Optimality of a Linear Decision Rule in Discrete Time AK Model

Surprisingly, formal proof on the optimality of a linear decision rule in the discrete time AK model with a CRRA utility function has not been established in the growth literature while that in the continuous time counterpart is well-established. This note fills such a gap: I provide a formal proof that consumption being linearly related to investment is a sufficient and necessary condition for Pareto optimality in the discrete time AK model.

PROBABILISTIC APPROACH TO DETERMINING PRODUCTION FUNCTIONS

The article considers a probabilistic method for determining production functions. The method consists in finding the expected value of the function that determines the economic and mathematical principle of production. It is assumed that the factors of production and/or their specific values included in this function are random variables. It is shown that depending on the principle of production such averaging gives different probabilistic classes of production functions. Functions that are elements of the same class differ from each other in the probability distribution of the relations of production factors to their specific values. Two probabilistic classes of produc-tion functions are constructed. The first class is generated by the Leontief production principle, the second – by generalization of this principle for the case of partially or completely fungible factors of production. There are established the laws of probability distribution and the conditions, under which the linear combination of the AK-model and the Cobb-Douglas production function, as well as the CES production function, are elements of the class of Leontief production functions. It is shown that the linear production function belongs to the class of generalized Leontief production functions. The probability density functions of the products number for these two classes of pro-duction functions are found.

Teaching Arabic to Non-Native Speakers between Communication and Pragmatics:Qualitative Approach in Light of the Common European Framework of Reference for Teaching Foreign Languages

This research is qualitative in nature. It aims to investigate descriptively, analytically, and comparatively the modern AK model represented by the Sudan Open University Series, and the European framework, the common reference for Teaching Foreign Languages, to uncover what was achieved in them in terms of communication and language use. Accordingly, an integrated, multi-media approach has been adopted to enable the production and reception activities, and the spread of Arabic in vast areas of the world. Such a spread helps Arabic language to be in a hegemonic position with the other living languages. The study is based on getting benefit from human experiences and joint work in the field of teaching Arabic to non-Arabic speakers to meet the needs of learners. Such knowledge helps to overcome the pragmatic dimension dilemmas, and the duality between formal and colloquial, leading as a result to have a global recognition of its outputs. The study revealed the importance of building the communication and pragmatic capabilities of language learners since they both represent the life and vitality of language. It further necessitates rebuilding curricula and updating them in a way that makes communication and the use of language a reality. The research recommended eliminating any difficulties that face the Arabic language learner from the non-speakers, by making use of what was provided by the Common European Framework of Reference for Teaching Foreign Languages.

Biosorbent Prepared from Calotropis Gigantean Stems for Adsorption of Cu(II) Ions from Aqueous Solution

Calotropis gigantea stems (CGS) has the potential to use as biosorbent for adsorption of Cu(II) ions. In this study, the CGS biosorbent (CGSB) was prepared by drying and grounding. The effect of independent variables on adsorption capacity were investigated. As the result, the maximum adsorption capacity of 53.457 mg/g was obtained the optimal condition which was initial Cu(II) ions concentration of 567.47 mg/L, CGSB size of less than 230 mesh, CGSB mass of 1 g, temperature of 27 oC, pH 5, and contact time of 60 min. The CGSB surface morphology was analysed using SEM. The adsorption of Cu(II) ions fitted well with pseudo first-order adsorption kinetic (PFO-AK) model (R2=0.99), and the PFO-AK adsorption capacity and rate constant obtained were 70.194 mg/g and 0.0877 g/mg.min, respectively. The adsorption isotherm of Cu(II) ions was in accordance with Freundlich model (R2=0.99), and the intensity and volume constants attained were 0.876 and 1.017 L/mg, respectively. This result showed that physical adsorption occurred dominantly than chemical adsorption. The application of CGSB on the wastewater of initial Cu(II) ions concentration of 389.31 mg/L from ex-mine pool of acid mine drainage (AMD) in Jantang village, Lhoong District, Aceh Besar, Aceh Province resulted in adsorption capacity of 37.52 mg/g with adsorption efficiency of 66.13%.

The Theory of Growth

This chapter reviews the theory of growth. As motivation, it first discusses a range of related facts, including structural change and facts on the ‘new economy. It then launches into the Solow Growth Model (SMG) and related issues. The question of convergence, growth/development accounting, and the world income distribution are discussed next. The later part of the chapter discusses Endogenous Growth Theory(ies) (EGT). After offering an intuitive discussion of the limitations of SMG that EGT aims to rectify, the chapter reviews the AK model, including the processes that underpin it and its properties, and human capital, including its two-sector formulation. Newer EGT models are then reviewed, including models based on expanding product variety and those based on improving quality and product replacement (‘creative destruction’). The chapter concludes with evidence, the policy implications of EGT, and directions of current research.

3 Theoretical Analysis of Economic Growth

This chapter presents a theoretical analysis of economic growth. The first growth model in modern economics is arguably the Harrod–Domar growth model, named after Roy Harrod and Evsey Domar. Under this model, the major obstacle to economic growth is a lack of investment, which in turn is caused by a lack of capital. Therefore, the solution to poor growth is to somehow plug the savings gap by increasing domestic savings or foreign aid. Two other growth models that emphasize the importance of investment and capital accumulation were proposed by Nobel Laureate Arthur Lewis and Walt Rostow. The main thesis behind Lewis’s model is the idea of unlimited surplus of rural labor. Growth is therefore predicated on the increase in size of the industrial sector in the economy. Meanwhile, Rostow posits a five-stage evolutionary growth model. He argues that the key to moving from one stage to the next is the extension of the existing structure of production, which again requires investment in the capital stock. The chapter also looks at the Solow–Swan model, which is often regarded as the first modern growth model, as well as the endogenous growth models such as the AK model; the Lucas Human Capital model; the Romer Knowledge Spillover and Product Variety models; and the Schumpeterian growth models.

Diclofenac-Derived Hybrids for Treatment of Actinic Keratosis and Squamous Cell Carcinoma

In this work, hybrid compounds 1–4 obtained by conjugation of the non-steroidal anti-inflammatory drug diclofenac, with natural molecules endowed with antioxidant and antiproliferative activity were prepared. The antiproliferative activity of these hybrids was evaluated on immortalized human keratinocyte (HaCaT) cells stimulated with epidermal growth factor (EGF), an actinic keratosis (AK) model, and on human squamous cell carcinoma (SCC) cells (A431). Hybrid 1 presented the best activity in both cell models. Self-assembling surfactant nanomicelles have been chosen as the carrier to drive the hybrid 1 into the skin; the in vitro permeation through and penetration into pig ear skin have been evaluated. Among the nanostructured formulations tested, Nano3Hybrid20 showed a higher tendency of the hybrid 1 to be retained in the skin rather than permeating it, with a desirable topical and non-systemic action. On these bases, hybrid 1 may represent an attractive lead scaffold for the development of new treatments for AK and SCC.

ECONOMIC INTEGRATION AND ENDOGENOUS GROWTH: AN EXPLANATION USING AK MODEL

<p><strong>Abstract:</strong> This research investigates the impacts of economic integration on endogenous growth by an application of the AK learning-by-doing model. Assuming that the knowledge that increases the productivity of labor will be created by accumulated capital, we divide economic integration into two different categories: one-way and two-way integration. The results show that two identical countries cannot have any benefits from economic integration. If two countries are different, the domestic country should only integrate with foreign countries that have a lower cost of capital of wage, or higher learning coefficient (the speed of transferring accumulated capital to knowledge) in the case of one-way integration. The same conclusion is still drawn in the case of two-way integration for two similar countries.</p><p><strong>Keywords</strong>: economic integration, endogenous growth, AK model</p>