Isotropisation at small scales of rotating helically-driven turbulence

We present numerical evidence of how three-dimensionalization occurs at small scale in rotating turbulence with Beltrami (ABC) forcing, creating helical flow. The Zeman scale $\ell_{\Omega}$ at which the inertial and eddy turn-over times are equal is more than one order of magnitude larger than the dissipation scale, with the relevant domains (large-scale inverse cascade of energy, dual regime in the direct cascade of energy $E$ and helicity $H$, and dissipation) each moderately resolved. These results stem from the analysis of a large direct numerical simulation on a grid of $3072^3$ points, with Rossby and Reynolds numbers respectively equal to 0.07 and $2.7\times 10^4$. At scales smaller than the forcing, a helical wave-modulated inertial law for the energy and helicity spectra is followed beyond $\ell_{\Omega}$ by Kolmogorov spectra for $E$ and $H$. Looking at the two-dimensional slow manifold, we also show that the helicity spectrum breaks down at $\ell_{\Omega}$, a clear sign of recovery of three-dimensionality in the small scales.Comment: 13 pages, 6 figure

Simultaneous fine structure observation of wind and temperature profiles by the Arecibo 430-MHz radar and in situ measurements

A simultaneous campaign of balloon and radar measurements took place on March 14 to 16, 1984, above the Arecibo 430-MHz radar. This radar was operating with a vertical resolution of 150 m following two antenna beam directions: 15 deg. from the zenith, respectively, in the N-S and E-W directions. The main results concerning the comparison between the flight and simultaneous radar measurements obtained on March 15, 1984 are analyzed. The radar return power profile (S/N ratio in dB) exhibits maxima which are generally well correlated with step-like structures in the potential temperature profile. These structures are generally considered as the consequence of the mixing processes induced by the turbulence. A good correlation appears in the altitude range 12.5 to 19 km between wind shears induced by a wave structure observed in the meridional wind and the radar echo power maxima. This wave structure is characterized by a vertical wavelength of about 2.5 km, and a period in the range 30 to 40 hours. These characteristics are deduced from the twice daily rawinsonde data launched from the San Juan Airport by the National Weather Service. These results pointed out an example of the interaction between wave and turbulence in the upper troposphere and lower stratosphere. Turbulent layers are observed at locations where wind shears related to an internal inertia-gravity wave are maxima

Effect of helicity and rotation on the free decay of turbulent flows

The self-similar decay of energy in a turbulent flow is studied in direct numerical simulations with and without rotation. Two initial conditions are considered: one non-helical (mirror-symmetric), and one with maximal helicity. The results show that, while in the absence of rotation the energy in the helical and non-helical cases decays with the same rate, in rotating flows the helicity content has a major impact on the decay rate. These differences are associated with differences in the energy and helicity cascades when rotation is present. Properties of the structures that arise in the flow at late times in each time are also discussed.Comment: 4 pages, 4 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

Sub-State Purchasing of Managed Behavioral Health Care: An Analysis of County-Level Managed Care Contracts

For this study, SAMHSA asked us to analyze county-level managed health care contracts that include behavioral health services. SAMHSA has indicated that sub-state entities, particularly counties, are beginning to explore the feasibility of contracting with managed care organizations, both to control costs and to improve coordination of services for the mental health or substance abuse systems they manage. In commissioning these various contract studies, SAMHSA was primarily interested in tracking the development of these new types of managed behavioral health care procurements and contracting practices, as well as determining whether there were exemplary commercial behavioral health provisions that could be adapted to public sector contracts

An Analysis of the Medicaid IMD Exclusion

This report examines the Medicaid Institutions for Mental Disease (IMD) exclusion, one of the very few instances in which federal Medicaid law prohibits federal contribution to the cost of medically necessary care furnished by licensed medical care providers to enrolled program beneficiaries. The report begins with a brief overview of Medicaid\u27s role in financing care for conditions and illnesses classified as mental diseases under professional medical guidelines and the allocation of state and federal funding responsibilities under Medicaid. The report then reviews the elements of the Medicaid IMD exclusion, as well as key judicial and administrative rulings related to the exclusion. The report concludes with a discussion of certain policy considerations related to the exclusion

Mental Illness and Addiction Disorders and Medicaid Managed Care

This Special Report on mental illness and addiction disorders is part of Negotiating the New Health System: A Nationwide Study of Medicaid Managed Care Contracts, now in its third edition. Negotiating the New Health System is a nationwide point-in-time study of agreements between state Medicaid agencies and managed care organizations (MCOs) offering general or specialized managed behavioral health care products. Each individual edition of Negotiating the New Health System is a point-in-time study or snapshot of these agreements for a particular year. However, the current series of editions, taken together, are beginning to form a longitudinal basis for reviewing the evolution of the agreements, for evaluating progress, and for identifying areas needing further work or scrutiny

The decay of Batchelor and Saffman rotating turbulence

The decay rate of isotropic and homogeneous turbulence is known to be affected by the large-scale spectrum of the initial perturbations, associated with at least two cannonical self-preserving solutions of the von K\'arm\'an-Howarth equation: the so-called Batchelor and Saffman spectra. The effect of long-range correlations in the decay of anisotropic flows is less clear, and recently it has been proposed that the decay rate of rotating turbulence may be independent of the large-scale spectrum of the initial perturbations. We analyze numerical simulations of freely decaying rotating turbulence with initial energy spectra $\sim k^4$ (Batchelor turbulence) and $\sim k^2$ (Saffman turbulence) and show that, while a self-similar decay cannot be identified for the total energy, the decay is indeed affected by long-range correlations. The decay of two-dimensional and three-dimensional modes follows distinct power laws in each case, which are consistent with predictions derived from the anisotropic von K\'arm\'an-Howarth equation, and with conservation of anisotropic integral quantities by the flow evolution

An Overview of Legal Developments in Managed Care Caselaw and Selected Case Studies of Legal Developments in State Contracting for Managed Behavioral Health Services

This analysis provides an overview of recent legal developments in managed care case law. Three types of cases are reviewed: claims brought by managed care enrollees against managed care companies and health plans; cases related either directly or indirectly to managed care and brought by both beneficiaries and managed care organizations against state Medicaid agencies and other public agencies engaged in the purchase of managed care; and cases brought by individual health professionals against managed care organizations