A Uniform Analysis of the Ly-alpha forest at z = 0 - 5: I. The sample and distribution of clouds at z > 1.7

We present moderate resolution data for 39 QSOs at z $\approx$ 2 obtained at the Multiple Mirror Telescope. These data are combined with spectra of comparable resolution of 60 QSOs with redshifts greater than 1.7 found in the literature to investigate the distribution of Ly-alpha forest lines in redshift and equivalent width. We find a value for $\gamma$, the parameter describing the number distribution of Ly-alpha forest lines in redshift, of $1.88\pm0.22$ for lines stronger than a rest equivalent width of 0.32 $\AA$, in good agreement with some previous studies. The Kolmogorov-Smirnov test was applied to the data and it is found that this single power law is a good fit over the relevant redshift ranges. Simulations of the Lyman alpha forest were performed to determine the completeness of the line lists and to test how well the analysis the underlying line statistics, given this level of completeness.Comment: minor corrections to text, 37 Latex pages, 11 encapsulated Postscript figures, uses emulateapj.sty, To appear in the Sept. 2000 ApJS, line lists and spectra available at http://qso.as.arizona.edu/~jscott/Spectra/index.htm

Chandra Detection of X-ray Absorption Associated with a Damped Lyman Alpha System

We have observed three quasars, PKS 1127-145, Q 1331+171 and Q0054+144, with the ACIS-S aboard the Chandra X-ray Observatory, in order to measure soft X-ray absorption associated with intervening 21-cm and damped Ly$\alpha$ absorbers. For PKS 1127-145, we detect absorption which, if associated with an intervening z_{abs}=0.312 absorber, implies a metallicity of 23% solar. If the absorption is not at z_{abs}=0.312, then the metallicity is still constrained to be less than 23% solar. The advantage of the X-ray measurement is that the derived metallicity is insensitive to ionization, inclusion of an atom in a molecule, or depletion onto grains. The X-ray absorption is mostly due to oxygen, and is consistent with the oxygen abundance of 30% solar derived from optical nebular emission lines in a foreground galaxy at the redshift of the absorber. For Q1331+171 and Q 0054+144, only upper limits were obtained, although the exposure times were intentionally short, since for these two objects we were interested primarily in measuring flux levels to plan for future observations. The imaging results are presented in a companion paper.Comment: 23 pages, 6 figures, accepted for publication in the Astrophysical Journa

A Uniform Analysis of the Ly-alpha forest at z = 0 - 5: II. Measuring the mean intensity of the extragalactic ionizing background using the proximity effect

A homogeneous sample of 99 moderate resolution QSO spectra at z > 1.7 were presented in Paper I, including 39 previously unpublished spectra from the Multiple Mirror Telescope. The statistics of the Lyman alpha forest were discussed. In this analysis, we demonstrate that a proximity effect is present in the data, ie. there exists a significant (5.5$\sigma$) deficit of lines at $z_{abs} \approx z_{em}$. Within 1.5 $h^{-1}$ Mpc of the QSO emission redshift, the significance does depend on QSO luminosity, in accordance with the theory that this effect is caused by enhanced ionization of hydrogen in the vicinity of the QSO from UV photons from the QSO itself. The photoionization model of Bajtlik, Duncan, and Ostriker (1988) permits an estimate of the mean intensity of the extragalactic background radiation at the Lyman limit. We compare the results of this standard analysis with those obtained using a maximum likelihood technique. The best fit value for $J(\nu_{0})$ is 7.0$^{+3.4}_{-4.4}$ x 10$^{-22}$ ergs/s/cm$^{2}$/Hz/sr, over the redshift range 1.7 < z < 3.8, using QSO redshifts based on narrow emission lines. The best fit value for the HI ionization rate is 1.9$^{+1.2}_{-1.0}$ x 10$^{-12}$ s$^{-1}$, in good agreement with models of the background which incorporate QSOs only. This large absorption line sample and these techniques for measuring the background and understanding the systematics involved allow us to place what we believe are are the firmest limits on the background at these redshifts.Comment: revised figures 13 and 14, and other minor corrections, 42 Latex pages, 23 encapsulated Postscript figures, uses emulateapj.sty, To appear in the Sept. 2000 ApJ

Comparison of dedicated BIOSS bifurcation stents with regular drug-eluting stents for coronary artery bifurcated lesions: Pooled analysis from two randomized studies

  Background: Coronary bifurcation treatment poses a therapeutic challenge. The aim of this study was to analyze pooled data of two randomized clinical trials, POLBOS I and POLBOS II, to compare 1-year follow-up results and identify possible prognostic factors. Methods: In POLBOS trials dedicated bifurcation BiOSS® stents were compared with regular drug eluting stents (rDES) in patients with stable coronary artery disease or non ST-segment elevation acute coronary syndrome (POLBOS I: paclitaxel eluting BiOSS® Expert vs. rDES; POLBOS II: sirolimus eluting BiOSS® LIM vs. rDES). Provisional T-stenting was the default strategy. Angiographic control was performed at 12 months. The primary endpoint was major adverse cardiovascular events (MACE) rate defined as the rate of cardiac death, myocardial infarction (MI) or target lesion revascularization (TLR). Results: 445 patients, with 222 patients in the BiOSS group and 223 patients in the rDES group, were analyzed. In 26.7% cases procedures were performed within distal left main, and true bifurca­tions which accounted for 81.6% of treated lesions. At 12 months the whole population exhibited no statistical differences in terms of MACE, TLR, MI or cardiac death between rDES and BiOSS groups. In multivariate analysis odds for MACE decreased with female sex (OR 0.433, 95% CI 0.178–0.942, p = 0.047) and with proximal optimization technique use (OR 0.208, 95% CI 0.097–0.419, p &lt; 0.001), whereas the odds for MACE increased with main vessel predilatation (OR 2.191, 95% CI 1.042–5.066, p = 0.049) and diabetes mellitus treated with insulin (OR 2.779, 95% CI 1.1–6.593, p = 0.024). Conclusions: Pooled data showed no significant difference between MACE and TLR rates for BiOSS® group vs. rDES group

Current trends and procedural outcomes in the era of rotational atherectomy expansion in Poland in the period 2014-2017 (based on the nationwide ORPKI registry)

Introduction: The availability of rotational atherectomy (RA) has recently increased in Poland, which was followed by an increase in the rate of RA procedures and catheterization laboratories performing RA. Aim: To assess current trends regarding the rapid increase in the number of RA procedures and catheterization laboratories performing RA. Material an methods: We analyzed patients treated with percutaneous coronary intervention (PCI) in the years 2014–2017 available in the nationwide ORPKI dataset. From the overall 431,467 patients treated with PCI, we extracted 1,873 treated with RA. We analyzed the relationship between frequency of RA usage, its distribution between low and high volume centers and procedural outcomes, procedural-related complications and the PCI effectiveness expressed as the target vessel patency rate after PCI. Results: The number of RA procedures increased from 181 in 2014 (0.19%) to 698 in 2017 (0.61%), with an over two-fold increase in the number of catheterization laboratories performing RA from 25 (15.5%) in 2014 to 55 (34.1%) in 2017. Besides the fact that patient characteristics have changed in the most recent years, the rate of procedural success expressed as procedure-related complications remained stable in the 3 years 2015–2017 and was around 3%, while the procedural effectiveness expressed as patent target coronary artery after PCI was stable and over 98% in all of the analyzed years. Conclusions: Along with the increasing number of RA procedures and catheterization laboratories performing RA in Poland, the procedural effectiveness remained stable during an observational period of 4 years

Chandra Discovery of a 300 kpc X-ray Jet in the GPS Quasar PKS1127-145

We have discovered an X-ray jet with Chandra imaging of the z=1.187 radio-loud quasar PKS1127-145. In this paper we present the Chandra X-ray data, follow-up VLA observations, and optical imaging using the HST WFPC2. The X-ray jet contains 273+/-5 net counts in 27ksec and extends ~30 arcsec, from the quasar core, corresponding to a minimum projected linear size of ~330/h_50 kpc. The evaluation of the X-ray emission processes is complicated by the observed offsets between X-ray and radio brightness peaks. We discuss the problems posed by these observations to jet models. In addition, PKS1127-145 is a Giga-Hertz Peaked Spectrum radio source, a member of the class of radio sources suspected to be young or ``frustrated'' versions of FRI radio galaxies. However the discovery of an X-ray and radio jet extending well outside the host galaxy of PKS1127-145 suggests that activity in this and other GPS sources may be long-lived and complex.Comment: 22 pages, 11 ps figures, 1 figure in a JPG file, 3 tables. AASTEX. Accepted by The Astrophysical Journa

A hunter-gatherer-farmer population model: Lie symmetries, exact solutions and their interpretation

The Lie symmetry classification of the known three-component reaction-diffusion system modelling the spread of an initially localized population of farmers into a region occupied by hunter-gatherers is derived. The Lie symmetries obtained for reducing the system in question to systems of ODEs and constructing exact solutions are applied. Several exact solutions of traveling front type are found, their properties are identified and biological interpretation is discussed

Radial versus femoral access in patients treated with percutaneous coronary intervention and rotational atherectomy

Background: The association between periprocedural complications and the type of vascular access in patients treated with percutaneous coronary intervention (PCI) and rotational atherectomy (RA) has not been investigated as frequently as in an overall group of patients treated with PCI. Aims: The aim of this study was to assess the associations between the type of vascular access and selected periprocedural complications in a group of patients treated with PCI and RA. Methods: ased on a nationwide Polish registry (National Registry of Percutaneous Coronary Interventions [ORPKI]), we analyzed 536 826 patients treated with PCI between the years 2014 and 2018. The study included 2713 patients (0.5% of the overall group of patients treated with PCI [n = 536 826]) treated with PCI and RA. Among them, 1018 (37.5%) were treated via femoral access, and 1653 (60.9%) via radial access. Subsequently, these patients were subject to comparison, which was proceeded by propensity score matching. Results: Following propensity score matching, multiple regression analysis revealed that patients undergoing PCI via femoral access experienced coronary artery perforation significantly less frequently than those managed via radial access (odds ratio, 0.29; 95% CI, 0.08–0.92; P = 0.04). We did not observe any significant associations between the type of vascular access and the periprocedural mortality rate (P = 0.99), cardiac arrest (P = 0.41), puncture‑site bleeding (P = 0.99), allergic reaction (P = 0.32), myocardial infarction (P = 0.48), no‑reflow phenomenon (P = 0.82), or the overall complication rate (P = 0.31). Conclusion: In patients treated with PCI and RA, femoral access is associated with a lower rate of coronary artery perforations as compared with radial access