Nonparametric estimation of extremal dependence

There is an increasing interest to understand the dependence structure of a random vector not only in the center of its distribution but also in the tails. Extreme-value theory tackles the problem of modelling the joint tail of a multivariate distribution by modelling the marginal distributions and the dependence structure separately. For estimating dependence at high levels, the stable tail dependence function and the spectral measure are particularly convenient. These objects also lie at the basis of nonparametric techniques for modelling the dependence among extremes in the max-domain of attraction setting. In case of asymptotic independence, this setting is inadequate, and more refined tail dependence coefficients exist, serving, among others, to discriminate between asymptotic dependence and independence. Throughout, the methods are illustrated on financial data.Comment: 22 pages, 9 figure

Hydrodynamics of the Chiral Dirac Spectrum

We derive a hydrodynamical description of the eigenvalues of the chiral Dirac spectrum in the vacuum and in the large $N$ (volume) limit. The linearized hydrodynamics supports sound waves. The stochastic relaxation of the eigenvalues is captured by a hydrodynamical instanton configuration which follows from a pertinent form of Euler equation. The relaxation from a phase of localized eigenvalues and unbroken chiral symmetry to a phase of de-localized eigenvalues and broken chiral symmetry occurs over a time set by the speed of sound. We show that the time is $\Delta \tau=\pi\rho(0)/2\beta N$ with $\rho(0)$ the spectral density at zero virtuality and $\beta=1,2,4$ for the three Dyson ensembles that characterize QCD with different quark representations in the ergodic regime.Comment: 6 page

Hydrodynamics of the Polyakov Line in SU(Nc)(N_c) Yang-Mills

We discuss a hydrodynamical description of the eigenvalues of the Polyakov line at large but finite $N_c$ for Yang-Mills theory in even and odd space-time dimensions. The hydro-static solutions for the eigenvalue densities are shown to interpolate between a uniform distribution in the confined phase and a localized distribution in the de-confined phase. The resulting critical temperatures are in overall agreement with those measured on the lattice over a broad range of $N_c$, and are consistent with the string model results at $N_c=\infty$. The stochastic relaxation of the eigenvalues of the Polyakov line out of equilibrium is captured by a hydrodynamical instanton. An estimate of the probability of formation of a Z(N$_c)$ bubble using a piece-wise sound wave is suggested.Comment: 5 pages, 2 figure

Hydrodynamical Description of the QCD Dirac Spectrum at Finite Chemical Potential

We present a hydrodynamical description of the QCD Dirac spectrum at finite chemical potential as an uncompressible droplet in the complex eigenvalue space. For a large droplet, the fluctuation spectrum around the hydrostatic solution is gapped by a longitudinal Coulomb plasmon, and exhibits a frictionless odd viscosity. The stochastic relaxation time for the restoration/breaking of chiral symmetry is set by twice the plasmon frequency. The leading droplet size correction to the relaxation time is fixed by a universal odd viscosity to density ratio $\eta_O/\rho_0=(\beta-2)/4$ for the three Dyson ensembles $\beta=1,2,4$.Comment: 5 page

Expression, purification and characterization of human myosin 9a

Myosins form a large family of actin-based motor proteins that are involved in different forms of cellular motility. Those include muscle contraction, intracellular transport, endo- and exocytosis and cell division and locomotion. Certain myosin isoforms are also involved in hearing and vision processes. So far, very little is known about the myosin class 9. Myosin 9 has been proposed to be involved in cell differentiation and morphology. Mammals express two class 9 myosins; myosin 9a is expressed in brain and its loss results in the formation of hydrocephalus, while myosin 9b appears to be involved in the directional movement of dendritic cells. On the structural level, myosin 9 contains a RhoGAP domain in its tail region, indicating it could link its mechanical activity along actin filaments to intracellular protein G signaling. So far, only myosin 9b orthologs have been investigated. Here, I used the baculovirus/insect cell system to express recombinant human myosin 9a constructs, optimized the purification procedure and examined the function of myosin 9a motor in vitro. Designed constructs contained the motor and neck domains of myosin 9a, fused to different N- and C-terminal tags to facilitate purification. I addressed the ATPase activity of myosin 9a (particularly the Minimal Motor Domain construct) in the absence and presence of F-actin by means of an NADH enzyme-linked assay. The mechanical activity of myosin 9a was addressed by means of the gliding filament assay. The velocity of actin gliding over the lawn of surface-bound myosin 9a molecules was largely independent from the motor density on the surface of a flow cell. In summary, this work presents the first successful purification of recombinant human myosin 9a motor constructs and describes basic mechanochemical properties of human myosin 9a motor. The results presented in this work provide framework for further investigation of myosin 9a properties, including investigation of the regulatory role of the tail domain of myosin 9a

Identical Twins x 3

CINEMA IS ABOUT creating images in motion. It reflects the essential denotation of an image as an optical reproduction of an object, scene, movement, gesture. It's about visual representations of our perceptions and ourselves. It's a medium through which directors project their visions, actors reincarnate themselves in ever new impersonations, and viewers watch the screen images as reflections of mimetic (or fantastic) reality. So far, it has been technology's greatest gift to the human imagination, a remarkable mirror of life-like illusions. Filmmakers naturally exploit cinema's fundamental reproductive nature, its inherent double-ness, often deliberately exploring questions of identity and reliability of our perceptions and judgements to engage us in fascinating games of visual deception and intellectual manipulation. Those themes typically involve mistaken identities, lookalikes, impostors, and alter egos, as well as incubi and body snatchers in their horror and sci-fi varieties. The protagonists live double (as in, say, Europa, Europa..

Do misery and happiness both love company? The emotional consequences of listening to experiences shared by others.

Sharing personal experiences and events is an important component of developing personal relationships and connecting with others. Two adages present contradictory thoughts on how “friends” will respond to personal accomplishments or difficulties. The first claims, “When times get rough, you will find out who your real friends are”; the other claims, “Misery loves company”. This study focuses on how sharing information affects individual mood in order to understand how sharing a personal experience may affect relationships and listeners. Previous research has focused on how the speaker potentially benefits from sharing personal experiences with others. Instead, this study attempts to understand how the listener is affected emotionally by having an event shared with them; do people typically enjoy hearing about others’ happiness or do people relish in the misery of others? The “Personal Experiences Survey” functions as a preliminary measure that asks participants to first act as a “speaker” in sharing their own personal experience and then asks them to be a “listener” and read another individual’s personal experience. Participants’ moods are measured both after acting as the “speaker” and as the “listener” in order to detect overall mood changes. The participants with the greatest increase in positive mood were those who shared their own positive experience and then read a positive experience; participants also preferred listening to events congruent to their present mood. Overall, this study shows that individuals focus on their own experiences, minimizing the experiences of others unless they, as a listener, benefit