Ovarian cystadenofibroma is a benign ovarian tumor that is characterized by a consistent percentage of masses, which remain indeterminate in ultrasonography and require magnetic resonance (MR) ...investigation; they may mimic borderline or malignant lesions. Three main morphologic patterns, resembling different ovarian neoplasms, can be identified in cystadenofibromas: multilocular solid lesions, unilocular cystic lesions with parietal thickening, and purely cystic masses. However, a cystoadenofibroma has typical features, such as T2-weighted hypointensity associated with no restrictions in diffusion-weighted imaging (the so-called "dark-dark appearance") and progressive post-contrast enhancement (type I perfusion curve). The purpose of this study was to review the features of ovarian cystadenofibromas in MR imaging and to suggest pearls and pitfalls regarding their correct diagnosis.
We propose a theoretical framework and develop a game-theoretical analysis to advance understanding of the cooperation dilemma in team production. We conceptualize team production as a process where ...productive and appropriative activities coexist, shifting the focus from whether team members cooperate to what type of cooperative behavior they are willing to adopt. Depending on the extent to which members cooperate to create value and compete to appropriate value, we can observe scenarios of full, partial, and no cooperation. After characterizing member behavior in the different scenarios, we study which form of cooperation can be sustained through repeated interaction, mutual monitoring, and reciprocity. To do so, we allow for different deviations from cooperation, which are then accompanied by different reactions according to an equivalent retaliation strategy. Our focus is on how member behavior and incentives to cooperate relate to team size. We also introduce conceptual elements that describe team production in organizational teams as well as interorganizational relationships.
Research summary: This article studies strategic interactions between firms that form alliances to exploit synergistic benefits. Firms cooperate to create value, but they can also compete to capture ...value. Fundamental questions rarely addressed by strategy scholars relate to how the configuration of control over resources influences firms' strategies, the potential for termination, and the emergence of cooperation and trust. The formal results reveal crucial aspects of the interorganizational rent-generating process and yield testable implications. With greater synergistic benefits, firms invest more, but they also compete more intensively to capture more value. With symmetric control, more value gets created, which limits the potential for termination, but also exacerbates the competition for value; from a relational perspective, this form of control augments the calculative rationale of cooperation and trust. Managerial summary: When forming an alliance to exploit synergies, firms engage in a complicated strategic interaction that is part cooperation and part competition. What happens when partner firms cooperate and invest to create value while competing and using costly adversarial tactics to capture value? The analysis reveals that with greater synergistic benefits, firms invest more in value creation, but the fear of opportunism pushes them to waste more resources on value capture tactics. The balance between value creation and value capture, and the possibility that the alliance is terminated depend on the configuration of control over resources. The analysis further reveals under what conditions there can be trust between the partners, such that they focus on value creation and avoid wasting resources in the competition for value.
Research summary
User demand affects the emergence and growth of platform ecosystems through indirect network effects. But how do these effects play out in the strategies of platform providers and ...complementors as the ecosystem evolves? We study how user preferences for ecosystem innovativeness (complement novelty and quality) and ecosystem size (number of complementors/complements), and demand‐based economies of scale, shape the strategic interactions between the platform provider and the complementors in the ecosystem. Using an analytical model, we identify the conditions that give rise to a trade‐off between ecosystem innovativeness and size; when (and why) this trade‐off generates a tension between value co‐creation and appropriation among ecosystem participants; and the strategic implications for ecosystem competitiveness and for the different stages of the ecosystem's evolution.
Managerial summary
Managing complementors’ incentives is critical for the success of a platform ecosystem. Such incentives may be offered not only for joining the platform, but also for contributing high‐quality, innovative complements throughout the ecosystem's evolution. In this article, we show that demand‐side economies of scale are the driving force of complementors’ incentives, and hence the key success factor for platform strategies. The strength of user preferences ultimately determines whether a larger ecosystem can also be more innovative, in which case all ecosystem participants can gain; or if instead there is a trade‐off between size and innovativeness, which could also lead to a tension between value co‐creation and appropriation among the platform provider and its complementors. The different stages of the evolution of a platform ecosystem call for different strategies that adapt to the evolution of user preferences.
A
bstract
We study the potential of fully-differential measurements of high-energy dilepton cross-sections at the LHC to probe heavy new physics encapsulated in dimension-6 interaction operators. The ...assessment is performed in the seven-dimensional parameter space of operators that induce energy-growing corrections to the Standard Model partonic cross-sections at the interference level, and in the two-dimensional subspace associated with the W and Y parameters. A considerable sensitivity improvement is found relative to single-differential measurements, owing to the possibility of probing at the interference level more directions in the seven-dimensional parameter space. The reduction of parton distribution function uncertainties in the fully-differential fit is also found to play a significant role. The results are interpreted in the minimal
Z′
new-physics model, providing a concrete illustration of the advantages of the fully-differential analysis. We find that high-energy dilepton measurements can extend the
Z′
exclusion and discovery potential well beyond the reach of direct searches in a large region of the parameter space.
Gravitational waves from supercool axions Rose, Luigi Delle; Panico, Giuliano; Redi, Michele ...
The journal of high energy physics,
04/2020, Letnik:
2020, Številka:
4
Journal Article
Recenzirano
Odprti dostop
A
bstract
We study the dynamics of the Peccei-Quinn (PQ) phase transition for the QCD axion. In weakly coupled models the transition is typically second order except in the region of parameters where ...the PQ symmetry is broken through the Coleman-Weinberg mechanism. In strongly coupled realizations the transition is often first order. We show examples where the phase transition leads to strong supercooling lowering the nucleation temperature and enhancing the stochastic gravitational wave signals. The models predict a frequency peak in the range 100–1000 Hz with an amplitude that is already within the sensitivity of LIGO and can be thoroughly tested with future gravitational wave interferometers.
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