Polar bears are inefficient predators of seabird eggs

Climate-mediated sea-ice loss is disrupting the foraging ecology of polar bears ( Ursus maritimus ) across much of their range. As a result, there have been increased reports of polar bears foraging on seabird eggs across parts of their range. Given that polar bears have evolved to hunt seals on ice, they may not be efficient predators of seabird eggs. We investigated polar bears' foraging performance on common eider ( Somateria mollissima ) eggs on Mitivik Island, Nunavut, Canada to test whether bear decision-making heuristics are consistent with expectations of optimal foraging theory. Using aerial-drones, we recorded multiple foraging bouts over 11 days, and found that as clutches were depleted to completion, bears did not exhibit foraging behaviours matched to resource density. As the season progressed, bears visited fewer nests overall, but marginally increased their visitation to nests that were already empty. Bears did not display different movement modes related to nest density, but became less selective in their choice of clutches to consume. Lastly, bears that capitalized on visual cues of flushing eider hens significantly increased the number of clutches they consumed; however, they did not use this strategy consistently or universally. The foraging behaviours exhibited by polar bears in this study suggest they are inefficient predators of seabird eggs, particularly in the context of matching behaviours to resource density.

Hospitalization Trajectories in Home- and Community-Based Services Recipients: The Influence of Physician and Social Care Density

Objectives Repeated hospitalizations among older adults receiving Home- and Community-Based Services (HCBS) may indicate unmet medical and social needs. This study examined all-cause hospitalization trajectories and the association between area-level resource density for medical and social care and the trajectory group membership. Methods The study participants included 11,223 adults aged 60 years or older who were enrolled in public HCBS programs in Michigan between 2008 and 2012. Data sources included the Michigan interRAI-Home Care, Dartmouth Atlas of Health Care Data, the American Community Survey, and the County Business Patterns from the Census Bureau. The group-based trajectory modeling was used to identify trajectories of hospitalization over 15 months. Correlates of the trajectories were examined using multinomial logistic regression. Results Four distinct hospitalization trajectory groups emerged: “never” (43.1%)—individuals who were rarely hospitalized during the study period, “increasing” (19.9%)—individuals who experienced an increased risk of hospitalization, “decreasing” (21.6%)—individuals with a decreased risk, and “frequent” (15.8%)—individuals with frequent hospitalizations. Older adults living in areas with a higher number of social service organizations for older adults and persons with disability were less likely to be on the “frequent” trajectory relative to the “decreasing” trajectory. The density of primary care physicians was not associated with the trajectory group membership. Discussion Area-level social care resource density contributes to changes in 15-month hospitalization risks among older adult recipients of HCBS.

Market shaping dynamics: interplay of actor engagement and institutional work

Purpose Combining institutional work and actor engagement (AE) literature, this paper aims to elucidate how the collective action of market shaping occurs through the interplay between market shapers’ institutional work and engagement of other market actors. While markets are shaped by actors’ purposive actions and recent literature notes the need to also mobilize AE, the underlying process remains nebulous. Design/methodology/approach This paper is conceptual but supported by an illustrative case study: the Winding Tree. This blockchain-based, decentralized travel marketplace shapes a market by decoupling existing resource linkages, creating new ones and stabilizing others through a dynamic, iterative process between the market shaper’s institutional work and others’ AE. Findings The paper develops a dynamic, iterative framework of market shaping through increased resource density, revealing the interplay between seven types of market shapers’ institutional work distilled from the literature and changes in other market actors’ engagement dispositions, behaviors and the diffusion of AE through the market. Originality/value This research contributes to the emergent market shaping and market innovation literature by illustrating how the engagement of market actors is a fundamental means of market shaping. Specifically, it advances understanding of how market shapers’ institutional work leads to new resource linkages and higher resource density in emergent market systems through AE. The resultant framework offers an original, critical foundation for future market shaping research.

How much is enough? The role of effort in market shaping

Purpose Market shaping research predominantly focusses on the activities of the market shaper, rather than the equally important roles of other market actors. Market shapers may enhance resource density and value creation within markets, yet such influences cannot exhaustively explain how markets get shaped. Other market actors also must and do exert effort in the value co-creation processes; this study aims to explore the effects of reducing their efforts, as a mechanism to facilitate market shaping. Design/methodology/approach This conceptual paper uses a theory adaptation approach to link value co-creation with market shaping and effort. It offers a conceptual framework and five propositions that outline the role of effort reduction in the value co-creation process to achieve market shaping. Findings The proposed conceptual framework indicates how enhanced resource density, resulting from the firm’s market shaping activities and reduced effort lead to enhanced value creation for market actors. Effort reduction can be achieved by reducing either the level of resource input required or the activities required to access, transform and combine resources to co-create value. Potential resource flows then may benefit the market shaper. Originality/value This research contributes to emergent market shaping literature by offering effort reduction as a viable tactic. Specifically, it broadens the scope of consideration of effort in value co-creation, and it advances understanding of resource density as a focal market shaping construct. The resultant framework offers a foundation for future market shaping research.

Resource-driven encounters among consumers and implications for the spread of infectious disease

Animals share a variety of common resources, which can be a major driver of conspecific encounter rates. In this work, we implement a spatially explicit mathematical model for resource visitation behaviour in order to examine how changes in resource availability can influence the rate of encounters among consumers. Using simulations and asymptotic analysis, we demonstrate that, under a reasonable set of assumptions, the relationship between resource availability and consumer conspecific encounters is not monotonic. We characterize how the maximum encounter rate and associated critical resource density depend on system parameters like consumer density and the maximum distance from which consumers can detect and respond to resources. The assumptions underlying our theoretical model and analysis are motivated by observations of large aggregations of black-backed jackals at carcasses generated by seasonal outbreaks of anthrax among herbivores in Etosha National Park, Namibia. As non-obligate scavengers, black-backed jackals use carcasses as a supplemental food resource when they are available. While jackals do not appear to acquire disease from ingesting anthrax carcasses, changes in their movement patterns in response to changes in carcass abundance do alter jackals' conspecific encounter rate in ways that may affect the transmission dynamics of other diseases, such as rabies. Our theoretical results provide a method to quantify and analyse the hypothesis that the outbreak of a fatal disease among herbivores can potentially facilitate outbreaks of an entirely different disease among jackals. By analysing carcass visitation data, we find support for our model's prediction that the number of conspecific encounters at resource sites decreases with additional increases in resource availability. Whether or not this site-dependent effect translates to an overall decrease in encounters depends, unexpectedly, on the relationship between the maximum distance of detection and the resource density.