25,813 research outputs found

    Income inequality in the digital era. WP C.S.D.L.E. "Massimo D'Antona", N. 9, 2002

    Get PDF
    [From the Introduction]. The changes in the employment relationship have been accompanied by a marked deterioration in income distribution.... The growing gap between rich and poor stands as a persistent reminder that current economic arrangements are not moving in the direction of economic justice. The dramatic extent of inequality offends our sense of decency and undermines social cohesion. In recent years, many economists have analyzed the trends in income distribution in order to isolate the causes of the current trends. In this paper I review the existing evidence and theories about the causes of rising income inequality. I suggest that the changing nature of the employment relationship is contributing to, or perhaps even driving, rising income inequality. The following chapter presents and evaluates several policy proposals for redressing inequality or ameliorating its effects

    Distributed representations accelerate evolution of adaptive behaviours

    Get PDF
    Animals with rudimentary innate abilities require substantial learning to transform those abilities into useful skills, where a skill can be considered as a set of sensory - motor associations. Using linear neural network models, it is proved that if skills are stored as distributed representations, then within- lifetime learning of part of a skill can induce automatic learning of the remaining parts of that skill. More importantly, it is shown that this " free- lunch'' learning ( FLL) is responsible for accelerated evolution of skills, when compared with networks which either 1) cannot benefit from FLL or 2) cannot learn. Specifically, it is shown that FLL accelerates the appearance of adaptive behaviour, both in its innate form and as FLL- induced behaviour, and that FLL can accelerate the rate at which learned behaviours become innate

    Modeling Hybrid Stars

    Full text link
    We study the so called hybrid stars, which are hadronic stars that contain a core of deconfined quarks. For this purpose, we make use of an extended version of the SU(3) chiral model. Within this approach, the degrees of freedom change naturally from hadrons (baryon octet) to quarks (u, d, s) as the temperature and/or density increases. At zero temperature we are still able to reproduce massive stars, even with the inclusion of hyperons.Comment: To appear in the proceedings of Conference C12-08-0

    Type 2 radio bursts, interplanetary shocks and energetic particle events

    Get PDF
    Using the ISEE-3 radio astronomy experiment data 37 interplanetary (IP) type II bursts have been identified in the period September 1978 to December 1981. These events and the associated phenomena are listed. The events are preceded by intense, soft X ray events with long decay times (LDEs) and type II and/or type IV bursts at meter wavelengths. The meter wavelength type II bursts are usually intense and exhibit herringbone structure. The extension of the herringbone structure into the kilometer wavelength range results in the occurrence of a shock accelerated (SA) event. The majority of the interplanetary type II bursts are associated with energetic particle events. These results support other studies which indicate that energetic solar particles detected at 1 A.U. are generated by shock acceleration. From a preliminary analysis of the available data there appears to be a high correlation with white light coronal transients

    Changing Negative Perceptions of Individuals With Facial Disfigurement: The Effectiveness of a Brief Intervention

    Get PDF
    Can a brief personal narrative by an individual with facial disfigurement enhance perceptions of their skills and personality? Participants (n = 224) mainly from Europe and the USA completed the study online. Four experimental conditions presented either a video clip or the audio soundtrack, relating either a positive message or a message about overcoming adversity. In the control condition, participants viewed a still facial photograph. Evaluations of sociability and resilience, emotional stability, leadership, and success in forming relationships, and expectations regarding future interactions, were all enhanced by the personal narratives compared to the still photograph. Experimental conditions did not differ from each other. It appears that a brief online intervention can be effective in encouraging future contact with individuals with facial disfigurement

    A note on the breathing mode of an elastic sphere in Newtonian and complex fluids

    Full text link
    Experiments on the acoustic vibrations of elastic nanostructures in fluid media have been used to study the mechanical properties of materials, as well as for mechanical and biological sensing. The medium surrounding the nanostructure is typically modeled as a Newtonian fluid. A recent experiment however suggested that high-frequency longitudinal vibration of bipyramidal nanoparticles could trigger a viscoelastic response in water-glycerol mixtures [M. Pelton et al., "Viscoelastic flows in simple liquids generated by vibrating nanostructures," Phys. Rev. Lett. 111, 244502 (2013)]. Motivated by these experimental studies, we first revisit a classical continuum mechanics problem of the purely radial vibration of an elastic sphere, also called the breathing mode, in a compressible viscous fluid, and then extend our analysis to a viscoelastic medium using the Maxwell fluid model. The effects of fluid compressibility and viscoelasticity are discussed. Although in the case of longitudinal vibration of bipyramidal nanoparticles, the effects of fluid compressibility were shown to be negligible, we demonstrate that it plays a significant role in the breathing mode of an elastic sphere. On the other hand, despite the different vibration modes, the breathing mode of a sphere triggers a viscoelastic response in water-glycerol mixtures similar to that triggered by the longitudinal vibration of bipyramidal nanoparticles. We also comment on the effect of fluid viscoelasticity on the idea of destroying virus particles by acoustic resonance

    Termination Shock Asymmetries as Seen by the Voyager Spacecraft: The Role of the Interstellar Magnetic Field and Neutral Hydrogen

    Get PDF
    We show that asymmetries of the termination shock due to the influence of the interstellar magnetic field (ISMF) are considerably smaller in the presence of neutral hydrogen atoms, which tend to symmetrize the heliopause, the termination shock, and the bow shock due to charge exchange with charged particles. This leads to a much stronger restriction on the ISMF direction and its strength. We demonstrate that in the presence of the interplanetary magnetic field the plane defined by the local interstellar medium (LISM) velocity and magnetic field vectors does not exactly coincide with the plane defined by the interstellar neutral helium and hydrogen velocity vectors in the supersonic solar wind region, which limits the accuracy of the inferred direction of the ISMF. We take into account the tilt of the LISM velocity vector with respect to the ecliptic plane and show that magnetic fields as strong as 3 ÎĽG or greater may be necessary to account for the observed asymmetry. Estimates are made of the longitudinal streaming anisotropy of energetic charged particles at the termination shock caused by the nonalignment of the interplanetary magnetic field with its surface. By investigating the behavior of interplanetary magnetic field lines that cross the Voyager 1 trajectory in the inner heliosheath, we estimate the length of the trajectory segment that is directly connected by these lines to the termination shock. A possible effect of the ISMF draping over the heliopause is discussed in connection with radio emission generated in the outer heliosheath

    Strategic decision-making process (SDMP) in times of crisis:evidence from Greek banks

    Get PDF
    This paper investigates the strategic decision making process (SDMP) of Greek banks’ top management in the context of profound organisational changes introduced in 2012 due to the aftermath of the 2008 global financial crisis. It focuses on the impact of three key dimensions of the SDMP, namely, rationality, intuition and political behaviour, relating to four changes introduced, namely, mergers and acquisitions, branch network rationalisation, integration of information technology (IT) and downsizing of operations and personnel. A survey questionnaire was conducted, targeting Greek banks’ top management. Out of 140 questionnaires, 78 were returned, a 55.71% response rate. Data was analysed using structural equation modelling. Research findings identify rationality as a key dimension of SDMP for all organisational changes, as there was high focus on identifying and analysing all required information, use of external financial advisors, and reliance on multiple methods of information gathering. Decision-makers used their intuition in the form of past experience when making acquisition decisions, whilst their personal judgment and “inner voice” were neglected.Finally, political behaviour was not displayed during this process, as decision-makers were open with each other about their interests and preferences, and there was no bargaining, negotiation or use of power amongst them. One limitation was that of not considering all the factors that might help measure SDMP. Also, this study was conducted in a period of political and financial uncertainty for Greek banks, as well as for the Greek economy in general, so findings may not be generalizable to other industries and countries. Conducting interviews could have offered deeper insight as well. This study’s value lies in the fact that the organisational changes were determined by Greece’s leaders, and thus the Greek banks had to operate under a dynamic, inflexible and non-autonomous environment. Also, this study extends prior SDMP research by examining the impact of the three key SDMP dimensions on four types of organisational change

    Forced-flow once-through boilers

    Get PDF
    A compilation and review of NASA-sponsored research on boilers for use in spacecraft electrical power generation systems is presented. Emphasis is on the heat-transfer and fluid-flow problems. In addition to space applications, much of the boiler technology is applicable to terrestrial and marine uses such as vehicular power, electrical power generation, vapor generation, and heating and cooling. Related research areas are discussed such as condensation, cavitation, line and boiler dynamics, the SNAP-8 project (Mercury-Rankine cycle), and conventional terrestrial boilers (either supercritical or gravity-assisted liquid-vapor separation types). The research effort was directed at developing the technology for once-through compact boilers with high heat fluxes to generate dry vapor stably, without utilizing gravity for phase separations. A background section that discusses, tutorially, the complex aspects of the boiling process is presented. Discussions of tests on alkali metals are interspersed with those on water and other fluids on a phenomenological basis
    • …