On the Adjudication of Conflicting Claims: An Experimental Study

This paper reports an experimental study on three well-known solutions for problems of adjudicating conflicting claims: the constrained equal awards, the proportional, and the constrained equal losses rules. We first let subjects play three games designed such that the unique equilibrium allocation coincides with the recommendation of one of these three rules. In addition, we let subjects play an additional game, that has the property that all (and only) strategy profiles in which players coordinate on the same rule constitute a strict Nash equilibrium. While in the first three games subjects’ play easily converges to the unique equilibrium rule, in the last game the proportional rule overwhelmingly prevails as a coordination device, especially when we frame the game as an hypothetical bankruptcy situation. We also administered a questionnaire to a different group of students, asking them to act as impartial arbitrators to solve (among others) the same problems played in the lab. Also in this case, respondents were sensitive to the framing of the questions, but the proportional rule was selected by the vast majority of respondents.Claims problems, Proportional rule, Experimental Economics

On the Adjudication of Conflicting Claims: An Experimental Study

This paper reports an experimental study on three well-known solutions for problems of adjudicating conflicting claims: the constrained equal awards, the proportional, and the constrained equal losses rules. We first let subjects play three games designed such that the unique equilibrium allocation coincides with the recommendation of one of these three rules. In addition, we let subjects play an additional game, that has the property that all (and only) strategy profiles in which players coordinate on the same rule constitute a strict Nash equilibrium. While in the first three games subjectsÕ play easily converges to the unique equilibrium rule, in the last game the proportional rule overwhelmingly prevails as a coordination device, especially when we frame the game as an hypothetical bankruptcy situation. We also administered a questionnaire to a different group of students, asking them to act as impartial arbitrators to solve (among others) the same problems played in the lab. Also in this case, respondents were sensitive to the framing of the questions, but the proportional rule was selected by the vast majority of respondents.Claims problems, Proportional rule, Experimental Economics

The truncated and evolving inner accretion disc of the black hole GX 339-4

The nature of accretion onto stellar mass black holes in the low/hard state remains unresolved, with some evidence suggesting that the inner accretion disc is truncated and replaced by a hot flow. However, the detection of relativistic broadened Fe emission lines, even at relatively low luminosities, seems to require an accretion disc extending fully to its innermost stable circular orbit. Modelling such features is however highly susceptible to degeneracies, which could easily bias any interpretation. We present the first systematic study of the Fe line region to track how the inner accretion disc evolves in the low/hard state of the black hole GX 339$-$4. Our four observations display increased broadening of the Fe line over two magnitudes in luminosity, which we use to track any variation of the disc inner radius. We find that the disc extends closer to the black hole at higher luminosities, but is consistent with being truncated throughout the entire low/hard state, a result which renders black hole spin estimates inaccurate at these stages of the outburst. Furthermore, we show that the evolution of our spectral inner disc radius estimates corresponds very closely to the trend of the break frequency in Fourier power spectra, supporting the interpretation of a truncated and evolving disc in the hard state.Comment: Accepted for publication in A&A. Some typos corrected from version

Revealing accretion onto black holes: X-ray reflection throughout three outbursts of GX 339-4

Understanding the dynamics behind black hole state transitions and the changes they reflect in outbursts has become long-standing problem. The X-ray reflection spectrum describes the interaction between the hard X-ray source (the power-law continuum) and the cool accretion disc it illuminates, and thus permits an indirect view of how the two evolve. We present a systematic analysis of the reflection spectrum throughout three outbursts (500+ observations) of the black hole binary GX 339-4, representing the largest study applying a self-consistent treatment of reflection to date. Particular attention is payed to the coincident evolution of the power-law and reflection, which can be used to determine the accretion geometry. The hard state is found to be distinctly reflection weak, however the ratio of reflection to power-law gradually increases as the source luminosity rises. In contrast the reflection is found dominate the power-law throughout most of the soft state, with increasing supremacy as the source decays. We discuss potential dynamics driving this, favouring inner disc truncation and decreasing coronal height for the hard and soft states respectively. Evolution of the ionisation parameter, power-law slope and high-energy cut-off also agree with this interpretation.Comment: Accepted for publication in MNRA

The peculiar Galactic center neutron star X-ray binary XMM J174457-2850.3

The recent discovery of a milli-second radio pulsar experiencing an accretion outburst similar to those seen in low mass X-ray binaries, has opened up a new opportunity to investigate the evolutionary link between these two different neutron star manifestations. The remarkable X-ray variability and hard X-ray spectrum of this object can potentially serve as a template to search for other X-ray binary/radio pulsar transitional objects. Here we demonstrate that the transient X-ray source XMM J174457-2850.3 near the Galactic center displays similar X-ray properties. We report on the detection of an energetic thermonuclear burst with an estimated duration of ~2 hr and a radiated energy output of ~5E40 erg, which unambiguously demonstrates that the source harbors an accreting neutron star. It has a quiescent X-ray luminosity of Lx~5E32 erg/s and exhibits occasional accretion outbursts during which it brightens to Lx~1E35-1E36 erg/s for a few weeks (2-10 keV). However, the source often lingers in between outburst and quiescence at Lx~1E33-1E34 erg/s. This unusual X-ray flux behavior and its relatively hard X-ray spectrum, a power law with an index of ~1.4, could possibly be explained in terms of the interaction between the accretion flow and the magnetic field of the neutron star.Comment: 10 pages, 3 figures, 2 tables, accepted to ApJ after minor revision (provided a more detailed description of the long-term X-ray behavior in Section 3.1 and Figure 1

Virtual mechanical product disassembly sequences based on disassembly order graphs and time measurement units

Recently, the approach that defines the total life cycle assessment (LCA) and the end of life (EoL) in the early design phases is becoming even more promising. Literature evidences many advantages in terms of the saving of costs and time and in the fluent organization of the whole design process. Design for disassembly (DfD) offers the possibility of reducing the time and cost of disassembling a product and accounts for the reusing of parts and of the dismantling of parts, joints, and materials. The sequence of disassembly is the ordered way to extract parts from an assembly and is a focal item in DfD because it can deeply influence times and operations. In this paper, some disassembly sequences are evaluated, and among them, two methods for defining an optimal sequence are provided and tested on a case study of a mechanical assembly. A further sequence of disassembly is provided by the authors based on experience and personal knowledge. All three are analyzed by the disassembly order graph (DOG) approach and compared. The operations evaluated have been converted in time using time measurement units (TMUs). As result, the best sequence has been highlighted in order to define a structured and efficient disassembly

Evaluation of the masonry and timber structures of San Francisco Church in Santiago de Cuba through nondestructive diagnostic methods

Recently, due to a renewed interest in the religious architectural heritage of the Caribbean island of Cuba, some important interventions for the restoration and reinforcement of the colonial churches of the island were carried out. The authors, collaborating with the Archdiocese of Santiago de Cuba in a project concerning the protection of Cuban churches, applied some nondestructive and noninvasive destructive tests for an in-depth study of the main characteristics of those structures. The diagnostic method, developed mainly for the historical buildings or monuments of Europe and North America, was used to study some peculiarities of the building construction traditions of this area. The proposed techniques revealed the existence of several original solutions, for example, defenses for seismic mitigation, developed to resist the earthquakes that frequently affect the area

Analysis of the plasma transport in numerical simulations of helicon plasma thrusters

The accurate simulation of the plasma transport in helicon sources is a key aspect to improve the design of Helicon Plasma Thrusters (HPTs). Specifically, the 3D-VIRTUS code was proven to provide satisfactory estimations of the propulsive performance of realistic HPTs (difference between measures and numerical estimations of the thrust <30%). Nonetheless, further investigations are needed to deepen the influence that the plasma chemistry model, the formulation of the energy equation, and the definition of the diffusion coefficients have on the results of the simulation. First, a quantitative analysis has been conducted on a simplified configuration of HPT to study each phenomenon separately. Second, the generalized fluid model has been benchmarked against measures of plasma density performed on a helicon source. The radiative decay reactions affect the estimation of the performance (e.g., thrust) up to 40%. The quasi-isotherm formulation of the energy equation affects results (e.g., electron density) up to 30%. Accounting for anomalous transport or defining diffusion coefficients classically does not have a major effect on the simulation (e.g., thrust varies less than 20%). The generalized formulation of the fluid model provides estimations of the plasma density, which are within the uncertainty band of the measures (i.e., differences <20%)

Delineating rainbow reflection and trapping with applications for energy harvesting

Important distinctions are made between two related wave control mechanisms that act to spatially separate frequency components; these so-called rainbow mechanisms either slow or reverse guided waves propagating along a graded line array. We demonstrate an important nuance distinguishing rainbow reflection from genuine rainbow trapping and show the implications of this distinction for energy harvesting designs, through inspection of the interaction time between slowed zero group velocity waves and the array. The difference between these related mechanisms is highlighted using a design methodology, applied to flexural waves on mass loaded thin Kirchhoff-Love elastic plates, and emphasised through simulations for energy harvesting in the setting of elasticity, by elastic metasurfaces of graded line arrays of resonant rods atop a beam. The delineation of these two effects, reflection and trapping, allows us to characterise the behaviour of forced line array systems and predict their capabilities for trapping, conversion and focusing of energy

transcriptional regulation of nuclear genes controlling plastid differentiation in tomato

ABSTRACTSeveral mechanisms which control transcription of genes encoding plastidial proteins in tomato are overviewed: light, the circadian clock, photooxidative stress and tissue-specific factors. Protein factors binding promoters of genes responding to such stimuli are described, as well as their abundance during the various phases of the light-dark cycle. Finally, the structure and regulation of a novel class of genes encoding plastidial enzymes, controlling carotenoid biosynthesis, are describe