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Single-molecule characterization of extrinsic transcription termination by Sen1 helicase

Extrinsic transcription termination typically involves remodeling of RNA polymerase by an accessory helicase. In yeast this is accomplished by the Sen1 helicase homologous to human senataxin (SETX). To gain insight into these processes we develop a DNA scaffold construct compatible with magnetic-trapping assays and from which S. cerevisiae RNA polymerase II (Pol II), as well as E...

Context-dependent compensation among phosphatidylserine-recognition receptors

Phagocytes express multiple phosphatidylserine (PtdSer) receptors that recognize apoptotic cells. It is unknown whether these receptors are interchangeable or if they play unique roles during cell clearance. Loss of the PtdSer receptor Mertk is associated with apoptotic corpse accumulation in the testes and degeneration of photoreceptors in the eye. Both phenotypes are linked to...

Cervical intramedullary immature teratoma with metastatic recurrence in an adult

Study design:Case report.Objectives:We present for the first time an adult patient with cervical intramedullary immature teratoma with metastatic recurrence.Setting:Peking university Shenzhen Hospital, Shenzhen, China.Methods:A 30-year-old woman presented with rapidly progressive quadriplegia. Magnetic resonance imaging (MRI) revealed an intramedullary tumor occupying C1–C2 of...

Producing Type Iax supernovae from a specific class of helium-ignited WD explosions

Context. It has recently been proposed that one subclass of Type Ia supernovae (SNe Ia) is sufficiently distinct and sufficiently common to be classified separately from the bulk of SNe Ia; the suggested class name is Type Iax supernovae (SNe Iax), after SN 2002cx. However, their progenitors are still uncertain.Aims. We study whether the population properties of this class might...

Envelope loss of RGB/AGB stars and the formation of hot subdwarfs

Low mass stars may lose their envelopes in the first giant branch (RGB) or the asymptotic giant branch (AGB) via envelope ejection (i.e. superwind). The envelope loss of AGB stars leads to the formation of carbon-oxygen (CO) white dwarfs (WDs), while the envelope loss of AGB stars may lead to the formation of helium WDs. We mainly focus here on where a RGB/AGB star loses its...

Design of an Experiment to Measure ann Using 3H(γ, pn)n at HIγS

We provide an update on the development of an experiment at TUNL for determining the 1S0 neutron-neutron (nn) scattering length (ann) from differential cross-section measurements of three-body photodisintegration of the triton. The experiment will be conducted using a linearly polarized gamma-ray beam at the High Intensity Gamma-ray Source (HIγS) and tritium gas contained in thin...

Design of an Experiment to Measure ann Using 3H(γ, pn)n at HIγS

We provide an update on the development of an experiment at TUNL for determining the 1S0 neutron-neutron (nn) scattering length (ann) from differential cross-section measurements of three-body photodisintegration of the triton. The experiment will be conducted using a linearly polarized gamma-ray beam at the High Intensity Gamma-ray Source (HIγS) and tritium gas contained in thin...

Super-Eddington wind scenario for the progenitors of type Ia supernovae: binary population synthesis calculations

Context. The super-Eddington wind scenario has been proposed as an alternative way for producing type Ia supernovae (SNe Ia). The super-Eddington wind can naturally prevent the carbon-oxygen white dwarfs (CO WDs) with high mass-accretion rates from becoming red-giant-like stars. Furthermore, it works in low-metallicity environments, which may explain SNe Ia observed at high...

Neutron-neutron quasifree scattering in nd breakup at 10 MeV

The neutron-deuteron (nd) breakup reaction provides a rich environment for testing theoretical models of the neutron-neutron (nn) interaction. Current theoretical predictions based on rigorous ab-initio calculations agree well with most experimental data for this system, but there remain a few notable discrepancies. The cross section for nn quasifree (QFS) scattering is one such...

Effects of tidally enhanced stellar wind on the horizontal branch morphology of globular clusters

Context. Metallicity is the first parameter to influence the horizontal branch (HB) morphology of globular clusters (GCs). It has been found, however, that some other parameters may also play an important role in affecting the morphology. While the nature of these important parameters remains unclear, they are believed to be likely correlated with wind mass-loss of red giants...

A single-degenerate channel for the progenitors of Type Ia supernovae with different metallicities

A single-degenerate channel for the progenitors of Type Ia supernovae (SNe Ia) is currently accepted, in which a carbon–oxygen white dwarf (CO WD) accretes hydrogen-rich material from its companion, increases its mass to the Chandrasekhar mass limit and then explodes as a SN Ia. Incorporating the prescription of Hachisu et al. for the accretion efficiency into Eggleton's stellar...

How young stellar populations affect the ages and metallicities of galaxies

al. 2006 [arXiv:astro-ph/0605426] Li , Z. , Zhang , F. , & Han , Z. 2006 , ChJAA, 6 , 669 Li , Z. , Han , Z. , & Zhang , F. 2007 , A &A, 464 , 853 Michard , R. 2005 , A &A, 441 , 451 Reda , F. M

The helium star donor channel for the progenitors of Type Ia supernovae

Type Ia supernovae (SNe Ia) play an important role in astrophysics, especially in the study of cosmic evolution. Several progenitor models for SNe Ia have been proposed in the past. In this paper we carry out a detailed study of the He star donor channel, in which a carbon–oxygen white dwarf (CO WD) accretes material from a He main-sequence star or a He subgiant to increase its...

Asymptotic Analysis of Large Cooperative Relay Networks Using Random Matrix Theory

. [10] T. Himsoon , W. P. Siriwongpairat , Z. Han , and K. J. R. Liu , “ Lifetime maximization via cooperative nodes and relay deployment in wireless networks , ” IEEE Journal on Selected Areas in ... Communications , vol. 25 , no. 2 , pp. 306 - 316 , 2007 . [11] Z. Han and H. V. Poor , “ Lifetime improvement in wireless sensor networks via collaborative beamforming and cooperative transmission , ” IET

A single-degenerate model for the progenitor of the Type Ia supernova 2002ic

Z. Han 1 Ph. Podsiadlowski 0 0 University of Oxford, Department of Astrophysics , Keble Road, Oxford OX1 3RH 1 National Astronomical Observatories/Yunnan Observatory, the Chinese Academy of Sciences

New stability criteria for discrete-time systems with interval time-varying delay and polytopic uncertainty

This paper is considered with the robust stability problem for linear discrete-time systems with polytopic uncertainty and an interval time-varying delay in the state. On the basis of a novel Lyapunov-Krasovskii functional, new delay-range-dependent stability criteria are established by employing the free-weighting matrix approach and a Jensen-type sum inequality. It is shown...

Methods and Software for Estimating Health Disparities: The Case of Children's Oral Health

Nancy F. Cheng 0 Pamela Z. Han 0 Stuart A. Gansky ) 0 0 3333 California Street, Suite 495, San Francisco, CA 94143-1361 ( The National Center for Health Statistics recently issued a monograph with ... California, Berkeley, Berkeley, California (Pamela Z. Han). Funding was provided by the National Institute for Dental and Craniofacial Research (grant R03DE018116). The California Oral Health Needs Assessment

Population synthesis for symbiotic stars with white dwarf accretors

We have carried out a detailed study of symbiotic stars (SySs) with white dwarf (WD) accretors by means of a population synthesis code. We estimate the total number of SySs with WD accretors in the Galaxy as 1200–15 000. This range is compatible with observational estimates. Two crucial physical parameters that define the birth rate and number of SySs are the efficiency of...

A binary model for the UV-upturn of elliptical galaxies

The discovery of a flux excess in the far-ultraviolet (FUV) spectrum of elliptical galaxies was a major surprise in 1969. While it is now clear that this UV excess is caused by an old population of hot helium-burning stars without large hydrogen-rich envelopes, rather than young stars, their origin has remained a mystery. Here we show that these stars most likely lost their...

Radially extended kinematics and stellar populations of the massive ellipticals NGC 1600, NGC 4125, and NGC 7619 - Constraints on the outer dark halo density profile

We present high quality long slit spectra along the major and minor axes out to 1.5–2 Re (14–22 kpc) of three bright elliptical galaxies (NGC 1600, NGC 4125, NGC 7619) obtained at the Hobby-Eberly Telescope (HET). We derive stellar kinematic profiles and Lick/IDS indices (Hβ, Mgb, Fe5015, Fe5270, Fe5335, Fe5406). Moreover, for NGC 4125 we derive gas kinematics and emission line...