Spectroastrometry of rotating gas disks for the detection of supermassive black holes in galactic nuclei. III. CRIRES observations of the Circinus galaxy

We present new CRIRES spectroscopic observations of BrGamma in the nuclear region of the Circinus galaxy, obtained with the aim of measuring the black hole (BH) mass with the spectroastrometric technique. The Circinus galaxy is an ideal benchmark for the spectroastrometric technique given its proximity and secure BH measurement obtained with the observation of its nuclear H2O maser disk. The kinematical data have been analyzed both with the classical method based on the analysis of the rotation curves and with the new method developed by us and based on spectroastrometry. The classical method indicates that the gas disk rotates in the gravitational potential of an extended stellar mass distribution and a spatially unresolved mass of (1.7 +- 0.2) 10^7 Msun, concentrated within r < 7 pc. The new method is capable of probing gas rotation at scales which are a factor ~3.5 smaller than those probed by the rotation curve analysis. The dynamical mass spatially unresolved with the spectroastrometric method is a factor ~2 smaller, 7.9 (+1.4 -1.1) 10^6 Msun indicating that spectroastrometry has been able to spatially resolve the nuclear mass distribution down to 2 pc scales. This unresolved mass is still a factor ~4.5 larger than the BH mass measurement obtained with the H2O maser emission indicating that it has not been possible to resolve the sphere of influence of the BH. Based on literature data, this spatially unresolved dynamical mass distribution is likely dominated by molecular gas and it has been tentatively identified with the circum-nuclear torus which prevents a direct view of the central BH in Circinus. This mass distribution, with a size of ~2pc, is similar in shape to that of the star cluster of the Milky Way suggesting that a molecular torus, forming stars at a high rate, might be the earlier evolutionary stage of the nuclear star clusters which are common in late type spirals.Comment: A&A in press. We wish to honor the memory of our great friend and colleague David Axon. He will be greatly missed by all of us. arXiv admin note: text overlap with arXiv:1110.093

Polarization Profiles of Scattered Emission Lines. II. Upstream Dust Scattering in the HH 1 Jet

Detailed comparisons are made between observations of scattered light upstream of the head of the HH~1 jet and predictions of simple scattering models. It is shown that, in order to unambiguously determine the velocity of the head of the jet (bow shock) with respect to the upstream dust, existing spectroscopic observations are insufficient and that spectropolarimetric observations of the scattered light are necessary. Such an independent measure of the bow shock velocity is important in order to test ``multiple outflow'' theories of Herbig-Haro jets. It is also shown 2that the scattering dust must have a very forward-throwing scattering phase function (\langle\cos\theta\rangle\msim 0.7) and slight evidence is found for a dust-gas ratio that is higher than average.Comment: 11 pages, uuencoded compressed postscript (including 9 figures), accepted for publication in Ap.J., IAUNAM_contrib.#34

Models relating the radio emission and ionised gas in Seyfert nuclei

Possible models are discussed in which the radio emitting components in Seyfert II nuclei can compress and accelerate the ambient nuclear medium to produce the characteristics of the narrow line region. A first order model, which considers only the expansion of the radio components, is briefly described. However, in many Seyfert nuclei it appears that the linear motion of the radio components is also important. This can result in shock heating of the ambient medium, and if the cooling time is long enough, can lead to a displacement between the radio component and the associated emission lines. This effect may be present in NGC 1068 and NGC 5929 and by considering ram pressure balance and the cooling length it is possible to estimate lobe velocities and ambient densities

Prevalence of reflux esophagitis among patients undergoing endoscopy in a secondary referral hospital in Giza, Egypt

Background: Gastro-esophageal reflux disease (GERD) is one of the most prevalent diseases seen in western countries. The prevalence of GERD is lower in the Asian population and the spectrum of the disease is mild. Data from Africa and the Middle East are sparse.Aim: The aim of the study was to determine the prevalence, severity and risk factors of reflux esophagitis (RE) among patients undergoing endoscopy in a secondary referral hospital in Egypt.Materials and methods: This was a retrospective study. Data on patients presenting with gastroesophageal reflux symptoms (RS) and scheduled for upper gastrointestinal endoscopy between January 2000 and January 2013 were collected.Results: Four hundred and thirty-three patients were assessed. Two hundred and fifty-four (59%) were male. Ages ranged from 18 to 85 years, mean 45± 15 years. One hundred and forty-four patients (33%) had a history of smoking, 120 (28%) were taking aspirin or non-steroidal anti-inflammatory drugs and 8 (2%) were consuming alcohol. The duration of RS ranged from one month to 20 years, mean 21 ± 30 months. One hundred and forty-six patients (34%) had the RS daily, 70 (16%) classified RS as severe intensity and 99 (23%) had acid regurgitation. One hundred and six patients (24%) were found to have RE. Ninety-eight of them (23%) showed grade 1. Barrett’s esophagus (BE) was diagnosed in seven patients (2%) and esophageal stricture in one (0.2%). One hundred and four patients (24%) had hiatus hernia (HH), 16 (4%) gastric ulcers and 45 (10%) duodenal ulcers. In multivariate analysis, male sex and HH were two independent risk factors for the development of RE.Conclusion: The prevalence of RE is low among patients undergoing endoscopy. Most of the patients had a mild degree of esophagitis. BE and stricture were rarely seen. Male sex and HH were risk factors of RE

Improving the quality of endoscopic polypectomy by introducing a colonoscopy quality assurance program

Background: Colonoscopy is a routine procedure in patients who present with bowel symptoms. Polyps can be identified and removed during colonoscopy. A colonoscopy quality-assurance program (CQAP) was instituted in 2003.Aim: The aim of the study was to determine the effect of instituting a CQAP on the quality of endoscopic polypectomy (EP) in our patients.Patients and methods: An Initial assessment of EP practice in 2003 showed that four patients had polyps. Cecal intubation had been achieved in only two patients and a complete polyp description (CPD) had not been documented. Polypectomy was performed in two patients but the completeness of removal and retrieval of the polyps had not been assessed and histology had not been recorded. A quality improvement process was therefore instituted. This required full colonoscopy to the cecum, CPD and polypectomy to be performed for every polyp. There should be a 90% retrieval rate of all excised polyps and follow up of all histology reports. Seventy-six patients were assessed prospectively over the period 2004–2011.Results: Cecal intubation rates increased from 65% in years 2004–2007 to 90% in years 2008–2011 (t-proportion = 2.4 &amp; CI= 4.7, highly significant). CPD rates increased from 35% to 100% (t-proportion = 6.5 &amp; CI= 12.7,  highly significant). EP rates increased from 59% to 100% (t-proportion = 3.5 &amp; CI= 6.9, highly significant). Percentage of procedures in which all polyps were judged completely removed increased from 41% to 86% (t-proportion = 3.6 &amp; CI= 7, highly significant). Polyp retrieval rates, with retrieval of P90% of all excised polyps, increased from 80% to 92% (t-proportion = 0.87 &amp; CI= 1.7, significant). Polyp histology documentation rates increased from 41% to 88% (t-proportion =3.7 &amp; CI= 7.3, highly significant).Conclusion: The implementation of a quality assurance and improvement program improved the quality of EP in patients with polyp(s) detected during colonoscopy.Keywords: Colonoscopy; Polypectomy; Quality assurance; Juvenile polyp

Spectroastrometry of rotating gas disks for the detection of supermassive black holes in galactic nuclei. I. Method and simulations

This is the first in a series of papers in which we study the application of spectroastrometry in the context of gas kinematical studies aimed at measuring the mass of supermassive black holes. The spectroastrometrical method consists in measuring the photocenter of light emission in different wavelength or velocity channels. In particular we explore the potential of spectroastrometry of gas emission lines in galaxy nuclei to constrain the kinematics of rotating gas disks and to measure the mass of putative supermassive black holes. By means of detailed simulations and test cases, we show that the fundamental advantage of spectroastrometry is that it can provide information on the gravitational potential of a galaxy on scales significantly smaller (~ 1/10) than the limit imposed by the spatial resolution of the observations. We then describe a simple method to infer detailed kinematical informations from spectroastrometry in longslit spectra and to measure the mass of nuclear mass concentrations. Such method can be applied straightforwardly to integral field spectra, which do not have the complexities due to a partial spatial covering of the source in the case of longslit spectra.Comment: Accepted for publication in A&

Colorectal cancer in Egypt is commoner in young people: Is this cause for alarm?

Background: Colorectal cancer (CRC) is the third most common cancer worldwide after lung and breast cancers with two-thirds of all CRCs occurring in the more developed regions of the world. CRC affects men and women of all racial and ethnic groups, and is most often found in those aged 50 years or older. Aim: The aim of the study was to determine the prevalence of CRC among patients undergoing colonoscopy in Egypt. Materials and methods: This was a descriptive cross-sectional hospital-based study. A total of 412 consecutive patients who underwent planned pancolonoscopy from January 2000 to January 2012 at our institution were assessed. All endoscopic examinations leading to a diagnosis of CRC were evaluated. The following parameters were analyzed: frequency of CRC, patient characteristics, indication for endoscopic examination, endoscopic findings, localization of CRC and histopathology. Results: CRC was diagnosed in 57 patients (14% of all colonoscopies). Fifty-six percent were female. The mean age was 51± 15 years (age range: 16–80 years). Twenty-five percent of cancers occurred in patients aged less than 40 years. The most frequent indication for colonoscopy was rectal bleeding (39%). The most common colonoscopy finding was mass (96%). Sixty-eight percent of CRC were located in the left colon and rectum. Ninety-one percent of CRC wereAdenocarcinoma. Conclusions: CRC is not uncommon among Egyptian patients subjected to colonoscopy. Thereare relatively higher CRC rates in patients under 40 years of age than reported in the West. This has implications relating to future epidemiological trends in Egypt. Physicians must have a greater awareness of the potential for CRC in young people in the Middle East.Keywords: Colorectal cancer; Birth cohort; Egypt