Black Holes and Random Matrices

We argue that the late time behavior of horizon fluctuations in large anti-de Sitter (AdS) black holes is governed by the random matrix dynamics characteristic of quantum chaotic systems. Our main tool is the Sachdev-Ye-Kitaev (SYK) model, which we use as a simple model of a black hole. We use an analytically continued partition function $|Z(\beta +it)|^2$ as well as correlation functions as diagnostics. Using numerical techniques we establish random matrix behavior at late times. We determine the early time behavior exactly in a double scaling limit, giving us a plausible estimate for the crossover time to random matrix behavior. We use these ideas to formulate a conjecture about general large AdS black holes, like those dual to 4D super-Yang-Mills theory, giving a provisional estimate of the crossover time. We make some preliminary comments about challenges to understanding the late time dynamics from a bulk point of view.Comment: 73 pages, 15 figures, minor errors correcte

Evaluation of Kelvin probe force microscopy for imaging grain boundaries in chalcopyrite thin films

In view of the outstanding performance of polycrystalline thin film solar cells on the basis of Cu In,Ga Se2, the electrical activity at grain boundaries currently receives considerable attention. Recently, Kelvin probe force microscopy KPFM has been applied to characterize of the properties of individual grain boundaries, observing a drop in the surface potential in many cases. We present finite element simulations of the electrostatic forces to assess the experimental resolution of KPFM. Depending on the tip sample distance, the observed drop in the work function amounts to only a fraction of the real surface potential drop. The simulations are considered for different grain boundary models and consequences for the quantitative evaluation of experimental results are discusse

Social participation of families with children with autism spectrum disorder in a science museum

This article describes a qualitative research study undertaken as a collaboration between museum and occupational therapy (OT) researchers to better understand museum experiences for families with a child or children impacted by autism spectrum disorder (ASD). Inclusion for visitors with ASD is an issue that museums are increasingly considering, and the social dimension of inclusion can be particularly relevant for this audience. The construct of social participation, used in OT, provides a promising avenue for museum professionals to think about inclusion. Social participation situates social and community experiences within the context of peoples’ diverse motivations and the strategies they use to navigate environments. This study took these multiple factors into account when observing families’ museum visits—including analysis of their motivations for visiting, environmental features that influenced their visit, family strategies used before and during the visit, and the families’ definitions of a successful visit. Learning more about these factors that are associated with social participation can inform future efforts to improve museum inclusion for families with children with ASD

Gluon fusion into Higgs pairs at NLO QCD and the top mass scheme

We present the calculation of the full next-to-leading order (NLO) QCD corrections to Higgs boson pair production via gluon fusion at the LHC, including the exact top-mass dependence in the two-loop virtual and one-loop real corrections. This is the first independent cross-check of the NLO QCD corrections presented in the literature before. Our calculation relies on numerical integrations of Feynman integrals, stabilised with integration-by-parts and a Richardson extrapolation to the narrow width approximation. We present results for the total cross section as well as for the invariant Higgs-pair-mass distribution at the LHC, including for the first time a study of the uncertainty due to the scheme and scale choice for the top mass in the loops

First karyological analysis of the endemic malagasy phantom gecko matoatoa brevipes (Squamata: Gekkonidae)

The genus Matoatoa includes two Malagasy endemic species, M. brevipes and M. spannringi. Due to their cryptic behaviour, the two species are known only from a handful of specimens and have been included in few molecular studies. Here we carried out a molecular barcoding analysis using a fragment of the mitochondrial NADH dehy-drogenase subunit 2 (ND2) and the first chromosomal analysis of M. brevipes. The molecular analysis confirmed the identity of the studied samples as M. brevipes. However, the level of genetic divergence (4% uncorrected p-distance) between our samples and other sequences of M. brevipes, suggests previously unrecognised diversity within the spe-cies. The karyotype of M. brevipes is composed of 2n = 34 chromosomes: the first pair is metacentric, while all the other pairs are telocentric and gradually decreasing in length (Arm Number, AN = 36). C-banding revealed little evidence of centromeric heterochromatin, while NOR-associated heterochromatin was found on the telomeres of a medi-um sized telocentric pair. No heteromorphic chromosome pairs were found in the karyotype of the species, suggesting that putative sex chromosomes are at an early stage of differentiation. Karyological comparisons with closely related species were performed with Christinus marmoratus, and representatives of the genera Phelsuma, Ebenavia, Paroedura and Uroplatus. Comparisons across genera suggest that chromosome diversification in this group of geckos probably occurred by means of chromosome fusions and inversions, leading to a reduction of the chromosome number and the formation of biarmed elements in different species

Biology of advanced uveal melanoma and next steps for clinical therapeutics

Uveal melanoma is the most common intraocular malignancy although it is a rare subset of all melanomas. Uveal melanoma has distinct biology relative to cutaneous melanoma, with widely divergent patient outcomes. Patients diagnosed with a primary uveal melanoma can be stratified for risk of metastasis by cytogenetics or gene expression profiling, with approximately half of patients developing metastatic disease, predominately hepatic in location, over a 15-yr period. Historically, no systemic therapy has been associated with a clear clinical benefit for patients with advanced disease, and median survival remains poor. Here, as a joint effort between the Melanoma Research Foundation's ocular melanoma initiative, CURE OM and the National Cancer Institute, the current understanding of the molecular and immunobiology of uveal melanoma is reviewed, and on-going laboratory research into the disease is highlighted. Finally, recent investigations relevant to clinical management via targeted and immunotherpies are reviewed, and next steps in the development of clinical therapeutics are discussed