This article deals with optimal control applied to vaccination and treatment strategies for an SIRS epidemic model with logistic growth and delay. The delay is incorporated into the model in order to modeled the latent period or incubation period. The existence for the optimal control pair is also proved. Pontryagin’s maximum principle with delay is used to characterize these optimal controls. The optimality system is derived and then solved numerically using an algorithm based on the forward (...) and backward difference approximation. (shrink)

How much should the present generations sacrifice to reduce emissions today, in order to reduce the future harms of climate change? Within climate economics, debate on this question has been focused on so-called “ethical parameters” of social time preference and inequality aversion. We show that optimal climate policy similarly importantly depends on the future of the developing world. In particular, although global poverty is falling and the economic lives of the poor are improving worldwide, leading models of climate (...) economics may be too optimistic about two central predictions: future population growth in poor countries, and future convergence in total factor productivity (TFP). We report results of small modifications to a standard model: under plausible scenarios for high future population growth (especially in sub-Saharan Africa) and for low future TFP convergence, we find that optimal near-term carbon taxes could be substantially larger. (shrink)

Microbial systems biology has made enormous advances in relating microbial physiology to the underlying biochemistry and molecular biology. By meticulously studying model microorganisms, in particular Escherichia coli and Saccharomyces cerevisiae, increasingly comprehensive computational models predict metabolic fluxes, protein expression, and growth. The modeling rationale is that cells are constrained by a limited pool of resources that they allocate optimally to maximize fitness. As a consequence, the expression of particular proteins is at the expense of others, causing trade‐offs between (...) cellular objectives such as instantaneous growth, stress tolerance, and capacity to adapt to new environments. While current computational models are remarkably predictive for E. coli and S. cerevisiae when grown in laboratory environments, this may not hold for other growth conditions and other microorganisms. In this contribution, we therefore discuss the relationship between the instantaneous growth rate, limited resources, and long‐term fitness. We discuss uses and limitations of current computational models, in particular for rapidly changing and adverse environments, and propose to classify microbial growth strategies based on Grimes's CSR framework. (shrink)

Future population growth is uncertain and matters for climate policy: higher growth entails more emissions and means more people will be vulnerable to climate-related impacts. We show that how future population is valued importantly determines mitigation decisions. Using the Dynamic Integrated Climate-Economy model, we explore two approaches to valuing population: a discounted version of total utilitarianism (TU), which considers total wellbeing and is standard in social cost of carbon dioxide (SCC) models, and of average utilitarianism (AU), which (...) ignores population size and sums only each time period’s discounted average wellbeing. Under both approaches, as population increases the SCC increases, but optimal peak temperature decreases. The effect is larger under TU, because it responds to the fact that a larger population means climate change hurts more people: for example, in 2025, assuming the United Nations (UN)-high rather than UN-low population scenario entails an increase in the SCC of 85% under TU vs. 5% under AU. The difference in the SCC between the two population scenarios under TU is comparable to commonly debated decisions regarding time discounting. Additionally, we estimate the avoided mitigation costs implied by plausible reductions in population growth, finding that large near-term savings ($billions annually) occur under TU; savings under AU emerge in the more distant future. These savings are larger than spending shortfalls for human development policies that may lower fertility. Finally, we show that whether lowering population growth entails overall improvements in wellbeing—rather than merely cost savings—again depends on the ethical approach to valuing population. (shrink)

In this essay we develop and argue for the adoption of a more comprehensive model of research ethics than is included within current conceptions of responsible conduct of research (RCR). We argue that our model, which we label the ethical dimensions of scientific research (EDSR), is a more comprehensive approach to encouraging ethically responsible scientific research compared to the currently typically adopted approach in RCR training. This essay focuses on developing a pedagogical approach that enables scientists to better understand and (...) appreciate one important component of this model, what we call intrinsic ethics . Intrinsic ethical issues arise when values and ethical assumptions are embedded within scientific findings and analytical methods. Through a close examination of a case study and its application in teaching, namely, evaluation of climate change integrated assessment models, this paper develops a method and case for including intrinsic ethics within research ethics training to provide scientists with a comprehensive understanding and appreciation of the critical role of values and ethical choices in the production of research outcomes. (shrink)

Cloud computing (ClC) has become a more popular computer paradigm in the preceding few years. Quality of Service (QoS) is becoming a crucial issue in service alteration because of the rapid growth in the number of cloud services. When evaluating cloud service functioning using several performance measures, the issue becomes more complex and non-trivial. It is therefore quite difficult and crucial for consumers to choose the best cloud service. The user's choices are provided in a quantifiable manner in the (...) current methods for choosing cloud services. Hence, this study attempts to achieve this objective through construction. decision-making framework so-called cloud services evaluator (CSsEv). The main indicator and its sub-indicators are formed as nodes at levels(n) in tree soft sets (TSSs). Thereafter Single Value Neutrosophic Sets (SVNSs) as branch of neutrosophic sets which conjunction with the Multi-Criteria Decision Making (MCDM) technique to facilitate analysis and evaluation process for the available Cloud services providers. Hence, entropy is employed to obtain indicators and sub_indicators weights and Complex Proportional Assessment utilizes these weights to facilitate the decision process of selecting optimal ClSPs. (shrink)

The prevalence of optimality models in the literature of evolutionary biology is testimony to their popularity and importance. Evolutionary biologist R. C. Lewontin, whose criticisms of optimality models are considered here, reflects that "optimality arguments have become extremely popular in the last fifteen years, and at present represent the dominant mode of thought." Although optimality models have received little attention in the philosophical literature, these models are very interesting from a philosophical point of view. As will (...) be argued, optimality models are central to evolutionary thought, yet they are not readily accomodated by the traditional view of scientific theories. According to the traditional view, we would expect optimality models to employ general, empirical laws of nature, but they do not. Fortunately, the semantic view of scientific theories, a recent alternative to the traditional view, more readily accomodates optimality models. As we would expect on the semantic view, optimality models can be construed as specifications of ideal systems. These specifications may be used to describe empirical systems--that is, the specifications may have empirical instances. But the specifications are not empirical claims, much less general, empirical laws. Although philosophers have yet to discuss the general features and uses of optimality models, these topics have stimulated much recent discussion among evolutionary biologists. Their discussions raise a number of precautions concerning the proper use of optimality models. Moreover, many of their caveats can be interpreted as general reminders that 1) optimality models specify ideal systems whose empirical instantiations may be quite restricted, and that 2) optimality models should not be construed as general, empirical laws. As G. F. Oster and E. O. Wilson caution, "the prudent course is to regard optimality models as provisional guides to further empirical research and not necessarily as the key to deeper laws of nature." It seems, then, that the semantic view of theories is more sensitive to the nature and limitations of optimality models than is the more traditional view of theories. (shrink)

Tobacco is a significant product providing considerable economic benefits to countries worldwide, while its increased consumption causes health and socio-economic losses for smokers and non-smokers. This paper constructs a decomposition system of tobacco taxation: the population aging factor is included in the influencing factors of personal tax, and personal tax revenue is regarded as the product of tax structure, macro tax burden, regional economy, reciprocal aging, and the elderly population. This article conducts an empirical study on the relationship between taxation (...) and economic growth. The estimated coefficients of business tax and corporate income tax are significant at the significance level of 0.1, with a consumption tax and time-variable coefficients reporting a 0.02 level of significance. The T statistic value and the explanatory degree of the variables involved in the model to the explained variables are also very high, reaching more than 95%. We find that increasing the macro tax burden negatively impacts economic growth. Therefore, the study suggests that for fostering the industry’s economic growth, the country needs to ensure the optimal macro tax burden of 17.5%, with different types of taxes influencing economic growth. Personal tax reform should pay attention to the phenomenon of aging, adjust the tax structure to increase personal tax income, provide policy support and guarantee for the elderly labor force, and encourage the re-employment of silver-haired people to alleviate the adverse impact of aging on taxation. (shrink)

Combinatorial network optimization appears to fit well as a model of brain structure: connections in the brain are a critically constrained resource, hence their deployment in a wide range of cases is finely optimized to “‘save wire". This review focuses on minimization of large-scale costs, such as total volume for mammal dendrite and axon arbors and total wirelength for positioning of connected neural components such as roundworm ganglia (and also mammal cortex areas). Phenomena of good optimization raise questions about mechanisms (...) for their achievement: the examples of optimized neuroanatomy here turn out to include candidates for some of the most complex biological structures known to be derivable purely from simple physical energy minimization processes. Part of the functional role of such fine-tuned wiring optimization may be as a compact strategy for generating self-organizing complex neuroanatomical.. (shrink)

The study investigates the possibility of applying texture analysis (TA) for testing Duchenne Muscular Dystrophy (DMD) therapies. The work is based on the Golden Retriever Muscular Dystrophy (GRMD) canine model, in which 3 phases of canine growth and/or dystrophy development are identified: the first phase (0–4 months of age), the second phase (from over 4 to 6 months), and the third phase (from over 6 months to death). Two differentiation problems are posed: (i) the first phase vs. the second (...) phase and (ii) the second phase vs. the third phase. Textural features are derived from T2-weighted Magnetic Resonance Imaging (MRI) images. In total, 37 features provided by 8 different TA methods (statistical, filter-based, and model-based) have been tested. The work focuses on finding such textural features that evolve along with the dog’s growth. These features are indicated by means of statistical analyses and eliminated from further investigation, as they may disturb the correct assessment of response to treatment in dystrophy. The relative importance of each remaining feature is then assessed with the use of the Monte Carlo (MC) procedure. Furthermore, feature selection based on the MC procedure is employed to find the optimal subset of age-independent features. Finally, three classifiers are used for evaluating different sets of textural features: Adaptive Boosting (AB), back-propagation Neural Network (NN), and nonlinear Support Vector Machines (SVM). The best subsets of age-independent features ensure 80.0% and 78.5% of correctly identified phases of dystrophy progression, for the first (i) and second (ii) differentiation problem respectively. (shrink)

Growth modelling is of interest to scientists in various disciplines. In our article, we will collect 17 models designed for growth modelling, appraise these models and contribute to the discussion of their applicability. The merit of the paper lies in studying the convergence properties of nonlinear regression in selected models. Our studies will be performed mainly concerning the quality of the obtained estimates, which are closely related to the intrinsic curvature of the model according to (...) Bates and Watts. This curvature determines the size of the linearization domains. Only if the initial solution is in this domain, then the convergence of the estimate in nonlinear regression is guaranteed. The primary goal is to design a methodology for selecting a growth model. We will demonstrate fruitfulness of our methodology on the weight measurements of 10 calves under 25 months of age from cowsheds in the village Záluží in the Czech Republic. Estimated parameters of growth curves, sizes of linearization domain, calculated residues and coefficients of determination indices will be the subject of discussion. (shrink)

The hybridization of two or more energy sources into a single power station is one of the widely discussed solutions to address the demand and supply havoc generated by renewable production, heating power, and cooling power) and its energy storage issues. Hybrid energy sources work based on the complementary existence of renewable sources. The combined cooling, heating, and power is one of the significant systems and shows a profit from its low environmental impact, high energy efficiency, low economic investment, and (...) sustainability in the industry. This paper presents an economic model of a microgrid system containing the CCHP system and energy storage considering the energy coupling and conversion characteristics, the effective characteristics of each microsource, and energy storage unit is proposed. The random forest regression model was optimized by the gravitational search algorithm. The test results show that the GSA-RFR model improves prediction accuracy and reduces the generalization error. The detail of the MG network and the energy storage architecture connected to the other renewable energy sources is discussed. The mathematical formulation of energy coupling and energy flow of the MG network including wind turbines, photovoltaic, CCHP system, fuel cell, and energy storage devices are presented. The testing system has been analysed under load peak cutting and valley filling of energy utilization index, energy utilization rate, the heat pump, the natural gas consumption of the microgas turbine, and the energy storage unit. The energy efficiency costs were observed as 88.2% and 86.9% with heat pump and energy storage operation comparing with GSA-RFR-based operation costs as 93.2% and 93% in summer and winter season, respectively. The simulation results extended the rationality and economy of the proposed model. (shrink)

Lucio Baccaro and Jonas Pontusson make a significant contribution to comparative political economy with their approach to analyzing growth in advanced economies, which focuses on the demand side of the economy and distributive conflict. In contrast to Baccaro and Pontusson, however, we view their approach as reinforcing recent developments in varieties of capitalism rather than undermining them. We also believe that the type of modern macroeconomics used by Carlin and Soskice is better placed than their post-Keynesian framework to analyze (...) growth models, and that their approach is not inconsistent with it. Modern macroeconomic models incorporate, as they do not, a role for the state—including monetary and fiscal policy—and provide a coherent framework within which to analyze both the supply and demand sides of the economy; they also enable us to understand the interactions between economies and hence the role of growth models in global imbalances. (shrink)

In lieu of an abstract, here is a brief excerpt of the content:Foundations For Flow:A Philosophical Model For Studio InstructionKrista RiggsThe need for a new approach to studio instruction becomes evident when the current state of the profession and the effects of typical teaching methods are considered. In a profession with relatively little demand for a large supply of candidates for professional employment, realistically very few undergraduate music performance majors will achieve success as either orchestral players or as soloists. Extreme (...) competitiveness and the political hierarchy common in a typical music studio setting can squelch creativity and hinder a student's possibility to attain optimal experience in performance. Such an environment can pose a threat to a student's self-image and motivation, possibly becoming detrimental to the success of the student in any chosen occupation, whether ultimately within music or outside the profession.1As Roland Persson notes, studio teachers are generally hired primarily for their performance accomplishments and place in the historic lineage of their instrument's pedagogy without much regard for previous training in educational theories.2 With a lack of training in instructional methods or developmental theories, college music teachers tend to conduct lessons in the manner in which they were taught. Thus, little attention may be paid to individual differences or developmental issues.3 Studio instruction has also traditionally been approached [End Page 175] in a maestro-like, authoritarian manner with one-directional commands given as law from master teacher to seemingly subordinate students. Such a manner of teaching may contradict the tendency of creative individuals to show more deviant traits of critical and independent thought, possibly hindering the student's potential for artistic growth.4Many music students tend to gain much of their concept of self-worth based on how they perceive their musical ability to be assessed by their studio instructor.5 A dependency for approval can lead to the pursuit of unachievable perfection that can be detrimental to the emotional development and self-confidence of the student.6 A common focus on a final product in instruction rather than on the creative process of personal and artistic growth can also contribute to the detrimental setting of unrealistic goals and resulting lack of self-esteem in the student. Evaluation of artistically, intellectually, and emotionally developing students against an unattainable perceived aesthetic ideal or in comparison to other students of differing strengths and levels of development can hinder motivation while increasing anxiety, extreme competition, and negative emotional response in the learning experience.7 In a more personalized curriculum that centers on individual strengths and weaknesses through a mentoring approach, each student may be guided to develop the intellectual, emotional, physical, and spiritual faculties leading to optimal experience. From creative flow and the peak experiences of self-actualization comes intrinsic motivation for students to pursue creativity as a way of life, with further motivation to find moments for artistic expression and personal satisfaction in all aspects of their being.8A new model concerned with the development of the "whole" student as an individual can serve as a philosophical supplement to studio instructors who may not have received much training in developmental issues, educational theories, or related facets of the psychology of learning and performance. Although each aspect of the model can be considered separately, the potential of guiding a student toward the attainment of optimal experience is increased when all aspects are considered according to strengths and weaknesses present in the individual student. Incorporating the theories and ideas in studio instruction may help enhance a student's artistic and personal development while also strengthening a healthy mentoring relationship between teacher and student. While the model presents aspects of psychology alongside developmental and educational theories, the focus remains as a philosophical synthesis of diverse ideas into a unified system with flow at the center. Rather than aiming to deconstruct or refute opposing theories, the model synthesizes supporting ideas. As Estelle Jorgensen notes, the purpose of a synthesis-oriented or "synoptic" model is not so much to argue or refute contrasting views as it is to build upon the supporting theories and ideas of other writers. The "body of thought" serves an explanatory purpose [End Page 176] of the "clarification of terms and exposition... (shrink)

In this paper, we analyse the simplest possible three-dimensional model of endogenous growth to account for the relationship between financial intermediation and economic growth. In our setting, households maximize an interim utility function and firms maximize profit. Households can save money only through banks which offer firms investment loans. We show that under very general assumptions, investments realized by firms depend not only on savings accumulated by banks but also on financial intermediation technology ϕ(θ). Using mathematical methods of (...) dynamical systems, we found stationary states of the system and study their stability. (shrink)

Cluster growth models are utilized for a wide range of scientific and engineering applications, including modeling epidemics and the dynamics of liquid propagation in porous media. Invasion percolation is a stochastic branching process in which a network of sites is getting occupied that leads to the formation of clusters. The occupation of sites is governed by their resistance distribution; the invasion annexes the sites with the least resistance. An iterative cluster growth model is considered for computing the (...) expected size and perimeter of the growing cluster. A necessary ingredient of the model is the description of the mean perimeter as the function of the cluster size. We propose such a relationship for the site square lattice. The proposed model exhibits the expected phase transition of percolation models, i.e., it diverges at the percolation threshold p c. We describe an application for the porosimetry percolation model. The calculations of the cluster growth model compare well with simulation results. (shrink)

This article revisits the macroeconomic foundations and political economy of national growth models. It argues that the neo-Kaleckian model, which inspired the emergent growth model perspective and focuses primarily on the functional income distribution, can be usefully complemented by theories of private household consumption that focus on the personal distribution of income. The examples of the export-led and debt-led growth models of Germany and the United States, respectively, show how institutional differences help to explain why (...) different countries developed different patterns of income distribution and how income distribution and institutions interacted to generate financial imbalances in different sectors of the economy. (shrink)

Because of the important role which the ‘autocatalytic’ or ‘logistic’ equation has played in determining the direction of a good deal of research both in demography and in the study of individual growth phenomena, a critical and comparative evaluation of those leading ideas inRobertson's book which pertain to this equation and of some of the criticisms levelled against it seemed to be of interest. The present paper shows that, contrary to common belief,Robertson did not really assume that the autocatalytic (...) reactions to which he compared growth processes, took place in closed systems . On the other hand, he does not seem to have found a satisfactory representation of how the growth phenomena of the individual cells in an organism might interact to yield the overall growth of the organism as a whole. Nor is the manner in which he made his equation account for the openness of the individual cells free from possible criticism. An alternative equation is here proposed, which will be discussed in another paper. The properties of the solutions of this equation are such that the autocatalytic theory might never have gained a foothold if this, more realistic, equation would have been the object of the initial studies. (shrink)

This article concentrates on the critique by John Rawls and Derek Parfit of the use of a discount rate in economics. In a presentation of the basic economics underlying the use of a discount rate, the inherently problematic nature of people’s preferences with respect to time are highlighted. The second part discusses the role of the discount rate in economic optimal growth models. An outline of the economic theory of optimal growth is provided, pointing out (...) how Rawls’s analysis of justice between generations fits nicely into this economic discussion, thus explaining his interest in the discount rate. For Rawls the basic problem with the discount rate is that one variable is caught between two objectives: guaranteeing an efficient and at the same time a fair solution. Finally Derek Parfit’s analysis of the use of discount rates is examined. Parfit points out that a discount rate is often used as a crude rule of thumb which wrongly represents our reasons for discounting. The article concludes with a discussion of a study undertaken by a number of respected economists for the IPCC which exhibits all the mistakes that Parfit warns us against. (shrink)

Inequality of incomes is one of the significant factors forming the social capital. Two views dominate among economists dealing with the influence of inequality of income on economic growth. On the one hand, a too low inequality of income does not motivate people to increase the labour productivity. A low inequality of income might result from an extended social care system and overloading GDP with social transfers. A good example of it may be a situation when the unemployed refuses (...) to accept a job offer and prefers the unemployment benefit rather to a slightly higher salary. Moreover, a lack of incentives for the employee who fails to acknowledge the economic sense of increasing the productivity of his work might lead to the slower growth of economy. On the other hand, a contrary view suggests that an increase of the inequality of income has a negative impact on the economy. The accumulation of wealth by a small number of citizens raises doubts about good use of that wealth for investments necessary for the growth of the economy. An excessive inequality of income is confronted with disapproval of the significant part of society and regarded as unfair and unjustified. It may also increase the crime level and decrease the trust and, more generally, lead to the weakening of social capital. The arguments above lead to a hypothesis that the influence of the inequality of income on the growth of the economy has a non-linear character. We confirmed this hypothesis in growth models of the US and Swedish economies. We assess the historically optimal inequality of income measured by the Gini coefficient at 46% and 24% for the US and Sweden respectively. The optimal inequality of income in Poland was assessed previously at 29%. The dissimilarities may result from the cultural differences, educational level differences, ethnic differences and differences in diligence. (shrink)

This article argues that the quiet politics of informal business-state interaction explains the political determinants of growth regimes. Building on the business power literature within the study of comparative capitalism, it shows that the noisy politics of elections often leads to changes of government but rarely to fundamental changes in the growth regime. Rather, growth models can be traced to the interactions and interests of dominant corporations within a country and its policymaking elites. The argument is (...) developed through a comparative case study research design, using the case of foreign direct investment–led growth in Ireland and Hungary. FDI-led growth regimes are a universe of cases that rely on state-led industrial and enterprise policies targeting the capital investment of foreign-owned multinational firms. Despite periods of noisy electoral politics challenging basic tenets of the FDI-led growth model in both Hungary and Ireland, the continuity of FDI-oriented growth is traced to the corporate politics of business-state elite deals. (shrink)

Adopting deep approaches to learning can have a profound impact on learning outcomes. The extent of change in the learning approach could be attributed to the effect of contextual factors. After a substantive review, it was found that research interested in investigating the longitudinal effect of deep approaches to learning on learning outcomes were rarely directly concerned with the longitudinal state and trend of the approach itself. Moreover, the limitations of past analytical methods, has not been appropriately acknowledged. This study (...) examined deep approaches to learning in students from kindergarten to third grade using a multilevel structural equation modeling indicator-specific growth model. This was used to highlight the methodological issues to investigate the effect of context and the states, stability, and changes in deep approaches to learning over this developmental period. The current study comprised of a large-scale sample of 21,490 kindergarteners in kindergarten. Results showed: there was a contextual effect on the longitudinal changes of deep approaches to learning; deep approaches to learning was high but showed considerable individual differences; most indicators relating to deep approaches to learning declined, whereas the trend were relatively stable over time. Corresponding suggestions were proposed at the end of this article. (shrink)

This article challenges the general thesis that an unconditional basic income, set at the highest sustainable level, is required for maximizing the income-leisure opportunities of the least advantaged, when income varies according to the responsible factor of labor input. In a linear optimal taxation model (of a type suggested by Vandenbroucke 2001) in which opportunities depend only on individual productivity, adding the instrument of a uniform wage subsidy generates an array of undominated policies besides the basic income maximizing policy, (...) including a “zero basic income” policy which equalizes the post-tax wage rate. The choice among such undominated policies may be guided by distinct normative criteria which supplement the maximin objective in various ways. It is shown that most of these criteria will be compatible with, or actually select, the zero basic income policy and reject the basic income maximizing one. In view of the model's limited realism, the force of this main conclusion is discussed both in relation to Van Parijs' argument for basic income in Real Freedom for All (1995) and to some key empirical conditions in the real world. Footnotes1 I am grateful for useful comments on various stages of this paper by Marc Fleurbaey, Susan Hurley, Mathias Hild, Dirk Van de gaer, Frank Vandenbroucke, Alex Voorhoeve, Roland van der Veen, Andrew Williams, Chris Woodard and an anonymous referee. Above all I thank Loek Groot for his contribution. The research has also been supported by the Netherlands Organization for Scientific Research (NWO), and the Social and Political Theory Program of the Research School of Social Sciences, Australian National University. (shrink)

Optimal strategy, one of the main transit assignment models, can better demonstrate the flexibility for passengers using routes in a transit network. According to the basic optimal strategy model, passengers can board trains based on their frequency without any capacity limitation. In the metropolitan cities such as Beijing, Shanghai, and Hong Kong, morning commuters face huge transit problems. Especially for the metro system, there is heavy rush in metro stations. Owing to the limited train capacity, some passengers (...) cannot board the first coming train and need to wait for the next one. To better demonstrate the behavior of passengers pertaining to the limited train capacity, we consider capacity constraints for the basic optimal strategy model to represent the real situation. We have proposed a simulation-based algorithm to solve the model and apply it to the Beijing Subway to demonstrate the feasibility of the model. The application of the proposed approach has been demonstrated using the computational results for transit networks originating from practice. (shrink)

Individual zone of optimal functioning is a psychological model studied and applied to quantify athletes’ anxiety and predicts their achievement in sports competitions. This study aimed to determine the application of the IZOF model to evaluate music performance anxiety in pianists because the causes of anxiety in athletes and musicians may be similar. A total of 30 college-level piano-major students were included in the study, and the anxiety level in performance was scored by the Competitive State Anxiety Inventory-2 questionnaire. (...) In the first phase, participants recalled and self-scored the four important performances in the past year. Notably, seven piano teachers scored the performances. Both results were combined to identify the individual IZOF zone. Each student showed different anxiety scores for cognitive state anxiety, somatic state anxiety, and self-confidence. In the second phase, all participants scored their anxiety level 1 day before the final performance, and the same judges evaluated the performance immediately afterward. A total of 60% of the participants who had at least two subscales inside the IZOF received performance scores greater than 90. In conclusion, the IZOF model provides information for both piano teachers and pianists to help review their anxiety intensity and predict their performance scores to some extent. (shrink)

Based on the data of four periods of CLHLS, the latent variable growth model was applied to 2344 older adults who completed four follow-up surveys, to study the trajectory of leisure activities and cognitive ability and explore the relationship between leisure activities and cognitive ability of older adults. The results showed that: leisure activities and cognitive ability of older adults showed a non-linear downward trend; leisure activities significantly and positively predicted the cognitive ability of older adults at every time (...) point; the initial level of leisure activity positively predicted the initial level of cognitive ability but negatively predicted the rate of cognitive decline; In addition, cognitive activities had a greater effect on cognitive ability than non-exercise physical activities; the rate of decline of leisure activities also significantly and positively predicted the rate of decline of cognitive ability; cross-lagged regression analysis further suggested the overall positive predictive effect of leisure activity on cognitive ability; overall, education level had a significant contribution to cognitive ability, and the higher the education level, the slower the decline of cognitive ability; and smoking could promote cognitive ability in older adults and no significant effect was found between alcohol drinking and cognitive ability. Accordingly, the government should encourage older adults to do more leisure activities, especially the cognitive activity, to effectively prevent cognitive decline. (shrink)

This paper develops an analytical approach to comparative political economy that focuses on the relative importance of different components of aggregate demand—in the first instance, exports and household consumption—and dynamic relations among the “demand drivers” of growth. We illustrate this approach by comparing patterns of economic growth in Germany, Italy, Sweden, and the United Kingdom over the period 1994–2007. Our discussion emphasizes that export-led growth and consumption-led growth have different implications for distributive conflict.

General theoretical aspects are reviewed of models for microbial growth and endogenous metabolism. The focus is on a generic cell model with two components. Growth is represented as the increase of one of these components (the structural scaffolding or 'frame'). A novel feature of the present generic model is the explicit modelling of (partial) metabolic shutdown under conditions where maintenance requirements cannot be met.Two different approaches to mechanistic underpinnings for the classic models are outlined. The first (...) approach is based on a bimolecular reaction between the non-permanent biomass component and the permanent biomass component. The second approach is based on cellular control systems. (shrink)

We examine the comportment of the global trajectory of a piecewisely conceived single species population growth model. Formulation relies on what we develop as the principle of limiting factors for population growth, adapted from the law of the minimum of Liebig and the law of the tolerance of Shelford. The ensuing paradigm sets natality and mortality rates to express through extreme values of population growth determining factor. Dynamics through time occur over different growth phases. Transition points (...) are interpreted as thresholds of viability, starvation, and intraspecific competition. In this delivery, we focus on the qualitative study of the global trajectory expressed on continuous time and on exploring the feasibility of analytical results against data on populations growing under experimental or natural conditions. All study cases sustained fittings of high reproducibility both at empirical and interpretative slants. Possible phase configurations include regimes with multiple stable equilibria, sigmoidal growth, extinction, or stationarity. Here, we also outline that the associating discrete-time piecewise model composes the logistic map applied over a particular region of the phase configuration. Preliminary exploratory analysis suggests that the logistic map’s chaos onset could surpass once the orbit enters a contiguous phase region. (shrink)

Parameters of a Bertalanffy type of temperature dependent growth model are fitted using data from a population of stone loach ( Barbatula barbatula ). Over two periods respectively in 1990 and 2010 length data of this population has been collected at a lowland stream in the central part of the Netherlands. The estimation of the maximum length of a fully grown individual is given special attention because it is in fact found as the result of an extrapolation over a (...) large interval of the entire lifetime. It is concluded that this parameter should not at forehand be set at one fixed value for the population at that location due to varying conditions over the years. (shrink)

This article advocates for a hermeneutic model for children-AI interactions in which the desirable purpose of children’s interaction with artificial intelligence systems is children's growth. The article perceives AI systems with machine-learning components as having a recursive element when interacting with children. They can learn from an encounter with children and incorporate data from interaction, not only from prior programming. Given the purpose of growth and this recursive element of AI, the article argues for distinguishing the interpretation of (...) bias within the artificial intelligence ethics and responsible AI discourse. Interpreting bias as a preference and distinguishing between positive and negative bias is needed as this would serve children's healthy psychological and moral development. The human-centric AI discourse advocates for an alignment of capacities of humans and capabilities of machines by a focus both on the purpose of humans and on the purpose of machines for humans. The emphasis on mitigating negative biases through data protection, AI law, and certain value-sensitive design frameworks demonstrates that the purpose of the machine for humans is prioritized over the purpose of humans. These top–down frameworks often narrow down the purpose of machines to do-no-harm and they miss accounting for the bottom-up views and developmental needs of children. Therefore, applying a growth model for children-AI interactions that incorporates learning from negative AI-mediated biases and amplifying positive ones would positively benefit children’s development and children-centric AI innovation. Consequently, the article explores: What challenges arise from mitigating negative biases and amplifying positive biases in children-AI interactions and how can a growth model address these? To answer this, the article recommends applying a growth model in open AI co-creational spaces with and for children. In such spaces human–machine and human–human value alignment methods can be collectively applied in such a manner that children can become sensitized toward the effects of AI-mediated negative biases on themselves and others; enable children to appropriate and imbue top-down values of diversity, and non-discrimination with their meanings; enforce children’s right to identity and non-discrimination; guide children in developing an inclusive mindset; inform top-down normative AI frameworks by children’s bottom-up views; contribute to design criteria for children-centric AI. Applying such methods under a growth model in AI co-creational spaces with children could yield an inclusive co-evolution between responsible young humans in the loop and children-centric AI systems. (shrink)

The article points out the important contribution made by the concept of “growth models” to comparative political economy. It emphasizes Baccaro and Pontusson’s critique of the standard model of “varieties of capitalism.”.

The high levels of land use, inputs, and investment, along with the specific forms of organization and management that characterized Cuba's state extensive growth model during the 1980s, could not overcome the challenges posed by the integrated care required by the sugarcane crop and corresponding industrial activities. Starting in 1993, large state farms have been converted into Basic Units of Cooperative Production with some degree of autonomy. Although first-year production results are not satisfactory, it is too early to evaluate (...) their performance. Their establishment, however, is a step in the right direction to alleviate the problems that the previous forms of organization and management inherent to the state extensive growth model were unable to solve. (shrink)

In a recent paper, Potochnik (Biol Philos 24(2):183–197, 2009) analyses some uses of optimality modelling in light of the anti-adaptationism criticism. She distinguishes two broad classes of such uses (weak and strong) on the basis of assumptions held by biologists about the role and the importance of natural selection. This is an interesting proposal that could help in the epistemological characterisation of some biological practices. However, Potochnik’s distinction also rests on the assumption that all optimality modelling represent the selection dynamic (...) involved in the system of phenomena being considered. Since this assumption does not hold for models belonging to optimal foraging theory (OFT)—one of behavioural ecology’s important modelling traditions—Potochnik’s proposal has to be critically reappraised. In this paper, we briefly discuss what is optimality modelling and what it means for a model to represent a dynamic of selection or of evolution. Then, we demonstrate that OFT modelling is unable to represent either past or contemporary selection dynamics. In order to make this point, we carefully delineate the theory’s rationale. This allows us to identify and analyse the assumptions on which the theory is built, and to circumscribe precisely the role that natural selection plays in it. Next, we show that the distinction of weak and strong uses of optimality modelling is seriously weakened when OFT modelling is taken into account. More precisely, the distinction is either irrelevant (if the assumption that selection dynamics are represented in all optimality modelling is held) or of a modest utility (if the assumption is dropped). However, we suggest that Potochnik’s original proposal could be saved, and that it even constitutes a tool to appraise the marks left in the literature by the evolution of optimality modelling practices in the last four decades, provided that it is made into a tripartite distinction. (shrink)

We review how leaky competing accumulators (LCAs) can be used to model decision making in two‐alternative, forced‐choice tasks, and we show how they reduce to drift diffusion (DD) processes in special cases. As continuum limits of the sequential probability ratio test, DD processes are optimal in producing decisions of specified accuracy in the shortest possible time. Furthermore, the DD model can be used to derive a speed–accuracy trade‐off that optimizes reward rate for a restricted class of two alternative forced‐choice (...) decision tasks. We review findings that compare human performance with this benchmark, and we reveal both approximations to and deviations from optimality. We then discuss three potential sources of deviations from optimality at the psychological level—avoidance of errors, poor time estimation, and minimization of the cost of control—and review recent theoretical and empirical findings that address these possibilities. We also discuss the role of cognitive control in changing environments and in modulating exploitation and exploration. Finally, we consider physiological factors in which nonlinear dynamics may also contribute to deviations from optimality. (shrink)

The propensity account of fitness intends to solve the classical tautologicity issue by identifying fitness with a disposition, the ability to survive and reproduce. As proponents recognized early on, this account requires operational independence from actual reproductive success to avoid circularity and vacuousness charges. They suggested that operational independence is achieved by measuring fitness values through optimality models. Our goal in this article is to develop this suggestion. We show that one plausible procedure by which these independent operationalizations could (...) be thought to take place, and which is in accordance with what is said in the optimality literature, is unsound. We provide two independent lines of reasoning to show this. We then provide a sketch of a more adequate account of the role of optimality models in evolutionary contexts and draw some consequences. (shrink)

Against the scourge of the COVID-19 pandemic, college students’ learning engagement has become a key issue in universities and society. Guided by the theories of existential positive psychology and social perception, we explored the positive effect of a growth mindset on learning engagement during the COVID-19 pandemic. A total of 1,040 college students from universities in Henan Province of China effectively completed online questionnaires. The results showed that growth mindset was positively related to learning engagement and negatively associated (...) with perceived COVID-19 event strength and perceived stress; perceived COVID-19 event strength was positively related to perceived stress, while perceived COVID-19 event strength and perceived stress were negatively associated with learning engagement. Growth mindset affected learning engagement through three indirect paths: the mediating role of perceived COVID-19 event strength, the mediating role of perceived stress, and the serial mediating role of both perceived COVID-19 event strength and perceived stress. The results indicated that the growth mindset could contribute to college students’ learning engagement through the roles of perceived COVID-19 event strength and perceived stress during the COVID-19 pandemic. This study advances the understanding of the mechanism underlying the relationship between growth mindset and college students’ learning engagement during the COVID-19 pandemic. Furthermore, the findings of the study have important implications for promoting college students’ learning engagement during the pandemic. (shrink)

Bimanual robots have been studied for decades and regulation on internal force of the being held object by two manipulators becomes a research interest in recent years. In this paper, based on impedance model, a method to obtain the optimal target position for bimanual robots to hold an object is proposed. We introduce a cost function combining the errors of the force and the position and manage to minimize its value to gain the optimal coordinates for the robot (...) end effectors. To implement this method, two necessary algorithms are presented, which are the closed-loop inverse kinematics method to work out joint positions from desired EE pose and the generalized-momentum-based external force observer to measure the subjected force acting on the EE so as to properly compensate for the joint torques. To verify the effectiveness, practicality, and adaptivity of the proposed scheme, in the simulation, a bimanual robot system with three degrees of freedom in every manipulator was constructed and employed to hold an object, where the results are satisfactory. (shrink)