81 research outputs found

    Risky choices in strategic environments: An experimental investigation of a real options game

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    Managers frequently make decisions under conditions of fundamental uncertainty due the stochastic nature of the outcomes and competitive rivalry. In this study, we experimentally test a theoretical model under fundamental uncertainty and competitive rivalry by designing a sequential interaction game between two players. The first mover can decide either to choose a sure outcome that assigns a risky outcome to the second mover or to pass the decision to the second mover. If the second player gets the chance to decide, she can choose between a sure outcome, conditioned by the assignment of a risky payoff to the first mover, or the sharing of the risky outcome with the first mover. We then introduce the following experimental treatments: (i) relegating second-mover participants to a purely passive role and substituting them with a random device (absence of strategic uncertainty - that is, when the source of uncertainty is a human subject); (ii) providing information about the behaviour of second-mover counterparts; and (iii) completely removing the second-mover participant.We find that decision makers are sensitive to the presence or absence of strategic uncertainty; indeed, in the presence of strategic uncertainty, first movers more often diverge from the behaviour predicted by the model. Given our experimental results, the theoretical model needs to be revisited. The standard model of monetary payoff-maximizing agents should be substituted by one of decision makers who maximize a utility function which includes the psychological cost induced by strategic uncertainty. (C) 2019 Published by Elsevier B.V

    High resolution 3D visualization of the spinal cord in a post-mortem murine model

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    A crucial issue in the development of therapies to treat pathologies of the central nervous system is represented by the availability of non-invasive methods to study the three-dimensional morphology of spinal cord, with a resolution able to characterize its complex vascular and neuronal organization. X-ray phase contrast micro-tomography enables a high-quality, 3D visualization of both the vascular and neuronal network simultaneously without the need of contrast agents, destructive sample preparations or sectioning. Until now, high resolution investigations of the post-mortem spinal cord in murine models have mostly been performed in spinal cords removed from the spinal canal. We present here post-mortem phase contrast micro-tomography images reconstructed using advanced computational tools to obtain high-resolution and high-contrast 3D images of the fixed spinal cord without removing the bones and preserving the richness of micro-details available when measuring exposed spinal cords. We believe that it represents a significant step toward the in-vivo application

    Steerable3D: An ImageJ plugin for neurovascular enhancement in 3-D segmentation

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    PurposeImage processing plays a fundamental role in the study of central nervous system, for example in the analysis of the vascular network in neurodegenerative diseases. Synchrotron X-ray Phase-contrast micro-Tomography (SXPCT) is a very attractive method to study weakly absorbing samples and features, such as the vascular network in the spinal cord (SC). However, the identification and segmentation of vascular structures in SXPCT images is seriously hampered by the presence of image noise and strong contrast inhomogeneities, due to the sensitivity of the technique to small electronic density variations. In order to help with these tasks, we implemented a user-friendly ImageJ plugin based on a 3D Gaussian steerable filter, tuned up for the enhancement of tubular structures in SXPCT images.MethodsThe developed 3D Gaussian steerable filter plugin for ImageJ is based on the steerability properties of Gaussian derivatives. We applied it to SXPCT images of ex-vivo mouse SCs acquired at different experimental conditions.ResultsThe filter response shows a strong amplification of the source image contrast-to-background ratio (CBR), independently of structures orientation. We found that after the filter application, the CBR ratio increases by a factor ranging from ~6 to ~60. In addition, we also observed an increase of 35% of the contrast to noise ratio in the case of injured mouse SC.ConclusionThe developed tool can generally facilitate the detection/segmentation of capillaries, veins and arteries that were not clearly observable in non-filtered SXPCT images. Its systematic application could allow obtaining quantitative information from pre-clinical and clinical images

    Virtual unrolling and deciphering of Herculaneum papyri by X-ray phase-contrast tomography

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    A collection of more than 1800 carbonized papyri, discovered in the Roman 'Villa dei Papiri' at Herculaneum is the unique classical library survived from antiquity. These papyri were charred during 79 A.D. Vesuvius eruption, a circumstance which providentially preserved them until now. This magnificent collection contains an impressive amount of treatises by Greek philosophers and, especially, Philodemus of Gadara, an Epicurean thinker of 1st century BC. We read many portions of text hidden inside carbonized Herculaneum papyri using enhanced X-ray phase-contrast tomography non-destructive technique and a new set of numerical algorithms for 'virtual-unrolling'. Our success lies in revealing the largest portion of Greek text ever detected so far inside unopened scrolls, with unprecedented spatial resolution and contrast, all without damaging these precious historical manuscripts. Parts of text have been decoded and the 'voice' of the Epicurean philosopher Philodemus is brought back again after 2000 years from Herculaneum papyri

    Virtual unrolling and deciphering of Herculaneum papyri by X-ray phase-contrast tomography

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    A collection of more than 1800 carbonized papyri, discovered in the Roman ‘Villa dei Papiri’ at Herculaneum is the unique classical library survived from antiquity. These papyri were charred during 79 A.D. Vesuvius eruption, a circumstance which providentially preserved them until now. This magnificent collection contains an impressive amount of treatises by Greek philosophers and, especially, Philodemus of Gadara, an Epicurean thinker of 1st century BC. We read many portions of text hidden inside carbonized Herculaneum papyri using enhanced X-ray phase-contrast tomography non-destructive technique and a new set of numerical algorithms for ‘virtual-unrolling’. Our success lies in revealing the largest portion of Greek text ever detected so far inside unopened scrolls, with unprecedented spatial resolution and contrast, all without damaging these precious historical manuscripts. Parts of text have been decoded and the ‘voice’ of the Epicurean philosopher Philodemus is brought back again after 2000 years from Herculaneum papyri

    Eliciting taxpayer preferences increases tax compliance

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    Two experiments show that eliciting taxpayer preferences on government spending—providing taxpayer agency--increases tax compliance. We first create an income and taxation environment in a laboratory setting to test for compliance with a lab tax. Allowing a treatment group to express nonbinding preferences over tax spending priorities, leads to a 16% increase in tax compliance. A followup online study tests this treatment with a simulation of paying US federal taxes. Allowing taxpayers to signal their preferences on the distribution of government spending, results in a 15% reduction in the stated take-up rate of a questionable tax loophole. Providing taxpayer agency recouples tax payments with the public services obtained in return, reduces general anti-tax sentiment, and holds satisfaction with tax payment stable despite increased compliance with tax dues. With tax noncompliance costing the US government $385billion annually, providing taxpayer agency could have meaningful economic impact. At the same time, giving taxpayers a voice may act as a two-way "nudge," transforming tax payment from a passive experience to a channel of communication between taxpayers and government

    Virtual unrolling and deciphering of Herculaneum papyri by X-ray phase-contrast tomography

    Get PDF
    A collection of more than 1800 carbonized papyri, discovered in the Roman 'Villa dei Papiri' at Herculaneum is the unique classical library survived from antiquity. These papyri were charred during 79 A.D. Vesuvius eruption, a circumstance which providentially preserved them until now. This magnificent collection contains an impressive amount of treatises by Greek philosophers and, especially, Philodemus of Gadara, an Epicurean thinker of 1st century BC. We read many portions of text hidden inside carbonized Herculaneum papyri using enhanced X-ray phase-contrast tomography non-destructive technique and a new set of numerical algorithms for 'virtual-unrolling'. Our success lies in revealing the largest portion of Greek text ever detected so far inside unopened scrolls, with unprecedented spatial resolution and contrast, all without damaging these precious historical manuscripts. Parts of text have been decoded and the 'voice' of the Epicurean philosopher Philodemus is brought back again after 2000 years from Herculaneum papyri

    Does the sole description of a tax authority affect tax evasion? The impact of described coercive and legitimate power.

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    Following the classic economic model of tax evasion, taxpayers base their tax decisions on economic determinants, like fine rate and audit probability. Empirical findings on the relationship between economic key determinants and tax evasion are inconsistent and suggest that taxpayers may rather rely on their beliefs about tax authority’s power. Descriptions of the tax authority’s power may affect taxpayers’ beliefs and as such tax evasion. Experiment 1 investigates the impact of fines and beliefs regarding tax authority’s power on tax evasion. Experiments 2-4 are conducted to examine the effect of varying descriptions about a tax authority’s power on participants’ beliefs and respective tax evasion. It is investigated whether tax evasion is influenced by the description of an authority wielding coercive power (Experiment 2), legitimate power (Experiment 3), and coercive and legitimate power combined (Experiment 4). Further, it is examined whether a contrast of the description of power (low to high power; high to low power) impacts tax evasion (Experiments 2-4). Results show that the amount of fine does not impact tax payments, whereas participants’ beliefs regarding tax authority’s power significantly shape compliance decisions. Descriptions of high coercive power as well as high legitimate power affect beliefs about tax authority’s power and positively impact tax honesty. This effect still holds if both qualities of power are applied simultaneously. The contrast of descriptions has little impact on tax evasion. The current study indicates that descriptions of the tax authority, e.g., in information brochures and media reports, have more influence on beliefs and tax payments than information on fine rates. Methodically, these considerations become particularly important when descriptions or vignettes are used besides objective information
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