An alternative model for the origin of gaps in circumstellar disks

Motivated by recent observational and numerical studies suggesting that collapsing protostellar cores may be replenished from the local environment, we explore the evolution of protostellar cores submerged in the external counter-rotating environment. These models predict the formation of counter-rotating disks with a deep gap in the gas surface density separating the inner disk (corotating with the star) and the outer counter-rotating disk. The properties of these gaps are compared to those of planet-bearing gaps that form in disks hosting giant planets. We employ numerical hydrodynamics simulations of collapsing cores that are replenished from the local counter-rotating environment, as well as numerical hydrodynamic simulations of isolated disks hosting giant planets, to derive the properties of the gaps that form in both cases. Our numerical simulations demonstrate that counter-rotating disks can form for a wide range of mass and angular momentum available in the local environment. The gap that separates both disks has a depletion factor smaller than 1%, can be located at a distance from ten to over a hundred AU from the star, and can propagate inward with velocity ranging from 1 AU/Myr to >100 AU/Myr. Unlike our previous conclusion, the gap can therefore be a long-lived phenomenon, comparable in some cases to the lifetime of the disk itself. For a proper choice of the planetary mass, the viscous \alpha-parameter and the disk mass, the planet-bearing gaps and the gaps in counter-rotating disks may show a remarkable similarity in the gas density profile and depletion factor, which may complicate their observational differentiation.Comment: 13 pages, 13 figures, accepted for publication in Astronomy & Astrophysic

Methodological and conceptual limitations in exercise addiction research

The aim of this brief analytical review is to highlight and disentangle research dilemmas in the field of exercise addiction. Research examining exercise addiction is primarily based on self-reports, obtained by questionnaires (incorporating psychometrically validated instruments), and interviews, which provide a range of risk scores rather than diagnosis. Survey methodology indicates that the prevalence of risk for exercise addiction is approximately 3 percent among the exercising population. Several studies have reported a substantially greater prevalence of risk for exercise addiction in elite athletes compared to those who exercise for leisure. However, elite athletes may assign a different interpretation to the assessment tools than leisure exercisers. The present paper examines the: 1) discrepancies in the classification of exercise addiction; 2) inconsistent reporting of exercise addiction prevalence; and 3) varied interpretation of exercise addiction diagnostic tools. It is concluded that there is the need for consistent terminology, to follow-up results derived from exercise addiction instruments with interviews, and to follow a theory-driven rationale in this area of research

Reform of the European Union financial supervisory and regulatory architecture and its implications for Asia

European Union countries offer a unique experience of financial regulatory and supervisory integration, complementing various other European integration efforts following the second world war. Financial regulatory and supervisory integration was a very slow process before 2008, despite significant cross-border integration especially of wholesale financial markets.However, the policy framework proved inadequate in the context of the major financial crisis in the EU starting in 2007, and especially in the euro area after 2010. That crisis triggered major changes to European financial regulation and to the financial supervisory architecture, most prominently with the creation of three new European supervisory authorities in 2011 and the gradual establishment of European banking union starting in 2012. The banking union is a major structural institutional change for the EU, arguably the most significant since the introduction of the euro. Even in its current highly incomplete form, and with no prospects for rapid completion, the banking union has improved financial supervision in the euro area and increased the euro area’s resilience. Asian financial integration lags well behind Europe, and there is no comparable political and legal integration. Nevertheless, Asia can draw useful lessons from European experiences in multiple areas that include the harmonisation of the micro-prudential framework, proper macro-prudential structures, and participation in global financial authorities

Efficiency and Security of Process Transparency in Production Networks - A View of Expectations, Obstacles and Potentials

Much of the resilience and flexibility of production networks lies in the transparency of processes that allows timely perception of actual process states and adequate decisions or intervention at the proper point of the production system. Such degree of observability and permeability do, however, bear risks of malevolent tapping or interference with the information stream which, in the case of production systems, can put both business and physical processes at risk, requiring careful exploration of security threats in horizontal and vertical integration, and individual end-to-end connections likewise. Also, different levels of networked production present specific needs—high throughput and low time lag on the shop-floor level, or tolerances for confidence, gambling and bounded-rational views in cross-company relations—that may conflict with security policies. The paper presents a systematic summary of such apparently contradicting preferences, and possible approaches of reconciliation currently perceived to be relevant on various abstraction levels of production networks.status: publishe