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The authors compare sentiment level with sentiment shock from different angles to determine which measure better captures the relationship between sentiment and stock returns.

This paper examines the relationship between investor sentiment and contemporaneous stock returns. It also proposes a model of systems science to explain the empirical findings.

The authors find that sentiment shock has a higher explanatory power on stock returns than sentiment itself, and sentiment shock beta exhibits a much higher statistical significance than sentiment beta. Compared with sentiment level, sentiment shock has a more robust linkage to the market factors and the sentiment shock is more responsive to stock returns.

This is the first study to compare sentiment level and sentiment shock. It concludes that sentiment shock is a better indicator of the relationship between investor sentiment and contemporary stock returns.

The patterns of health and social care provision in the community have always been complex. The Government's current call to integrate systems of care can be seen as a search for greater simplicity and predictability, but people in these systems know that any new networks will be equally complex. This article argues that our organisations and systems should no longer be viewed and managed as ‘machines’ with inherent rationality, and suggests that the new intellectual discipline of complexity theory offers a more relevant model with which to view the real world where we operate under the constraints of limited time, knowledge and processing power. The author is a general practitioner with an interest in applying complexity insights to health care organisation.

Smallholder value chains are dynamic, changing over time in sudden, unpredictable ways as they adapt to shocks. Understanding these dynamics and adaptation is essential for these chains to remain competitive in turbulent markets. Many guides to value chain development, though they focus welcome attention on snapshots of current structure and performance, pay limited attention to the dynamic forces affecting these chains or to adaptation. The paper aims to discuss these issues.

This paper develops an expanded conceptual framework to understand value chain performance based on the theory of complex adaptive systems. The framework combines seven common properties of complex systems: time, uncertainty, sensitivity to initial conditions, endogenous shocks, sudden change, interacting agents and adaptation.

The authors outline how the framework can be used to ask new research questions and analyze case studies in order to improve our understanding of the development of smallholder value chains and their capacity for adaptation.

The framework highlights the need for greater attention to value chain dynamics.

The framework offers a new perspective on the dynamics of smallholder value chains.

Existing literature acknowledges information systems development (ISD) to be a complex activity. This complexity is magnified by the continuous changes in user requirements due to changing organizational needs in changing external competitive environments. Research findings show that, if this increasing complexity is not managed appropriately, information systems fail. The paper thus aims to portray the sources of complexity related to ISD and to suggest the use of complexity theory as a frame of reference, analyzing its implications on information system design and development to deal with the emergent nature of IS.

Conceptual analysis and review of relevant literature.

This article provides a conceptual model explaining how top‐down “official” and bottom‐up “emergent” co‐evolutionary adaptations of information systems design with changing user requirements will result in more effective system design and operation. At the heart of this model are seven first principles of adaptive success drawn from foundational biological and social science theory: adaptive tension, requisite complexity, change rate, modular design, positive feedback, causal intricacy, and coordination rhythm. These principles, translated into the ISD context, outline how IS professionals can use them to better enable the co‐evolutionary adaptation of ISD projects to changing stakeholder interests and broader environmental changes.

This paper considers and recognizes the different sources of complexity related to ISD before suggesting how they could be better dealt with. It develops a framework for change to deal with the emergent nature of ISD and enable more expeditious co‐evolutionary adaptation.

This paper seeks to explore new complex venture approaches needed because the classical twentieth century system engineering model does not accommodate the complexities of twenty‐first century ventures, especially those with significant knowledge management components.

A complexity literature review was performed to identify the attributes of complex ventures. Then the fundamental differences in defining, developing, and implementing complicated traditional systems and complex ventures were explored. The resultant complex venture model builds on the insights derived from chaos and complexity theories; observations of several acquisition successes and failures; and doctoral research on agile enterprise decision support.

Successful traditional systems engineering complicated systems models' built‐in assumptions do not scale to the needed twenty‐first century complex solutions. It is necessary to develop a complex venture model that guides the engineering solutions that: describe complex ventures as flows of intelligence, energy and matter provide value in a dynamic co‐evolving context; provide leadership, not control, with clear and consistent venture‐wide vision that guides empowered individual agent decision making; institute tiered situationally‐aware decision making in both time and place; address factors (material and non‐material) contributing to solution success; provide for rapidly changing context and the co‐evolutionary ventures, including unexpected users, uses, and implementations.

A complex venture conceptual model informs the architecting and systems engineering acquisition practices for this new solution category.

The study aims to decrease the effect of solid particles on a butterfly valve, which will cause seal failure and leakage, providing a reference for anti-wear design.

In this paper, computational fluid dynamics discrete element method (CFD-DEM) simulation was conducted to study the solid–liquid two-phase flow characteristics and erosion characteristics of a butterfly valve with a different opening.

Abrasion at 10% opening is affected by high-speed jets in upper and lower parts of the pipeline, where the erosion is intense. The impact of the jet on the upper part of 20% opening begins to weaken. With the top backflow vortex disappearing, the effect of lower jet is enhanced. Meanwhile, the bottom backflow vortex phenomenon is obvious, and the abrasion position moves downward. At 30% opening, the velocity is further weakened, and the circulation effect of lower flow channel is more obvious than that of the upper one.

It is the first time to use DEM to investigate the two-phase flow and erosion characteristics at a small opening of a butterfly valve, considering the effect of inter-particle collision. Therefore, this study carries on the thorough analysis and discussion. At the same opening degree, with increasing of the particle size, the abrasion of valve frontal surface increases when the size is less than 150 µm and decreases when it is greater than 150 µm. For the valve backflow surface, this boundary value becomes 200 µm.

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-07-2020-0264/

Retail has evolved over the past century alongside megatrends such as urbanization, consumerism and digitalization. To contribute to existing knowledge on patterns of retail form evolution, the purpose of this paper is to investigate when and how novel retail forms have evolved in the Swedish sporting goods market.

An evolutionary approach that encompasses population thinking is used to interpret the history of sporting goods retailing in Sweden from the interwar era onwards. Drawing on archival data and interviews, the focus in the historical analysis is on the evolution of retail form variation in terms of size, strategy, product range and retail channel (online/offline).

The paper suggests that evolutionary mechanisms cumulatively have changed the sports retail population from a rather homogenous set of smaller generalist stores toward a larger variety and specialization in mainly two directions: one trajectory toward small and service-focused niche specialists and the other toward high-volume sales outlets.

The paper provides a detailed empirical account of sports retail history in Sweden and an application of theoretical concepts contributing to an integrated investigation of empirical issues and theoretical positions. It concludes that being able to attain “closures” – finding ways to close off a section of the market and avoid direct competition – has historically been a crucial capability for individual retailers to thrive.

The purpose of this paper is to consider why entrepreneurship theorising has become fragmented and how the research problem might be resolved.

The authors first examine how entrepreneurial constructs reflect only part of what we “mean” by the construct to argue that we use different social constructions. This explains why theories are fragmented. But the authors then ask how we might use and reconcile this diversity, pointing to the utility of the constructs as part of a complex whole. The authors discuss entrepreneurship as a complex adaptive system showing how connections and relatedness help explain the power of entrepreneurship to use and adapt to change.

The authors' proposition of entrepreneurial endeavours as a complex adaptive system provides a fresh theoretical platform to examine aspects of entrepreneurship and improve theorising.

The authors argue that this idea of connecting can also be used at the level of practice – how the connections that entrepreneurs use may help to explain some of what goes on in entrepreneurial practice.

The paper's contribution is a relatively novel way of connecting diverse theorising.

During a routine benchmarking and scalability study of CFD codes for typical large-scale wind engineering runs, it was observed that the resulting loads for buildings varied considerably with the number of parallel processors employed. The differences remained very small at the beginning of a typical run, and then grew progressively to a state of total dissimilitude. A “butterfly-effect” for such flows was suspected and later confirmed. The paper aims to discuss these issues.

A series of numerical experiments was conducted for massively separated flows. The same geometry – a cube in front of an umbrella – was used to obtain the flowfields using different grids, different numbers of domains/processors, slightly different inflow conditions and different codes.

In all of these cases the differences remained very small at the beginning of a typical run, they then grew progressively to a state of total dissimilitude. While the mean and maximum loads remained similar, the actual (deterministic) instantiations were completely different. The authors therefore suspect that for flows of this kind a “butterfly effect” is present, whereby even very small (roundoff) errors can have a pronounced effect on the actual deterministic instantiation of a flowfield.

This implies that for flows of this kind the CFD runs have to be carried out to much larger times than formerly expected (and done) in order to obtain statistically relevant ensembles.

For practical calculations this implies running to much larger times in order to reach statistically relevant ensembles, with the associated much higher CPU time requirements.

This is the first time such a finding has been reported in the numerical wind engineering context.

In order to mitigate the effects of climate change, the UK government has set a target of achieving net zero greenhouse gas (GHG) emissions by 2050. Agricultural GHG emissions in 2017 were 45.6 million tonnes of carbon dioxide equivalent (CO₂e; 10% of UK total GHG emissions). Farmland hedgerows are a carbon sink, storing carbon in the vegetation and soils beneath them, and thus increasing hedgerow length by 40% has been proposed in the UK to help meet net zero targets. However, the full impact of this expansion on farm biodiversity is yet to be evaluated in a net zero context. This paper critically synthesises the literature on the biodiversity implications of hedgerow planting and management on arable farms in the UK as a rapid review with policy recommendations. Eight peer-reviewed articles were reviewed, with the overall scientific evidence suggesting a positive influence of hedgerow management on farmland biodiversity, particularly coppicing and hedgelaying, although other boundary features, e.g. field margins and green lanes, may be additive to net zero hedgerow policy as they often supported higher abundances and richness of species. Only one paper found hedgerow age effects on biodiversity, with no significant effects found. Key policy implications are that further research is required, particularly on the effect of hedgerow age on biodiversity, as well as mammalian and avian responses to hedgerow planting and management, in order to fully evaluate hedgerow expansion impacts on biodiversity.