Tests for covariance matrices, particularly for high dimensional data

Test statistics for sphericity and identity of the covariance matrix are presented, when the data are multivariate normal and the dimension, p, can be larger than the sample size, n. The statistics, derived under very general conditions, follow an approximate normal distribution for large p, also when p >> n. Simulation results, particularly emphasizing the case when p can be much larger than n, show that the proposed statistics are accurate for both size control and power. A discussion of the commonly used assumptions for high dimensional set up is also given, with the conclusions applicable in general as well as in the special case of high dimensional covariance testing

Optical phonons in new ordered perovskite Sr2Cu(Re0.69Ca0.31) Oy system observed by infrared reflectance spectroscopy

We report infrared reflectivity spectra for a new correlated cupric oxide system Sr2Cu(Re0.69Ca0.31)Oy with y ~ 0.6 at several temperatures ranging between 8 and 380 K. The reflectivity spectrum at 300 K comprises of several optical phonons. A couple of residual bands located around 315 and 653 cm-1 exhibit exceptionally large intensity as compared to the other ones. The overall reflectivity spectrum lifts up slightly with increasing temperature. The energy and damping factor of transverse-optical phonons are determined by fitting the imaginary dielectric constant by Lorentz oscillator model and discussed as a function of temperature in terms of lattice anharmonicity.Comment: 9 pages, 3 figures, presented at ISS2005, to appear in Physica

More on Five Dimensional EVH Black Rings

In this paper we continue our analysis of arXiv:1308.1478[hep-th] and study in detail the parameter space of three families of doubly spinning black ring solutions: balanced black ring, unbalanced ring and dipole-charged balanced black rings. In all these three families the Extremal Vanishing Horizon (EVH) ring appears in the vanishing limit of the dimensionful parameter of the solution which measures the ring size. We study the near horizon limit of the EVH black rings and for all three cases we find a (pinching orbifold) AdS$_3$ throat with the AdS$_3$ radius $\ell^2=8 G_5 M/(3\pi)$ where $M$ is the ring mass and $G_5$ is the 5d Newton constant. We also discuss the near horizon limit of near-EVH black rings and show that the AdS$_3$ factor is replaced with a generic BTZ black hole. We use these results to extend the EVH/CFT correspondence for black rings, a 2d CFT dual to near-EVH black rings.Comment: 30 page

Escape from immunotherapy: possible mechanisms that influence tumor regression/progression

Tumor escape is one major obstacle that has to be addressed prior to designing and delivering successful immunotherapy. There is compelling evidence to support the notion that immunogenic tumors, in murine models and cancer patients, can be rejected by the immune system under optimum conditions for activating adaptive and nonadaptive antitumor immune responses. Despite this capability, a large number of tumors continue to grow and evade recognition and/or destruction by the immune system. The limited success in current immunotherapeutic strategies may be due to a variety of reasons: failure of effector cells to compete with the growing tumor burden, production of humoral factors by tumors that locally block cytotoxicity, antigen/MHC loss, T-cell dysfunction, production of suppressor T cells—to name but a few causes for therapeutic ineffectiveness for the particular malignancy being treated. To optimize immunotherapy strategies, correction of immune-activating signals, eradication of inhibitory factors, and the evasion from newly developed immunoresistant tumor phenotypes need to be simultaneously considered