Community structures and role detection in music networks

We analyze the existence of community structures in two different social networks obtained from similarity and collaborative features between musical artists. Our analysis reveals some characteristic organizational patterns and provides information about the driving forces behind the growth of the networks. In the similarity network, we find a strong correlation between clusters of artists and musical genres. On the other hand, the collaboration network shows two different kinds of communities: rather small structures related to music bands and geographic zones, and much bigger communities built upon collaborative clusters with a high number of participants related through the period the artists were active. Finally, we detect the leading artists inside their corresponding communities and analyze their roles in the network by looking at a few topological properties of the nodes.Comment: 14 pages 7 figure

The microscopic nature of localization in the quantum Hall effect

The quantum Hall effect arises from the interplay between localized and extended states that form when electrons, confined to two dimensions, are subject to a perpendicular magnetic field. The effect involves exact quantization of all the electronic transport properties due to particle localization. In the conventional theory of the quantum Hall effect, strong-field localization is associated with a single-particle drift motion of electrons along contours of constant disorder potential. Transport experiments that probe the extended states in the transition regions between quantum Hall phases have been used to test both the theory and its implications for quantum Hall phase transitions. Although several experiments on highly disordered samples have affirmed the validity of the single-particle picture, other experiments and some recent theories have found deviations from the predicted universal behaviour. Here we use a scanning single-electron transistor to probe the individual localized states, which we find to be strikingly different from the predictions of single-particle theory. The states are mainly determined by Coulomb interactions, and appear only when quantization of kinetic energy limits the screening ability of electrons. We conclude that the quantum Hall effect has a greater diversity of regimes and phase transitions than predicted by the single-particle framework. Our experiments suggest a unified picture of localization in which the single-particle model is valid only in the limit of strong disorder

Designing a Complaint and Grievance System and Other Member Assistance Services Under Medicaid Managed Care

Medicaid beneficiaries enrolled in managed care arrangements have two basic sets of procedural protections when benefits are denied. The first set consists of the right to timely and adequate notice of any action affecting [a] claim for medical assistance, as well as a fair hearing in the case of any individual whose claim for medical assistance under the plan is denied or is not acted upon with reasonable promptness. The second is the right to internal grievance procedures to challenge the denial of coverage *** or payment [of medical] assistance. The Health Care Financing Administration (HCFA) is expected to delineate the specific elements of each of these procedural safeguards in a managed care environment -- as well as how the two sets of protections relate to each other -- in forthcoming regulations implementing the Balanced Budget Act (BBA) of 1997. This Issue Brief examines how state Medicaid agencies approach the issue of grievances and appeals in their contracts with managed care organizations (MCOs) furnishing comprehensive services. The source of information for this Issue Brief is the MCO contract data base maintained by the Center for Health Services Research and Policy and supported in part by the Substance Abuse and Mental Health Services Administration. As a result, this Issue Brief focuses on grievance and appeals procedures for enrollees of managed care organizations and does not address the procedural protections available to individuals who are enrolled in other forms of managed care, such as primary care case management systems

Cultural Competence in Medicaid Managed Care Purchasing: General and Behavioral Health Services for Persons with Mental and Addiction-Related Illnesses and Disorders

This Issue Brief explores cultural competence. Employing the data base from the large-scale Medicaid contract analysis conducted annually by the Center for Health Services Research and Policy (CHSRP) (now CHPR), we examine the approaches that state agencies take in implementing the concept of cultural competence in the design and implementation of their managed care systems

Pegram v Herdrich: Implications for Consumer Protections in Managed Care

This Report, prepared for the Substance Abuse and Mental Health Services Administration, provides a brief overview of the United States Supreme Court\u27s landmark decision in Pegram v Herdrich (hereinafter referred to as Herdrich). This report begins with a brief overview of the debate in the courts over how to distinguish between legal challenges to the conduct of managed care companies in which all state remedies are preempted by ERISA and those that may proceed under state law. It then summarizes the facts of the Herdrich case and the Court\u27s holding. The report concludes with a discussion of the implications of the decision for federal and state consumer protection legislation. A point of caution should be raised. The Herdrich decision is so new, and its implications so potentially far-reaching, that legal scholars, policy makers, lawyers, and judges undoubtedly will be pondering and debating its meaning and reach for years. However, in light of the enormous attention now focused on managed care accountability, the decision will attract a great deal of attention. Consequently, at least a preliminary analysis is warranted

Coverage Decision-Making in Medicaid Managed Care: Key Issues in Developing Managed Care Contracts

Coverage provisions are the most complex part of any managed care contract. This is particularly true for Medicaid agencies, because of important differences between Medicaid and insurance. This Issue Brief identifies general issues that should be addressed as managed care contracts are developed and drafted, and it specifically explores the challenges faced by public purchasers when drafting managed care coverage provisions

Coverage Decisions Versus the Quality of Care: An Analysis of Recent ERISA Judicial Decisions and Their Implications for Employer-Insured Individuals

This Issue Brief, prepared for the Substance Abuse and Mental Health Services Administration, examines the evolution of this framework for analyzing health claims emanating from the conduct of ERISA-covered managed care arrangements and considers its implications for the provision of treatment for mental illness and addiction disorders. Both studies and anecdotal evidence suggest that managed care companies impose particularly rigorous controls over treatment for mental illness and addiction disorders. It is therefore perhaps not surprising that legal challenges to treatment decisions frequently involve individuals with these conditions. Consequently, to the extent that courts are in fact on the verge of re-conceptualizing their approach to analyzing managed care cases under ERISA, the implications for treatment of mental illness and addiction disorders may be especially significant