Anisotropy, inhomogeneity and inertial range scalings in turbulent convection

This paper provides a detailed study of scale-by-scale budgets in turbulent Rayleigh-B\'enard convection and aims at testing the applicability of Kolmogorov (1941) and Bolgiano (1959) theories for this flow. Particular emphasis is laid on anisotropic and inhomogeneous effects: the SO(3) decomposition of structure functions (Arad et al 1999) and a method of description of inhomogeneities proposed by Danaila et al (2001) are used to derive inhomogeneous and anisotropic generalizations of Kolmogorov and Yaglom equations applying to RB convection. The various terms in these equations are computed using data from a DNS of turbulent Boussinesq convection at \rayleigh=10^6 and \prandtl=1 with aspect ratio A=5. The analysis of the isotropic component demonstrates that the shape of the third-order velocity structure function is significantly influenced by buoyancy forcing and large-scale inhomogeneities, while the mixed third-order structure function appearing in Yaglom equation exhibits a clear scaling exponent 1 in a small range of scales. The magnitudes of the various low $\ell$ degree anisotropic components of the equations are also estimated and are shown to be comparable to their isotropic counterparts at moderate to large scales. Finally, a qualitative analysis shows that the influence of buoyancy forcing at scales smaller than the Bolgiano scale is likely to remain important up to \rayleigh=10^9, thus preventing Kolmogorov scalings from showing up in convective flows at lower Rayleigh numbers.Comment: 28 pages, 18 figures, accepted for publication in J. Fluid Mec

The Early Bird Waits for the Worm: May Federal Judgments Be Registered Prior to Appeal?

The federal registration statute, codified at 28 U.S.C. § 1963, permits a judgment creditor to register his or her judgment in another state by simply filing a copy of the judgment with the clerk of the registering court. Registration is permitted when the judgment becomes final by appeal, when the time to appeal expires, or when the court that entered the judgment orders registration for good cause shown. The majority of courts have interpreted good cause as a showing that the judgment debtor lacks assets in the forum jurisdiction to fulfill the judgment, but possesses substantial assets in the registering jurisdiction. District courts are split, however, on whether there must be a pending appeal before registration can be ordered. Registration gives the judgment creditor power to create a lien on the judgment debtor’s property in another district. The effect of the registered judgment depends on a state’s laws regarding liens. Liens in some states may reach personal property, creating the potential for a registered judgment to have harsh effects on the debtor’s livelihood and placing restrictions on the alienability of real property. The posting of a supersedeas bond can stay the enforcement of a judgment and alleviate the need for registration. This Note argues that a judgment creditor should be permitted to register her judgment without waiting for the judgment debtor to file an appeal. However, a court should have discretion to consider whether permitting registration when the judgment debtor has not yet posted a supersedeas bond would cause irreparable harm to a good faith debtor, and if so, grant the debtor time to post a bond

The Early Bird Waits for the Worm: May Federal Judgments Be Registered Prior to Appeal?

The federal registration statute, codified at 28 U.S.C. § 1963, permits a judgment creditor to register his or her judgment in another state by simply filing a copy of the judgment with the clerk of the registering court. Registration is permitted when the judgment becomes final by appeal, when the time to appeal expires, or when the court that entered the judgment orders registration for good cause shown. The majority of courts have interpreted good cause as a showing that the judgment debtor lacks assets in the forum jurisdiction to fulfill the judgment, but possesses substantial assets in the registering jurisdiction. District courts are split, however, on whether there must be a pending appeal before registration can be ordered. Registration gives the judgment creditor power to create a lien on the judgment debtor’s property in another district. The effect of the registered judgment depends on a state’s laws regarding liens. Liens in some states may reach personal property, creating the potential for a registered judgment to have harsh effects on the debtor’s livelihood and placing restrictions on the alienability of real property. The posting of a supersedeas bond can stay the enforcement of a judgment and alleviate the need for registration. This Note argues that a judgment creditor should be permitted to register her judgment without waiting for the judgment debtor to file an appeal. However, a court should have discretion to consider whether permitting registration when the judgment debtor has not yet posted a supersedeas bond would cause irreparable harm to a good faith debtor, and if so, grant the debtor time to post a bond

Secondary Hematoma Expansion and Perihemorrhagic Edema after Intracerebral Hemorrhage: From Bench Work to Practical Aspects.

Intracerebral hemorrhages (ICH) represent about 10-15% of all strokes per year in the United States alone. Key variables influencing the long-term outcome after ICH are hematoma size and growth. Although death may occur at the time of the hemorrhage, delayed neurologic deterioration frequently occurs with hematoma growth and neuronal injury of the surrounding tissue. Perihematoma edema has also been implicated as a contributing factor for delayed neurologic deterioration after ICH. Cerebral edema results from both blood-brain barrier disruption and local generation of osmotically active substances. Inflammatory cellular mediators, activation of the complement, by-products of coagulation and hemolysis such as thrombin and fibrin, and hemoglobin enter the brain and induce a local and systemic inflammatory reaction. These complex cascades lead to apoptosis or neuronal injury. By identifying the major modulators of cerebral edema after ICH, a therapeutic target to counter degenerative events may be forthcoming

Dynamical evolution of the chiral magnetic effect: Applications to the quark-gluon plasma

We study the dynamical evolution of the so-called chiral magnetic effect in an electromagnetic conductor. To this end, we consider the coupled set of corresponding Maxwell and chiral anomaly equations, and we prove that these can be derived from chiral kinetic theory. After integrating the chiral anomaly equation over space in a closed volume, it leads to a quantum conservation law of the total helicity of the system. A change in the magnetic helicity density comes together with a modification of the chiral fermion density. We study in Fourier space the coupled set of anomalous equations and we obtain the dynamical evolution of the magnetic fields, magnetic helicity density, and chiral fermion imbalance. Depending on the initial conditions we observe how the helicity might be transferred from the fermions to the magnetic fields, or vice versa, and find that the rate of this transfer also depends on the scale of wavelengths of the gauge fields in consideration. We then focus our attention on the quark-gluon plasma phase, and analyze the dynamical evolution of the chiral magnetic effect in a very simple toy model. We conclude that an existing chiral fermion imbalance in peripheral heavy ion collisions would affect the magnetic field dynamics, and consequently, the charge dependent correlations measured in these experiments.Comment: 41 pages, 14 figures, 3 appendices. Version 2: new global structure (appendix added), more explanations and additional references. Version accepted for publication in Physical Review D journa