Efficient Coordination in Weakest-Link Games RIEDL, ARNO; ROHDE, INGRID M. T.; STRUBEL, MARTIN
The Review of economic studies,
04/2016, Letnik:
83, Številka:
2 (295)
Journal Article
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Coordination problems resembling weakest-link games with multiple Pareto ranked equilibria are ubiquitous in the economy and society. This makes it important to understand if and when agents are able ...to coordinate efficiently. Existing research on weakest-link games shows an overwhelming inability of people to coordinate on efficient equilibria, especially in larger groups. We show experimentally that freedom of neighbourhood choice overcomes the problem and leads to fully efficient coordination. This implies substantial welfare effects with achieved welfare being about 50% higher in games with neighbourhood choice than without it. We identify exclusion of low effort providers who in response start providing high effort as the simple but effective mechanism enforcing efficient coordination. A variety of other treatments show that the efficiency result as well as the identified mechanism are robust to changes in the information condition, payoff specification, and a substantial increase in group size. Moreover, we find that neighbourhood choice boosts efficiency even when exclusion does not materially affect the excluded agent. Our results are widely applicable on the societal and organizational level, e. g. containment of diseases, fight against terrorism, and co-authorship networks.
The microbiome of freshwater sponges is rarely studied, and not a single novel bacterial species has been isolated and subsequently characterized from a freshwater sponge to date. A previous study ...showed that 14.4% of the microbiome from Ephydatia fluviatilis belong to the phylum Planctomycetes. Therefore, we sampled an Ephydatia sponge from a freshwater lake and employed enrichment techniques targeting bacteria from the phylum Planctomycetes. The obtained strain spb1T was subject to genomic and phenomic characterization and found to represent a novel planctomycetal species proposed as Planctopirus ephydatiae sp. nov. (DSM 106606 = CECT 9866). In the process of differentiating spb1T from its next relative Planctopirus limnophila DSM 3776T, we identified and characterized the first phage – Planctopirus phage vB_PlimS_J1 – infecting planctomycetes that was only mentioned anecdotally before. Interestingly, classical chemotaxonomic methods would have failed to distinguish Planctopirus ephydatiae strain spb1T from Planctopirus limnophila DSM 3776T. Our findings demonstrate and underpin the need for whole genome-based taxonomy to detect and differentiate planctomycetal species.
This paper introduces time-tradeoff (TTO) sequences as a general tool to analyze intertemporal choice. We give several applications. For empirical purposes, we can measure discount functions without ...requiring any measurement of or assumption about utility. We can quantitatively measure time inconsistencies and simplify their qualitative tests. TTO sequences can be administered and analyzed very easily, using only pencil and paper. For theoretical purposes, we use TTO sequences to axiomatize (quasi-)hyperbolic discount functions. We demonstrate the feasibility of measuring TTO sequences in an experiment, in which we tested the axiomatizations. Our findings suggest rejections of several currently popular discount functions and call for the development of new ones. It is especially desirable that such discount functions can accommodate increasing impatience.
The ability of any incident reporting system to improve patient care is dependent upon robust reporting practices. However, under-reporting is still a problem worldwide. We aimed to reveal the ...barriers experienced while reporting an incident through a nationwide survey in Japan. We conducted a cross-sectional survey. All first- and second-year residents who took the General Medicine In-Training Examination (GM-ITE) from February to March 2021 in Japan were selected for the study. The voluntary questionnaire asked participants regarding the number of safety incidents encountered and reported within the previous year and the barriers to reporting incidents. Demographics were obtained from the GM-ITE. The answers of respondents who indicated they had never previously reported an incident (non-reporting group) were compared to those of respondents who had reported at least one incident in the previous year (reporting group). Of 5810 respondents, the vast majority indicated they had encountered at least one safety incident in the past year (n = 4449, 76.5%). However, only 2724 (46.9%) had submitted an incident report. Under-reporting (more safety incidents compared to the number of reports) was evident in 1523 (26.2%) respondents. The most frequently mentioned barrier to reporting an incident was the time required to file the report (n = 2622, 45.1%). The barriers to incident reporting were significantly different between resident physicians who had previously reported and those who had never previously reported an incident. Our study revealed that resident physicians in Japan commonly encounter patient safety incidents but under-report them. Numerous perceived and experienced barriers to reporting remain, which should be addressed if incident reporting systems are to have an optimal impact on improving patient safety. Incident reporting is essential for improving patient safety in an institution, and this study recommends establishing appropriate interventions according to each learner's barriers for reporting.
Phosphoenolpyruvate carboxykinase (PEPCK) is well known for its role in gluconeogenesis. However, PEPCK is also a key regulator of TCA cycle flux. The TCA cycle integrates glucose, amino acid, and ...lipid metabolism depending on cellular needs. In addition, biosynthetic pathways crucial to tumor growth require the TCA cycle for the processing of glucose and glutamine derived carbons. We show here an unexpected role for PEPCK in promoting cancer cell proliferation in vitro and in vivo by increasing glucose and glutamine utilization toward anabolic metabolism. Unexpectedly, PEPCK also increased the synthesis of ribose from non-carbohydrate sources, such as glutamine, a phenomenon not previously described. Finally, we show that the effects of PEPCK on glucose metabolism and cell proliferation are in part mediated via activation of mTORC1. Taken together, these data demonstrate a role for PEPCK that links metabolic flux and anabolic pathways to cancer cell proliferation.
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•PEPCK promotes tumor growth by increasing glucose and glutamine metabolism•PEPCK increases anabolic metabolism, including ribose synthesis from glutamine•PEPCK promotes mTORC1 activity•PEPCK increases glycolysis and proliferation via mTORC1 activation
Montal et al. report that PEPCK increases tumor growth by promoting metabolic flexibility. PEPCK increases the utilization of both glucose and glutamine toward anabolic metabolism. In addition, the ability of PEPCK to increase glucose metabolism and cell proliferation was mediated in part via activation of mTORC1.
Heated or cooled fluids at supercritical pressure show large variations in thermophysical properties, such as the density, dynamic viscosity and molecular Prandtl number, which strongly influence ...turbulence characteristics. To investigate this, direct numerical simulations were performed of a turbulent flow at supercritical pressure (CO
$_{2}$
at 8 MPa) in an annulus with a hot inner wall and a cold outer wall. The pseudo-critical temperature lies close to the inner wall, which results in strong thermophysical property variations in that region. The turbulent shear stress and the turbulent intensities significantly decrease near the hot inner wall, but increase near the cold outer wall, which can be partially attributed to the mean dynamic viscosity and density stratification. This leads to decreased production of turbulent kinetic energy near the inner wall and vice versa near the outer wall. However, by analysing a transport equation for the coherent streak flank strength, it was found that thermophysical property fluctuations significantly affect streak evolution. Near the hot wall, thermal expansion and buoyancy tend to decrease streak coherence, while the viscosity gradient that exists across the streaks interacts with mean shear to act as either a source or a sink in the evolution equation for the coherent streak flank strength. The formation of streamwise vortices on the other hand is hindered by the torque that is the result of the kinetic energy and density gradients. Near the cold wall, the results are reversed, i.e. the coherent streak flank strength and the streamwise vortices are enhanced due to the variable density and dynamic viscosity. The results show that not only the mean stratification but also the large instantaneous thermophysical property variations that occur in heated or cooled fluids at supercritical pressure have a significant effect on turbulent structures that are responsible for the self-regeneration process in near-wall turbulence. Thus, instantaneous density and dynamic viscosity fluctuations are responsible for decreased (or increased) turbulent motions in heated (or cooled) fluids at supercritical pressure.
•Laser Doppler Anemometry identifies coherent structures in the flow.•The coherent structures wavelength is predicted with a new correlation.•Excitation occurs when the gap vortex streets move in the ...flow at twice the rod natural frequency.
Gap vortex streets characterise many industrial applications involving rod bundle flows, such as heat exchangers and nuclear reactors. These structures, known as gap vortex streets, may excite the structural components of the bundle to resonance, leading to fretting and fatigue. This work aims to measure these coherent structures and the resulting displacement and oscillation frequency of the neighbouring rod, to provide unique data for fluid-structure interaction studies and to develop a general correlation for estimating the coherent structure’s wavelength. A water loop was built to host a hexagonal rod bundle. Fluorinated Ethylene Prophylene (FEP), a refractive index matching (RIM) material, was used to have undisturbed optical access in the area around the central rod. The flow was measured with Laser Doppler Anemometry (LDA) to detect coherent structures, while the vibrations were measured with a high speed camera. A new correlation for estimating the wavelength of the coherent structures is derived with dimensional analysis based on experimental evidence. The correlation is tested on different geometries: rectangular channels with single or half-rods, and two rod bundles, within the pitch-to-diameter ratio (P/D) range 1.02–1.2. Moreover fluctuations in the flow, given by the detected coherent structures, govern the structural response of the rod. The rod is excited to resonance if these fluctuations match twice the natural frequency of the rod.
Enzootic pneumonia incurs major economic losses to pork production globally. The primary pathogen and causative agent, Mycoplasma hyopneumoniae, colonises ciliated epithelium and disrupts mucociliary ...function predisposing the upper respiratory tract to secondary pathogens. Alleviation of disease is reliant on antibiotics, vaccination, and sound animal husbandry, but none are effective at eliminating M. hyopneumoniae from large production systems. Sustainable pork production systems strive to lower reliance on antibiotics but lack of a detailed understanding of the pathobiology of M. hyopneumoniae has curtailed efforts to develop effective mitigation strategies. M. hyopneumoniae is considered an extracellular pathogen. Here we show that M. hyopneumoniae associates with integrin β1 on the surface of epithelial cells via interactions with surface-bound fibronectin and initiates signalling events that stimulate pathogen uptake into clathrin-coated vesicles (CCVs) and caveosomes. These early events allow M. hyopneumoniae to exploit an intracellular lifestyle by commandeering the endosomal pathway. Specifically, we show: (i) using a modified gentamicin protection assay that approximately 8% of M. hyopneumoniae cells reside intracellularly; (ii) integrin β1 expression specifically co-localises with the deposition of fibronectin precisely where M. hyopneumoniae cells assemble extracellularly; (iii) anti-integrin β1 antibodies block entry of M. hyopneumoniae into porcine cells; and (iv) M. hyopneumoniae survives phagolysosomal fusion, and resides within recycling endosomes that are trafficked to the cell membrane. Our data creates a paradigm shift by challenging the long-held view that M. hyopneumoniae is a strict extracellular pathogen and calls for in vivo studies to determine if M. hyopneumoniae can traffic to extrapulmonary sites in commercially-reared pigs.
Development of efficient sequences for the total syntheses of (±)-actinophyllic acid (rac-1) and (−)-actinophyllic acid (1) are described. The central step in these syntheses is the aza-Cope/Mannich ...reaction, which constructs the previously unknown hexacyclic ring system of actinophyllic acid in one step from much simpler tetracyclic precursors. The tetracyclic hexahydro-1,5-methano-1H-azocino4,3-bindole ketone rac-37 is assembled from o-nitrophenylacetic acid in four steps, with oxidative cyclization of a dienolate derivative of tricyclic precursor rac-35 being the central step. In the first-generation synthesis, this intermediate is transformed in two steps to homoallyl amine rac-43, whose formaldiminium derivative undergoes efficient aza-Cope/Mannich reaction to give pentacyclic ketone rac-44. In four additional steps, this intermediate is advanced to (±)-actinophyllic acid. The synthesis is streamlined by elaborating ketone rac-37 to β-hydroxyester intermediate rac-53, which is directly transformed to (±)-actinophyllic acid upon exposure to HCl and paraformaldehyde. This concise second-generation total synthesis of (±)-actinophyllic acid is realized in 22% overall yield from commercially available di-tert-butyl malonate and o-nitrophenylacetic acid by a sequence that proceeds by way of only six isolated intermediates. The first enantioselective total synthesis of (−)-actinophyllic acid (1) is accomplished by this direct sequence from tricyclic keto malonate (S)-35. Catalytic enantioselective reduction of α,β-unsaturated ketone 66 is the key step in the preparation of intermediate (S)-35 from the commercially available Boc-amino acid 65. Discussed also is the possibility that the aza-Cope/Mannich reaction might be involved in the biosynthesis of (−)-actinophyllic acid.
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