Estrogen receptor-␣ (ER␣) can induce the expression of genes in response to estrogen by binding to estrogen response elements in the promoters of target genes. There is growing evidence that ER␣ can alter patterns of gene expression in response to ligand by regulating the activity of other factors through a direct proteinprotein interaction. To identify other factors that are regulated by ER␣, a yeast two-hybrid screen was performed that identified a novel Cys 2 His 2 zinc finger protein named ZER6. The ZER6 protein contains a Kruppelassociated box domain and six Cys 2 His 2 zinc fingers. Transcripts from the ZER6 gene can have alternate 5 exons and encode either a p71 or p52 isoform. The p52-ZER6 protein interacts strongly with ER␣ in the presence of 17␤-estradiol, whereas the p71-ZER6 isoform has a HUB-1 amino-terminal domain that inhibits the interaction with ER␣. A consensus ZER6 binding element was defined using PCR-assisted binding site selection. In COS-1 cells, both the p52 and p71 isoforms can activate transcription through the ZER6 binding element; however, in the presence of ER␣, transactivation by the p52 isoform is specifically repressed. Overexpression of the p52 isoform was able to abrogate activation by p71-ZER6. Expression of ZER6 was largely restricted to the mammary gland with a lower level of expression in the kidney. We conclude that ZER6 is a novel zinc finger transcription factor in which regulation of transcription in hormone-responsive cells can be controlled by the relative level of expression of two distinct isoforms. Two human estrogen receptors (ERs)1 have been identified: ER␣ and ER␤ (1-4). These nuclear receptors are members of the steroid-thyroid-retinoic acid superfamily of transcription factors (5). In the classic model of transactivation by the receptor, ligand-activated ER␣ forms a homodimer, which is able to bind specific DNA regulatory sequences in the promoters of ER␣ target genes called estrogen response elements (6). This mechanism of transactivation by ER␣ induces the expression of a set of target genes in hormone-responsive tissues and tumors. Several ER␣ target genes have been described in hormoneresponsive breast tumors including progesterone receptor (7), pS2(8), transforming growth factor-␣ (9), cathepsin D (10), HSP27(11), and GREB1(12). The promoters of these genes are directly activated by ER␣, and induction of target gene expression is dependent upon the ability of ER␣ to bind to DNA.Over the past several years, data have been accumulating demonstrating that ER␣ can alter the expression of genes independent of direct DNA binding. One mechanism that has been proposed is through the ability of ER␣ to regulate the activity of other nuclear transcription factors by mechanisms involving direct protein-protein interactions. In many cases the interactions between ER␣ and other nuclear factors have been shown to be ligand-dependent. One example of this alternate mechanism of gene regulation is the effect of ER␣ on expression of genes regulated by AP1(13). ER␣ and ER␤ ha...

stgf is a community code employed for outer-region R-matrix calculations, describing electron-impact collisional processes. It is widely recognised that the original version of stgf was written by M. J. Seaton in 1983, but through constant refinement over the next decades by worldwide contributors has evolved into its current form that more reflects modern coding practice and current computer architectures. Despite its current wide acceptance, it was never formally published.Therefore, we present an updated high-performance parallel version of pstgf, that balances the requirements of small university clusters, yet can exploit the computational power of cutting edge supercomputers. There are many improvements over the original stgf, but most noticeably, the full introduction of MQDT options that provide subsequent integration with ICFT (Intermediate Coupling Frame Transformation) codes, and for either Breit-Pauli/DARC (Dirac Atomic R-matrix Codes), better load balancing, high levels of vectorisation and simplified output. Semantically, the program is full fortran 90 in conjunction with MPI (Message Passing Interface) though has CUDA fortran options for the most numerically intensive code sections.

The spectra currently emerging from modern ground- and space-based astronomical instruments are of exceptionally high quality and resolution. To meaningfully analyse these spectra, researchers utilise complex modelling codes to replicate the observations. The main inputs to these codes are atomic data such as excitation and photoionisation cross sections, as well as radiative transition probabilities, energy levels, and line strengths. In this publication, the current capabilities of the numerical methods and computer packages used in the generation of these data are discussed. Particular emphasis is given to Fe-peak species and the heavy systems of tungsten and molybdenum. Some of the results presented to highlight certain issues and/or advances have already been published in the literature, while other sections present new recently evaluated atomic data for the first time.

The rich emission and absorption line spectra of Fe I may be used to extract crucial information on astrophysical plasmas, such as stellar metallicities. There is currently a lack, in quality and quantity, of accurate level-resolved effective electron-impact collision strengths and oscillator strengths for radiative transitions. Here, we discuss the challenges in obtaining an accurate model of the neutral iron atom and compare our theoretical fine-structure energy levels with observation for several increasingly large models. Radiative data is presented for several transitions for which the atomic data is accurately known.

The Fe i spectra emitted by astrophysical sources contain information on plasma parameters such as chemical abundances and magnetic fields. However, to determine these parameters requires detailed plasma modeling, which in turn needs accurate atomic data for processes such as radiative decay and electron-impact excitation in Fe i. A lack of fine-structure resolved collision strengths for transitions in Fe i is addressed in this paper with the presentation of data obtained from a Dirac R-matrix calculation. The suitability of our choice of target description is shown, with our energies generally within 7% of literature values. Various A-values are compared with other theoretical and experimental results, and the quality of the collision strengths produced in this work demonstrated. A comparison of 300- and 1000-level close-coupling expansions is made, the latter shown to eliminate pseudoresonances in the collision strengths at electron energies between 0.5 and 1.0 Ry. Maxwell-averaged effective collision strengths are presented, and the convergence of our data is shown in the temperature range 1000–100,000 K.