-water: A promising structural biomarker for cognitive decline in aging and mild cognitive impairment

Abstract Diffusion MRI derived free-water (FW) metrics show promise in predicting cognitive impairment and decline in aging and Alzheimer’s disease (AD). FW is sensitive to subtle changes in brain microstructure, so it is possible these measures may be more sensitive than traditional structural neuroimaging biomarkers. In this study, we examined the associations among FW metrics (measured in the hippocampus and two AD signature meta-ROIs) with cognitive performance, and compared FW findings to those from more traditional neuroimaging biomarkers of AD. We leveraged data from a longitudinal cohort (nparticipants = 296, nobservations = 870, age at baseline: 73 ± 7 years, 40% mild cognitive impairment [MCI]) of older adults who underwent serial neuropsychological assessment (episodic memory, information processing speed, executive function, language, and visuospatial skills) and brain MRI over a maximum of four time points, including baseline (n = 284), 18-month (n = 246), 3-year (n = 215), and 5-year (n = 125) visits. The mean follow-up period was 2.8 ± 1.3 years. Structural MRI was used to quantify hippocampal volume, in addition to Schwarz and McEvoy AD Signatures. FW and FW-corrected fractional anisotropy (FAFWcorr) were quantified in the hippocampus (hippocampal FW) and the AD signature areas (SchwarzFW, McEvoyFW) from diffusion-weighted (dMRI) images using bi-tensor modeling (FW elimination and mapping method). Linear regression assessed the association of each biomarker with baseline cognitive performance. Additionally, linear mixed-effects regression assessed the association between baseline biomarker values and longitudinal cognitive performance. A subsequent competitive model analysis was conducted on both baseline and longitudinal data to determine how much additional variance in cognitive performance was explained by each biomarker compared to the covariate only model, which included age, sex, race/ethnicity, apolipoprotein-ε4 status, cognitive status, and modified Framingham Stroke Risk Profile scores. All analyses were corrected for multiple comparisons using an FDR procedure. Cross-sectional results indicate that hippocampal volume, hippocampal FW, Schwarz and McEvoy AD Signatures, and the SchwarzFW and McEvoyFW metrics are all significantly associated with memory performance. Baseline competitive model analyses showed that the McEvoy AD Signature and SchwarzFW explain the most unique variance beyond covariates for memory (ΔRadj2 = 3.47 ± 1.65%) and executive function (ΔRadj2 =2.43 ± 1.63%), respectively. Longitudinal models revealed that hippocampal FW explained substantial unique variance for memory performance (ΔRadj2 = 8.13 ± 1.25%), and outperformed all other biomarkers examined in predicting memory decline (pFDR = 1.95 x 10-11). This study shows that hippocampal FW is a sensitive biomarker for cognitive impairment and decline, and provides strong evidence for further exploration of this measure in aging and AD.

Regulating Digital Piracy Consumption

Regulators across the globe have imposed penalties on consumers for digital piracy consumption. Contrary to expectations, however, digital piracy consumption has continued to grow. The authors develop a simple model of competition between a copyright holder and a pirate firm to offer a plausible account for this observation as well as actionable guidelines for optimal regulation design. The core of this idea is to endogenize the pirate firm's strategic investment in antitracking technologies that help consumers evade a regulator's penalty. The authors find that as the penalty rises, piracy consumption can surprisingly increase after decreasing first; relatedly, the copyright holder and the society may suffer from tighter regulation. Depending on the cost of antitracking technologies of the pirate firm, the regulator optimally sets the penalty to operate in two different regimes. When the technology is available at a low cost, the regulator can achieve the goals of maximizing social welfare and minimizing piracy consumption simultaneously by setting a moderate penalty that maximizes consumers’ expected penalty and tolerates some level of piracy consumption. In contrast, when the technology is costly, the regulator should set a relatively high penalty to completely impede piracy supply. Additionally, the authors show that supply-side regulation does not substitute away demand-side regulation, and educating consumers about copyright protection may unintentionally lead to an increase in piracy consumption. Last, the authors identify complex nonmonotonic long-run effects of piracy consumption regulation on the copyright holder's incentives for content creation and copyright protection.

The new flexible generalized class of distributions with applications to different fields

We propose a new generator which has been used as a generalized class, and can also be helpful in generating new flexible generalized classes of distributions for continuous random variable. The newly proposed generator-cum-generalized class does not involve any extra parameter, and its functional form plays an important role along with baseline models to develop flexible models. In literature, such classes had been reported as Marshall-Olkin G-class, exponentiated G-class, Transmuted G-class, exponentiated generalized G-class, and Flexible G-class. So, any parent (or baseline) model can be substituted in the proposed class which has no extra burden on the parameters of the class. Some needful characteristics of the newly proposed class are obtained. Furthermore, a special model of the class, that is, the flexible Kumaraswamy distribution is considered and its properties are reported. The parameters estimation is dealt through the method of maximum likelihood, and a simulation is carried out to assess the performance of model’s parameters. Four real-life data sets are analyzed to show usefulness of the proposed model in comparison to some well-established competitive models. It is found that the proposed model yields low values of the goodness-of-fit statistics as compared to the other models, and hence our proposed model performed better as compared to others on these four data sets.

Local population dynamics of gray wolves Canis lupus and Eurasian lynx Lynx lynx exhibit consistency with intraspecific contest competition models

AbstractIn Europe, the gray wolf and Eurasian lynx populations are recovering after various levels of persecution. The two species differ in their social structure and spatial patterns of aggregation. Using model selection, we investigated the consistency of the available time series data on local wolf and lynx sub‐populations with a number of single‐species population growth models that pertain to two types of intraspecific competition, namely, scramble (SC) and contest competition (CC), and reflect random (R) or aggregated (A) distribution of individuals. The applied models of population growth—the Ricker (SCR), Skellam (CCR), Hassell (SCA), and Beverton–Holt (CCA) models—were all parameterized in terms of intrinsic growth rate and carrying capacity with unified definitions. The projected carrying capacity was allowed to show a temporal trend, which was justified by an observed increase in prey abundance in recent decades. For both species, the models pertaining to contest competition outperformed the scramble competition models, and the Beverton–Holt model had the greatest weight. However, for the lynx, the difference of performance between the scramble and contest competition models was considerably smaller than that for the wolves. In most of the models, when it was meaningful, an optional time lag operator was added to account for a delay in individual maturity and reproduction. However, the models with a time lag had a worse fit than the models without it. This study promotes the application of population models that reflect intraspecific competition for modeling population dynamics in a single‐ or multi‐species framework.

A Mathematical Model of Population Competition in a Polluted Area

Anthropogenic impact onthe environment leads toa change in the species structureof ecosystems. An external inhibitory effect on competing populations leads toa change in their numbers. One ofthe tasks of forecasting isthe theoretical study of the directions of population change. The paper develops a mathematical model of competitionbetween two populations, taking into account the changein the rate of population growth and the change in the capacity of the ecological niche. An assessmentof the directions of population changeis given. The model is representedby the Cauchy problem for a systemof ordinary differential equations.

Decisions and coordination in low-carbon supply chains with a wholesale price constraint under government subsidies

Motivated by the challenge of meeting carbon-conscious consumers and carbon regulations, this paper expounded on the decisions and coordination in low-carbon supply chains with a wholesale price constraint (WPC). The WPC is the behavior of large retailers (e.g., Walmart, Amazon, and E.Leclerc) that pursue a profit margin that does not fall below a certain level, which can affect supply chain operations. First, we develop a competition model, revealing that the WPC can result in a loss of total supply chain profit and a shortage in carbon emission reduction and then pose systematic challenges. Following this, we design a Nash bargaining-based cooperation model, showing that it can coordinate the supply chain and achieve a continuous allocation of optimal profits according to the bargaining power of firms. Lastly, our extended analysis incorporates the external influence of government subsidies for low-carbon technologies and designs the optimal subsidy mechanism. We demonstrate that, while government subsidies can reduce cost pressures on the supplier and provide incentives to reduce carbon emission, they can also induce the retailer to set a higher WPC for greater profitability, so the performance loss remains prominent. In this circumstance, we construct a Nash bargaining-based cooperation model that can coordinate the supply chain. Overall, our insights can help firms achieve scientific carbon emission reduction and formulate a reasonable WPC, as well as provide a quantitative basis for government carbon regulations.

Private ownership in monopolistic competition models

Motivated by empirical evidence, I study the properties of a monopolistic competition model with private ownership. Toward that goal, I consider a monopolistic competition model with additive preferences, homogeneous workers and homogeneous firms. I then introduce in such a standard framework a single additional ingredient: private ownership. Private ownership means that each firm is owned and managed by a single household called the entrepreneur, and this entrepreneur receives profits as sole revenues. In turn, private ownership changes the nature of entry. Free entry in the industry is no longer satisfied. Rather, the number of firms is now determined through occupational choice. Armed with this new framework, I provide a full characterization of a market equilibrium, and compare it to the standard model with collective ownership and free entry. Notably, I find new results concerning optimality, the transmission of aggregate shocks and the ability of the new model to replicate well-established empirical facts.

(Green) Strategic Orientation, Innovation Capabilities, and (Green) Competitive Advantage in the Coal Mining Industry

Despite its economic importance, the coal mining industry confronts significant environmental challenges. Indonesia prefers coal to renewables because of its lower cost. This study investigates the influence of green strategic orientation in promoting business model innovation and a green competitive advantage in the coal mining industry. The findings indicate that a green strategy orientation enhances green competitive advantage through innovation capability. Environmental and innovation capabilities are critical for successfully implementing business model innovation. This study identifies significant aspects that contribute to green competitive advantage and business model innovation. While the study offers useful insights, it has practical and managerial consequences for business sustainability in the coal mining industry.

A Cancer Subpopulation Competition Model Reveals Optimal Levels of Immune Response that Minimize Tumor Size.

Breast cancer is a complex disease with significant phenotypic heterogeneity of cells, even within a single breast tumor. Emerging evidence underscores the significance of intratumoral competition, which can serve as a key contributor to cancer drug resistance, imparting substantial clinical implications. Understanding the competitive dynamics is paramount as it can significantly influence disease progression and treatment outcomes. In the present work, a mathematical model was developed using a system of differential equations to describe the dynamic interactions between two cancer subtypes (each further classified into cancer stem cells and tumor cells) and innate immune cells. The purpose of the model is to comprehensively understand the competitive interactions between the heterogeneous subpopulations. The equilibrium points and stability analysis for each equilibrium point were established. Model simulations showed that the competition between two cancer subtypes directly affects the number of both species. When competition between two cancer subtypes is strong, increasing the immune response rate specific to the more competitive species effectively reduces the tumor size. However, if the competition is relatively weak, an optimal immune response rate is required to minimize the total number of tumor cells. Rates below the optimal level fail to reduce the population of the stronger species, whereas rates above the optimal level can lead to the recurrence of the weaker species. Overall, this model provides insights into breast cancer dynamics and guides the development of effective treatment strategies.

Convolutional neural networks optimization using multi-objective particle swarm optimization algorithm

This paper presents a heuristic-based convolutional neural network architecture optimization scheme (HeuCNN). First, CNN architectures are encoded as particles in optimization space with two objectives test error and number of parameters. Then, the effectiveness of CNN particles is represented by a heuristic in optimization space. It is mathematically proven and experimentally shown that the proposed heuristic assigns the best values for CNNs with higher performances. Uniform and nonuniform distribution of CNN particles in optimization space are analyzed and behavior of CNNs moving towards higher test error and higher number of parameters are also mathematically proven. CNN architecture search is proposed based on particle swarm optimization (PSO) by new algorithms for particle difference and velocity computation as well as particle update rules. Limitations of HeuCNN are explained and primary insights are presented to address its challenges as future works. Evaluation of HeuCNN on 9 publicly available datasets and comparing with 38 constant and optimized CNN peer competitive models reveal that HeuCNN achieves the best test error and the lowest number of parameters simultaneously. Source codes, data and software associated with this research will be available online after the publication of the paper.

Food policies: balancing health and market in the era of ubiquitous ultra-processed foods

As the development of modern food systems continues to reshape dietary habits, the need for effective food policies to counter the rise of ultra-processed foods (UPFs) becomes increasingly urgent. UPFs are industrial formulations of several highly refined ingredients and additives with little or no nutritional value but potentially harmful health effects. In this paper, we develop a simple model of duopolistic competition in which food manufacturers compete by choosing the degree of food sophistication of their products (i.e., the degree of food formulation and processing). We show that when firms compete for market shares, an unhealthy degree of food sophistication is a strategically stable Nash–Bertrand equilibrium outcome. Furthermore, we compare the effectiveness of alternative health-related food policies. Our model highlights the shortcomings of nutrient-to-limit regulations and suggests that policy interventions should prioritize whole-food reformulation-based approaches within an 'ecological' regulatory framework.

Developing an evaluation model for urban tourism competitiveness: combining community construction and community service to foster sustainable development of cities.

This study aims to develop a comprehensive evaluation model for urban tourism competitiveness in China. Given China's transition into a mature tourist destination, there is a pressing need for a framework that can assess the effectiveness of its urban tourism strategies. The model presented in this study is designed to provide a holistic understanding of the factors influencing urban tourism competitiveness in the Chinese context. The methodology employed in this study combines both qualitative and quantitative approaches. A modified version of Porter's Diamond Model serves as the primary framework, augmented by the IMD World Competitiveness Center: International Institute for Management Development (IMD) framework to incorporate social governance and environmental dimensions. To derive comprehensive scores for sustainable development, a linear weighted evaluation method was used, incorporating the coefficient of variation entropy weight method. This approach allows for a quantitative assessment of urban tourism competitiveness from 2008 to 2019. The key findings of the study reveal significant challenges within the current urban tourism landscape in China. These challenges include homogeneous competition, a lack of strategic management, and insufficient service quality. Furthermore, the study identifies the need for greater emphasis on sustainable tourism development, balancing economic benefits with the preservation of cultural and natural assets. Based on the findings, the study proposes several solutions to address the identified challenges. These solutions include creating boutique inland tourism routes, developing unique urban tourism brands, and enhancing regional cooperation and management practices. Additionally, the study emphasizes the importance of integrating community development and services into the evaluation model to foster sustainable tourism development. The proposed solutions offer actionable insights for policymakers and planners seeking to improve the competitiveness and sustainability of urban tourism in China.

Noninvasive brain stimulation to improve motor outcomes after stroke.

This review highlights recent developments in noninvasive brain stimulation (NIBS) techniques and applications for improving motor outcomes after stroke. Two promising areas of development relate to deep brain neuromodulation and the use of single-pulse transcranial magnetic stimulation (TMS) within a prediction tool for predicting upper limb outcome for individual patients. Systematic reviews highlight the inconsistent effect sizes of interventional NIBS for motor outcome after stroke, as well as limited evidence supporting the interhemispheric competition model. To improve the therapeutic efficacy of NIBS, studies have leveraged metaplasticity and priming approaches. Transcranial temporal interference stimulation (tTIS) and low-intensity focused ultrasound stimulation (LIFUS) are emerging NIBS techniques with potential for modulating deeper brain structures, which may hold promise for stroke neurorehabilitation. Additionally, motor evoked potential (MEP) status obtained with single-pulse TMS is a prognostic biomarker that could be used to tailor NIBS for individual patients. Trials of interventional NIBS to improve stroke outcomes may be improved by applying NIBS in a more targeted manner. This could be achieved by taking advantage of NIBS techniques that can be targeted to deeper brain structures, using biomarkers of structural and functional reserve to stratify patients, and recruiting patients in more homogeneous time windows.

The enigmatic life history of the bamboo explained as a strategy to arrest succession

AbstractBamboos are perennial woody grasses that display an enigmatic mix of traits. Bamboo is highly shade intolerant like early‐successional trees. Without secondary xylem, bamboos cannot continue to grow once they reach a maximum height or replace xylem damaged by hydraulic stress and must instead replace each stem after a few years using vegetative propagation via rhizomes. These traits of bamboo would appear to make them inferior to trees in competition for both light and water in all but early‐successional wet locations. However, some species competitively exclude trees and form persistent monodominant stands across large areas in tropical and temperate forests, including areas that are not mesic. Moreover, bamboo paradoxically postpones seed production for decades to over a century, and then flowers semelparously and dies synchronously. The delayed reproduction appears to be inconsistent with an early‐successional strategy to colonize disturbed areas as soon as they form, while the simultaneous death over large areas appears to be inconsistent with a late‐successional strategy to gain and hold space. Bamboo exhibits great diversity in its growth form and life histories along the tropical‐temperate geographical cline, with tropical bamboo being taller with shorter rhizome lengths and flowering interval lengths than temperate bamboo. We hypothesize that all of the above characteristics of bamboo are essential elements of competitive strategies to arrest succession in a lineage that lacks secondary xylem. To develop this Arrested Succession Hypothesis, we construct mathematical models of competition for recently disturbed areas between a tree species and a species with bamboo's enigmatic characteristics. We modeled the growth of bamboo genetic individuals from seedlings after seed germination to clonal culms at mass flowering and then placed these individuals in competition with one another and with trees in simple models of competition for light. Results explain how bamboo's traits allow it to persist in forests late in succession despite its hydraulic disadvantages, and form monodominant stands in the temperate zone, but not in tropical forests. They explain why bamboo is semelparous with synchronized reproduction, and why maximum culm size and age, reproductive interval, and rhizome length differ between the tropics and the temperate zone.

Do Protective Tariffs Influence Firms’ Competitive Stance? Application of a Competitive Leverage Model in The Presence of Simultaneous Equation and Sample Selectivity Bias

ABSTRACT: We propose a Competitive Leverage model, and apply it to analyze the impact of tariffs on the attitudes of domestic import-competing firms, especially regarding their disincentives to maintain a Competitive Stance against foreign competitors in the domestic market. We propose that tariffs are a disincentive to the pursuit and maintenance of production efficiency in firms and industries. When countries implement tariff protection for their domestic firms, the most common excuse sounds reasonable, except that it is also economically flawed. While the short-run impacts of such a measure might seem plausible, its long-term effects appear to be less than favorable, and may, in fact, turn out to be damaging to the economy. The paper applies the competitive leverage concept in a unique way to highlight how tariffs distort the output levels of domestic firms, and gives an empirical analysis of the model, using USA data to verify the predictions of the model. Particularly, we develop a Cournot-competition type Competitive Leverage model, and use it to examine the role played by tariffs as a disincentive to a typical firm’s pursuit and maintenance of production efficiency. The competitive leverage model is formulated and applied to verify the effects of tariff protection from the typical domestic firm’s strategic interaction standpoint. We further apply cross-sectional data to carry out an empirical analysis of the model, to verify how tariffs impact the domestic firm’s output and pricing decisions. Our findings would enable us to contribute to the debate about the need to remove protective tariffs, on the grounds that tariffs do not only enable domestic firms to operate inefficiently, but also tends to distort the output and pricing outcomes that would otherwise have been realized in the free market. The results from the study are used to propose some major policy implications of imposing tariff protection, among which are that there is need for implementation of more deliberately sustained Research and development program on the part of domestic firms in the economy, to enable them withstand vigorous competition in a free-trade world. Also, since protective tariffs significantly increase firms’ profit rates, which in turn enables them to unduly earn and accumulate economic rents that amount to inefficiencies and distortions in free-market prices and quantities outcomes, governments should always resist any pressures from big businesses to impose protective tariffs against competition from international rivals. Yet a clear public policy implication from this paper is that, at the macro level, as the results suggest that a government policy that aims at protecting domestic firms through imposition of tariffs may have an adverse effect on the firms’ competitive stance in the industry, a practical message is for the government to impose only a moderate tariff at the most, if it must, especially as it relates to agricultural products.

Transforming Advanced Practice RN Compensation: Strategies for Equity in Total Pay.

As the advanced practice RN (APRN) workforce rapidly expands, nursing leaders are grappling with the challenge of establishing equitable and competitive compensation models. This column explores the lessons learned by 2 pioneering APRN leaders who navigated these workforce and compensation challenges within their own healthcare organizations. By sharing their experiences building sustainable APRN infrastructure and addressing pay discrepancies, the authors provide valuable insights and strategies that can help other nursing leaders transform their APRN compensation approaches and ensure their advanced clinicians are appropriately valued and rewarded.