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Sohl, Timo, and Govert Vroom. "Organizational Impediments to Business Model Diversification." Academy of Management Proceedings 2016, no. 1 (January 2016): 11312. http://dx.doi.org/10.5465/ambpp.2016.11312abstract.
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Straub, Timothy J., and Olga Zhaxybayeva. "A null model for microbial diversification." Proceedings of the National Academy of Sciences 114, no. 27 (June 19, 2017): E5414—E5423. http://dx.doi.org/10.1073/pnas.1619993114.
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Whether prokaryotes (Bacteria and Archaea) are naturally organized into phenotypically and genetically cohesive units comparable to animal or plant species remains contested, frustrating attempts to estimate how many such units there might be, or to identify the ecological roles they play. Analyses of gene sequences in various closely related prokaryotic groups reveal that sequence diversity is typically organized into distinct clusters, and processes such as periodic selection and extensive recombination are understood to be drivers of cluster formation (“speciation”). However, observed patterns are rarely compared with those obtainable with simple null models of diversification under stochastic lineage birth and death and random genetic drift. Via a combination of simulations and analyses of core and phylogenetic marker genes, we show that patterns of diversity for the generaEscherichia,Neisseria, andBorreliaare generally indistinguishable from patterns arising under a null model. We suggest that caution should thus be taken in interpreting observed clustering as a result of selective evolutionary forces. Unknown forces do, however, appear to play a role inHelicobacter pylori, and some individual genes in all groups fail to conform to the null model. Taken together, we recommend the presented birth−death model as a null hypothesis in prokaryotic speciation studies. It is only when the real data are statistically different from the expectations under the null model that some speciation process should be invoked.
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Conybeare, John A. C. "A Portfolio Diversification Model of Alliances." Journal of Conflict Resolution 36, no. 1 (March 1992): 53–85. http://dx.doi.org/10.1177/0022002792036001003.
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Wimalasiri, Eranga M., Ebrahim Jahanshiri, Vimbayi Chimonyo, Sayed N. Azam-Ali, and Peter J. Gregory. "Crop model ideotyping for agricultural diversification." MethodsX 8 (2021): 101420. http://dx.doi.org/10.1016/j.mex.2021.101420.
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Zhang, Hua, Gongming Qian, Lee Li, and Zhengming Qian. "Intra- and inter-regional expansion: a nonlinear model." Management Decision 57, no. 7 (July 8, 2019): 1554–66. http://dx.doi.org/10.1108/md-04-2017-0359.
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Purpose The purpose of this paper is to differentiate between intra- and inter-regional diversification and explore how each affects firm performance. Existing studies show that both intra- and inter-regional expansion provide benefits and incur costs but the findings are mixed. This study aims to explain the mixed findings. Design/methodology/approach This study uses secondary data and quantitative methodologies to test hypotheses. Findings Using data from 663 Canadian firms over a six-year period (2006–2011), the authors find that the relationship between firm performance and the depth and width of intra-regional expansion is nonlinear. The authors also find a sigmoid-shaped relationship between firm performance and inter-regional diversification, i.e., performance initially increases with home regional diversification, decreases with bi-regional diversification and finally increases again with multi-regional diversification. Originality/value The findings of this study shed light on the current debate on the merits of inter- and intra-regional diversification and have important theoretical and managerial implications.
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Hroznyi, Ihor, Oleh Kuzmak, Olena Kuzmak, and Olha Rusinova. "Modeling of diversification of foreign economic interactions." Problems and Perspectives in Management 16, no. 1 (February 22, 2018): 155–65. http://dx.doi.org/10.21511/ppm.16(1).2018.15.
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The article developed a basic simulation model of diversification of foreign economic interactions, which makes it possible to assess the mutual influence of key economic indicators and their reaction to changes in the equilibrium in world markets. The peculiarity of the developed model of diversification of foreign economic interactions is its functioning as a complex dynamic system in which many factors are interrelated, and the connections are dynamic. This makes it possible to calculate a simulation model that takes into account hidden and subtle connections. While modeling foreign economic interactions and evaluating the influence of various regulators on them, in addition to the stage of model development itself, mandatory parameterization of this model is proposed, that is, the determination of specific types of dependence between the factors included in the model and the parameters of these dependencies. The implementation of this model can be carried out in any simulation package.
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Ganzarain, Jaione, and Nekane Errasti. "Three stage maturity model in SME’s toward industry 4.0." Journal of Industrial Engineering and Management 9, no. 5 (December 20, 2016): 1119. http://dx.doi.org/10.3926/jiem.2073.
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Purpose: To address the challenges regarding the concept of Industry 4.0 and the diversification methodology and based on the strategic guidance towards Industry 4.0, we propose a process model as a guiding framework for Industry 4.0 collaborative diversification vision, strategy and action building. In this paper we suggest a stage process model to guide and train companies to identify new opportunities for diversification within Industry 4.0. Systematically carrying out the stages will take a company to their individual specific vision and collaborative vision between different companies in the Industry 4.0 scenario.Design/methodology/approach: This new collaborative diversification methodology involves industry within the pilot program; from the diversification and capacity assessment analysis of the company`s profile, skills and technologies that dominates, to identify the diversification opportunity map and its business modeling within the Industry 4.0 paradigm.Findings: The application of maturity models to the Industry 4.0 may help organizations to integrate this methodology into their culture. Results show a real need for guided support in developing a company-specific Industry 4.0 vision and specific project planning.Originality/value: Industry 4.0 promotes a vision where recent developments in information technology are expected to enable entirely new forms of cooperative engineering and manufacturing. The vision of industry 4.0 describes a whole new approach to business operations, and especially the production industries. To address the challenges regarding the concept of Industry 4.0 and the diversification methodology discussed above, and based on the strategic guidance towards Industry 4.0, we propose a unique process model as a guiding framework for Industry 4.0 collaborative diversification vision, strategy and action building.
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Griswold, Cortland K. "Epistasis can accelerate adaptive diversification in haploid asexual populations." Proceedings of the Royal Society B: Biological Sciences 282, no. 1802 (March 7, 2015): 20142648. http://dx.doi.org/10.1098/rspb.2014.2648.
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A fundamental goal of the biological sciences is to determine processes that facilitate the evolution of diversity. These processes can be separated into ecological, physiological, developmental and genetic. An ecological process that facilitates diversification is frequency-dependent selection caused by competition. Models of frequency-dependent adaptive diversification have generally assumed a genetic basis of phenotype that is non-epistatic. Here, we present a model that indicates diversification is accelerated by an epistatic basis of phenotype in combination with a competition model that invokes frequency-dependent selection. Our model makes use of a genealogical model of epistasis and insights into the effects of balancing selection on the genealogical structure of a population to understand how epistasis can facilitate diversification. The finding that epistasis facilitates diversification may be informative with respect to empirical results that indicate an epistatic basis of phenotype in experimental bacterial populations that experienced adaptive diversification.
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Hautmann, Michael. "Diversification and diversity partitioning." Paleobiology 40, no. 2 (2014): 162–76. http://dx.doi.org/10.1666/13041.
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Model calculations predict that pathways of alpha- and beta-diversity in diversifying ecosystems notably differ depending on the relative role of competition, predation, positive effects of species' interactions, and environmental parameters. Four scenarios are discussed, in which alpha- and beta-diversity are modeled as a function of increasing gamma-diversity. The graphic illustration of this approach is herein called α-β-γ plot, in which the x-axis indicates increasing diversification rather than absolute time. In purely environmentally controlled systems, beta-diversity maintains near-maximum values throughout the diversification interval, whereas mean alpha-diversity increases linearly, with a slope being reciprocal to beta-diversity. A second scenario is based on the assumption that increasing richness will have predominantly positive effects on the addition of further species; here, alpha- and beta-diversity increase simultaneously (though not necessarily at the same rates) and without reaching a predictable upper limit. In ecosystems that are characterized by low competition between species, mean alpha-diversity asymptotically approaches a saturation level, whereas the increase in beta-diversity accelerates until alpha-diversity stagnates, and then continues to rise linearly. If competition is high, addition of species first increases beta-diversity until no further habitat contraction is possible, followed by a period in which alpha-diversity increase through adaptive divergence becomes the principal drive of diversification. Because there is a continuous transition between the late stage of the low-competition model and the early stage of the high-competition scenario, both can be combined in a single model of diversity partitioning under the premise of a diversity-dependent increase of competition. This summary model predicts three phases of diversity accumulation: (1) a niche overlap phase, (2) a habitat contraction phase, and (3) a niche differentiation phase. The models herein discussed provide a potential tool to assess the question which factors primary controlled the diversification of life over geological times.
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Koren, Miklós, and Silvana Tenreyro. "Technological Diversification." American Economic Review 103, no. 1 (February 1, 2013): 378–414. http://dx.doi.org/10.1257/aer.103.1.378.
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Economies at early stages of development are frequently shaken by large changes in growth rates, whereas advanced economies tend to experience relatively stable growth rates. To explain this pattern, we propose a model of technological diversification. Production makes use of input-varieties that are subject to imperfectly correlated shocks. Endogenous variety adoption by firms raises average productivity and provides diversification benefits against variety-specific shocks. Firm-level and aggregate volatility thus decline as a by-product of the development process. We quantitatively assess the model's predictions and find that it can generate patterns of volatility and development consistent with the data. (JEL D21, D24, E23, O33, O47)
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Orlova, E. V. "Mechanism and model of credit portfolio diversification." Issues of Risk Analysis 17, no. 1 (February 27, 2020): 78–89. http://dx.doi.org/10.32686/1812-5220-2020-17-1-78-89.
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Under conditions of demand for credit resources growing in Russian economy the importance of credit risks assessment and their influence on the credit organizations efficiency is increased. Empirical studies show that credit risks in the banking today are increasing nonlinearly relative to the main characteristics of the credit — the level of credit risk, credit terms, interest rate. Therefore, the formation of the most acceptable from the point of view of risk reducing of the bank’s credit portfolio is a scientifically based and practically important problem. The aim of the work is to justify the need for and develop a new mechanism for managing the bank's credit portfolio, ensuring its diversification and reduction of credit risks. The materials of the study were the statistical data of the Bank of Russia and Rosstat. Methods used in the work are: system analysis, control theory, statistical data processing and operational research. A mechanism for managing the quality of a bank credit portfolio is proposed, featuring a combination of quantitative and qualitative criteria for assessing the quality of the credit portfolio and allow to monitor of the credit portfolio, to make decisions on approving or rejecting a credit application in accordance with the permissible values of risk factors. A model has been developed for optimizing the structure of the credit portfolio, which makes it possible to form an optimal ratio of long-term and short-term credits, ensuring the maximum yield of the credit portfolio taking into account credit risk in the context of various credit policy types. A practical importance of the investigation are the positive results of the implementation of the proposed mechanism and model of credit portfolio management into the credit organization, ensuring the growth of its profitability and promoting an increase in competitiveness.
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Khan, Hina A., and Mohamed A. Sharaf. "Model-Based Diversification for Sequential Exploratory Queries." Data Science and Engineering 2, no. 2 (March 27, 2017): 151–68. http://dx.doi.org/10.1007/s41019-017-0038-0.
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Okanga, B., and A. Drotskie. "A transformational leadership model for managing change and transformation linked to diversification investments." Southern African Business Review 20, no. 1 (March 27, 2019): 414–45. http://dx.doi.org/10.25159/1998-8125/6058.
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Owing to its relationship with change and transformation, transformational leadership theory should be relevant to managing change and transformation linked to diversification investments. However, the question of what model of transformational leadership would be appropriate for managing change and transformation linked to diversification investments has not been addressed. The purpose of this research was to explore managers’ perceptions of the links between transformational leadership and diversification strategies. Using a qualitative research method, this study provides a critical analysis of the transformational leadership theories and triangulation with the behaviours of 30 purposively sampled managers from ten firms involved in different diversification activities. The aim of this was to determine the most appropriate transformational leadership model for managing change and transformation linked to diversification investments. Besides the degree of industry predictability and certainty, the findings echoed the reasoning in the full-range transformational leadership theory that a continuum of transformational-transactional leadership behaviours enhances effective management of diversification-related changes and transformation. However, no similar transformational leadership model was found to have been adopted by prior studies or enterprises engaged in different diversification activities. The study should fi ll this gap by identifying a new transformational leadership theory that links the full-range transformational leadership theory to Ansoff’s model for diversification and growth improvement strategies.
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Chalmandrier, Loïc, Camille Albouy, Patrice Descombes, Brody Sandel, Soren Faurby, Jens-Christian Svenning, Niklaus E. Zimmermann, and Loïc Pellissier. "Comparing spatial diversification and meta-population models in the Indo-Australian Archipelago." Royal Society Open Science 5, no. 3 (March 2018): 171366. http://dx.doi.org/10.1098/rsos.171366.
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Reconstructing the processes that have shaped the emergence of biodiversity gradients is critical to understand the dynamics of diversification of life on Earth. Islands have traditionally been used as model systems to unravel the processes shaping biological diversity. MacArthur and Wilson's island biogeographic model predicts diversity to be based on dynamic interactions between colonization and extinction rates, while treating islands themselves as geologically static entities. The current spatial configuration of islands should influence meta-population dynamics, but long-term geological changes within archipelagos are also expected to have shaped island biodiversity, in part by driving diversification. Here, we compare two mechanistic models providing inferences on species richness at a biogeographic scale: a mechanistic spatial-temporal model of species diversification and a spatial meta-population model. While the meta-population model operates over a static landscape, the diversification model is driven by changes in the size and spatial configuration of islands through time. We compare the inferences of both models to floristic diversity patterns among land patches of the Indo-Australian Archipelago. Simulation results from the diversification model better matched observed diversity than a meta-population model constrained only by the contemporary landscape. The diversification model suggests that the dynamic re-positioning of islands promoting land disconnection and reconnection induced an accumulation of particularly high species diversity on Borneo, which is central within the island network. By contrast, the meta-population model predicts a higher diversity on the mainlands, which is less compatible with empirical data. Our analyses highlight that, by comparing models with contrasting assumptions, we can pinpoint the processes that are most compatible with extant biodiversity patterns.
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Karkowska, Renata. "Model of Risk Diversification in the Banking Sector." Folia Oeconomica Stetinensia 19, no. 1 (June 1, 2019): 31–42. http://dx.doi.org/10.2478/foli-2019-0003.
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Abstract Research background: Motivation for this study is the rapid development of conglomerate banking stimulated by the synergy between the traditional and parallel investment activity of banks before the 2007–2008 financial crisis. Existing studies do not answer the question about the positive influence of diversification on bank stability. They state that the combination of lending and non-interest income allows benefits to be derived from risk diversification. However, on the other hand they emphasise that non-interest and interest incomes are strongly correlated, which does not bring positive effects from diversification. Purpose: Scientific problem aimed to be solved is to verify how the diversification of activities in commercial banks into non-interest products (i.e. trading, securities-based investment activities, and derivatives) brings positive effects such as income stabilization and risk reduction. We examine the implications of banks’ risk adjusted ROA that manifest themselves as spreading and growing instability. Research methodology: We use a panel regression model, through a dataset that covers 777 international banks, in 91 selected countries of the world, spanning the period of 1996–2015. Results: We document that the diversification of a bank’s operations is varied and depends on a bank’s characteristics, including asset size. Novelty: The study contributes to the on-going discussion on the separation of retail and investment banks with a view to enhancing their profit stability.
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Smith, Garrett C. C., and Jeffrey M. Coy. "Corporate diversification." Review of Accounting and Finance 17, no. 3 (August 13, 2018): 405–24. http://dx.doi.org/10.1108/raf-11-2016-0172.
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Purpose The purpose of this study is to compare two theories that relate the proportion of diversified firms in the economy and the implied discount for diversified firms: the first is a real-options model predicting a positive relationship between the discount and management’s choice to operate a diversified firm; the second is based on catering theory, in which a negative relationship is predicted, as management is attentive to investor preference concerning diversified firms. Design/methodology/approach This study proposes a new aggregate measure of the diversification discount. The authors’ measure allows for decomposition of the discount into firm-level mispricing, industry-level mispricing and long-run fundamental value components. Findings Results support a catering theory of diversification. The discount appears to be the result of firm-level mispricing. Thus, providing an explanation for why, in light of the observed discount, a large number of diversified firms persist. Originality/value To the authors’ knowledge, this is the first study to provide evidence that firm-level mispricing may drive the observed diversification discount.
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Cieślik, Andrzej. "Export Diversification Curve in Light of the Ricardian Model." Gospodarka Narodowa 288, no. 2 (April 30, 2017): 5–27. http://dx.doi.org/10.33119/gn/100724.
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Mammen, Jan. "Wealth creation through corporate diversification – the bondholders’ perspective." Investment Management and Financial Innovations 17, no. 4 (November 10, 2020): 94–101. http://dx.doi.org/10.21511/imfi.17(4).2020.09.
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The influence of corporate diversification on firm value is an important field in strategy research. Studies in strategic management and finance research have analyzed value creation through product and geographic diversification from a shareholder’s perspective. This study completes this picture by analyzing the bondholders’ perspective. It is suggested that product diversification creates value for bondholders, while geographic diversification destroys bondholder value. The hypotheses are tested on a sample of S&P 1,200 firms in 2001–2011 using a fixed-effects panel model. Drawing on prior research, bondholder value creation is measured using the Merton model. The empirical results support the hypothesis that bondholders gain value through product diversification but lose value through geographic diversification. Considering prior research results, these results show that product diversification is preferable for bondholders, while geographic diversification is preferable from a shareholder’s perspective. The opposite effects of both diversification strategies on shareholders, respectively, bondholders offer an important new perspective on corporate diversification. The results show that firms with a high level of corporate debt should struggle to justify a strategy involving geographic dispersion of activities and support a more diversified product portfolio strategy. This study also offers several avenues for investigating the bondholder’s perspective on corporate diversification in more detail.
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ANTONCIC, BOSTJAN. "IMPACTS OF DIVERSIFICATION AND CORPORATE ENTREPRENEURSHIP STRATEGY MAKING ON GROWTH AND PROFITABILITY: A NORMATIVE MODEL." Journal of Enterprising Culture 14, no. 01 (March 2006): 49–63. http://dx.doi.org/10.1142/s0218495806000040.
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Diversification strategy is an important driver of organizational conduct and performance. Despite its recognized linkage to other strategy-making elements, such as corporate entrepreneurship, research has devoted minimal attention to explicitly investigating relationships among diversification, corporate entrepreneurship and performance elements. This study contributes to a better understanding of diversification strategy driven corporate entrepreneurship and performance by testing a normative model on a sample of 449 Slovenian firms. The findings demonstrate that single business and vertical diversification make some difference in organizational growth and profitability in terms of their direct effects, but not indirectly with the mediation of corporate entrepreneurship strategy-making elements, which can be independently of diversification important for performance improvement.
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Heller, Yuval. "Overconfidence and Diversification." American Economic Journal: Microeconomics 6, no. 1 (February 1, 2014): 134–53. http://dx.doi.org/10.1257/mic.6.1.134.
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Experimental evidence suggests that people tend to be overconfident in the sense that they overestimate the accuracy of their private information. In this paper, we show that risk-averse principals might prefer overconfident agents in various strategic interactions because these agents help diversify the aggregate risk. This may help understanding why successful analysts and entrepreneurs tend to be overconfident. In addition, a different interpretation of the model presents a novel evolutionary foundation for overconfidence, and explains various stylized facts about this bias. (JEL D81, D82)
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Hanink, D. M., and R. G. Cromley. "A Risk-Return Model for Multiregion and Multiproduct Diversification of the Firm." Environment and Planning A: Economy and Space 19, no. 1 (January 1987): 81–92. http://dx.doi.org/10.1068/a190081.
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The purpose of this paper is to demonstrate that the integration of locational considerations into product-diversification planning has the potential of supplying gains to the firm by providing hedges against both product-portfolio and location-portfolio risk. An efficient diversification frontier for region – product strategic planning is generated from hypothetical data for purposes of illustration. Results of the analysis are in agreement with Wahlroos's theory of the diversification of the firm.
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Novack-Gottshall, Philip M. "General models of ecological diversification. I. Conceptual synthesis." Paleobiology 42, no. 2 (April 5, 2016): 185–208. http://dx.doi.org/10.1017/pab.2016.3.
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AbstractEvolutionary paleoecologists have proposed many explanations for Phanerozoic trends in ecospace utilization, including escalation, seafood through time, filling of an empty ecospace, and tiering, among others. These hypotheses can be generalized into four models of functional diversification within a life-habit ecospace framework (functional-trait space). The models also incorporate concepts in community assembly, functional diversity, evolutionary diversification, and morphological disparity. The redundancy model produces an ecospace composed of clusters of functionally similar taxa. The partitioning model produces an ecospace that is progressively subdivided by taxa along life-habit gradients. The expansion model produces an ecospace that becomes progressively enlarged by the accumulation of taxa with novel life habits. These models can be caused by a wide range of ecological and evolutionary processes, but they are all caused by particular “driven” mechanisms. A fourth, neutral model also exists, in which ecospace is filled at random by life habits: this model can serve as a passive null model. Each model produces distinct dynamics for functional diversity/disparity statistics when simulated by stochastic simulations of ecospace diversification. In this first of two companion articles, I summarize the theoretical bases of these models, describe their expected statistical dynamics, and discuss their relevance to important paleoecological trends and theories. Although most synoptic interpretations of Phanerozoic ecological history invoke one or more of the driven models, I argue that this conclusion is premature until tests are conducted that provide better statistical support for them over simpler passive models.
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Caselli, Francesco, Miklós Koren, Milan Lisicky, and Silvana Tenreyro. "Diversification Through Trade*." Quarterly Journal of Economics 135, no. 1 (September 19, 2019): 449–502. http://dx.doi.org/10.1093/qje/qjz028.
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Abstract A widely held view is that openness to international trade leads to higher income volatility, as trade increases specialization and hence exposure to sector-specific shocks. Contrary to this common wisdom, we argue that when country-wide shocks are important, openness to international trade can lower income volatility by reducing exposure to domestic shocks and allowing countries to diversify the sources of demand and supply across countries. Using a quantitative model of trade, we assess the importance of the two mechanisms (sectoral specialization and cross-country diversification) and show that in recent decades international trade has reduced economic volatility for most countries.
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SEKINE, Ryoji, and Daisuke KIGA. "Waddington Landscape Based Experimental Model of Phenotypic Diversification." Seibutsu Butsuri 53, no. 6 (2013): 319–20. http://dx.doi.org/10.2142/biophys.53.319.
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Rajewsky, Klaus. "The DNA Deamination Model of Somatic Antibody Diversification." Journal of Immunology 194, no. 5 (February 20, 2015): 2041–42. http://dx.doi.org/10.4049/jimmunol.1403252.
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Vences, Miguel, Katharina C. Wollenberg, David R. Vieites, and David C. Lees. "Madagascar as a model region of species diversification." Trends in Ecology & Evolution 24, no. 8 (August 2009): 456–65. http://dx.doi.org/10.1016/j.tree.2009.03.011.
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Doebeli, Michael, and Iaroslav Ispolatov. "A model for the evolutionary diversification of religions." Journal of Theoretical Biology 267, no. 4 (December 2010): 676–84. http://dx.doi.org/10.1016/j.jtbi.2010.09.013.
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Saracco, Fabio, Riccardo Di Clemente, Andrea Gabrielli, and Luciano Pietronero. "From Innovation to Diversification: A Simple Competitive Model." PLOS ONE 10, no. 11 (November 6, 2015): e0140420. http://dx.doi.org/10.1371/journal.pone.0140420.
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Beal Cohen, Allegra A., Jasmeet Judge, Rachata Muneepeerakul, Anand Rangarajan, and Zhengfei Guan. "A model of crop diversification under labor shocks." PLOS ONE 15, no. 3 (March 3, 2020): e0229774. http://dx.doi.org/10.1371/journal.pone.0229774.
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Zhang, Quan-Guo, Han-Shu Lu, and Angus Buckling. "Temperature drives diversification in a model adaptive radiation." Proceedings of the Royal Society B: Biological Sciences 285, no. 1886 (September 5, 2018): 20181515. http://dx.doi.org/10.1098/rspb.2018.1515.
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The warmer regions harbour more species, attributable to accelerated speciation and increased ecological opportunities for coexistence. While correlations between temperature and energy availability and habitat area have been suggested as major drivers of these biodiversity patterns, temperature can theoretically also have direct effects on the evolution of diversity. Here, we experimentally studied the evolution of diversity in a model adaptive radiation of the bacterium Pseudomonas fluorescens across a temperature gradient. Diversification increased at higher temperatures, driven by both faster generation of genetic variation and stronger diversifying selection. Specifically, low temperatures could limit the generation of diversity, suggested by the observation that supply of genetic variation through immigration increased diversity at low, but not high temperatures. The two major determinants of mutation supply, population size and mutation rate, both showed a positive temperature dependence. Stronger diversifying selection in warmer environments was suggested by promoted coexistence, and further explicitly inferred by the ability of evolved phenotypes to invade the ancestral type from rare. We discuss possible physiological and environmental mechanisms underlying the findings, most of which are likely to be general.
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Beckett, Amber C., John T. Loh, Abha Chopra, Shay Leary, Aung Soe Lin, Wyatt J. McDonnell, Beverly R. E. A. Dixon, et al. "Helicobacter pylorigenetic diversification in the Mongolian gerbil model." PeerJ 6 (May 18, 2018): e4803. http://dx.doi.org/10.7717/peerj.4803.
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Helicobacter pylorirequires genetic agility to infect new hosts and establish long-term colonization of changing gastric environments. In this study, we analyzedH. pylorigenetic adaptation in the Mongolian gerbil model. This model is of particular interest becauseH. pylori-infected gerbils develop a high level of gastric inflammation and often develop gastric adenocarcinoma or gastric ulceration. We analyzed the whole genome sequences ofH. pyloristrains cultured from experimentally infected gerbils, in comparison to the genome sequence of the input strain. The mean annualized single nucleotide polymorphism (SNP) rate per site was 1.5e−5, which is similar to the rates detected previously inH. pylori-infected humans. Many of the mutations occurred within or upstream of genes associated with iron-related functions (fur,tonB1,fecA2,fecA3, andfrpB3) or encoding outer membrane proteins (alpA, oipA, fecA2, fecA3, frpB3andcagY). Most of the SNPs within coding regions (86%) were non-synonymous mutations. Several deletion or insertion mutations led to disruption of open reading frames, suggesting that the corresponding gene products are not required or are deleterious during chronicH. pyloricolonization of the gerbil stomach. Five variants (three SNPs and two deletions) were detected in isolates from multiple animals, which suggests that these mutations conferred a selective advantage. One of the mutations (FurR88H) detected in isolates from multiple animals was previously shown to confer increased resistance to oxidative stress, and we now show that this SNP also confers a survival advantage whenH. pyloriis co-cultured with neutrophils. Collectively, these analyses allow the identification of mutations that are positively selected duringH. pyloricolonization of the gerbil model.
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Sohl, Timo, and Govert Vroom. ""Business Model Diversification, Resource Relatedness, and Firm Performance"." Academy of Management Proceedings 2014, no. 1 (January 2014): 10894. http://dx.doi.org/10.5465/ambpp.2014.158.
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Salinas, Gonzalo. "Chile: A Role Model of Export Diversification Policies?" IMF Working Papers 2021, no. 148 (May 2021): 1. http://dx.doi.org/10.5089/9781513573373.001.
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Adeoba, Mariam I., and Kowiyou Yessoufou. "Analysis of temporal diversification of African Cyprinidae (Teleostei, Cypriniformes)." ZooKeys 806 (December 13, 2018): 141–61. http://dx.doi.org/10.3897/zookeys.806.25844.
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Recent evidence that freshwater fishes diversify faster than marine fishes signifies that the evolutionary history of biodiversity in freshwater system is of particular interest. Here, the evolutionary diversification events of African Cyprinidae, a freshwater fish family with wide geographic distribution, were reconstructed and analysed. The overall diversification rate of African Cyprinidae is 0.08 species per million year (when extinction rate is very high, i.e., ε = 0.9) and 0.11 species per million year (when ε = 0). This overall rate is lower than the rate reported for African Cichlids, suggesting that African freshwaters might be less conducive for a rapid diversification of Cyprinidae. However, the observed diversification events of African Cyprinidae occurred in the last 10 million years. The temporal pattern of these events follows a non-constant episodic birth-death model (Bayes Factor > 28) and the rate-constant model never outperformed any of the non-constant models tested. The fact that most diversification events occurred in the last 10 million years supports the pattern reported for Cyprinidae in other continent, e.g., Asia, perhaps pointing to concomitant diversification globally. However, the diversification events coincided with major geologic and paleo-climatic events in Africa, suggesting that geological and climatic events may have mediated the diversification patterns of Cyprinidae on the continent.
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Rather, Akhter Mohiuddin. "Portfolio selection using mean-risk model and mean-risk diversification model." International Journal of Operational Research 14, no. 3 (2012): 324. http://dx.doi.org/10.1504/ijor.2012.047093.
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Bailey, Susan F., Jeremy R. Dettman, Paul B. Rainey, and Rees Kassen. "Competition both drives and impedes diversification in a model adaptive radiation." Proceedings of the Royal Society B: Biological Sciences 280, no. 1766 (September 7, 2013): 20131253. http://dx.doi.org/10.1098/rspb.2013.1253.
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Competitors are known to be important in governing the outcome of evolutionary diversification during an adaptive radiation, but the precise mechanisms by which they exert their effects remain elusive. Using the model adaptive radiation of Pseudomonas fluorescens , we show experimentally that the effect of competition on diversification of a focal lineage depends on both the strength of competition and the ability of the competitors to diversify. We provide evidence that the extent of diversification in the absence of interspecific competitors depends on the strength of resource competition. We also show that the presence of competitors can actually increase diversity by increasing interspecific resource competition. Competitors that themselves are able to diversify prevent diversification of the focal lineage by removing otherwise available ecological opportunities. These results suggest that the progress of an adaptive radiation depends ultimately on the strength of resource competition, an effect that can be exaggerated or impeded by the presence of competitors.
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Swathi. M and P. Sridharan. "Determinants of Export Diversification: Evidence from Fractional Logit Estimation Model." Foreign Trade Review 57, no. 2 (February 3, 2022): 160–77. http://dx.doi.org/10.1177/00157325211072922.
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This article empirically explores the key drivers of export diversification in a large panel of 101 countries consisting of 43 high-income, 47 middle-income, and 11 low-income countries from 1995 to 2019. Considering the fractional nature of the dependent variable (Herfindahl-Hirschman Index), the estimates are obtained using the fractional logit technique with a set of potential determinants of export diversification for all country samples and three sub-samples. The results reveal that human capital accumulation, GDP per capita, population, trade openness, the share of manufactured output to GDP, and FDI are important determinants of export diversification. However, the share of agriculture to GDP and official exchange rate promotes export concentration. Contrary to our all-country estimation, GDP per capita and population act as deterrents to export diversification in low-income countries. In addition, the results show that the value-added in agriculture plays a dominant role in strengthening the export structure of high-income countries. Our findings suggest that policymakers should implement and reform policies targeting human capital accumulation, trade openness, investment, and value addition in the manufacturing sector for diversifying the export structure. JEL Codes: C33, F14, J24, O1
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Friesenbichler, Evelyn, Michael Hautmann, and Hugo Bucher. "The main stage of recovery after the end-Permian mass extinction: taxonomic rediversification and ecologic reorganization of marine level-bottom communities during the Middle Triassic." PeerJ 9 (July 20, 2021): e11654. http://dx.doi.org/10.7717/peerj.11654.
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The recovery of marine life from the end-Permian mass extinction event provides a test-case for biodiversification models in general, but few studies have addressed this episode in its full length and ecological context. This study analyses the recovery of marine level-bottom communities from the end-Permian mass extinction event over a period of 15 Ma, with a main focus on the previously neglected main phase during the Middle Triassic. Our analyses are based on faunas from 37 lithological units representing different environmental settings, ranging from lagoons to inner, mid- and outer ramps. Our dataset comprises 1562 species, which belong to 13 higher taxa and 12 ecological guilds. The diversification pattern of most taxa and guilds shows an initial Early Triassic lag phase that is followed by a hyperbolic diversity increase during the Bithynian (early middle Anisian) and became damped later in the Middle Triassic. The hyperbolic diversity increase is not predicted by models that suggest environmental causes for the initial lag phase. We therefore advocate a model in which diversification is primarily driven by the intensity of biotic interactions. Accordingly, the Early Triassic lag phase represents the time when the reduced species richness in the wake of the end-Permian mass extinction was insufficient for stimulating major diversifications, whereas the Anisian main diversification event started when self-accelerating processes became effective and stopped when niche-crowding prevented further diversification. Biotic interactions that might drive this pattern include interspecific competition but also habitat construction, ecosystem engineering and new options for trophic relationships. The latter factors are discussed in the context of the resurgence of large carbonate platforms, which occurred simultaneously with the diversification of benthic communities. These did not only provide new hardground habitats for a variety of epifaunal taxa, but also new options for grazing gastropods that supposedly fed from microalgae growing on dasycladaceans and other macroalgae. Whereas we do not claim that changing environmental conditions were generally unimportant for the recovery of marine level-bottom communities, we note that their actual role can only be assessed when tested against predictions of the biotic model.
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Lam, Weng Siew, Weng Hoe Lam, and Saiful Hafizah Jaaman. "Portfolio Optimization with a Mean–Absolute Deviation–Entropy Multi-Objective Model." Entropy 23, no. 10 (September 28, 2021): 1266. http://dx.doi.org/10.3390/e23101266.
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Investors wish to obtain the best trade-off between the return and risk. In portfolio optimization, the mean-absolute deviation model has been used to achieve the target rate of return and minimize the risk. However, the maximization of entropy is not considered in the mean-absolute deviation model according to past studies. In fact, higher entropy values give higher portfolio diversifications, which can reduce portfolio risk. Therefore, this paper aims to propose a multi-objective optimization model, namely a mean-absolute deviation-entropy model for portfolio optimization by incorporating the maximization of entropy. In addition, the proposed model incorporates the optimal value of each objective function using a goal-programming approach. The objective functions of the proposed model are to maximize the mean return, minimize the absolute deviation and maximize the entropy of the portfolio. The proposed model is illustrated using returns of stocks of the Dow Jones Industrial Average that are listed in the New York Stock Exchange. This study will be of significant impact to investors because the results show that the proposed model outperforms the mean-absolute deviation model and the naive diversification strategy by giving higher a performance ratio. Furthermore, the proposed model generates higher portfolio mean returns than the MAD model and the naive diversification strategy. Investors will be able to generate a well-diversified portfolio in order to minimize unsystematic risk with the proposed model.
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Farhangzadeh, Banafsheh. "Tobin’s q, RoA, Diversification and Risk." International Letters of Social and Humanistic Sciences 50 (March 2015): 146–54. http://dx.doi.org/10.18052/www.scipress.com/ilshs.50.146.
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This study aims to explain the link between corporate diversification, firm performance and risk. To test the research hypotheses, a sample of 63 companies listed in Tehran Stock Exchange over the period 2008-2012 was taken. We construct two models with Tobin’s q, RoA, Size, Debt, Growth and Standard deviation of stock returns. Analysis of the research models is based on panel(data) analysis. In these models the presence or absence of effects models (fixed or random) is reviewed and finally the best model is estimated. Inference is based on significant level or p-value, thus likely that any value or significance level of the test is less than 0.05 is rejected at the 95 percent confidence level. The results indicate that there is no significant relationship between diversification strategy, firm performance and risk.
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Pehrsson, Anders. "Business relatedness in international diversification." European Business Review 31, no. 2 (March 11, 2019): 197–217. http://dx.doi.org/10.1108/ebr-03-2018-0069.
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Purpose Business relatedness is important in international diversification because it enables a firm’s transfer of resources to business units operating in foreign markets. The purpose of this paper is to develop a conceptual model based on a review of the major contributions of studies regarding the relatedness of subsidiaries, joint ventures or any other foreign unit. Design/methodology/approach The paper examines theory bases, the relatedness construct, data issues and the key achievements of previous studies. Drawing on organizational learning, transaction costs economics and industrial organization, a conceptual model and propositions are developed that intend to close important research gaps. Findings The model includes competitive strategy as a mediator of the effects of relatedness on foreign unit performance, type of foreign unit – that is, a wholly owned unit or joint venture – as a moderator; and competition barriers as a moderator. Research limitations/implications In future research, the propositions need to be transformed into testable hypotheses. It is recommended to treat relatedness as a multidimensional concept. Practical implications A firm is primarily advised to evaluate how its relatedness with foreign units enables knowledge transfer. A foreign cost leadership strategy benefits from product relatedness, while a differentiation strategy calls for resource relatedness. Originality/value The proposed model is unique as it includes an actionable component that mediates the effects of relatedness on international performance, i.e. competitive strategy, and concerns both wholly owned foreign units and international joint ventures.
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Houfi, Mohamed Ali. "Is the impact of the Economic Diversification on Economic Growth Symmetric or Asymmetric? Evidence from Saudi Arabia." International Journal of Economics and Finance 13, no. 10 (August 30, 2021): 1. http://dx.doi.org/10.5539/ijef.v13n10p1.
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This paper presents our investigation of the impact of economic diversification on economic growth in Saudi Arabia for the 1990-2018 period. To this end, we used linear and nonlinear error-correction models (i.e., the ARDL, Pesaran et al. (2001), and NARDL, Shin et al. (2014), models) that are suited to capture the symmetric and asymmetric effects of economic diversification on economic growth based on the Solow model. As a measure of economic diversification, we used the Herfindahl index. In the linear and the nonlinear specifications, our results show that, economic diversification has a positive effect on the economic growth only in the long term. Furthermore, using the Wald test, the symmetric hypothesis in this relationship is not rejected, indicating that economic growth responds symmetrically to positive and negative changes in economic diversification. Our results also reveal that Saudi Arabia had relative success in achieving its goal of attaining a degree of economic diversification and enhancing its economic growth.
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Ferreira, Gustavo F. C., and R. Wes Harrison. "From Coffee Beans to Microchips: Export Diversification and Economic Growth in Costa Rica." Journal of Agricultural and Applied Economics 44, no. 4 (November 2012): 517–31. http://dx.doi.org/10.1017/s1074070800024081.
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In the wake of a severe economic crisis in the 1980s Costa Rica abandoned an import substitution model of development adopted in the 1960s and implemented policies supporting foreign investment and the diversification of its exports. This study presents an application of the model proposed by Herzer and Nowak-Lehnmann to test the hypothesis that export diversification has contributed to economic growth in Costa Rica via externalities of learning-by-doing and learning-by-exporting over the period of 1965–2006. After using the autoregressive distributed lags and dynamic ordinary least squares models no long-run relationship was found between export diversification and growth.
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Nguyen, Phong Hoang, and Duyen Thi Bich Pham. "Income diversification and cost-efficiency of Vietnamese banks." International Journal of Managerial Finance 16, no. 5 (April 10, 2020): 623–43. http://dx.doi.org/10.1108/ijmf-06-2019-0230.
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PurposeThe study examines the impact of income diversification on cost efficiency of Vietnamese commercial banks over the period 2005–2017.Design/methodology/approachIncome diversification indicators are designed based on measures of diversifying loan portfolio. Besides the traditional model, we use the Fractional Regression to estimate the model with dependent variables defined on the unit interval.FindingsThrough the two-stage DEA analysis, we find that the income diversification has a positive impact on the cost efficiency of banks. In addition, this impact is stronger for unlisted banks and in the phase of banking system ongoing restructuring.Originality/valueThe use of a variety of income diversification measures and estimation methods for models with bounded dependent variable has provided a reliable empirical evidence of the advantages of implementing a strategy on structural diversity of both interest and non-interest income in the emerging banking markets such as Vietnam.
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THANH, VU HUU, NGUYEN MINH HA, and MICHAEL MCALEER. "ASSET INVESTMENT DIVERSIFICATION, BANKRUPTCY RISK AND THE MEDIATING ROLE OF BUSINESS DIVERSIFICATION." Annals of Financial Economics 16, no. 01 (March 2021): 2150001. http://dx.doi.org/10.1142/s2010495221500019.
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This paper explores the structural relationship among asset investment diversification, business diversification and the bankruptcy risk of firms. Asset investment diversification is divided into two components, namely related and unrelated asset investment diversification, while business diversification includes related and unrelated business diversification. In the hypothetical relationship, business diversification is proposed to play a mediating role to explain the effect of asset investment diversification on bankruptcy risk. Specifically, related and unrelated asset investment diversification affect bankruptcy risk through two mediators, namely related and unrelated business diversification. Hence, it is vital to employ the general linear structural model (GSEM) with panel data on 470 businesses publicly listed in Vietnam from 2008 to 2017. Surprisingly, the empirical results show that both related and unrelated asset diversification have positive impacts on bankruptcy risk. Nevertheless, only related business diversification plays a mediating role between related asset diversification and bankruptcy risk, while unrelated business diversification has an insignificant mediating effect on the relationship between unrelated asset diversification and bankruptcy risk.
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Zhou, Zhongbao, Enming Chen, Helu Xiao, Tiantian Ren, and Qianying Jin. "Performance evaluation of portfolios with fuzzy returns." RAIRO - Operations Research 53, no. 5 (October 8, 2019): 1581–600. http://dx.doi.org/10.1051/ro/2019071.
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The existing literature on DEA (Data Envelopment Analysis) for evaluating fuzzy portfolios usually takes risk as an input and return as an output. This assumption is actually not congruent with the real investment process, where the input is the initial wealth and the output is the corresponding terminal wealth. As for the risk and return, which are essentially two indicators derived from the terminal wealth, both should be regarded as outputs. In addition, few studies have employed the diversification model (nonlinear DEA) to estimate the fuzzy portfolio efficiency (PE), despite the fact that there are many studies available within the framework of classical probability theory. Further, the relationship between DEA and diversification models needs to be defined. In this paper, we take the initial wealth as an input, while the return and risk of terminal wealth are taken as desirable and undesirable outputs, respectively. We construct different evaluation models under the fuzzy portfolio framework. The relationships among the evaluation model based on a real frontier, the diversification model and the DEA model are investigated. We show the convergence of the diversification and DEA models under the fuzzy theory framework. Some simulations as well as empirical analysis are presented to further verify the effectiveness of the proposed models. Finally, we check the robustness of the evaluation results by using the bootstrap re-sampling approach.
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Larsen, Ryan, David Leatham, and Kunlapath Sukcharoen. "Geographical diversification in wheat farming: a copula-based CVaR framework." Agricultural Finance Review 75, no. 3 (September 7, 2015): 368–84. http://dx.doi.org/10.1108/afr-07-2014-0020.
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Purpose – Portfolio theory suggests that geographical diversification of production units could potentially help manage the risks associated with farming, yet little research has been done to evaluate the effectiveness of a geographical diversification strategy in agriculture. The paper aims to discuss this issue. Design/methodology/approach – The paper utilizes several tools from modern finance theory, including Conditional Value-at-Risk (CVaR) and copulas, to construct a model for the evaluation of a diversification strategy. The proposed model – the copula-based mean-CVaR model – is then applied to the producer’s acreage allocation problem to examine the potential benefits of risk reduction from a geographical diversification strategy in US wheat farming. Along with the copula-based model, the multivariate-normal mean-CVaR model is also estimated as a benchmark. Findings – The mean-CVaR optimization results suggest that geographical diversification is a viable risk management strategy from a farm’s profit margin perspective. In addition, the copula-based model appears more appropriate than the traditional multivariate-normal model for conservative agricultural producers who are concerned with the extreme losses of farm profitability in that the later model tends to underestimate the minimum level of risk faced by the producers for a given level of profitability. Originality/value – The effectiveness of geographical diversification in US wheat farming is evaluated. As a methodological contribution, the copula approach is used to model the joint distribution of profit margins and CVaR is employed as a measure of downside risk.
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Ali, Muhammad Uzair, Gong Zhimin, Muhammad Rizwanullah, Xiong Wu, and Itbar Khan. "The Impact of Corporate Strategy on the Capital Structure of Pakistani Companies (Diversification and Capital Structure)." Risk and Financial Management 2, no. 1 (May 19, 2020): p27. http://dx.doi.org/10.30560/rfm.v2n1p27.
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Research into the capital structure of firms has been the subject of extensive empirical investigation. This study seeks to extend the debate by examining the endogenous influence of corporate strategy on financing decisions made by firms. Diversification is one of the corporate strategies that allow a company to enter business lines that are same or different from current operations as well as operate in several economic markets. Financial choices need to be evaluated because of their close interaction with management choices. Optimal capital structure plays a key role in achieving the overriding goal of financial management. The study sought to discover the impact of corporate diversification strategies on financial choices because study main focus is diversification strategy (A type of corporate strategy). For purposes of comparison, the current study used four of the nine Rumelt categories which correspond to Wrigley's original four, which were single product strategy, dominant strategy, related firm strategy and unrelated firm strategy. Panel data model was constructed and using a sample of 120 companies listed on the Pakistan Stock Exchange and data was obtained for companies with seven years’ quarterly data annually from 2010 to 2017. Using empirical tests, we found no relationship between diversification and leverage. Our analysis suggests that Diversifications strategy impact on capital structure indicate that this focus of enquiry has considerable potential for further resolution of the capital structure puzzle.
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Fordyce, James A. "Host shifts and evolutionary radiations of butterflies." Proceedings of the Royal Society B: Biological Sciences 277, no. 1701 (July 7, 2010): 3735–43. http://dx.doi.org/10.1098/rspb.2010.0211.
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Ehrlich and Raven proposed a model of coevolution where major host plant shifts of butterflies facilitate a burst of diversification driven by their arrival to a new adaptive zone. One prediction of this model is that reconstructions of historical diversification of butterflies should indicate an increase in diversification rate following major host shifts. Using reconstructed histories of 15 butterfly groups, I tested this prediction and found general agreement with Ehrlich and Raven's model. Butterfly lineages with an inferred major historical host shift showed evidence of diversification rate variation, with a significant acceleration following the host shift. Lineages without an inferred major host shift generally agreed with a constant-rate model of diversification. These results are consistent with the view that host plant associations have played a profound role in the evolutionary history of butterflies, and show that major shifts to chemically distinct plant groups leave a historical footprint that remains detectable today.
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Erfort, Olga, Irina Erfort, and Larisa Zbarazskaya. "Financing higher education in Ukraine: The binary model versus the diversification model." International Journal of Educational Development 49 (July 2016): 330–35. http://dx.doi.org/10.1016/j.ijedudev.2016.03.009.
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