Noncolliding system of continuous-time random walks

The continuous-time random walk is defined as a Poissonization of discrete-time random walk. We study the noncolliding system of continuous-time simple and symmetric random walks on ${\mathbb{Z}}$. We show that the system is determinantal for any finite initial configuration without multiple point. The spatio-temporal correlation kernel is expressed by using the modified Bessel functions. We extend the system to the noncolliding process with an infinite number of particles, when the initial configuration has equidistant spacing of particles, and show a relaxation phenomenon to the equilibrium determinantal point process with the sine kernel.Comment: AMS-LaTeX, 19 pages, no figure. arXiv admin note: text overlap with arXiv:1307.1856 by other authors. v2: AMS-LaTeX 19 pages, minor corrections made for publication in Pacific Journal of Mathematics for Industr

Rock Joint Surfaces Measurement and Analysis of Aperture Distribution under Different Normal and Shear Loading Using GIS

Geometry of the rock joint is a governing factor for joint mechanical and hydraulic behavior. A new method of evaluating aperture distribution based on measurement of joint surfaces and three dimensional characteristics of each surface is developed. Artificial joint of granite surfaces are measured,processed, analyzed and three dimensional approaches are carried out for surface characterization. Parameters such as asperity's heights, slope angles, and aspects distribution at micro scale,local concentration of elements and their spatial localization at local scale are determined by Geographic Information System (GIS). Changes of aperture distribution at different normal stresses and various shear displacements are visualized and interpreted. Increasing normal load causes negative changes in aperture frequency distribution which indicates high joint matching. However, increasing shear displacement causes a rapid increase in the aperture and positive changes in the aperture frequency distribution which could be due to unmatching, surface anisotropy and spatial localization of contact points with proceeding shear

Revision of the Ptilomera-Group of the Gerridae, with Descriptions of three New Species (Heteroptera)

During a recent visit to Paris I had the opportunity to examine the collection of Gerridae in the National Museum of Natural History. In this collection I found two very interesting and apparently new species of the Ptilomera-group. I have since discovered still another new species belonging to this group, in the collection of the British Museum (Natural History) in London. The Ptilomera-group may constitute a new subfamily of Gerridae, the Ptilomerinae m., and while describing these three new species, I have taken the opportunity to revise the group and to diagnose the new subfamily. My sincere thanks are due to Prof. E.-L. Bouvier and Dr. E. Séguy of the National Museum of Natural History, Paris, and to Major E. E. Austen and Mr. W. E. China of the British Museum, London, for the kindness shown to me during my stay in Paris and London respectively.Peer reviewe

Time-Reversal Symmetry in Non-Hermitian Systems

For ordinary hermitian Hamiltonians, the states show the Kramers degeneracy when the system has a half-odd-integer spin and the time reversal operator obeys \Theta^2=-1, but no such a degeneracy exists when \Theta^2=+1. Here we point out that for non-hermitian systems, there exists a degeneracy similar to Kramers even when \Theta^2=+1. It is found that the new degeneracy follows from the mathematical structure of split-quaternion, instead of quaternion from which the Kramers degeneracy follows in the usual hermitian cases. Furthermore, we also show that particle/hole symmetry gives rise to a pair of states with opposite energies on the basis of the split quaternion in a class of non-hermitian Hamiltonians. As concrete examples, we examine in detail NxN Hamiltonians with N=2 and 4 which are non-hermitian generalizations of spin 1/2 Hamiltonian and quadrupole Hamiltonian of spin 3/2, respectively.Comment: 40 pages, 2 figures; typos fixed, references adde

Characterization of self-regulatory mechanisms and internal dynamics of ETS transcription factor PU.1

The ETS family of transcription factors bind to site-specific DNA via DNA-binding domains called the ETS domains. The ETS domains are structurally homologous but divergent in primary sequences. PU.1 is an essential transcription factor and its biological activity is primarily controlled by up- and down-regulation of its expression. Aside from down-regulated expression, only a few inhibitory mechanisms are known for PU.1. The most understood one involves PU.1 forming a heterodimer with other protein partners, such as GATA-1. However, unlike auto-inhibited ETS-family members whose activity is regulated by autoinhibitory elements that reduce the net affinity of binding to specific DNA, PU.1 has no such regulatory mechanism at the protein-DNA level. We report here that PU.1, unlike its auto-inhibited paralog Ets-1, forms a 2:1 complex with site-specific DNA (\u3e10 bp) in a negatively cooperative manner. We also detected potential interface (193DKDK196) of the PU.1 dimer by using heteronuclear single quantum correlation (HSQC) NMR. Self-titration of PU.1 is a negative feedback mechanism at the protein-DNA level. Following these findings, our group found the presence of the IDRs flanking the ETS domain does not change the DNA binding modes of the PU.1 ETS domain, yet the PEST domain modifies DNA recognition by the ETS domain through changing DNA binding affinities. We successfully assigned ~90% or more backbone amide resonances in the 1H-15N HSQC spectra of hPU.1 constructs with and without IDRs, in the absence and presence (1:1 complex) of DNA. Using the fully assigned HSQC spectra, we studied fast (ps to ns) time scale internal dynamics of PU.1 protein. Spin relaxation rates and heteronuclear 1H{15N}-NOE were acquired for the hPU.1 proteins with and without DNA by NMR. We demonstrated that the PEST domain remains disordered but becomes more dynamic upon specific DNA binding. In terms of DNA recognition, the presence of the PEST domain increases the affinity of 1:1 complex of the ETS domain with cognate DNA, without perturbing the structure or changing the fast time scale backbone motions of the ETS domain

Spirituality Countering Dehumanization: A Cypher on Asian American Hip Hop Flow

Flow—an artistic connection to the beat—is essential to the experience and cultural mix of Hip Hop. “Flow” is also a term from positive psychology that describes a special out-of-body state of consciousness, first articulated by Mihaly Csikszentmihalyi. When Hip Hop performers get into artistic flow, they sometimes become immersed in psychological flow, and this article examines the combination for Asian American Hip Hop. Based on my national survey of Asian Americans in Hip Hop, I argue that dual flow inspires spiritual transformation and mitigates the dehumanization of social marginalization. However, the combination of terms presents problematic possibilities, given that Hip Hop emerged in diasporic communities and applying psychology can seem like an imposition of Western science on peoples dispersed by Western imperialism. This article takes up my argument as a theme of a cypher, with each voice authentically coming from me yet embodying its own flow and perspective, and each subsequent voice critiquing the previous with evidence, insight, and dignity. In this way, like the non-hierarchical conversational style of Hip Hop, the article does not come to definitive conclusions about Asian American Hip Hop, but rather debates the utility of dual flow and Asian Americans’ cultural location within Hip Hop

Zero modes, energy gap, and edge states of anisotropic honeycomb lattice in a magnetic field

We present systematic study of zero modes and gaps by introducing effects of anisotropy of hopping integrals for a tight-binding model on the honeycomb lattice in a magnetic field. The condition for the existence of zero modes is analytically derived. From the condition, it is found that a tiny anisotropy for graphene is sufficient to open a gap around zero energy in a magnetic field. This gap behaves as a non-perturbative and exponential form as a function of the magnetic field. The non-analytic behavior with respect to the magnetic field can be understood as tunneling effects between energy levels around two Dirac zero modes appearing in the honeycomb lattice, and an explicit form of the gap around zero energy is obtained by the WKB method near the merging point of these Dirac zero modes. Effects of the anisotropy for the honeycomb lattices with boundaries are also studied. The condition for the existence of zero energy edge states in a magnetic field is analytically derived. On the basis of the condition, it is recognized that anisotropy of the hopping integrals induces abrupt changes of the number of zero energy edge states, which depend on the shapes of the edges sensitively.Comment: 36 pages, 20 figures; added discussion on experiments in Sec.VI, cited Refs.[35]-[40], and reworded Sec.IV

A Monograph of the Helotrephidae, subfamily Helotrephinae (Hem. Heteroptera)

Since the family Helotrephidae was described, the authors have been able to borrow (thanks to the courtesy of Prof. Bouvier and Dr. Séguy, of the National Museum of Natural History, Paris, and of Dr. Bischoff, of the Zoological Museum, Berlin), the type material of Helotrephes bouvieri Kirk. and H. martini Kirk., a specimen of H. emerita Horv., and a new species which it is proposed to describe as H. kirkaldyi.Peer reviewe

Delocalization induced by low-frequency driving in disordered superlattices

We study the localization properties of disordered semiconductor superlattices driven by ac-fields. The localization length of the electrons in the superlattice increases when the frequency of the driving field is smaller than the miniband width. We show that there is an optimal value of the amplitude of the driving field for which the localization length of the system is maximal. This maximum localization length increases with the inverse of the driving frequency.Comment: 5 pages, 4 figure