Core excitations across the neutron shell gap in ²⁰⁷Tl

The single closed-neutron-shell, one proton-hole nucleus 207Tl was populated in deep-inelastic collisions of a 208Pb beam with a 208Pb target. The yrast and near-yrast level scheme has been established up to high excitation energy, comprising an octupol

Androgen receptor phosphorylation, turnover, nuclear transport, and transcriptional activation : specificity for steroids and antihormones

Nuclear transport, phosphorylation, ligand binding, and degradation rate of the recombinant androgen receptor (AR) were analyzed in transfected COS cells in the presence of various steroids and antiandrogens. Transcriptional activation was assessed in CV1 cells by cotransfection with an androgen-responsive chloramphenicol acetyltransferase (CAT) reporter vector. Hormone binding specificity of recombinant AR was essentially identical to endogenous AR. AR localized in the nucleus in the presence of methyltrienolone (R1881, a synthetic androgen), dihydrotestosterone, testosterone, hydroxyflutamide, cyproterone acetate, estradiol, progesterone, and RU486. In the absence of hormone or with the antiandrogen, flutamide, AR remained largely in the cytoplasm with a perinuclear distribution. AR was degraded rapidly (t1/2 = 1 h) except in the presence of androgen (t1/2 = 6 h) which accounted for an apparent 2-4-fold androgen-induced increase in AR phosphorylation, indicating that AR phosphorylation was not enhanced by androgen. CAT activity was stimulated by R1881, dihydrotestosterone, testosterone, cyproterone acetate, estradiol, progesterone, and RU486 in a dose-dependent manner. The antiandrogens, flutamide and hydroxyflutamide, lacked agonist activity and inhibited R1881-induced activation of CAT and androgen stabilization of AR. Steroids and antiandrogens with moderate to low affinity for AR promoted both nuclear transport and transcriptional activation but only at high hormone concentrations. Hydroxyflutamide acted as a true antiandrogen since it lacked agonist activity and was an inhibitor of androgen-induced transcriptional activation

One-Loop Renormalization of Lorentz-Violating Electrodynamics

We show that the general Lorentz- and CPT-violating extension of quantum electrodynamics is one-loop renormalizable. The one-loop Lorentz-violating beta functions are obtained, and the running of the coefficients for Lorentz and CPT violation is determined. Some implications for theory and experiment are discussed.Comment: 12 pages, accepted for publication in Physical Review

Persistence, Motivation, and Resilience: Older Youth Aging Out of Foster Care Attending Historically Black Colleges and Universities (HBCUs)

Persistence, Motivation and Resilience: Older Youth Aging Out of Foster Care Attending Historically Black Colleges and Universities ABSTRACT Many young adults involved with the child welfare system have a unique set of circumstances and needs. As they come of age, separated from their families of origin, additional services and supports are warranted to achieve their goals in life. This qualitative study explores the experiences of youth who have been impacted by the foster care system and are enrolled at a Historically Black College and University (HBCU) in the Mid-Atlantic region. Using a phenomenological approach, participants were interviewed regarding their motivation to attend an HBCU. Journey to College and Current College Experiences were two major themes that emerged from the interviews, along with several sub themes. The need for additional research and implications for child welfare social work practice are discussed

A ligand-dependent bipartite nuclear targeting signal in the human androgen receptor. Requirement for the DNA-binding domain and modulation by NH2-terminal and carboxyl-terminal sequences.

The amino acid sequence requirements for androgen-dependent androgen receptor nuclear import were determined by immunostaining transiently expressed full-length wild type and mutant human androgen receptors (AR) in monkey kidney COS cells and measuring transcriptional activity by cotransfection with a luciferase reporter vector in monkey kidney CV1 cells. Mutagenesis studies revealed a bipartite nuclear targeting sequence in the DNA binding and hinge regions at amino acids 617-633, consisting of two clusters of basic amino acids separated by 10 amino acids, (sequence: see text). In a series of deletion mutants, AR NH2-terminal fragments (residues 1-639 through 1-723) displayed constitutive nuclear import, and transcriptional activity was similar to that of the ligand-activated full-length wild type AR. In contrast, nuclear import and transcriptional activation were inhibited by sequence extensions into the steroid-binding domain (1-771). Constitutive nuclear import was regained in part by NH2-terminal deletions of full-length AR. Expression of AR/pyruvate kinase chimeras defined a sequence required for pre-dominant nuclear localization as residues 580-661, comprised of the second zinc finger region of the DNA-binding domain, the 17-amino-acid putative targeting sequence, and 28 residues of flanking carboxyl-terminal sequence. These studies suggest that the bipartite nuclear targeting sequence of AR includes flanking sequence and is modulated by interactions between the NH2-and carboxyl-terminal regions

Improvement of the CORS method for Cepheids radii determination based on Stromgren photometry

In this paper we present a modified version of the CORS method based on a new calibration of the Surface Brightness function in the Stromgren photometric system. The method has been tested by means of synthetic light and radial velocity curves derived from nonlinear pulsation models. Detailed simulations have been performed to take into account the quality of real observed curves as well as possible shifts between photometric and radial velocity data. The method has been then applied to a sample of Galactic Cepheids with Stromgren photometry and radial velocity data to derive the radii and a new PR relation. As a result we find log R = (1.19 +- 0.09) + (0.74 +- 0.11) log P (r.m.s=0.07). The comparison between our result and previous estimates in the literature is satisfactory. Better results are expected from the adoption of improved model atmosphere grids.Comment: 13 pages including 12 postscript figures and 3 jpeg figures; accepted for publication on A&

Conjugation-Length Dependence of Spin-Dependent Exciton Formation Rates in Pi-Conjugated Oligomers and Polymers

We have measured the ratio, r = $\sigma_S/\sigma_T$ of the formation cross section, $\sigma$ of singlet ($\sigma_S$) and triplet ($\sigma_T$) excitons from oppositely charged polarons in a large variety of $\pi$-conjugated oligomer and polymer films, using the photoinduced absorption and optically detected magnetic resonance spectroscopies. The ratio r is directly related to the singlet exciton yield, which in turn determines the maximum electroluminescence quantum efficiency in organic light emitting diodes (OLED). We discovered that r increases with the conjugation length, CL; in fact a universal dependence exists in which $r^{-1}$ depends linearly on $CL^{-1}$, irrespective of the chain backbone structure. These results indicate that $\pi$-conjugated polymers have a clear advantage over small molecules in OLED applications.Comment: 5 pages, 4 figure

Magnetic exchange, anisotropy and excitonic fluctuations in a [Ni^II₇] Anderson wheel

The solvothermal reaction of Ni(ClO4)2·6H2O with hmpH and picH in a basic MeOH solution affords [Ni7(hmp)7.55(pic)4.45](ClO4)2·6MeOH (1·6MeOH) directly upon cooling the mother liquor. The metallic skeleton of 1 describes a [NiII7] centred hexagon, commonly referred to as an Anderson wheel. Magnetic measurements reveal ferromagnetic exchange between the central Ni ion and the ring Ni ions, and antiferromagnetic exchange between neighbouring ring Ni ions. They also confirm the presence of easy-plane anisotropy for the central Ni ion, and easy-axis anisotropy for the ring Ni ions, in agreement with DFT calculations and neutron scattering. For the analysis of the latter we apply an excitonic formalism using a Green's function response theory.</p

Octupole transitions in the 208Pb region

The 208Pb region is characterised by the existence of collective octupole states. Here we populated such states in 208Pb + 208Pb deep-inelastic reactions. γ-ray angular distribution measurements were used to infer the octupole character of several E3 transitions. The octupole character of the 2318 keV 17− → 14+ in 208Pb, 2485 keV 19/2 − → 13/2 + in 207Pb, 2419 keV 15/2 − → 9/2 + in 209Pb and 2465 keV 17/2 + → 11/2 − in 207Tl transitions was demonstrated for the first time. In addition, shell model calculations were performed using two different sets of two-body matrix elements. Their predictions were compared with emphasis on collective octupole states.This work is supported by the Science and Technology Facilities Council (STFC), UK, US Department of Energy, Office of Nuclear Physics, under Contract No. DEAC02-06CH11357 and DE-FG02-94ER40834, NSF grant PHY-1404442