734 research outputs found
Central limit theorems for long range dependent spatial linear processes
Central limit theorems are established for the sum, over a spatial region, of observations from a linear process on a d d-dimensional lattice. This region need not be rectangular, but can be irregularly-shaped. Separate results are established for the cases of positive strong dependence, short range dependence, and negative dependence. We provide approximations to asymptotic variances that reveal differential rates of convergence under the three types of dependence. Further, in contrast to the one dimensional (i.e., the time series) case, it is shown that the form of the asymptotic variance in dimensions d > 1 critically depends on the geometry of the sampling region under positive strong dependence and under negative dependence and that there can be non-trivial edge-effects under negative dependence for d > 1. Precise conditions for the presence of edge effects are also given
Children's working understanding of knowledge sources : confidence in knowledge gained from testimony
In three experiments children aged between 3 and 5 years (N = 38; 52; 94; mean ages 3;7 to 5;2) indicated their confidence in their knowledge of the identity of a hidden toy. With the exception of some 3-year-olds, children revealed working understanding of their knowledge source by showing high confidence when they had seen or felt the toy, and lower confidence when they had been told its identity by an apparently well-informed speaker, especially when the speaker subsequently doubted the adequacy of his access to the toy. After a 2-minute delay, 3-to 4- year olds, unlike
4- to 5-year-olds, failed to see the implications of the speakerâs doubt about his access
Extremal limit of the regular charged black holes in nonlinear electrodynamics
The near horizon limit of the extreme nonlinear black hole is investigated.
It is shown that resulting geometry belongs to the AdS2xS2 class with different
modules of curvatures of subspaces and could be described in terms of the
Lambert functions. It is demonstrated that the considered class of Lagrangians
does not admit solutions of the Bertotti-Robinson type
Radio Observations of the January 20, 2005 X-Class Event
We present a multi-frequency and multi-instrument study of the 20 January
2005 event. We focus mainly on the complex radio signatures and their
association with the active phenomena taking place: flares, CMEs, particle
acceleration and magnetic restructuring. As a variety of energetic particle
accelerators and sources of radio bursts are present, in the flare-ejecta
combination, we investigate their relative importance in the progress of this
event. The dynamic spectra of {Artemis-IV-Wind/Waves-Hiras with 2000 MHz-20 kHz
frequency coverage, were used to track the evolution of the event from the low
corona to the interplanetary space; these were supplemented with SXR, HXR and
gamma-ray recordings. The observations were compared with the expected radio
signatures and energetic-particle populations envisaged by the {Standard
Flare--CME model and the reconnection outflow termination shock model. A proper
combination of these mechanisms seems to provide an adequate model for the
interpretation of the observational data.Comment: Accepted for publication in Solar Physic
HOPX functions as a tumour suppressor in head and neck cancer.
Head and neck squamous cell carcinoma (HNSCC) is generalized term that encompasses a diverse group of cancers that includes tumours of the oral cavity (OSCC), oropharynx (OPSCC) and nasopharynx (NPC). Genetic alterations that are common to all HNSCC types are likely to be important for squamous carcinogenesis. In this study, we have investigated the role of the homeodomain-only homeobox gene, HOPX, in the pathogenesis of HNSCC. We show that HOPX mRNA levels are reduced in OSCC and NPC cell lines and tissues and there is a general reduction of HOPX protein expression in these tumours and OPSCCs. HOPX promoter methylation was observed in a subset of HNSCCs and was associated with a worse overall survival in HPV negative tumours. RNAseq analysis of OSCC cells transfected with HOPX revealed a widespread deregulation of the transcription of genes related to epithelial homeostasis and ectopic over-expression of HOPX in OSCC and NPC cells inhibited cell proliferation, plating efficiency and migration, and enhanced sensitivity to UVA-induced apoptosis. Our results demonstrate that HOPX functions as a tumour suppressor in HNSCC and suggest a central role for HOPX in suppressing epithelial carcinogenesis
Horizons, Constraints, and Black Hole Entropy
Black hole entropy appears to be ``universal''--many independent
calculations, involving models with very different microscopic degrees of
freedom, all yield the same density of states. I discuss the proposal that this
universality comes from the behavior of the underlying symmetries of the
classical theory. To impose the condition that a black hole be present, we must
partially break the classical symmetries of general relativity, and the
resulting Goldstone boson-like degrees of freedom may account for the
Bekenstein-Hawking entropy. In particular, I demonstrate that the imposition of
a ``stretched horizon'' constraint modifies the algebra of symmetries at the
horizon, allowing the use of standard conformal field theory techniques to
determine the asymptotic density of states. The results reproduce the
Bekenstein-Hawking entropy without any need for detailed assumptions about the
microscopic theory.Comment: 16 pages, talk given at the "Peyresq Physics 10 Meeting on Micro and
Macro structures of spacetime
Extracellular NK histones promote immune cell anti-tumor activity by inducing cell clusters through binding to CD138 receptor
Background: Natural killer (NK) cells are important anti-tumor cells of our innate immune system. Their anti-cancer activity is mediated through interaction of a wide array of activating and inhibitory receptors with their ligands on tumor cells. After activation, NK cells also secrete a variety of pro-inflammatory molecules that contribute to the final immune response by modulating other innate and adaptive immune cells. In this regard, external proteins from NK cell secretome and the mechanisms by which they mediate these responses are poorly defined. Methods: TRANS-stable-isotope labeling of amino acids in cell culture (TRANS-SILAC) combined with proteomic was undertaken to identify early materials transferred between cord blood-derived NK cells (CB-NK) and multiple myeloma (MM) cells. Further in vitro and in vivo studies with knock-down of histones and CD138, overexpression of histones and addition of exogenous histones were undertaken to confirm TRANS-SILAC results and to determine functional roles of this material transferred. Results: We describe a novel mechanism by which histones are actively released by NK cells early after contact with MM cells. We show that extracellular histones bind to the heparan sulfate proteoglycan CD138 on the surface of MM cells to promote the creation of immune-tumor cell clusters bringing immune and MM cells into close proximity, and thus facilitating not only NK but also T lymphocyte anti-MM activity. Conclusion: This study demonstrates a novel immunoregulatory role of NK cells against MM cells mediated by histones, and an additional role of NK cells modulating T lymphocytes activity that will open up new avenues to design future immunotherapy clinical strategies
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